PARAS 0014.BlastMitigationStrategies - Finalguidebook

PARAS PROGRAM FOR APPLIED
RESEARCH IN AIRPORT SECURITY
PARAS 0014 August 2018
Blast Mitigation Strategies for

Non-Secure Areas at Airports
Guidebook
National Safe Skies Alliance, Inc.
Sponsored by the Federal Aviation Administration

Deborah Blass
Arup USA, Inc.
New York, NY
© 2018 National Safe Skies Alliance, Inc. All rights reserved.
COPYRIGHT INFORMATION
Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from
publishers or persons who own the copyright to any previously published or copyrighted material used herein.
National Safe Skies Alliance, Inc. (Safe Skies) grants permission to reproduce material in this publication for
classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be
used to imply Safe Skies or FAA endorsement of a particular product, method, or practice. It is expected that those
reproducing the material in this document for educational and not-for-profit uses will give appropriate
acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request
permission from Safe Skies.
NOTICE
The project that is the subject of this report was a part of the Program for Applied Research in Airport Security
(PARAS), managed by Safe Skies and funded by the FAA.
The members of the technical panel selected to monitor this project and to review this report were chosen for their
special competencies and with regard for appropriate balance. The report was reviewed by the technical panel and
accepted for publication according to procedures established and overseen by Safe Skies.
The opinions and conclusions expressed or implied in this report are those of the individuals or organizations who
performed the research and are not necessarily those of Safe Skies or the FAA.
Safe Skies and the FAA do not endorse products or manufacturers.
Blast-Mitigation Strategies for Non-Secure Areas at Airports ii

NATIONAL SAFE SKIES ALLIANCE, INC.

National Safe Skies Alliance (Safe Skies) is a non-profit organization that works with airports, government, and
industry to maintain a safe and effective aviation security system. Safe Skies’ core services focus on helping airport
operators make informed decisions about their airport security technology and procedures.
Through the Airport Security System Integrated Support Testing (ASSIST) Program, Safe Skies conducts
independent, impartial evaluations of security equipment, systems, and processes at airports throughout the nation.
Individual airports use the results to make informed decisions when deploying security technologies and procedures.
Through the Performance and Operational System Testing (POST) Program, Safe Skies assesses the continued
operational effectiveness of airport-owned security technologies.
Through the Program for Applied Research in Airport Security (PARAS), Safe Skies provides a forum for
addressing security problems identified by the aviation industry.
A Board of Directors and an Oversight Committee oversee Safe Skies’ policies and activities. The Board of
Directors focuses on organizational structure and corporate development; the Oversight Committee approves
PARAS projects and sets ASSIST Program priorities.
Funding for our programs is provided by the Federal Aviation Administration.
Blast-Mitigation Strategies for Non-Secure Areas at Airports iii

PROGRAM FOR APPLIED RESEARCH IN AIRPORT SECURITY

The Program for Applied Research in Airport Security (PARAS) is an industry-driven program that develops near-
term practical solutions to security problems faced by airport operators. PARAS is managed by Safe Skies, funded
by the Federal Aviation Administration, and modeled after the Airport Cooperative Research Program of the
Transportation Research Board.
Problem Statements, which are descriptions of security problems or questions for which airports need guidance,
form the basis of PARAS projects. Submitted Problem Statements are reviewed once yearly by the Safe Skies
Oversight Committee, but can be submitted at any time.
A project panel is formed for each funded problem statement. Project panel members are selected by Safe Skies,
and generally consist of airport professionals, industry consultants, technology providers, and members of
academia—all with knowledge and experience specific to the project topic. The project panel develops a request for
proposals based on the Problem Statement, selects a contractor, provides technical guidance and counsel throughout
the project, and reviews project deliverables.
The results of PARAS projects are available to the industry at no charge. All deliverables are electronic, and most
can be accessed directly at www.sskies.org/paras.
PARAS PROGRAM OFFICER

Jessica Grizzle Safe Skies Special Programs Manager
PARAS 0014 PROJECT PANEL

Timothy Curran Sacramento County Sheriff’s Department
Sean Cusson LAM-LHA USA, LLC
Anthony Lopez Denver Police Department
Jeremy Martelle CHA Companies, Inc.
Chad Menge Metropolitan Washington Airports Authority
Amir Neeman Amir Neeman Consulting, LLC
Christian Samlaska Seattle-Tacoma International Airport
Larry Studdiford Studdiford Technical Solutions, LLC
Blast-Mitigation Strategies for Non-Secure Areas at Airports iv

AUTHOR ACKNOWLEDGMENTS
Arup would like to acknowledge the following for their contributions in the development of this
guidebook:
• National Safe Skies Alliance’s Program for Applied Research in Airport Security (PARAS),
which provided funding. Particular thanks are given to the program manager, Jessica Grizzle.
• The PARAS 0014 Project Panel Members, who also provided significant review and
contributions.
• The airports who provided invaluable input during interviews to facilitate identification of the
motivation and objective of this research; the direction of this guidebook was shaped, in part,
thanks to their input:
o Boise Airport
o Dallas/Fort Worth International Airport
o Fresno Yosemite International Airport
o General Mitchell International Airport
o Jacksonville International Airport
o Oakland International Airport
o San Antonio International Airport
o San Francisco International Airport
o San Jose International Airport
o Wichita Dwight D. Eisenhower National Airport
• This research was supported by Mark Gardner, Director of Engineering at bmk Engineering,
Inc., who provided constructability review and drafting, cost estimating, and technical writing
support.
• Lastly, this research would not have been possible without the help of Arup’s network of security
designers, aviation security experts, blast engineers, aviation planners, pedestrian modelers, cost
estimators, technical writers, and graphic designers who provided support from around the globe.
Not all can be listed; however, particular appreciation is given to:
o Deborah Blass, Project Manager and Principal Investigator
o Sam Noli, Subject Matter Expert – Blast Mitigation
o Stacey Peel, Project Reviewer and Subject Matter Expert – Aviation Security, Risk and
Compliance
o René Rieder, Jr., Project Director and Subject Matter Expert – Aviation Security
Blast-Mitigation Strategies for Non-Secure Areas at Airports v

CONTENTS
SUMMARY xi
SECTION 1: OVERVIEW OF GUIDEBOOK 1
1.1 Introduction 1
1.2 Motivation 2
1.2.1 Input from Airports 2
1.2.2 Gaps in Current Guidance 6
1.3 Guidebook Objective 8
1.4 Application 8
SECTION 2: BACKGROUND INFORMATION 9
2.1 Basic Principles of Blast Loading 9
2.2 Historical Explosive Events and Future Trends 11
2.2.1 Istanbul Atatürk Airport 11
2.2.2 Brussels Airport 12
2.2.3 Madrid-Barajas Airport 13
2.2.4 Other Notable Incidents 14
2.2.5 Example Explosive Sizes in Historic Attacks 15
2.2.6 Evolving Threats 15
2.3 Introduction to Technical Blast Concepts 16
2.3.1 Design-Basis Threat 16
2.3.2 Performance Criteria 17
2.3.3 Expected Damage 19
2.4 Introduction to Blast Analysis 22
2.5 Design and Procurement of Blast-Mitigation Measures 25
2.5.1 Roles during the Design Process 25
2.5.2 The Procurement Process 27
SECTION 3: COMPLIANCE AND RISK-BASED REQUIREMENTS 29
3.1 International Requirements and Risk-Based Approach to Non-Secure Area Security 29
3.2 The Risk Assessment Process 31
3.3 United States Compliance Requirements 33
3.4 Note about Blast Risks 33
SECTION 4: MITIGATION MEASURES 34
4.1 Physical Measures 36
4.1.1 Reinforced Concrete Detailing 36
4.1.2 Structural Steel Detailing 38
4.1.3 Progressive and Disproportionate Collapse Resistance 39
4.1.4 Facade Measures 42
4.1.5 Vehicle Security Barriers 48
Blast-Mitigation Strategies for Non-Secure Areas at Airports vi

4.1.6 Physical Measure Retrofits for Existing Airports 54

4.1.7 Physical Measure Cost Estimations 59
4.2 Technological Measures 62
4.2.1 Video Surveillance 62
4.2.2 Emerging Technologies 63
4.2.3 Technology Systems Cost Estimations 64
4.2.4 Existing Constraints 65
4.2.5 New Airport Considerations 65
4.3 Operational Measures 66
4.3.1 Agreement on Operational Measures 66
4.3.2 Operational Measures for Detection, Deterrence, and Prevention 67
4.3.3 Changing Passenger Habits 74
4.3.4 Operational Cost Measures Estimations 76
4.4 Crowd Management 77
4.4.1 Crowding at Airports 78
4.4.2 Departure Flow 82
4.4.3 Security Checkpoints 83
4.4.4 Additional Crowd Reduction Measures 83
4.4.5 Arrival Flow 84
4.4.6 Traditional Analysis versus Passenger Simulation Model 84
4.5 Architectural Design Measures 87
4.6 Elevated Threat Levels 88
SECTION 5: IMPLEMENTATION 90
5.1.1 Framework Objective 90
5.1.2 Role of the Risk Assessment in the Framework 91
5.2 Step 1: Assessment of Vulnerabilities 92
5.2.1 Life Safety 92
5.2.2 Commerce 93
5.2.3 Operations 93
5.2.4 Managing Vulnerabilities 93
5.3 Step 2: Assessment of Measures 95
5.3.1 List 95
5.3.2 Classify 95
5.3.3 Score 96
5.4 Step 3: Financial Costs 99
5.5 Step 4: Effectiveness of Measure Combinations 100
REFERENCES 104
ABBREVIATIONS, ACRONYMS, & INITIALISMS 107
Blast-Mitigation Strategies for Non-Secure Areas at Airports vii

EVALUATION OF MITIGATION MEASURES A-1

CASE STUDY USING THE FRAMEWORK B-1
COST DATA C-1
INDICATIVE BLAST-MITIGATION DETAILS D-1
LIST OF TABLES & FIGURES

Table 1-1. Airports Interviewed 2
Table 2-1. Common Blast Design-Basis Threats Used for Airports 17
Table 2-2. ASCE Levels of Protection 18
Table 2-3. Design Process Timeline 26
Table 4-1. Capability Comparison of Various Measure Types 35
Table 4-2. Example Levels of Facade Blast Enhancements 48
Table 4-3. Vehicle Penetration Rating (ASTM F2656) 49
Table 4-4. ASTM F2656 Vehicle Size and Speed Rating 50
Table 4-5. Example Structural Retrofitting Techniques 56
Table 4-6. Summary of Retrofit Measure Applicability 59
Table 4-7. Summary of Physical Enhancement Options and ROM Costs 60
Table 4-8. Hostile Vehicle Mitigation (HVM) Enhancement ROM Costs 61
Table 4-9. ROM Costs for Select Technology Systems 64
Table 4-10. Methods of EDC Security Screening 69
Table 4-11. ROM Costs for Operational Measures 77
Table 4-12. Waiting Time Standards (ADRM 9 and 10) 78
Table 4-13. Space Standards (ADRM 9 and 10) 80
Table 4-14. Level of Service Standards for Passageways (Odoni 2003) 80
Table 4-15. Example Radii of Casualties due to Blast Wave for Typical PBIEDs 81
Table 5-1. Example Vulnerability Weightings for Theoretical Airport 94
Table 5-2. Mitigation Measure Classification 96
Table 5-3. Definitions for the Various HVM Tiers of Performance 98
Table 5-4. Default Effectiveness Scores for the Various HVM Tiers of Performance 98
Table 5-5. Factors to Apply to Baseline Cost Estimate for Example Cities 100
Table 5-6. Example ROM Costs for HVM 100
Table B-1. Airport-Specific Areas Vulnerable to a VBIED B-2
Table B-2. Airport-Specific Areas Vulnerable to a PBIED B-2
Table B-3. Individual VBIED Mitigation Measures Considered at the Example Airport B-5
Table B-4. Example Scoring of Mitigation Measures Against Proposed Security Metrics B-5
Table B-5. Mitigation Measures and Listed Annual Financial Cost B-6
Table B-6. Assessment Summary of A, B, and C Mitigation Combinations B-6
Table B-7. Comparison and Selection of Combination Measure B-7
Blast-Mitigation Strategies for Non-Secure Areas at Airports viii

Table B-8. Individual PBIED Mitigation Measures Considered at the Example Airport B-11
Table B-9. Example Scoring of Mitigation Measures Against Proposed Security Metrics B-12
Table B-10. Mitigation Measures and Listed Annual Financial Cost B-12
Table B-11. Assessment Summary of A, B, C, and D Mitigation Combinations B-13
Table B-12. Summary of Selected Combination Measure (Combination B) B-13
Figure 1-1. Overview of Guidebook Contents 1

Figure 2-1. Simplified Blast Wave Interaction with Building 10
Figure 2-2. Damage after Atatürk Explosion 12
Figure 2-3. Damage after the Madrid Airport Bombing Resulted in Demolition 14
Figure 2-4. Timeline Showing Approximate VBIED Explosive Sizes for Significant Events in Pounds of
Equivalent TNT 15
Figure 2-5. Graphical Representation of Performance Criteria 19
Figure 2-6. Demonstration of DBT and Performance of Varying Levels of Enhancement 21
Figure 2-7. Sample Calculation of Blast Loading 22
Figure 2-8. Single Degree of Freedom 23
Figure 2-9. Multiple Degree of Freedom 24
Figure 2-10. Finite Element Analysis 24
Figure 3-1. Determining Risk Reduction Measures at the National and Operator Level 32
Figure 3-2. The International Aviation Security Framework 32
Figure 4-1. Various Measures That Shape a Blast-Mitigation Strategy 34
Figure 4-2. Blast Shockwave Propagation through the RC Member, Which Induces Spall 36
Figure 4-3. An RC Panel Damaged by Spall 36
Figure 4-4. Breached RC Panel 37
Figure 4-5. Spall Plate Installed at the Back of an RC Wall 37
Figure 4-6. RC Column Wrapped in a Steel Jacket 38
Figure 4-7. Sections of the Base of a Steel-Encased Column 39
Figure 4-8. 3-D View of a Steel Column Encased in Reinforced Concrete 39
Figure 4-9. Alternate Load Path Method 41
Figure 4-10. Catenary Action of the PVB Interlayer 44
Figure 4-11. Different Glass-Breaking Mechanisms – Annealed, Heat-Strengthened, and Tempered
Glass 45
Figure 4-12. Frame Aluminum Section with a Steel Plate Insert 47
Figure 4-13. Framing Box Section (Unitized) 48
Figure 4-14. Framing Split-Section with a Blast Clip 48
Figure 4-15. Steel Bollards 51
Figure 4-16. Steel Retractable Bollards 51
Figure 4-17. Jersey Barriers 52
Figure 4-18. Concrete Knee Wall 53
Blast-Mitigation Strategies for Non-Secure Areas at Airports ix

Figure 4-19. Wedge Barriers 54

Figure 4-20. Drop Arms 54
Figure 4-21. Two-Side Supported Slab (One-Way Spanning) 56
Figure 4-22. Four-Side Supported Slab (Two-Way Spanning) 56
Figure 4-23. LiDAR System Supplementing CCTV 64
Figure 4-24. Operational Requirements Criteria 66
Figure 4-25. Australian Police Officers at Airport 68
Figure 4-26. Free Running Explosives Detection Canine Accompanied by Handler 69
Figure 4-27. Implementing UVSS 71
Figure 4-28. Types of Communication Techniques 72
Figure 4-29. Targeted Passenger Screening 73
Figure 4-30. Vigilance Posters 74
Figure 4-31. Changing Passenger Habits to Achieve Risk Reduction 75
Figure 4-32. SeMS Elements 76
Figure 4-33. Example Vulnerability of Crowding 81
Figure 4-34. Hourly Arrival Passenger Volume for Mid-Sized Airport 85
Figure 4-35. Hourly Departure Passenger Volume for Mid-Sized Airport 85
Figure 5-1. Framework Process 91
Figure 5-2. Example Vulnerability Assessment, Arrival and Departures Hall (left); Fuel Farm (right) 94
Figure 5-3. Vulnerability Weightings for Various Areas of a Theoretical Airport 94
Figure 5-4. Tiers of Performance and Scoring 97
Figure 5-5. Scoring of Hostile Vehicle Mitigation as a Blast-Mitigation Measure 99
Figure 5-6. Example of Combined Mitigation Measure Output 101
Figure 5-7. Example of Expenditure Splits for Security Combinations under Consideration 102
Figure 5-8. Breakdown of Mitigation Measures (Vulnerability-Based): Example New Airport vs. Example
Existing Airport 102
Figure 5-9. Breakdown of Mitigation Measures (Metric-Based): Example New Airport vs. Example
Existing Airport 103
Figure 5-10. Summary of Framework Relationship to the Risk Assessment Process 103
Figure B-1. Airport Layout B-2
Figure B-2. VBIED Risk B-3
Figure B-3. Output from the Excel-based Tool – Measure Combination Options B-6
Figure B-4. Expenditure Breakdown for Selected Combination of Measures B-7
Figure B-5. Attack Paths and Design Basis B-8
Figure B-6. Selected Vetting Points (Highlighted in Blue) B-9
Figure B-7. Indicative Threat Areas: PBIEDs B-10
Figure B-8. Graphic Representation of Combined Mitigations vs. Cost B-13
Figure B-9. Expenditure Breakdown for Selected Combination of Measures B-13
Figure B-10. Example Details to Improve Finishes Resilience against a PBIED B-14
Blast-Mitigation Strategies for Non-Secure Areas at Airports x

SUMMARY
This guidebook facilitates the implementation of effective blast-mitigation strategies in non-secure airport
areas to reduce risks of explosive attacks. Certain solutions may be effective at one airport but not at
another. Each airport faces unique constraints, such as different vulnerabilities and risks, and varying
sizes and financial capabilities. Therefore, this guidebook is not prescriptive but instead provides a
process by which airports can implement the most appropriate strategies. A holistic approach is taken to
determine risk-reduction measures, whereby a balanced security strategy is achieved by combining
physical, technological, and operational solutions.
The main concepts in this guidebook are as follows:

• In the absence of regulations in the non-secure areas of airports, implementing a risk-based
approach to identify blast-mitigation strategies is good practice and recommended by
international and domestic aviation security guidelines.
• Existing airports’ needs are different from new airports’ needs, and small airports have different
needs from large airports. Further, each airport has a unique risk profile and appetite for
managing those unique risks.
• Identifying a blast-mitigation strategy should take into consideration measures that are most
effective for the unique characteristics and risk of that particular airport. Good-practice blast-
mitigation strategies for non-secure airport areas should incorporate a variety of measures, from
physical—structural and facade hardening; to technological—analytics and emerging capabilities
like millimeter wave detection; operational—explosives detection canines, patrols, and crowd
management; and architectural—terminal and roadway layout, materials, and detailing. Each
type of measure has unique pros and cons in terms of functional (i.e., protective capabilities such
as deter, detect, and defend) and non-functional (i.e., cost, passenger impacts, and adaptability)
effects. Identifying a suitable strategy should consider these characteristics together with the
unique needs of that airport.
• A framework process has been developed to identify combinations of measures that should be
combined to form a cost-effective, holistic blast-mitigation strategy. The process is applicable to
all airports and projects, and is customizable. To facilitate execution of the quantitative portion
of the framework process, an Excel-based tool accompanies this guidebook.
Blast-Mitigation Strategies for Non-Secure Areas at Airports xi

SECTION 1: OVERVIEW OF GUIDEBOOK
1.1 Introduction
Arup USA, Inc. (Arup) was contracted to develop this guidebook addressing blast-mitigation strategies
in non-secure areas of airports by National Safe Skies Alliance, Inc. through their Program of Applied
Research in Airport Security (PARAS).
This guidebook helps professionals involved in airport design and operations develop blast-mitigation
strategies customized to their specific risks, contexts, and needs. The aim is to answer the following
question: How can I mitigate the blast risk at my airport?
This guidebook covers several aspects of effective blast mitigation strategies in detail:
• Damage to be expected as a result of various threats (Section 2)

• Legislation requirements and the need for a risk-based approach (Section 3)
• Costs and effectiveness of various blast-mitigation measures (Section 4)
• Implementation plan (Section 5)
Figure 1-1. Overview of Guidebook Contents
Section 2: Section 3: Section 5:

Section 4:
Background Requirements Measure
Mitigation-
Information Risk-based Selection
Measure Options
Blast threats and assessment and Combinations
Costs and
associated compliance and
effectiveness
damage requirements implementation
As mitigation measures are considered, a risk assessment will help decision-makers understand the risks
unique to the airport and site and, therefore, develop targeted and proportionate measures. Measures
must also be compliant with relevant legislation.
After airports have gone through the measure-selection process, residual risks should be evaluated in
accordance with the risk-assessment process.
Unless otherwise stated, the terms “risk-reduction measures” and “security measures” refer collectively
to nonspecific measures and may include operational, physical, design, or technology security measures,
Blast-Mitigation Strategies for Non-Secure Areas at Airports 1

e.g., guards, bollards, standoff distance, or CCTV, respectively. Where reference is specific to the blast
threat and risk, the terms “blast protection” and “blast-risk-mitigation measures” will be used.
1.2 Motivation
This guidebook was created to address challenges faced by airports in implementing blast protection. As
part of the development of this guidebook, Arup interviewed airport professionals and undertook
research to identify existing gaps in currently available guidance.
The information obtained from interviews and gap-analysis research influenced the objective and
intended application of this guidebook.
1.2.1 Input from Airports

Arup conducted interviews with airport representatives to better understand the users’ expectations for
blast-mitigation-related guidance. Arup interviewed 10 airports of various sizes (Table 1-1). Their
feedback is summarized below.
Table 1-1. Airports Interviewed
Airport Interview Department within

Airport
Category Date Organization
Dallas/Fort Worth International Airport

8/10/17 Police Department
Large Hub (DFW)
San Francisco International Airport (SFO) 9/26/17 Security Department
Oakland International Airport (OAK) 8/14/17 Security Department
San Jose International Airport (SJC) 8/24/17 Operations Department
Public Safety and Security
Jacksonville International Airport (JAX) 8/18/17
Medium Hub Department
General Mitchell International Airport Planning and Engineering
8/8/17
(MKE) Department
San Antonio International Airport (SAT) 8/17/17 Security Department
Wichita Dwight D. Eisenhower National
8/7/17 Operations Department
Airport (ICT)
Small Hub Boise Airport (BOI) 8/3/17 Police Department
Fresno Yosemite International Airport
8/24/17 Public Safety Department
(FAT)
1.2.1.1 Experience Implementing Blast-Mitigation Strategies
PROJECT IMPLEMENTATION
Several of the individuals interviewed have had experience incorporating blast-mitigation strategies at
their airports, ranging from structural hardening to operational measures. Almost all were confident that
the airport’s security team would be involved in new projects at their airport and could therefore request
the consideration of blast mitigation. However, if the security department were not as active in the
project planning process, its input could be overlooked or incorporated late in the process. To ensure a

cost-efficient and effective security outcome, airport security departments must proactively participate in
the early stages of project planning.
Interviewees consistently suggested that to determine design-basis threats, airport security stakeholders
(e.g., law enforcement, Transportation Security Administration [TSA], Federal Bureau of Investigation
[FBI], private security, and corporate security) should gather intelligence, determine the threat, and
identify the assets that require protection. Most airports did not have a pre-existing threat or risk
assessment. Almost all interviewees noted that it was difficult to determine how exactly to protect
against those identified threats and what level of blast protection was required. They stated that the
ultimate decisions regarding blast-protection measures are made by the senior management on the
airport board, the chief airport operator, or similar high-level executives; these positions have the
authority to make risk-based financial decisions, which are otherwise unregulated. The involvement of
the security team in decision-making varied from nonexistent, with decisions made in a private meeting
without security’s involvement, to significant, with decisions heavily influenced by security.
Just over half of the airports interviewed have taken proactive steps to evaluate vehicle-borne
improvised explosive device (VBIED) and person-borne improvised explosive device (PBIED) threats
to their airports from physical and design perspectives:
• Some integrated blast-protection measures into their design, based on the airport
owner/operator’s decision to follow recommendations made by their blast consultant.
• Some excluded blast-protection measures from their design, based on the airport
owner/operator’s decision to follow the blast consultant’s recommendation that physical
protection is not necessary, for example, due to large standoffs (i.e., distance between vehicle
access and terminal buildings) or robust structures.
• In all cases, the blast-protection studies were incorporated as part of another capital project, such
as a terminal renovation, that was not initiated with the objective of providing blast protection.
Although the interviewees were generally familiar with the PARAS 0004 document, Recommended
Security Guidelines for Airport Planning, Design, and Construction (formerly issued by TSA under the
same name), it does not appear to be used frequently by the airports interviewed. A few individuals
stated that the architects or designers on the planning team used this document on projects. One airport
noted that to understand the application of current best practices, the airport sends a representative to
other airports around the world.
Another airport said that although the budget is always considered, the primary concern at their airport is
to implement strategies to fix identified problems; however, when it comes to blast mitigation, the
airport is unsure how to clearly identify the problem or determine whether there even is a problem.
Some individuals suggested that the incorporation of security measures is dependent on the CEO or
COO, and that some CEOs put greater emphasis on security than others. In summary, there is variability
among airports regarding the need to include or prioritize blast mitigation in their projects.
CURRENT MITIGATION STRATEGIES
The airport representatives interviewed were overwhelmingly dissatisfied with the amount of currently
available information and guidance resources relevant to blast mitigation. However, there was some
consistency in the risk-mitigation measures being considered by most airports:
• Law enforcement patrols in and around terminals to look for suspicious packages and persons
• Hostile vehicle mitigation measures at doorways along the landside curb
• Police presence in terminal front of house (FoH) and at curbside to deter aggressors

• Random canine patrols through the terminal FoH and parking garages
• Landside vehicular traffic controls (passive and active)
• Landside loading dock deliveries scheduled and received by the expecting entity; otherwise, they
are turned away
• Video surveillance coverage; however, this is mostly used for post-incident investigation, as not
all coverage is actively monitored (too many cameras, not enough people for active monitoring)
• Recurrent training for all airport employees, including for non-security personnel, such as
incident response and reporting of suspicious activities
• Plans and procedures to achieve greater standoff to vehicles during elevated threat levels
• Contracted security services to monitor areas like parking garages and loading docks (medium
and large airports only)
One of the medium-sized airports interviewed is implementing additional measures beyond those
typically adopted, including visual explosives screening of all trucks going to the loading dock prior to
their admittance near the terminal, new blast-designed facade, video analytics to detect suspicious
packages and vehicles, and headway bars to limit the size of vehicles allowed to approach the terminal.
These measures have been implemented as a direct result of recommendations made by a consultant.
However, a risk assessment was not undertaken to determine these measures.
In a heightened threat condition, most airports interviewed have a plan in place that involves
coordinating with TSA and law enforcement to reroute vehicle lanes to achieve more standoff to the
terminal, restrict parking to certain areas, and perform vehicle inspections (a TSA requirement for a
number of airports). Additionally, most airports will provide increased police presence in the non-secure
areas of the airport during elevated threat levels.
1.2.1.2 Challenges of Incorporating Blast Protection

For most airports, the three biggest challenges of incorporating blast-protection measures were as
follows:
• Buy-in by decision-makers
• Costs of the measures
• Lack of clarity in determining what measures are needed and where
Every airport interviewed made a direct or implied reference to all three of these challenges.
BUY-IN AND RESOURCE ALLOCATION
Blast-protection measures are not typically considered a high enough priority for a budget to be
allocated, with many airports noting passenger experience (e.g., murals, terminal cleanups, etc.)
initiatives being prioritized over security investment, including blast protection. Additionally, one
airport noted that it was difficult to get the planning department to focus on relatively small-scale
projects such as blast protection when they are often focused on large (e.g., $20-30 million) capital
projects.
One airport highlighted that the project funding source influenced the prioritization of resources. For
example, projects funded by grants—e.g., apron and taxiway rehabilitation, erosion control and drainage
improvements, or taxiway lighting—were given resource-allocation priority compared with revenue-
funded projects such as terminal expansion/renovation (which would include blast protection).

Buy-in by decision-makers was cited as the biggest challenge for one airport, with another airport stating
that understanding the risk was the greatest challenge to establishing buy-in: it is difficult to justify
capital investment to mitigate something “that may never happen.” This was underscored by another
airport’s observation that the Brussels Airport attack (March 2016) influenced their ability to secure
investment because the event happened to occur at the same time they were seeking funding.
The need to ensure compliance with regulations appears to have an influence on securing buy-in. One
airport noted that at the time of their terminal reconstruction, the now-retracted “Special Category
Airport 3,” also known as the “300-foot rule,” was being publicized by the TSA, and it was therefore
easier to secure funding for a blast study.
COST OF BLAST PROTECTION
In general, airports reported the high cost of incorporating blast protection as a major challenge. The
following examples were cited in the interviews:
• One airport discovered partway through a glass-facade-strengthening project that in order to gain
the greatest security value from a blast-protection investment, strengthening the terminal’s
support structure and columns would also likely be required. This type of unexpected and costly
upgrade underscores the “excessive” cost perception of blast protection.
• One individual mentioned that their airport had studied what was required to protect against a
van or car explosive adjacent to the terminal and deemed the cost “ridiculous.” This view and
lack of understanding of the risk further reduced the credibility of blast protection as a valid
security measure.
• The level of revenue (investment source) relative to the cost of blast protection, including expert
advice/consultancy and the measures themselves, is significant at smaller airports; the money is
simply not available.
• One airport noted that blast protection is an “afterthought” in capital projects, resulting in it
becoming even more costly and then “nobody wants to do it.”
• One airport noted that achieving certain protection measures, such as obtaining greater vehicle
standoff and separating the loading dock from the terminal, requires large-scale changes to the
existing airport configuration that are neither economically nor operationally feasible.
Several airports cited cost as the overall biggest challenge to implementing blast-protection measures.
This perspective highlights the implications associated with not having a risk-based security culture.
Without an understanding of what blast-protection measures buy in terms of risk reduction (or return on
investment), blast-protection measures are viewed only as a cost. This guidebook aims to help airports
realize the value achieved by introducing various blast-protection measures, using a risk-based
approach.
PERCEIVED AMBIGUITY IN GUIDANCE
Ambiguity about which guidance to follow, what measures to implement and where, and what scale or
level of protection should be implemented was cited by at least one airport as the single biggest
challenge in incorporating blast protection.
The interviews indicate there is a perception that blast-protection measures are best determined by an
external entity or authority, particularly in an unregulated environment such as landside. This leads to
confusion about which guidance to follow, since any guidance documents available on the topic only
make recommendations, which do not have the authority of requirements. Furthermore, due to the site-
specific nature of security risks, the information varies among the available guidance.

Generally, because the airports do not understand what level of risk or protection they should be
pursuing, they do not know which guidance and measures to adopt. Some airports have used expert
advice from consultants, but the value of the investment is not always recognized throughout the
organization due to the absence of a risk-based culture.
Another consistent desire among the airports interviewed was for an external authority to determine
measures and clearly communicate those through authoritative guidance.
1.2.2 Gaps in Current Guidance

In most nations, including the United States, there are no legislated requirements specifically for blast
protection; it is up to the airport owner/operator to make these decisions. 1 Australia, for example,
legislates that the airport’s security program be based on a security risk assessment, which negates the
need to dictate blast protection for all airports. This approach is consistent with the International Civil
Aviation Organization’s (ICAO) expectation that Contracting States, of which the United States is one,
“establish and implement policies and procedures … based upon a security risk assessment” 2 and that
they ensure “that security measures are established for landside areas to mitigate the risk of and to
prevent possible acts of unlawful interference in accordance with risk assessments.” 3 Furthermore, the
ICAO expects Contracting States to “ensure that landside areas are identified.” 4
The information currently available about risk assessment provides airport owners and operators with
clear guidance on the risk-assessment process. However, the guidance is limited to conducting the risk
assessment and does not extend to guidance on mitigating the risk, i.e., how to determine which
measures to use to mitigate which risks, how to determine an acceptable level of risk reduction, and how
to measure the effectiveness of measures in reducing risks, either on their own or in combination.
Regarding blast protection, there is little guidance on the level of protection that should be achieved.
This is to be expected given that the risks and risk appetites are different for each airport, and therefore
the level of protection will be unique to each airport.
The literature review conducted in the process of developing this guidebook found that there is little
discussion of the non-security impacts of implementing various blast-mitigation measures (both positive
and negative). These include airline and airport operational disruption during implementation, influence
on architectural objectives, operational changes required to facilitate implementation/operation and
maximize the security value of measures, supporting infrastructure changes required to facilitate the
implementation/operation, and indirect benefits of blast-protection measures. Examples include the
following:
• Establishment of standoff may require rerouting of approach roads and may influence parking
design or result in greater walking distances for passengers.
• Retrofitting of facade glazing for resilience requires the deployment of scaffolding or temporary
closure of terminal areas, which could affect passenger experience and airline operations.
• No-parking zones in front of the terminal help improve traffic efficiency in passenger pick-up
and drop-off zones.
• Reducing queuing times improves the passenger experience and increases the amount of time
passengers spend on the airside, where they are likely to make purchases.
1
Except Singapore, which recently passed the Infrastructure Protection Act of 2017, mandating that blast be considered.
2
Annex 17 Standard 3.1.3
3
4

• Blast-mitigation requirements may influence the use of particular materials, and the shapes and
sizes of various terminal elements, which may impact architectural objectives.
• Changes to screening, resourcing, and training may impact both airport and airline employees, as
well as passenger experiences.
Selection of security measures should consider all implications, not just a measure’s ability to mitigate a
security risk. This is particularly relevant when comparing different measures available to reduce the
same risk, e.g., standoff versus structural strengthening. There is, however, little guidance available to
assist with this important process. Further, little to no cost information is made available to airports to
enable them to assess and compare the whole-of-life cost—capital and operating cost—of specific
security measures.
The most widely available guidance documents regarding blast protection are specific to typical building
structures. Variations in airport structures can be significant for large airports such that the specific
building requirements in these guidance documents are not entirely applicable. Additionally, there is no
guidance available relating to nonbuilding areas within airports, such as bus stops or fuel farms.
The Federal Highway Administration’s (FHWA) Bridge Security Design Manual (June 2017), can be
used for the design of elements such as raised roadways common at airports. However, the FHWA
document, along with many others (e.g., American Society of Civil Engineers (ASCE) 59-11 Blast
Protection of Buildings or Unified Facilities Criteria (UFC) 3-340-02 Structures to Resist the Effects of
Accidental Explosions), is intended for a highly technical audience of specialist engineers. The contents
are largely incomprehensible to anyone without significant structural design engineering experience.
Design according to such standards also remains somewhat prescriptive. While blast-resistant design is
often identified as a branch of performance-based design, standards such as ASCE 59-11 require the end
user of a building to make judgments about the anticipated threat size and desired level of performance.
Often such end users are unaware of or lack experience to understand the choices they are being asked to
make and the potential outcomes (e.g., costs or aesthetics) of their decisions. It is often difficult for
organizations to retain experience or knowledge in this area because blast is typically considered only
when assets are built, replaced, or substantially refurbished.
Blast-resistant design requires a holistic approach that demands input from a wide range of individual
specialists including but not limited to threat and risk, airport operations, architectural, project
management/delivery, airport security operations, communications/IT, quantity surveying, and various
engineering disciplines. Despite this multidisciplinary need, guidance tends to be targeted to risk
assessments and structural engineering, without reference to this broader input.
Also neglected in many industry guidance documents is the importance of recovery and reinstatement of
services following a blast incident. While the documents above reference business-continuity objectives,
these are typically ill-defined. The dominant feature of the blast-specific design and guidance documents
reviewed was an emphasis on structural and facade performance—critical building services were often
referenced only with regard to their physical hardening or placement to reduce exposure to blast effects.
Assessment of the consequences of blast effects on services is not well-defined. Furthermore, despite
significant law enforcement agency needs following a blast (e.g., time and access control for forensic
investigation), there is little to no general guidance available for the industry to draw on to inform their
business-continuity planning.

1.3 Guidebook Objective

This document’s objective is to guide airports in their development of a blast-mitigation strategy. The
strategy proposed herein takes a holistic approach to reducing risks of a blast event, considering both
non-security and security needs and impacts. To support this objective, the guidebook includes examples
of mitigation measures and their considerations and consequences of implementation, such as the
benefits and disadvantages, operational impacts, and rough order-of-magnitude costs.
The guidebook’s holistic approach includes:
• Physical factors (e.g., structural and facade hardening, vehicle barriers, etc.)
• Technological factors (e.g., CCTV and analytics, etc.)
• Operational factors (e.g., canine patrols and behavioral detection officers, etc.)
• Architectural layouts (e.g., crowd management, etc.)
The guidebook does not attempt to replicate specific guidance such as risk assessment or structural
engineering specifications that are already available. Rather, it clarifies their application in the context of
blast mitigation. Since each airport has a unique combination and configuration of size, landside assets,
risk profile, and risk appetite, the guidebook does not prescribe particular measures. It is designed to
apply to airports of all sizes and addresses risks associated with all non-secure areas. The guidebook also
draws upon previously published information, such as the PARAS 0004 document.
As confirmed by the interviews, airports rely heavily on the technical design community, such as
architects, to determine security measures. Therefore, this guidebook is also intended for use by
designers including architects, planners, and engineers who may be working with airport security
stakeholders or airport owners on a project that requires blast protection.
It may not always be obvious when a blast strategy is required—some projects inadvertently introduce
or increase security risks without any defined security scope. This further underscores the need for a
security risk assessment and early consultation with the airport’s security team in any capital project.
1.4 Application
The guidebook is intended for professionals involved in determining blast-protection measures at
airports. This includes airport owners and operators as the ultimate security-risk owners; airport security
managers who facilitate the implementation of risk-mitigation measures; and the design community,
such as architects, engineers, and planners. The guidebook is applicable to all airports in the United
States. Although not every strategy will be applicable to every airport, the guidebook is designed to help
airports evaluate whether each strategy is applicable to their specific contexts.
This guidebook should be reviewed before the start of any new landside facility, security, transportation
planning, or construction project for awareness of potential project implications. It should be used as a
reference for the basis of design during the course of any applicable landside projects. In a request for
proposals, an airport can require that this guidebook be used as a security reference.
Implementing appropriate blast-risk-mitigation strategies is the responsibility of the

airport. The architect, blast consultant/engineer, and airport security manager are well
suited to collectively facilitate and manage the process of blast mitigation for an airport.

SECTION 2: BACKGROUND INFORMATION
This section provides information to improve baseline knowledge about blasts, including the following:
• The basics of blast loading and analysis to help users understand why and how certain
mitigations may work
• A review of historical attacks, including means and methods, and the implications associated
with certain mitigation measures
• Examples of blast threat sizes and the damage that could be expected as a result of those threats,
to provide airports with a greater understanding of the risk management and acceptance process
in the blast context
2.1 Basic Principles of Blast Loading

An explosion is typically caused by a chemical reaction. When an explosive material is ignited, it burns
quickly. In the burning process, a large amount of hot gas is produced and rapidly expands. This rapid
release of gas pressurizes the air around the detonation, which creates a blast wave: air moving faster
than the speed of sound. The intensity of the blast wave dissipates over time and distance. Severe
damage to structures or individuals occurs immediately adjacent to the detonation source.
The blast wave creates a short-term pressure on any surface it encounters. The surface could be an
exterior building facade, an interior structural column, or a person. It is essentially a very high wind load
for a very short period of time. Typically, the duration of a sustained wind gust is up to 20 seconds. A
typical blast load duration is less than 20 milliseconds, or less than 0.1% of the duration of a sustained
wind gust.
Blast loading is expressed in terms of pressure, time duration, and impulse. The pressure is expressed in
terms of psi (pounds per square inch) or psf (pounds per square foot) and defines the peak magnitude at
which the blast wave impacts the surface. Blast-designed facades are typically designed for blast
pressure in the 4 psi to 10 psi (576 psf to 1,440 psf) range. A typical exterior facade for wind is designed
for a continuous load of 30 psf to 35 psf.
Time duration is expressed in terms of msec (milliseconds) and defines how long the blast wave is
impacting the surface. Typical building facades are designed assuming the pressure reduces to 0 psi at
the end of the time duration. The impulse is expressed in terms of psi-msec and accounts for the total
energy impacting the facade based on the peak pressure and time duration. Higher pressures and longer-
duration events increase the total energy.
There are three main variables in determining the magnitude of the blast load at any given surface: size
of the threat (explosive type and size), standoff (distance from threat to surface), and line of sight (angle)
from threat to surface. The standoff distance plays a key role in the blast loading, as the total energy in
the blast wave is directly proportional to the standoff. If the standoff is doubled, the impulse is reduced
by about 46%. The other design-controlled variable is the line of sight from the threat to the surface. The
worst-case scenario is that in which the surface is perpendicular to the blast wave, creating a fully
“reflected” pressure loading. If the threat can be restricted to an angle (say, 45 degrees), the impulse is
reduced about 15% as it creates a “side-on” loading.
See Figure 2-1 for a simplified picture showing standard design conditions. The threat (truck) is located
on the roadway with a standoff from the threat to the building facade. The building facade depicts the
intensity of the blast wave on the facade’s surface, with a higher magnitude at the base and a smaller

magnitude at the upper levels, as the distance away from the threat increases. In the blast engineering
industry, the threat is typically specified in pounds of trinitrotoluene (TNT). Conversion factors for other
types of explosives to TNT equivalence are available in various blast engineering references such as
ASCE 59-11 and Blast Effects of Buildings by Cormie, Mays, and Smith (2009). More information
regarding typical explosive sizes are presented in Section 2.3.
Figure 2-1. Simplified Blast Wave Interaction with Building
Source: bmk Engineering
When a threat is in a confined space, such as a lobby or mail room, the blast pressure is confined, which
increases the total impulse on surrounding surfaces. The blast wave will reflect off adjacent walls and
increase the time duration a surface experiences the blast load. Typical blast-protection measures for
confined spaces include pressure relief panels or walls that are designed to fail and alleviate the other
walls from the blast load.
After the initial blast wave, a vacuum is created that will almost immediately refill itself with the
surrounding atmosphere. This creates a very strong negative pressure on the surface. This negative
pressure can minimize debris propelling into occupied space but is hard to accurately predict. Because of
the large unknown, this negative pressure is ignored during design to produce a slightly conservative
design solution.
Most facade systems are designed to resist the impulse as the controlling factor; therefore, increasing
standoff or changing the line of sight will reduce the total energy the surface must absorb.
After a blast wave strikes a surface or body, high-velocity shockwaves will continue to pass through the
surface or body. These shockwaves carry energy through the surface. If the individual surface elements

are unable to resist these waves, these elements will either break apart and become flying debris or
structurally fail, causing major damage to the surrounding area. In people, the shockwaves will travel
through internal organs and tissues, causing severe damage. Any flying debris could also cause
lacerations and other injuries to anybody inside the buildings. Flying debris is the leading cause of
injuries in a blast event.
Additionally, when a bomb explodes, the bomb casing and any additional shrapnel (nails, screws, or
other items included in the bomb) will be violently propelled outward and away from the explosion at
extremely hazardous speed. This fragmentation from the bomb casing and its shrapnel is referred to as
primary fragmentation. When these fragments strike buildings, concrete, masonry, glass, and other
facade elements, they may fragment even further and cause even more damage. This is known as
secondary fragmentation.
Lastly, the explosion may also create a fireball and high temperatures, which could result in burns on a
human body or cause secondary fires, depending on whether other fuel sources or flammable materials
are located near the source of explosion. Fire and heat are often mistakenly interpreted to cause the
major damage in a blast event; however, the damage described in the paragraphs of this section is
primarily due to the pressurized air—the blast wave.
2.2 Historical Explosive Events and Future Trends

Though the nature of terrorism is evolving, historic attacks can prove informative when it comes to
mitigating effects of similar events in the future. This section presents a selection of relevant historic
explosive incidents at airports and their impacts, based on a review of open sources. A discussion of
anticipated future attack methods, reviewed from available intelligence, is also included.
2.2.1 Istanbul Atatürk Airport

On June 28, 2016, a coordinated terrorist attack was launched against Terminal 2 at Istanbul Atatürk
Airport in Turkey. The attack occurred while the airport was operating at a higher threat level in
response to information provided by intelligence authorities, although post-incident investigation
showed that the perpetrators had conducted reconnaissance over a period of two to three weeks prior to
the attack and had exploited vulnerabilities observed.
According to information reported, including reports from TAV Security Services (the private security
company employed at the airport), the three attackers arrived by taxi and avoided behavioral assessment
by being dropped off in a lane at FoH that they knew (from reconnaissance previously conducted) was
unlikely to be overseen by police. A CCTV operator identified them as suspicious and sought police
assistance. This resulted in a police officer initially following one of the attackers, before intervening
inside the terminal, at which time the police officer was shot.
The next attack occurred on the arrivals level, where an area of mass gathering was sought out to
detonate the PBIED. The other two attackers sought to access the departures level by shooting at the
FoH terminal screening checkpoint (the checkpoint required passage just to enter the terminal). One
attacker succeeded in penetrating the departures hall on the first floor of the terminal building, where he
opened fire on passengers as he moved inside the terminal, possibly toward the sterile area or the VIP
lounge. The attacker detonated a PBIED near the entrance to the departures hall. The third attacker was
shot by an armed immigration officer on the arrivals level but was still able to detonate the PBIED.
Post-incident investigations showed that the modus operandi and objectives of the terrorists evolved
rapidly during the attack, including moving between departures and arrivals levels. These changes are

thought to be a direct result of interventions by law enforcement agencies, which had the effect of
reducing the impact of the attacks planned.
The attack resulted in the deaths of 45 people and injured at least 239 others.
The attackers were collectively armed with at least one automatic weapon (AK-47), a handgun, and two
grenades. Additionally, each attacker carried a PBIED hidden in a vest. It appears the attackers timed the
start of their attack on the terminal screening checkpoint to coincide with iftar, the evening meal that
marks the end of each day’s fast during Ramadan, most likely in an attempt to catch airport police and
security personnel off-guard. Because the event also coincided with a change of shifts, airport security
managers were able to deploy additional staff at extremely short notice. The gun attack on the screening
checkpoint lasted approximately 10 to 15 minutes. The entire duration of the attack was approximately
45 minutes.
No significant structural damage was caused by the incidents; however, some non-structural elements
were damaged, creating debris in the terminal.
The airport was closed for several hours after the attack. The next morning, incoming and outgoing
flights were operating, though some were canceled or delayed.
Figure 2-2. Damage after Atatürk Explosion
Source: Associated Press
2.2.2 Brussels Airport

On March 22, 2016, three improvised explosive devices (IED) exploded in Brussels, Belgium, killing 35
people and injuring over 300 others. Two of the IEDs were manually detonated by terrorists nine
seconds apart in the main terminal building at Brussels Airport at 0700 GMT, while a third device
exploded on a train at Maelbeek Metro station in central Brussels at 0800 GMT. All three attacks were
suicide-bomb attacks. Belgian authorities identified the attackers as Belgian nationals. Daesh (Islamic
State) claimed responsibility for the Brussels attacks via a statement on its Amaq agency.

The attackers at Brussels Airport utilized automatic weapons and IEDs packed with nails concealed
within two suitcases. One exploded at check-in row 11 on Level 3 of the Departures Hall and the second
exploded at check-in row 2 in the Departures Hall. Gunfire from automatic weapons (probably AK-47
assault rifles) prior to the explosion was reported. At least 13 people were killed in the explosions and
more than 80 injured. A third unexploded IED was discovered and disposed of by security forces in a
controlled detonation.
The locations of the explosions in the terminal building suggests that the attackers may have tried to use
a pincer-style attack by detonating one device, causing the crowd to run, and then using a second device
in the midst of the fleeing crowd. This suggestion is supported by the fact that the IEDs were packed
with shrapnel and partially explains the high number of injuries relative to fatalities.
The attack at Maelbeek Metro station involved the manual detonation of an IED in a train carriage as the
train ran along the platform at Maelbeek station. The explosion killed at least 15 people and injured
more than 170 others. The source of the explosion is suspected to be a belt device worn by the bomber.
Maelbeek station is in central Brussels and serves as a transport hub for several European Union
administration buildings.
All IEDs used in the attacks are suspected of being composed of triacetone triperoxide (TATP), a highly
unstable homemade explosive. TATP has been used by terrorists inspired by Daesh.
The blast did not cause structural damage to the terminal building, but non-structural elements suffered
damage, such as the suspended ceiling at some locations within the terminal.
The airport was closed after the attacks, and flights were diverted to other airports. On April 3, flights
began resuming. As a response to the attack, an extra 1,600 police officers were deployed to train
stations, airports, and border crossings.
2.2.3 Madrid-Barajas Airport

On December 30, 2006, an IED placed in a van exploded in the parking area of Terminal 4 of Madrid-
Barajas Airport in Spain. Two people were killed while at least 31 were injured during the incident. The
VBIED contained approximately 800 kg (1,800 pounds) of explosives, which, in addition to causing the
casualties, led to the partial collapse of the five-story parking garage.
The Basque separatist group ETA has claimed responsibility for the attack. The organization had
declared a permanent ceasefire on March 24, 2006; after the attack, ETA still insisted on respecting the
ceasefire.
A few days prior to the attack, the vehicle was stolen from southwestern France and later loaded with
the explosives. On December 29, the van was parked in unit D of Terminal 4 and the driver left the
airport by a taxi. The next day, approximately an hour before the explosion, the authorities were
informed by an anonymous caller warning about the event. Police were able to evacuate the area before
the van exploded. After the explosion, regular air traffic was suspended at Terminal 4 for several hours,
but flights at the other terminals were not affected by the event.
Demolition of the parking garage was required as the damage was uneconomical to repair.

Figure 2-3. Damage after the Madrid Airport Bombing Resulted in Demolition
Source: Enrique Dans/Flickr (CC by 2.0)
2.2.4 Other Notable Incidents
2.2.4.1 1975 – LaGuardia Airport Bombing

On December 29, 1975, an IED exploded in LaGuardia Airport in New York City, killing 11 people and
injuring 74. The explosive device was placed in a coin-operated locker in the baggage claim area in the
main terminal, populated with people. The explosion (equivalent to the force of approximately 20 to 25
sticks of dynamite) tore apart the locker, resulting in flying shrapnel that caused 11 deaths and injured
many others. It is suspected that Croatian nationals were responsible for the attack; however, the case is
still unsolved.
2.2.4.2 2011 – Moscow Domodedovo International Airport

A suicide bombing killed 37 people and injured over 100 others at Moscow Domodedovo International
Airport on January 24, 2011. The explosion occurred at the entrance of the international arrivals hall,
aimed at foreigners and Russians alike. It is thought that the perpetrator entered the building from the
parking garage, avoiding being screened by metal detection on his way to the arrivals hall, carrying 7 kg
(15 pounds) of explosives. A few days after the attack, Russia’s Investigative Committee announced that
the suicide bomber had connections with North Caucasus.

2.2.5 Example Explosive Sizes in Historic Attacks

Credible sources of explosive charge sizes used in PBIED attacks are not widely available. The official
account of the London July 7, 2005 bombings estimates the backpack-sized explosives used were
between 2 and 5 kg (5 and 11 pounds) of high explosives. This size is also similar to that found in the
analysis of the PBIED suicide belt detonated at the Domodedovo Airport in Moscow in 2011. The 2004
Madrid bombings are reported to have involved the use of backpacks each containing 10 kg (22 pounds)
of explosives.
The range of VBIED charge sizes also varies. Figure 2-5 shows estimates for historic events.
Figure 2-4. Timeline Showing Approximate VBIED Explosive Sizes for Significant Events
in Pounds of Equivalent TNT
Oklahoma
City:
4,000 lbs
Marriott
Beirut St. Mary Axe,
Hotel,
Embassy: London:
Jakarta:
2,000 lbs 800 lbs
480 lbs
1980 1990 2000 2010

Beirut Intl World Trade HSBC Bank,
Airport: Center, NY: Istanbul:
12,000 lbs 900 lbs 450 lbs
Manchester
City Center:
1,800 lbs
Source: FEMA 430, 2007 and Hadden, J.D. et al, 2007
2.2.6 Evolving Threats

Terrorists are constantly changing their methods of attack and targets; adapting quickly and creatively is
necessary to achieve their objectives. Our protection implementation must evolve or risk being outpaced
by innovative terrorists. For example, the Islamic State (ISIS) has made deadly adaptations to its use of
drones, including dropping bombs; drones are a relatively new technology but have become readily
available. The nature of terrorism is unpredictable, and methods of delivery are also hard to predict.
Although the greatest progression in creation of successful IEDs and target-shifting to the civilian
population has been seen in Iraq, the rest of the world should remain aware of the tactics and
technologies being used there, as the methods developed may spread globally. Recently, terrorist groups
such as al-Qaeda have implemented changes in their organizational learning by utilizing the internet and
social media to transfer knowledge (of bomb-making, for example) to a broader base of followers.
Denying access to explosives is the first step in the reduction of IED incidents. However, when
traditional explosives become difficult to obtain, bomb makers will adapt and turn to other materials,

such as common chemicals, as precursors to manufacture explosives. Although legislation has been
considered to restrict access to these chemicals and some has passed, it is not effective and is not
expected to remove all chemicals that may be used to make explosives from retail shelves. Where
legislation is not successful, increased information-sharing between intelligence agencies, law-
enforcement, and first responders is recommended to help disrupt the process of bomb makers.
Because terrorist events are unpredictable and data about historic events is limited, it is not possible to
accurately quantify the savings achieved from blast-mitigation strategies. Although there is merit in
making it more difficult for terrorists to achieve their objectives, intelligence suggests that IED attacks
will continue and evolve in regard to both composition and method of delivery, the latter in order to
attempt to bypass security measures. Implementing blast-mitigation strategies, therefore, may not be
able to prevent all attacks, but an achievable objective is to reduce the likelihood and severity of such
attacks.
2.3 Introduction to Technical Blast Concepts

Protecting against explosive threats requires identification of credible threat scenarios, within reasonable
ability of prediction. For example, a terrorist wearing a suicide vest will carry out the attack in a
different way than a terrorist who has loaded a vehicle with explosives. Based on analysis of previous
attacks, the former is often permeating into the terminal building or plaza areas, targeting crowds of
people, and the latter is often an abandoned vehicle left in a location where detonation could cause
structural collapse. Because there are significant differences in threat scenarios, development of criteria
for damage acceptance should be similarly distinct.
For example, operational downtime targets for a small blast event should be very low. Impacts of the
event should be contained to the immediate affected area so that operations can continue largely
unaffected in other areas. However, for a large blast event, operational downtime targets may range from
a day to a few days, as the blast event may render a structure too dangerous for personnel. Redundancy
and contingency plans for resuming operations are important factors in this latter case, as well.
Furthermore, the post-attack needs of law enforcement agencies will impact recovery efforts.
Therefore, it is as important to specify reasonable and achievable performance criteria as it is to specify
credible threat scenarios. It is typically expected that the risk assessment process will identify the
design-basis threats (DBT) and performance criteria; however, sometimes additional follow-up after the
risk assessment process is required to define specifics needed before designing can proceed. The
following sections provide information on this topic.
2.3.1 Design-Basis Threat

DBTs are the credible and probable attack scenarios against which something should be designed.
Strictly speaking, in blast-resistant design, specifying a DBT ultimately includes identifying the
following:
• Explosive size charge, in pounds of TNT equivalence

• Standoff, i.e., the distance between the asset or target and the origin of detonation
Although equivalent TNT size charges are used to define the DBTs, due to tight control and limited
availability of these explosive materials, terrorists often use IEDs. These are usually a mix of homemade
explosives and commercially available chemicals, such as agricultural fertilizer and household cleaning
chemicals. In some extreme cases, nails and other similar sharp metallic objects are included in the
explosive mix to increase the damage efficiency and injury radius. The predictability of these devices is

low, particularly in regard to impacts from shrapnel; a blast engineer/consultant will be able to make
estimates to define the DBTs appropriately. If a type of explosive other than TNT is specified, data from
various reference books can be used to convert the explosive to its TNT equivalent. One such reference
is Blast Effects on Buildings, 2nd edition, by D. Cormie, G. Mays, and P. Smith (2009).
To determine the standoff, the means and methods of the attack should be considered to identify specific
locations where the origin of detonation may occur. These details may be developed through conducting
a threat, vulnerability, and risk assessment (TVRA). A TVRA is a risk assessment and threat
identification exercise that identifies the most credible level of threat to which an asset, such as a
building or parking garage, may be vulnerable. This assessment is usually led by a security consultant
with expertise in understanding the current threat trends and recent attacks. To ensure the TVRA
captures the full spectrum of potential threats and all the development vulnerabilities, it is imperative
that all project stakeholders and relevant design disciplines attend the workshop or consultation. This
type of workshop can be hosted and facilitated by a blast engineer/consultant with aviation experience.
Table 2-1 provides benchmark DBTs based on Arup’s global experience in blast mitigation of airports.
Table 2-1. Common Blast Design-Basis Threats Used for Airports
VBIED PBIED
Charge Charge
Standoff Standoff
Weight Weight
(feet) (feet)
(pounds) (pounds)
200 100 10 3
500 100 25 3
1,000 100 50 3
2,000 100 75 3
2,000 150 100 3
2.3.2 Performance Criteria

Performance criteria for blast threats identify objectives to achieve in the event of a particular DBT
scenario. It is common for these objectives to refer to physical or structural performance of the building
and the facade; however, performance criteria may also refer to operational requirements such as
downtime. Performance criteria must be identified for designers so they know the extent of mitigation
measures that should be incorporated (e.g., 1-inch or 3-inch-thick glass).
Blast performance criteria are often categorized in terms of a “level of protection.” Terminology such as
performance criteria, level of protection, acceptable damage, and response limits are all similar
concepts and define the response of a structure, element, building, or even operations objective in the
event of a blast.
2.3.2.1 Background
The objectives of existing guidance are best summarized by Chapter 3.2 of ASCE 59-11, which is a
technical reference for blast mitigation, primarily focused on structural hardening:

• Limit Structural Collapse. All structural elements shall be designed and detailed to respond in
a manner consistent with the defined level of protection to the direct and indirect effects of the
specified explosive threats in accordance with this Standard. When these blast effects are
expected to cause plastic hinging or localized failure of individual structural elements, the
damaged state of the structural system as a whole shall be evaluated to verify that global stability
is maintained.
• Maintain Building Envelope. All exterior structural and nonstructural elements, including
openings, shall be designed and detailed to reduce the potential of a breach that would allow the
overpressures from the specified exterior explosive threats to enter the interior of the building,
consistent with the defined level of protection. For facade components, including windows and
doors, both resistance-based and hazard-based design approaches shall be acceptable.
• Minimize Flying Debris. Barriers, site furnishings, landscaping features, and structural and
nonstructural elements, including exterior openings such as windows and doors, and interior
overhead mounted items, shall be located, designed, and detailed to reduce the potential for
producing hazardous secondary fragments due to the specified explosive threats, consistent with
the defined level of protection.
These objectives relate principally to the design (hardening) of building structures and are substantially
(although not exclusively) related to the design of such structures to resist vehicle-borne attacks or
attacks specifically targeted at the building structure.
This is often specified as a “level of protection.” Examples of level-of-protection tiers are specified
within ASCE 59-11, as described in Table 2-2 and shown in Figure 2-5.
Table 2-2. ASCE Levels of Protection
ASCE 59-11
Level of Description of Performance Expected Structural Damage
Protection
Collapse prevention; surviving occupants will likely be

Damage is expected, up to the
able to evacuate but the building is unlikely to be safe
I (Very Low) onset of total collapse, but
enough for them to return; contents may not remain
progressive collapse is unlikely.
intact.
Damage is expected, such that
Life safety; surviving occupants will likely be able to
the building is not likely to be
II (Low) evacuate and then return only temporarily; contents will
economically repairable, but
likely remain intact for retrieval.
Property preservation; surviving occupants may have to
Damage is expected, such that
evacuate temporarily but will likely be able to return after
the building is likely to be
III (Medium) cleanup and repairs to resume operations; contents will
economically repairable, and
likely remain at least partially functional but may be
impaired for a time.
Continuous occupancy; all occupants will likely be able
Only superficial damage is
IV (High) to stay and maintain operations without interruption;
expected.
contents will likely remain fully functional.

Figure 2-5. Graphical Representation of Performance Criteria
Source: Arup
Although the wording to define a particular tier of performance may vary among industry guidance
documents, the principle of performance criteria is the same. Performance criteria or objectives can be
defined in accordance with any applicable document, or even modified as required to meet owners’
needs.
2.3.2.2 Setting Performance Criteria

As demonstrated above, there is a sliding scale for desirable performance that is more complex than
simply requesting a “blast-resistant” design. In order for designers to develop mitigation strategies,
specific performance criteria regarding blast-resistance need to be identified by the airport, as this
influences the types and quantities of measures that are incorporated into the design. This section of the
guidebook provides guidance on identifying those criteria.
PARAS 0004 recommends targeting a Medium level of protection in a blast event as a starting point.
Performance criteria are typically defined for each DBT scenario and will be different based on each
airport’s desired objectives and risk tolerance.
This concept is best explained using an example: A relatively higher level of protection is often
specified for a PBIED threat than a VBIED threat. This is because in the event of a PBIED threat, an
airport may desire the event to be contained to the area where the incident occurred, and operations
should continue in the remainder of the concourse. In contrast, for a VBIED threat, which may have
significant structural impacts and require a large emergency response, specifying a higher level of
protection would become extremely onerous on the design. Furthermore, although the consequences of a
VBIED event may be higher than a PBIED event, the likelihood of a VBIED is often much lower due to
the amount of explosive material needed to be gathered and successfully detonated without being
caught. Therefore, these items are considered in an airport’s risk appetite.
2.3.3 Expected Damage

The extent of physical enhancements to either facade or structure varies based upon the following:
• Size of the DBT

• Available standoff to the element being considered
• Performance criteria required
Often decision-makers are not aware of the physical and cost implications of enhancing their structure or
facade when choosing a basis for design. Figure 2-6 illustrates a simplified relationship among DBT,

standoff, and reasonable mitigation measures. The graphic focuses only on facades and columns, which
generally are the most critical components for blast mitigation.
The curves represent the applicability of various types of enhanced measures, showing what can be
reasonably achieved in terms of threat size and standoff. The area under the curves represents the
scenarios whereby such a measure would not typically meet a reasonable performance. For example, it
is not generally commercially feasible to mitigate high threat sizes at relatively low standoffs while still
maintaining a high level of protection. This graphic is indicative only and is aimed at providing context
for decision-makers in the early stages of a project. Further information on the construction details
shown can be found in Appendix D.

Figure 2-6. Demonstration of DBT and Performance of Varying Levels of Enhancement
Source: Arup

2.4 Introduction to Blast Analysis

Once the DBT and performance criteria have been established, the next step in the design process is to
perform the actual blast analysis. Blast analysis is a multistep process that begins with the determination
of the blast loading, progresses into preliminary calculations, advances to coordination with other design
disciplines, and culminates with final design analysis as part of the final building documents.
Blast analysis is a unique subset of structural engineering. When a structural engineer designs a
structure, they are designing a building to last over time without any damage. A blast analysis is
designed typically to protect the facade and structure enough for people to evacuate the building;
however, it is expected that major reconstruction will be required after an event. In this situation, the
blast analysis is allowing certain failure under this unique scenario, while the structural engineer is
designing for no failure under conventional load scenarios (wind, snow, etc.)
Blast analysis is typically required when either of the following takes place:
• A blast vulnerability assessment of an existing building is performed to understand what the

existing building is “good for”
• Physical blast-mitigation measures such as facade enhancements or structural resiliency are
identified as required to reduce risks
When blast protection of a building is required as determined by regulatory requirements or desire by

the risk owner (typically the owner/operator for airports), analysis is performed to understand and
mitigate the blast risk through design options.
The first step is to calculate the applied pressure on the surface to be analyzed. As discussed in Section
2.1, there are three parameters needed: threat size, standoff, and line of sight. With this information,
several computer programs can be utilized to calculate the blast loading profile: pressure, impulse, and
time duration. See Figure 2-7 for example output.
Figure 2-7. Sample Calculation of Blast Loading
Source: Arup
The second step in the analysis is to perform preliminary calculations based on design parameters from
other design professions. For example, the blast engineer will work with an architect on the facade
system: glass size, mullion spacing, and the supporting structure. Once these parameters are understood,
a single degree-of-freedom (SDOF) analysis is performed. SDOF takes a complex analysis and
simplifies an element into a mass (weight of member) and spring (strength of the member).

See Figure 2-8 for a depiction of the mass-and-spring concept. The blast load [p(t)] is applied to the
mass (m) and the deflection of the spring (k) is calculated. The deflection is the maximum distance the
blast load was able to pull the mass based on the resistance strength of the spring. That deflection is then
compared to an allowable deflection, based on the design criteria, to determine if the member (i.e., its m
or k) needs to be enhanced.
Figure 2-8. Single Degree of Freedom
Upon completion of the preliminary calculations, it is likely that some changes to the design need to be
made. This could be as simple as providing a cost-effective enhancement—heavier beams or thicker
glass. However, sometimes the designing engineer needs more of an in-depth study on the overall effect
of the analysis on the project. If a cost-effective design solution is unachievable, the team can reevaluate
some of the initial assumptions in the design. This could include the standoff, threat size, level of
protection, etc.
Depending upon the project site, gaining more standoff might not be achievable without major
alterations to the design or function of the facility, especially in existing facilities. Increased standoff is
typically incorporated by adding curbs or vehicle barriers. In any project condition, increasing standoff
is difficult, as land is a valuable commodity in any design. However, it can be a key aspect to the design
and aid in significantly reducing hardening costs to the facility.
During this design process, if warranted, a more detailed analysis could be performed above the SDOF.
These processes take additional engineering time but may result in an overall cost savings to the project.
The most common analysis is multiple degree-of-freedom (MDOF). In this approach, the SDOF model
is applied in a series of elements. For example, the analysis is first performed on the glazing, which will
result in some absorption of the blast load. The glazing reaction is then applied to the mullion, so the
mullion resists less energy than if analyzed as a SDOF element. See Figure 2-9 for an example of
MDOF.

Figure 2-9. Multiple Degree of Freedom
Lastly, the most detailed analysis is a finite element analysis (FEA). In a finite element model, the
member to be analyzed is subdivided into much smaller, simpler parts called finite elements. Then, the
simple equations that model these finite elements are assembled into a larger system of equations that
models the entire member. Although more time-intensive, FEA is typically required when complexities
exist, such as close-in detonations, curved or atypical geometries, or a need to understand details of
performance.
Figure 2-10. Finite Element Analysis
Source: Arup
Upon completion of the analysis, the last step in the design process is to incorporate all the blast design
requirements into the construction documents. Most of the structural items such as slabs, beams, and
columns are incorporated into the construction documents’ drawings. Non-structural items like
windows, precast panels, etc. are incorporated into the construction documents’ specifications.

2.5 Design and Procurement of Blast-Mitigation Measures

The incorporation of blast-mitigation strategies should be reviewed for all landside projects on a risk
basis. The likelihood, credibility, and consequences of such events that might occur at a specific airport
will determine what types of blast-mitigation measures should be incorporated.
The need for a blast-mitigation strategy may not be immediately obvious, as some projects inadvertently
introduce or increase the risk to the airport even if there is no apparent security scope. For example,
changing the design of an approach road could inadvertently increase the attractiveness of a building as
a target, or the road design could allow for increased vehicle speed and therefore greater consequences
in the event of a penetrative VBIED attack.
2.5.1 Roles during the Design Process

Traditionally, physical security experts and blast engineers are the primary disciplines involved in the
development of a strategy to defend the structure against a blast attack. However, as technology has
significantly improved security capabilities, greater flexibility is desired to respond to changing threats
quickly; there is an increasing recognition of the value of and reliance on operational security measures;
and there is increasing pressure on airports to address other business objectives, such as architectural
design. Greater benefits can be achieved if the design process includes close collaboration between the
various security and planning stakeholders. Thus, the approach to incorporating blast-mitigation
strategies should include physical, technological, and operational security stakeholders, as well as
designers and planners. As discussed in detail in Section 5, an effective blast-mitigation strategy will
encompass measures from all of these areas.
The aim of retaining a threat and risk specialist as well as a blast engineer or consultant is to achieve the
following key objectives:
1. Seek expert advice in identifying the real and credible threats, vulnerabilities, and risks of the
asset in consideration. This facilitates evidence-based understanding of the risks, therefore
allowing objective allocation of limited resources.
2. Reduce cost through use of limited resources targeted to the airport’s unique risks, thus avoiding
one-size-fits-all security measures, which can result in wasted resources or counterproductive
measures.
3. Facilitate continual and informative engagement between the client stakeholders, designers,
security consultants, law enforcement, and other relevant stakeholders.
4. Improve security by helping clients and designers mitigate the risks of a blast threat. This
includes advising the client on feasible physical mitigation measures, and often is followed by
blast analysis to design the measures. Although the blast consultant traditionally specializes in
physical measures, in collaboration with a security engineer, technological or operational
measures can also be identified where they should be incorporated to supplement physical
measures.
The advice from the specialist will initially help the client assess the real and credible threats and the
corresponding risks posed. Unfortunately, not all threats can be eliminated, but in many cases the risks
can be managed and mitigated through physical protective measures and targeted use of limited
resources.
Apart from providing expert advice and assisting in eliminating or mitigating the blast threats, a blast
engineer/consultant can also be sought to bring the project cost down by helping the clients and
designers understand the project’s real threat and produce a final design that is neither under- nor

overdesigned. Moreover, early engagement can flag security issues that may be easily solved during the
early phases of a project, potentially through other design disciplines, such as landscape architecture and
surface transport design.
Table 2-3 shows the design and construction timeline airports should follow for incorporating blast-
mitigation measures in design projects from initiation, through planning and development, to
implementation in construction. Continual engagement between airport stakeholders, designers, and the
blast consultant throughout the process is necessary. The benefit of spending this additional time can be
difficult to perceive, but it is instrumental in delivering a successful security strategy with measures that
are utilized effectively.
Table 2-3. Design Process Timeline
Phase Airport Role Design Team Role
The airport project management or planning

team should engage the airport's physical,
Project Airports may find it worthwhile to engage an
technological, and operational security
Initiation; external threat and risk specialist and blast
stakeholders to ensure blast requirements
Request for consultant to facilitate the identification of
are adequately captured within the RFP.
Proposal credible threats, credible risks, DBTs, and blast
Improperly specified or unclear requirements
(RFP) requirements, which vary based on the airport's
could result in major bid differences or
Development risk profile and appetite.
proposals that do not achieve the airport's
security objectives.
The design team, including blast and security consultants, the architect, and aviation planners,
should engage with relevant airport stakeholders in development of a security strategy that
responds to the risk assessment outcomes and meets the airport's risk appetite.
Combinations of mitigation-measure options should be considered at a high level using the
Conceptual framework process outlined in Section 5 of this guidebook. This includes preliminary
Design assessment of operational, technological, and physical measures. Impacts of various measures
should be interrogated across disciplines to identify potential conflicts or opportunities to design
out vulnerabilities early in the process.
Reasons for decisions should be documented so that the purpose of various measures can be
revisited in case modifications are required.
Mitigation measures should be developed by
the design team in consultation with the
security consultant and/or airport security
The operational security strategy should be team.
developed by the airport's security and law If required, blast analysis and technology
Design enforcement groups, with collaboration from
Development system design is to determine architectural,
an external consultant if desired. structural design, IT, and communications
through
Construction Airport stakeholders should periodically requirements and is to be coordinated with the
Documents review the mitigation measures developed by relevant design disciplines.
the design team and how these change the The design team should remain engaged with
risk assessment. the airport stakeholders to ensure that the
airport's operations and commercial and
security objectives, including risk appetite
threshold, are being met throughout the design
developments.

Phase Airport Role Design Team Role
The design team's blast consultant should

Procurement verify that all blast-mitigation strategies that are
and The airport will be involved in the bid process
to be designed by others are properly specified
Construction and liaise with the design team as needed to
in the construction documents. Clear
clarify RFIs.
identification of blast requirements, particularly
deferred design submittals, is imperative.
Integrate and apply technological and
operational measures. Airport security should
actively monitor and evaluate their
effectiveness and make modifications as Retaining the security and blast design team
necessary. for periodic review may be worthwhile to
Integrate and ensure the airport is aware of the latest
Evaluate Revisit the risk assessment periodically to methodologies and measures, and to
consider whether changes should be made or recommend modifications to the measures if
new measures should be introduced. The needed.
framework in Section 5 of this guidebook can
be used to consider costs and benefits of
changes to the blast-mitigation strategy.
2.5.2 The Procurement Process

Procurement of blast mitigation and physical security measures must be discussed at the earliest stage of
design. Multiple construction elements could be designed differently, depending on perceived
construction challenges at existing facilities.
Depending upon the potential staging of the work to keep most of a facility open, the proper restrictions
need to be adequately conveyed to the contractor facilitating the work. This would include noise and
time restrictions. If the work is going to occur only at night or during off hours, this will have to be
indicated because exterior work becomes more challenging without adequate lighting and additional
construction lights would be required. Subject to the location of lighting, this may have flight operations
implications. Additionally, it may influence the security risks to the airport, and this will need to be
mitigated accordingly (e.g., works that straddle the airside-landside boundary are most likely to require
additional guarding resources for supervision and inspection purposes).
If certain clearances and daily screening are required, this must be properly specified. For example, if
the contractor must plan over 30 minutes just to mobilize every day to get through screening and onto
the construction side, this needs to be conveyed to avoid additional costs for the contractor.
Furthermore, any travel lane restrictions need to be thought out in advance. If an airport has an overhead
roadway for departures and a roadway for arrivals, the phasing needs to be coordinated so that the areas
of construction are secured on both roadways simultaneously.
Impact on emergency response procedures during the construction period should be considered and
adjustments made in consultation with the relevant agencies. For example, whether or not construction
could change the location of emergency muster points or interfere with the usual emergency response
vehicle access is a possible consideration.
The construction documents should contain as much existing information as possible, including a
security-during-construction strategy. While unforeseen conditions can occur at any existing facility,
selective demolition during the design phase will prove to be a more cost-saving measure than trying to

redesign elements after the contractor has mobilized. Any delay during construction has been reported to
cost 10 or more times what could have been saved with some prudent investigations earlier in the
process.
For a vendor-supplied blast-mitigation product, a detailed specification is mandatory. The specification

needs to properly describe the blast loading, acceptable damage limits or performance criteria, and
acceptable design techniques for each product that will be designed and supplied by a vendor. For
example, the specification should not say “provide a low level of protection” window system. This will
lead to a contractor-favored interpretation and may not provide the security outcome or mitigation to the
airport’s risk appetite threshold as was expected during the design process. The specification
requirements should either be incorporated within the standard product specification or, if a standalone
blast specification is produced, be properly cross-referenced.
During the submission process, the owner and design team may need to be willing to accept slight
variations from the construction documents to accommodate vendor-specific products. For example,
most blast-tested window mullions are 2.5 inches wide and either 7.5 or 10.5 inches deep. However,
some vendors only use a 3-inch-wide mullion, which may be more cost-efficient and could be an
approved alternative. If the sight line is a requirement, the specification needs to be strict in the language
and should not include the approved equivalent alternative language.
Additionally, if there are any restrictions due to existing conditions that need to be included in the
drawings and specifications, they should be clearly stated. For example, it might be a requirement to
limit the reaction of a mullion to an existing concrete wall because the wall will not work under a higher
reaction. It is incumbent upon the blast engineer during design to verify that a product can be supplied to
meet the specification. Providing clear documentation ensures that vendors cannot provide a cheaper
alternative that might overstep the limitations of the existing conditions.

SECTION 3: COMPLIANCE AND RISK-BASED REQUIREMENTS
All security measures to be applied at an airport are determined by the need to do the following:
• Comply with legislation and national and airport policies.

• Reduce or accept risks that exceed the airport’s risk appetite. This is achieved by the following
risk-mitigation process: determining the risks that are unique to the airport/site; agreeing on
which of those risks that exceed the airport’s risk appetite threshold can be feasibly reduced or
must be accepted; identifying risk reduction measures; conducting a comparative analysis to
determine which measures are most appropriate to be applied; securing resources to apply those
measures; and implementing and monitoring the effectiveness of the measures.
Historically, the non-secure area of airports has not been security-regulated and, consistent with the
global trend towards risk-based and outcomes-focused security measures, it would be prudent for
airports to manage the area on the assumption that this will not change. Airports should therefore take a
risk-based approach to determining the security measures, including blast protection, in the non-secure
area.
This section is intended to help airports determine whether they need blast mitigation.
3.1 International Requirements and Risk-Based Approach to Non-Secure Area

Security
The ICAO is the specialized United Nations agency responsible for setting the Standards and
Recommended Practices (SARP) for civil aviation in accordance with the Convention on Civil Aviation,
commonly referred to as the Chicago Convention. ICAO’s remit is expansive and includes, but is not
limited to, meteorology, safety, search and rescue, facilitation, and security. The SARPs that pertain to
security are documented in Annex 17 Facilitation and Annex 9 Facilitation, with those relating to
landside security in Annex 17.
Contracting States (states who are signatories) to the Chicago Convention commit to apply (comply
with) the SARPs by establishing and maintaining their national aviation program in accordance with the
Standards, and will endeavor to apply the Recommendations. States do this by ratifying the SARPs.
The responsibility to align with the SARPs lies with the State’s Appropriate Authority. The Appropriate
Authority is responsible for the development, implementation, and maintenance of the national civil
aviation security program. It is the Appropriate Authority that is to comply with Annex 17 (not airports
or airlines). The Appropriate Authority is usually, but not always, the aviation security regulator.
Annex 17 is drafted to be outcome-focused. It is the responsibility of each State to determine how to
best apply the SARPs based on its national risk assessment. This expectation is stated in Standard 3.1.3:
Each Contracting State shall keep under constant review the level of threat to
civil aviation within its territory, and establish and implement policies and
procedures to adjust relevant elements of its national civil aviation security
programme accordingly, based upon a security risk assessment carried out by the
relevant national authorities.
Many States have adopted this outcome-focused approach to their own national program—they are
requiring industry to conduct their own risk assessments, drawing on national threat and risk information

to determine the measures that are necessary to reduce the risks that they identify and that exceed their
own risk appetites. This is increasingly prevalent in relation to the landside security risk. But unlike the
typical response to past terrorist threats, e.g., liquids, aerosols, and gels, Appropriate Authorities have
not issued prescriptive regulation following the high-profile landside attacks such as Glasgow (2009),
Brussels (2016), Istanbul (2016), and Fort Lauderdale (2017). This risk-based approach is consistent
with ICAO’s intent.
While outcomes-focused, ICAO is not silent on the landside security risk with the following SARPs
directly relevant to landside:
Standard 3.1.5 Each Contracting State shall establish a national aviation security
committee or similar arrangements for the purpose of coordinating security activities
between the departments, agencies and other organizations of the State, airport and
aircraft operators, air traffic service providers and other entities concerned with or
responsible for the implementation of various aspects of the national civil aviation
security programme.
Standard 3.2.4 Each Contracting State shall ensure that airport design requirements,
including architectural and infrastructure-related requirements necessary for the
implementation of the security measures in the national civil aviation security
programme, are integrated into the design and construction of new facilities and
alterations to existing facilities at airports.
Standard 3.2.2 Each Contracting State shall ensure that an authority at each airport
serving civil aviation is responsible for coordinating the implementation of security
controls.
Standard 3.2.3 Each Contracting State shall ensure that an airport security
committee at each airport serving civil aviation is established to assist the authority
mentioned under 3.2.2 in its role of coordinating the implementation of security
controls and procedures as specified in the airport security programme.
Standard 4.8.1 Each Contracting State shall ensure that landside areas are identified.
Standard 4.8.2 Each Contracting State shall ensure that security measures are
established for landside areas to mitigate the risk of and to prevent possible acts of
unlawful interference in accordance with risk assessments carried out by the relevant
authorities or entities.
Standard 4.8.3 Each Contracting State shall ensure coordination of landside security
measures in accordance with Standards 3.1.5, 3.2.2 and 3.2.3 between relevant
departments, agencies, other organizations of the State, and other entities, and
identify appropriate responsibilities for landside security in its national civil aviation
security programme.
The United States became a Contracting State in 1944 and the Appropriate Authority is the TSA. The
United States has ratified the security-related SARPs through the following legislation:

• 49 CFR 1540 – Civil Aviation Security: General Rules

• 49 CFR 1542 – Airport Security
• 49 CFR 1544 – Aircraft Operator Security: Air Carriers and Commercial Operators
• 49 CFR 1546 – Foreign Air Carrier Security
• 49 CFR 1548 – Indirect Air Carrier Security
• 49 CFR 1550 – Aircraft Security Under General Operating and Flight Rules
• 49 CFR 1560 – Secure Flight Program
In the United States, and most other nations, there are no regulatory or legislative requirements
explicitly for blast protection; actual implementation of risk reduction (including security or blast-
specific) measures typically lies with the “industry” or service providers, such as airport owners or
operators. Those risk-reduction measures should be guided by the national civil aviation security
program and their own/operator security risk assessment.
One exception to the above is Singapore: Singapore’s Infrastructure Protection Act requires selected
new buildings to integrate counterterrorism security measures, including blast mitigation, within their
designs as of September 11, 2017. The bill recognizes that buildings that house essential services, are
iconic, or have a high density of persons could be targeted by terrorists and therefore require adequate
building security measures in place. Specific measures such as video surveillance, security personnel,
vehicle barriers, and strengthening the building against blast effects are noted as efficient ways to secure
a building if implemented during design.
3.2 The Risk Assessment Process

As described above, ICAO sets outcome-based targets for landside areas but leaves the implementation
to individual States (i.e., countries). ICAO does not define landside, rather requiring through Standard
4.8.1 the Appropriate Authority to ensure this done. That said, in the past, ICAO has defined landside as
“The area of an airport and buildings to which both traveling passengers and the non-traveling public
have unrestricted access.”
Facilitating aviation security across the industry requires understanding the threat, conducting risk
assessments, determining risk appetite thresholds, and applying risk-reduction measures. Given the
systemic nature of the aviation industry, these activities will occur at different levels: international,
national, operator, and individual.
Figure 3-1 illustrates a risk-based approach to determining local/operator-level risk-reduction measures
in the context of the national aviation security framework:

Figure 3-1. Determining Risk Reduction Measures at the National and Operator Level
Compliance with the national civil aviation security program is assessed by the regulator. As States
increasingly move to outcomes-focused regimes (i.e., the risk-reduction measures are determined by the
operator based on their own risk assessment), the regulatory focus is likely to shift to (a) the quality of
the risk assessment and (b) the effectiveness of the applied risk-reduction measures.
In other words, States, via the Appropriate Authority, are expected to comply with Annex SARPs. It is
the Appropriate Authority that is audited by ICAO. The industry is not expected to comply with SARPs
but is expected to comply with the national aviation security framework. It will be the national aviation
security regulator, typically the Appropriate Authority, who will audit the industry.
Figure 3-2 illustrates the national aviation security framework and how the entities and key documents
relate to each other.
Figure 3-2. The International Aviation Security Framework
The individuals are typically employees or suppliers to the industry/operators. In order to implement the
necessary risk-reduction measure, the operators are reliant on those individuals to have the knowledge,
competence, and empowerment to act as appropriate to the policy and procedures set by the operator.
As described above, the international aviation security framework commences with a state becoming a
Contracting State by way of signing the Chicago Convention. It ratifies that Convention through the

enactment of legislation and establishment of an Appropriate Authority who is responsible for

establishing and maintaining a national aviation security program. The national aviation security
program is informed by a national risk assessment and complies with Annex 17.
Industry is then required to identify, develop, and implement their security risk-reduction measures in
accordance with their own operator risk assessment and national aviation security program. Individuals
engaged with the operators are provided with the knowledge and apply necessary skills to implement the
policies and procedures set by the operators. For auditing purposes, ICAO audits the Appropriate
Authority and the regulator, typically the Appropriate Authority, audits industry.
3.3 United States Compliance Requirements

Commercial airports are considered operational when issued a Federal Aviation Administration (FAA)
airport certification identified in 14 CFR 139 and supplemental FAA Advisory Circulars. As part of 14
CFR 139, a Federal Security Director is an identified TSA official who reviews and approves the
Airport Security Program (ASP). The ASP documents how the airport will meet the security
requirements identified in 49 CFR 1542. In addition to the ASP, FAA regulations require the airport to
develop a safety and security plan that incorporates hazard reporting, risk assessment, risk mitigation,
and assurance processes.
The safety and security plan includes a comprehensive risk assessment, covering everything from
terrorism to birds on the runway. The ASP is updated at minimum annually or sooner if there are
significant changes to the airport or terminal. In addition, when specific national and global threats are
identified, airports should consider a targeted risk assessment to adjust their security program to address
the specific threat. The complexity or level of the risk assessment is not defined, and airports complete
various levels of risk assessments each year as is deemed the best fit. TSA reviews the ASP annually or
sooner if significant changes warrant review.
3.4 Note about Blast Risks

Through the airport interviews, investigators observed that converting risk assessments to specific
security measures is not typically considered or undertaken, despite the benefits that it brings:
• Objective and justified investment decisions

• Alignment of security risk management with the airport’s overall enterprise risk appetite
• Ability to transparently demonstrate how much risk reduction a measure can buy (i.e., the risk
return-on-investment)
o Determines risk-mitigation measures unambiguously
o Allows for proportionate investment in security (versus under-resourcing or over-
engineering)
Contrary to many other security risks, such as theft and vandalism, terrorism and particularly blast
attacks can have catastrophically severe consequences. Airports should keep in mind that achieving
higher levels of protection against large, credible blast threats is unfeasible and impractical in many
cases. Substantial reductions in risk are possible; however, defining blast performance criteria too
onerously can quickly kill a project entirely due to financial infeasibility. This would have the opposite
effect than what is desired, as providing a baseline level of protection against blast risks is always
viewed as a better solution than not providing protection at all. Therefore, carrying out a risk-based
approach is recommended to be done in collaboration with a blast engineer or consultant who can advise
on this topic.

SECTION 4: MITIGATION MEASURES
This section is intended to help airports determine which blast mitigation measures are needed,
including physical, technological, operational, and other related mitigations such as architectural layout
and crowd management. The user should consider which measures are possible for implementation at
their airport. In Section 5, these possible measures are analyzed using a decision-making process to
determine the most effective strategy.
In addition to the measures within this section, the reader may want to consult other relevant publicly
available references that include information on blast-mitigation measures:
• PARAS 0004: Recommended Security Guidelines for Airport Planning, Design and
Construction
• ACI Landside Security Handbook, First Edition
• FEMA 427: Primer for Design of Commercial Buildings to Mitigate Terrorist Attacks
• Blast Effects on Buildings, Second Edition, by Cormie, et al.
This section outlines many of the blast-mitigation measures that can be employed. A holistic blast-
mitigation strategy is most effective when various types of mitigation measures are combined as shown
in Figure 4-1.
Figure 4-1. Various Measures That Shape a Blast-Mitigation Strategy
Physical
Measures
Holistic Architectural
Technological Blast- and Crowd
Measures Mitigation Management
Measures
Strategy
Operational
Measures
Physical measures generally take the most time to provide protection, as the design and construction
process may exceed the time required to hire additional operational staff, for example. Additionally,

although modifications can be made, they are also the least flexible type of measure in adapting to
changing threats. However, physical measures are capable of defending the asset and providing
protection as a last layer of defense in a security strategy. They also offer the most predictable
performance, not being subject to human error and not requiring active management to protect. What
might be surprising is that, although physical measures require a high initial investment, they require
little or no recurring expenditures over many years, resulting in average costs being the lowest of the
different types of measures.
On the opposite spectrum, operational measures are generally the quickest to implement, the most
flexible and the most adaptable. However, although operational measures provide some level of
deterrence, they do not provide a reliable defense on their own. They are highly dependent on the
effectiveness and response of particular individuals and are subject to human error. Also, providing an
additional security staffing position is relatively expensive.
Technological measures lie somewhere in the middle of the spectrum. In addition to the cost of the
technology and IT equipment, staffing is almost always required for active monitoring of systems. This
renders technological measures on average to be the most expensive of the three. However,
technological systems overall are the most effective in protection, able to offer deterrence, delay, and
detection capabilities with a relatively high degree of efficiency. Further, technological measures can be
implemented relatively quickly, especially if a robust IT structure is already in place. They are also able
to be implemented in almost any area of the airport and offer capabilities that can detect all types of
blast threats.
If designed-in, architectural measures such as roadway layout, terminal layout, thoughtful space
configuration, and pedestrian and queue planning require some design costs, but are relatively
inexpensive. Architectural design that incorporates principles of security can be effective in reducing
risks, but is typically not sufficient on its own.
The benefits of various measure types are summarized in Table 4-1, demonstrating that a holistic
approach incorporating all types of measures is necessary to meet protection needs and balance
implications. This matrix is just an overview to demonstrate the concept of a holistic strategy—many of
the categories are more complex than conveyed in this table.
Table 4-1. Capability Comparison of Various Measure Types
Not
Can be
Impact on subject Ability Ability Ability Ability
Measure Low Quick to Easily
Passenger to to to to to
Type Cost Implement Modified
Experience human Deter Detect Disarm Defend
Later
error
Physical X X X X
Technological X X X X
Operational X X X X X X
Architecture X X X X X

4.1 Physical Measures

This section describes common structural enhancements that can be adopted to mitigate a blast threat:
• Reinforced concrete (RC) detailing

• Structural steel detailing
• Progressive collapse resistance
• Building envelope
• Hostile vehicle mitigation (HVM) barriers
As discussed in Section 2, protection of critical structural members is the primary goal, and protection of
non-structural elements is secondary. Therefore, there is significant discussion regarding RC and
structural steel enhancements.
4.1.1 Reinforced Concrete Detailing

RC elements designed to withstand blast threats can tolerate large magnitude deformations over a short
duration. During this large deformation, the concrete cracks and high stresses occur in the member until
the load subsides and the member reaches equilibrium. To handle the large deformations, the
reinforcement detailing found in blast-resistant structural elements differs from the reinforcement found
in conventional RC structures; particular detail should be put into the connection design. Therefore, it is
important that advice from a blast engineer or consultant is sought throughout the design stage or retrofit
of RC structures and appropriate reinforcement detailing is implemented in the final RC design.
Spall of concrete is the structural phenomenon that describes the breaking and scabbing of concrete on
one side of a RC member, induced by a blast shockwave of high magnitude. As shown in Figure 4-2,
spall occurs when the blast shockwave travels through the section, reaches the opposite face, and causes
the tension capacity of the concrete to be exceeded. An example of a freestanding RC wall that
experienced spall is presented in Figure 4-3.
Figure 4-2. Blast Shockwave Propagation through the Figure 4-3. An RC Panel Damaged by Spall
RC Member, Which Induces Spall
Source: “Spalling of concrete subjected to blast

loading” by M. Foglar and M. Kovar (CC 2.0)
Source: Adapted from “Spalling of concrete subjected to

blast loading” by M. Foglar and M. Kovar (CC 2.0)

While spall refers to the loss of part of an RC member, the term “breach” signifies the complete loss of a
section thickness over a certain area, as illustrated in Figure 4-4. Breach of a section is usually observed
when an explosive charge is placed very close (PBIED or VBIED) or in direct contact (PBIED) with the
RC section.
There are a couple of strategies used to counteract spall and breach failure, depending on member type
(column or wall) and performance criteria. Typically, a steel plate installed on the back-side of an RC
wall will act as a fragment shield to prevent hazardous debris from injuring people or causing other
damage behind the wall as a result of spalling. It will also improve the wall’s performance, but may still
result in significant loss of concrete in the wall. The plate needs to be anchored sufficiently such that the
forces do not also propel the plate. A detail of an installed spall plate is presented in Figure 4-5.
Figure 4-4. Breached RC Panel Figure 4-5. Spall Plate Installed at the Back of an
RC Wall
Source: “Spalling of concrete subjected to blast

loading” by M. Foglar and M. Kovar (CC 2.0)
Source: UFC 3-340-02
Column steel jacketing is a structural enhancement used to strengthen RC columns. This type of
enhancement is especially used for columns susceptible to placed IED and vehicle attacks where
minimal standoff exists. Column steel jacketing involves full or partial-height wrapping of the column
with a steel plate. The steel jacket helps the column resist local shear failure due to a close-in charge, in
addition to increasing the column’s flexural and vertical load carrying capacities, as shown in Figure
4-6. This type of blast enhancement can be used for both new build and retrofit projects.

Figure 4-6. RC Column Wrapped in a Steel Jacket
Source: Arup
4.1.2 Structural Steel Detailing

As with RC structures, steel-framed structures and steel elements required to withstand blast loads
should be able to absorb and dissipate loads through deflection without inducing brittle failure in the
section. Also similarly to RC structures, the connection of steel members should be detailed and
designed to allow members to deflect before connections are failed. Failure to do so will result in
connection failure before the full member strength is realized.
Steel is much lighter and thinner than concrete, and therefore is not able to withstand effects of large
close-in blast loads as efficiently. In addition, the rebound in steel sections can be quite considerable
when compared to concrete sections.
4.1.2.1 Encased and Concrete-Filled Steel Columns

Where there is a possible threat of a terrorist placing an IED near an exposed steel column, the risk of
column failure may be mitigated by encasing the bottom section of the column in a block of concrete, as
shown in Figure 4-7 and Figure 4-8 (can also be a circular block). This type of enhancement can be
applied to both existing and new-build columns. An alternate option is to install architectural cladding
around the column to give the column the architectural look envisaged by the architect or designer,
while also increasing standoff.
For large VBIEDs, concrete encasement is likely required. For small PBIEDs, columns may be adequate
with or without cladding, depending on the performance criteria and DBT size. Other options include
welding cover plates to existing columns or filling tube sections with concrete or grout. For new
construction, this may not be possible if it has been planned to run utilities down a tube section.

Figure 4-7. Sections of the Base of a Steel-Encased Figure 4-8. 3-D View of a Steel Column
Column Encased in Reinforced Concrete
Source: Arup
Source: Arup
The above blast-mitigation enhancements are usually considered for an open web steel section. When a
column is represented by a non-open web steel section (i.e., rectangular, square, or circular-shaped
sections), it is more economical and practical to make holes in the section and pump high-strength grout
inside the column rather than encasing it in concrete. This method is similar to the steel jacketing system
described in the section above. As with the bottom concrete-encased column blast-mitigation measure,
this method can be applied to both new build and retrofitting projects.
4.1.3 Progressive and Disproportionate Collapse Resistance

Progressive collapse, not to be confused with disproportionate collapse, is a mechanism of damage
whereby structural members fail consecutively. The Institution of Structural Engineers Practical Guide
to Structural Robustness and Disproportionate Collapse in Buildings defines progressive collapse as:
The sequential spread of local damage from an initiating event, from element to element, resulting in the
collapse of a number of elements. Whilst undesirable, a progressive collapse may not be disproportionate.
Hence the term “progressive collapse” is not necessarily equivalent to “disproportional collapse.”
Disproportionate collapse is a collapse that is greater in extent than an amount judged by some scale to
be proportionate to the cause. A collapse may be disproportionate without being progressive and
similarly may be progressive in nature but remain proportionate. Design against disproportionate
collapse generally involves making the structure robust. Structural robustness is a quality of a structural
system that enables it to sustain local damage without failing to any great degree.
There are several ways in which structural robustness can be designed into a building. Each country has
structural codes to achieve robustness, but to varying degrees. The typical design approach methods are
as follows:

• Tie-force-based design method

• Alternate load path method
• Key element design method or specific local resistance
4.1.3.1 Design Requirements
TIE-FORCE-BASED DESIGN METHOD

This type of design method achieves structural robustness by providing a minimum level of continuity
throughout the structure. This continuity attempts to “tie” the structure together so that in the event of an
element loss, the remainder of the structure acts together to resolve the discontinuity due to the loss.
The key factor in the tie-force-based design method is to ensure that the building’s frame members are
mechanically connected to each other. This necessitates careful detailing practice in the connections
between members, as discussed in Sections 4.1.1 and 4.1.2. Furthermore, through the use of both
vertical and horizontal ties in the building, catenary action can be developed so that potential collapse
through element disengagement is avoided.
The main advantage of the tie-force-based method is that it is a relatively simple way to ensure a
minimum level of structural robustness. However, the disadvantage of the tie-force method is that it is
based on several assumptions that should be scrutinized and validated for the type of building
construction in question. More detailed and quantitative methods, such as the alternate load path
methods and key element design, are necessary to certify structural robustness in the building, especially
for structures that are at higher risk of accidental loading.
ALTERNATE LOAD PATH METHOD
The alternative load path method is a quantitative structural assessment of the building under damaged
conditions. This involves the removal of key structural elements, such as columns, shear walls, or
beams, and assessing the structure’s resilience to collapse.
By designing for column loss, a structure is equipped with a level of robustness that caters to various
underlying events that may or may not be terrorism-related. If a blast event causes the loss of a column,
the structure must withstand that loss without collapse to meet the specified performance criteria.
Alternatively, a column may be hardened such that it withstands the DBT scenario without failing.
However, this does not account for the potential for the DBT to be larger than specified. As the primary
structural goal is to prevent collapse, using alternate load path to design against element removal
regardless of DBT is largely considered a best practice.
The alternate load path method can be divided into four main steps (Figure 4-9):
1. Check the structure performance after removal of key element(s)
2. Check the area of floor slab that collapses
3. Check if floors above can bridge over the removed column
4. Check if the floor below can support debris from the collapsed floor

Figure 4-9. Alternate Load Path Method
Source: Arup
KEY ELEMENT DESIGN METHOD OR SPECIFIC LOCAL RESISTANCE

This method is based on the design of structural elements to withstand the prescribed accidental loading
(in this case a blast load), meaning that each element is proven to withstand the blast threat. The key
element design method may be elected in addition to the previous methods to protect elements that are
especially critical to maintaining structural stability.
4.1.3.2 Applicability to Airports

Design of airport structures against disproportionate collapse should adopt a risk-based approach.
Progressive and disproportionate collapse resistance is not explicitly required in structural code and is
therefore an owner-elected mitigation where risks of a blast threat (or other extreme event) are high.
Progressive or disproportionate collapse resistance will increase the cost of structural design, as floors
and beams will need to span greater distances than in a conventionally designed building. However, the
inherent robustness of structures designed in this manner is considered best practice and will
significantly reduce the risk of structural collapse in a blast event, which is the primary goal in most
identified performance criteria (refer to Section 2.3.2).
Consideration for progressive collapse-resistant measures should always be evaluated when a blast
threat is introduced. For single-story terminals, the risks may be low enough that explicit design to resist
progressive collapse does not warrant the cost, as the cost of replacement will be closer to the cost of
repair. However, for multistory terminals, the consequences associated with progressive or
disproportionate collapse are more severe.
To minimize risks during the evaluation, the designer may first, for example, design out vehicle-borne
threats by maintaining standoff from the structure. Maximizing standoff will minimize the blast load
arising from an explosive threat and will increase the size of the DBT needed to overcome the capacity
of the structure. Such measures will render the structure relatively insensitive to foreseeable hazards.
Where the DBT is increased to a level that is well above a reasonably foreseeable threat size,
vulnerabilities are designed out.

After designing out vulnerabilities as far as reasonably practicable, the vulnerability of the structure to
the remaining hazards must be undertaken on a case-by-case basis. This may involve one or more of
local blast or impact analysis, global analysis of the structural response, and/or element removal analysis
to protect against disproportionate collapse.
If the structure can be designed to withstand element loss, this makes the structural design essentially
insensitive to assumptions made about the size of the DBT, except where more than one column can be
lost in a single threat scenario. As such, it will always be preferable to design the structure for element
removal than using key element or specific local resistance methods. These should always be explored
first, but it must be recognized that for buildings with large spans, especially larger airport terminals,
developing specific local resistance can often be the only practical mechanism.
4.1.4 Facade Measures

The first layer of protection against hazardous blast load is provided by the building’s envelope or
facade. Facade protection measures are typically employed on the terminal exterior, and other areas of
the airport where there are many occupants, such as bus and train stations or stops. Architectural features
around the site may also incorporate elements of blast resistance to minimize the risk of hazardous
debris.
When the risk of structural collapse has been mitigated sufficiently, a facade appropriately designed to
withstand the DBT can protect the building’s occupants against both fatal blast pressures and impact
from hazardous debris. The facade alone cannot prevent structural collapse; however, if designed
improperly, the facade can actually contribute to collapse in a blast event. Therefore, its design and
detailing are extremely important.
Typically, an airport terminal landside facade is characterized as a curtain wall system made up of glass
panes spanning between framing elements (mullions and transoms), which then spans to a purposely
built secondary support structure (such as a truss) or the building’s structural frame, such as floor slabs.
Framing members should not span to primary structural members, such as columns, as this may induce
the failure of the primary structural system.
The facade system and its support structure should be considered together during design, as a change on
one may have an effect on the other. For example, strengthening of glass for blast resistance
subsequently requires a stronger structural support. If a stronger support cannot be accommodated, the
stronger glass results in an increased risk of structural failure, which could be disproportionate.
Therefore, strengthening of the glass may not be the best solution from a protection standpoint; the risk
of glazing hazards would need to be accepted (as the best option compared to risk of structural failure).
These cost, performance, and risk considerations are complex. Sometimes the impacts that might occur
from a facade change are not initially evident, and therefore this is one area that should be considered
carefully before procuring enhancements.
This section presents common blast-mitigation measures that should be considered during the design
stages of a new building’s envelope or the retrofitting of an existing facade.
4.1.4.1 Glass
Monolithic glass consists of a single sheet of glass. This type of glazing configuration is not
recommended for blast-resistant facades, as during a blast event there is nothing stopping the glass
shards from flying into the occupied space and injuring the occupants. To prevent this from happening,
the following mitigation measures can be adopted:

• Apply anti-shatter film (ASF) to the glazing units.

• Install or retrofit the facade with blast-engineered laminated glazing units.
ANTI-SHATTER FILM
Anti-shatter film (ASF) is a thin, transparent, adhesive polyester film, which is applied to the internal
face of a glass pane to hold the glass fragments together in case of fracture due to a blast threat. ASF
does not increase the strength of the glass pane, but acts as a mitigation measure against glass fragments.
The benefits of ASF are that it is applicable to existing glass panes, is not invasive, is inexpensive, and is
quick to apply. It is generally considered to be better than doing nothing, but on its own, it is
deemed to be the least beneficial mitigation measure, and is only considered when retrofitting
monolithic facades. Without attachment of the ASF to the frame, the failure mode is most likely to be
the entire glass pane flying inwards. This is generally considered to be an improvement compared to an
untreated glass pane, where hundreds of small shards fly at dangerous speeds, but it is not able to protect
people from blast pressures and will still be hazardous.
If the film is attached using structural silicone sealant or a mechanical fixing, increased performance can
be achieved if the frame can support the additional loads. However, typically existing non-blast-resistant
frames would not be expected to support much additional load, and therefore attachment of the film
could cause a disproportionate hazard. Engineering evaluation can help determine whether this is the
case. It should also be determined whether drilling bolt or screw holes in the frame may void the
warranty on the frame.
LAMINATED GLASS
A greater level of protection against a blast threat can be gained by use of laminated glass. Laminated
glass consists of a build-up of multiple glass sheets with a polyvinyl butyral (PVB) interlayer in-
between. The PVB interlayer is a stretchy bonding material that, upon cracking of the glass pane, retains
the glass fragments, preventing them from dispersing inside the building. A laminate glazing unit should
be considered as the minimal baseline for a new construction or facade replacement.
An ionoplast interlayer (i.e., SentryGlass) should be used with caution for blast applications because its
high strength results in greater reactions that must be carried through to the structure. PVB can range in
stiffness as well, and careful specification of PVB should also be considered. If polycarbonate is
required instead of glass (for example, due to ballistic needs), polyurethane interlayers may be required
instead of PVB due to bonding limitations of polycarbonate. Polycarbonate also results in high reactions,
and therefore, in these latter cases, design should be prepared to accommodate larger or stronger
structures than glass with PVB. It is noted that these can only be general comments, as project specifics
will dictate the actual requirements.

Figure 4-10. Catenary Action of the PVB Interlayer
Blast Pressure
Frame
Outer
Glass Lite
Structural Laminate
Silicone
Sealant Inner
Glass Lite
Source: Arup
Laminated glass is often used with structural silicone sealant (SSS). SSS is applied at the junction of the
glass and the frame to attach the two. If specified properly, the SSS can retain the glass in the frame and
allow the PVB to achieve its full capability, letting it stretch between the surrounding frames as shown
in Figure 4-10. The performance of a laminated glazing unit is highly dependent on the retention system
anchoring it to the framing members. This capacity also impacts the strength required for the frame and
support structures. Therefore, laminated glass should be selected only after careful consideration of
these factors.
Usually, the minimum interlayer thickness used for non-blast application or very low-level blast
application is 0.03-inch, while for a typical or higher-level blast application the minimum recommended
interlayer thickness is 0.06-inch. There are also manufacturing limitations depending on the pane
thickness, size, and glass type that should be coordinated with a glass manufacturer prior to specifying.
While a PVB interlayer between two or more glass sheets can provide excellent protection against blast
loads, different glass types can be specified and each comes with its own characteristics and physical
properties:
• Annealed glass is the most common type of architectural glass found in building facades and
internal glazing. Use of annealed glass in blast-resistant glazing is usually limited due to its
relatively low dynamic breaking strength of 11.6 ksi (kips per square inch; dynamic breaking
strength slightly varies between manufacturers and countries of production) and tendency to
break up into razor-like fragments. This irregular failure mechanism of the glass sheets may
cause a high level of hazard to the building’s occupants as the shards fly into the building (see
Figure 4-11.). Therefore, this glazing type is mostly reserved for external sacrificial layers,
where in the case of a blast threat the shards will only disperse on the outer side of the building.
Still, the use of annealed laminated glass does provide significant benefit over the use of
monolithic glass, regardless of type of glass.
• Heat-strengthened glass is essentially annealed glass that goes through a strengthening
procedure consisting of precompressing the outer skin through a reheating and cooling process.
This gives the glass a dynamic breaking strength of 17.4 ksi. Upon fracture, heat-strengthened
glass tends to break in larger shards and fragments compared to annealed glass, as shown in
Figure 4-11 and Figure 4-12. Fully tempered glass (or toughened glass) is annealed glass that has
been fast-heated and cooled several times. This procedure significantly increases the dynamic
breaking strength to about 26.0 ksi. Also, this treatment changes the failure pattern of the glass,
making it different from the annealed and heat-strengthened glass. Toughened glass tends to
break into small rock-sized, blunt-edged fragments, as shown in Figure 4-11. This specific brittle

failure mode of the glass has led to the reduction of specifying tempered/toughened glass over
heat-strengthened glass because the small rock-sized pieces reduce its ability to stick to the PVB.
However, for some locations, tempered glass requirements may govern for impact safety. In
these cases, use of laminated tempered glass still significantly reduces blast risk compared to
monolithic tempered glass.
It is important to consider other requirements and features such as thermal, impact, cleaning, and
sunshade integration on a case-by-case basis.
Figure 4-11. Different Glass-Breaking Mechanisms – Annealed, Heat-Strengthened, and Tempered Glass
Source: Arup
4.1.4.2 Glass Retention Systems

Retention of a glass pane can be provided by either a dry gasket system or SSS (the latter is also called
“wet glazing”). Glass retention within the frame is very important; if the bond or connection between the
glass and the frame were to fail, the glass pane would most likely be propelled into the building and
create additional hazard to the public, not to mention the blast pressures that would also enter the
building as the envelope failed.
A dry gasket system holds the glass pane through friction between the pane and the frame’s rebate,
while the SSS relies on the silicone bond between the glass and the frame.
It is typically recommended that the glass pane be bonded to the frame using SSS rather than relying on
a dry gasket system. This is especially recommended when using laminated glass panes, as the SSS bond
enables the PVB interlayer membrane to achieve its full capacity. On the other hand, gasket system glass
will not be able to achieve the PVB capacity due to the low resistance provided by the friction between
the pane and the rebate or frame.
The use of a dry gasket system is often preferred due to the ease of construction and relatively lower
cost compared to using SSS. In design cases, where the blast load acting on the facade is not of great
magnitude, it is possible to use a gasket system with deeper rebates, giving the system additional
redundancy, but this is not usually recommended. Advice from a security or blast consultant should be
sought when selecting the type of retention system to adopt in the design.

It should be noted that although it would create a hazardous condition, a strategy may be to allow
glazing failure in an effort to avoid a potentially catastrophic structural failure; this is a risk-based
decision that may be considered.
4.1.4.3 Framing
Framing elements are commonly represented by mullions and transoms, which are the vertical and
horizontal framing members, respectively. The primary function of the framing unit is to support and
allow the glass pane to fully develop its maximum resistance without any premature failure.
Framing used in non-blast applications does have some built-in resistance against minimal blast loads,
but it is usually not adequate to transfer the reaction forces from the glass pane due to its minimalistic
construction. For blast applications, several blast-mitigation measures can be adopted into the facade’s
framing. These measures only concern new builds and full replacement work. It is usually not
economical or practically feasible to modify pre-existing window frames, and would likely void any
manufacturer warranty. In such cases, it is recommended that the building’s facade be re-clad.
FRAME MATERIAL
Aluminum and steel are usually the two materials specified for framing elements that are part of a blast-
resistant facade, as they are ductile and therefore allow the member to go through a controlled large
plastic deformation without failing unexpectedly. In most cases, aluminum is the material of choice for
architects and facade designers, as it is lighter and cheaper than steel. Also, aluminum is highly
malleable, and complex extruded sections can be produced to increase the stiffness of the section while
keeping a relatively thin frame width and depth. Additionally, aluminum frames can be used in
conjunction with steel inserts, which can greatly increase the blast resistance of the section.
Additionally, some manufacturers that make aluminum window systems that may be used in typical
single-story buildings (but may be not for larger airport terminals) have blast-tested some of their
products. These manufacturers are knowledgeable regarding performance of their tested systems
compared to the tested DBT scenarios, but will request a blast engineer/consultant to determine
applicability to other scenarios. Most of these blast-tested systems, particularly those of US
manufacturers, are tested for blast loads applicable to US Government blast criteria, such as those from
the Department of Defense, the Department of Veterans Affairs, or the General Services Administration.
For airport applications, these tested manufacturer systems may be limited to single or two-story
spanning facades, which are only required to meet a relatively low level of protection. For check-in hall
facades at large international airports with complex designs, full-scale blast testing and/or engineering
analysis should be incorporated in order to demonstrate that the blast requirements are met.
From a blast perspective, steel is the preferred choice when the blast loads are relatively large. Steel
support systems are typically required for large curtain walls to support conventional loading like
gravity and wind. This may either be a structural backup to an aluminum-framed system or a customized
steel support system directly behind the glass. Conventionally designed steel-framed facades, although
robust, are likely to require additional enhancements to meet a blast requirement, such as deeper section
dimensions, thicker web members, or additional connection capacity.
4.1.4.4 Steel Inserts

As briefly mentioned above, an additional measure that can be taken to increase the resistance of
framing elements includes the incorporation of steel inserts in the extruded framing section (typically
aluminum). Steel inserts are slotted inside the extruded aluminum frame section, as shown in Figure

4-12. They may also be shaped as channels or other shapes that fit into the particular mullion extrusion.
During a blast event, the steel insert works in combination with the surrounding aluminum section to
increase the resistance of the overall section. The main advantage of combining steel inserts with an
outer aluminum section is that it is possible to achieve a relatively strong section while keeping the
overall width of the frame section slim. This approach aligns with most architectural requirements set by
architects and facade designers. However, designers should coordinate early with blast engineers as
sometimes cabling or utilities are preferred to be run through mullions, which might not be possible if
this method of steel support is used.
Figure 4-12. Frame Aluminum Section with a Steel Plate Insert
4.1.4.5 Blast Clips

Depending on the facade design, two types of framing sections can usually be specified: split-sections or
unitized (box) sections. Split sections are framing members that are composed of two separate entities
and are kept together with continuous or intermittent clips or bolts along the length of the frame.
Unitized systems, or box framing sections, are usually rectangular extruded sections that come as whole
units and do not require any clips or connections to be held together (Figure 4-13).
When split sections are specified on a blast-resistant facade, it is important that special blast clips are
also included in the design. Conventional clips are not able to resist the in-plane forces acting on the
frame, which will essentially try to split the section open. Figure 4-14 illustrates the framing split section
and the blast clips holding it together.
Without blast clips in stick systems, the mullions will most likely come apart at the seam when loaded
by a blast-designed glass pane due to the horizontal/in-plane forces created by the laminate in
combination with SSS. Therefore, introduction of blast-resistant glass and properly designed rebate is
only effective if the stick system is designed to withstand the blast loads imposed by the glass. It should
also be noted that blast clips in stick systems are limited in their capacity; unitized systems might be
better suited for cases with high blast loads or high performance criteria.

Figure 4-13. Framing Box Section (Unitized) Figure 4-14. Framing Split-Section with a Blast Clip
Source: Arup
Table 4-2 generalizes various level of blast protection that can be provided by a facade, using
approximate levels of protection.
Table 4-2. Example Levels of Facade Blast Enhancements
Level of
Glazing Framing
Protection
Anti-shatter film (ASF) applied to

Very Low None
the glass pane
Blast-resistant framing details that can resist blast
Laminated glass pane with a
pressures around 5 psi and impulses of around 30 psi-
Low minimum PVB interlayer thickness
msec; dry-gasketed with minimum 1-in rebate or
of 0.03-in
otherwise SSS
Blast-engineered single-laminated
Blast-engineered frame to retain glass to its capacity
Medium glass panes with a minimum PVB
using SSS, allowing full capability of PVB to be realized
interlayer thickness of 0.06-in
Blast-engineered frame to retain glass to its capacity (per
Blast-engineered double-laminated Medium) and also engineered to limit permanent
High glass panes designed to resist deformation of the frames; includes structural steel
larger-sized blast threats backup framing due to higher demands created by the
stronger glass
4.1.5 Vehicle Security Barriers

In addition to the hardening of structures, a significant portion of design guidance is directed towards
preventing VBIEDs from accessing or encroaching upon protected areas. In the context of blast
mitigation, the aim of such HVM schemes is to increase the standoff from VBIEDs, reducing the loads
on the protected areas. Furthermore, overt HVM measures can act as a deterrent.

The principles behind HVM are well explained in several sources including Federal Emergency
Management Agency (FEMA) 426 and the United Kingdom (UK) Centre for the Protection of National
Infrastructure (CPNI) Hostile Vehicle Mitigation Guide. Additionally, testing standards for impact-
tested vehicle security barriers are well established with ASTM F2656 (predominately US standards),
Publicly Available Specification (PAS) 68 (predominately UK standards), and International Workshop
Agreement (IWA) 14-1 (various places around the world). It should be noted that a well thought-out
HVM strategy encompasses other aspects of design aside from barriers, such as roadway layout, speed
limitation measures, etc.
4.1.5.1 Testing and Specifying Barriers

Since their development, these testing standards have become the industry standard for specifying
requirements for the design of HVM schemes. However, the high level of protection and impact
resistance afforded by such systems is not appropriate in all circumstances.
When specifying the vehicle barrier per ASTM F2656, three components are needed: the threat vehicle,
the threat speed, and the allowable penetration distance. Typically, the building facade has been
designed for a blast threat located at the line of barriers, so the penetration distance should be limited to
less than 3.3 feet (1 meter), which is a P1 designation (see Table 4-3). If P1 barriers are not achievable
due to existing condition, construction, architectural, or cost limitations, the design engineer will need to
specify a greater penetration early on during the design process, as this could influence the standoff
assumed for the blast analysis. Penetration greater than P2 should be avoided unless the implications of
this have been considered carefully.
Table 4-3. Vehicle Penetration Rating (ASTM F2656)
Designation Dynamic Penetration Rating
P1 Less than 1 meter (3.3 feet)

P2 1.01 to 7 meters (3.31 to 23.0 feet)
P3 7.01 to 30 meters (23.1 to 98.4 feet)
P4 30 meters (98 feet) or greater
The different variations for vehicle size and speed are shown in Table 4-4. The vehicle size is typically
determined at the beginning of the project based on the risk assessment and design criteria. The speed of
each condition can be calculated during the design process by a blast or security engineer. A commonly
specified vehicle size and speed for high-risk locations is the M50 (Medium-Duty Truck at 50 mph);
however, this speed may be high for most terminal areas. Purposeful specification of the design vehicle
should be made during the risk assessment in order to support effective allocation of resources. Very
few manufacturers have tests for the heavy goods vehicle or the small passenger car as they are very
rarely specified. If specified, manufacturers may want to provide a higher protection level due to greater
availability of those products.

Table 4-4. ASTM F2656 Vehicle Size and Speed Rating
Nominal Minimum
Condition
Test Vehicle Weight lbs (kg) Velocity mph
Designation
(km/h)
40 (65) C40
Small Passenger
2,430 (1,100) 50 (80) C50
Car (C)
60 (100) C60
65 (45) PU40
Pickup Truck
2,430 (1,100) 80 (50) PU50
(PU)
100 (60) PU60
30 (50) M30
Medium-Duty
15,000 (6,800) 40 (65) M40
Truck (M)
50 (80) M50
30 (50) H30
Heavy Goods
65,000 (29,500) 40 (65) H40
Vehicle (H)
50 (80) H50
4.1.5.2 Barrier Types

There are various types of passive and active barriers, each with unique benefits and drawbacks. In all
cases, it is important to consider the effects on pedestrian flow and egress for emergencies, especially at
airports where passengers have luggage that significantly reduces their ability to flow quickly around
barriers. Studies performed by CPNI demonstrate this effect. It is recommended to consult with
pedestrian planners and fire protection engineers to verify that code requirements will still be met with
the addition of barriers in high volume pedestrian areas.
STEEL BOLLARDS
Steel bollards are probably the most versatile of the passive barriers; they can be arranged to allow for
pedestrian movement, covers can be added to make them architecturally pleasing to match the
surrounding facility, and they can be operable (raised/lowered). The challenge is that many types need
deep foundations, which are not always achievable in existing facilities due to structural or utility
limitations. There are some manufacturers with more versatile shallow-bollard foundations, but the costs
of these products are high and the footprint plan increases 300% from that of a deep foundation. Despite
these negative factors, shallow-mount bollards are often procured anyway in order to avoid invasive
construction; most shallow-mount systems can be installed very quickly.

Figure 4-15. Steel Bollards
Source: bmk Engineering, design and construction project: 6711 Gateway

Drive, Colombia, MD
At roadway entrances that require access for maintenance vehicles or other authorized vehicles,
hydraulic or electric operable/retractable bollards can be used.
Figure 4-16. Steel Retractable Bollards
Source: bmk Engineering, anti-ram testing observation, Adelanto, CA
It should be noted that a continuous slew of bollards along a long terminal’s drop-off and pick-up zones
does not necessarily represent a well thought-out HVM strategy; security engineers and architects
should work together to avoid this and encourage architecturally pleasing barrier solutions, which may
be supplemented by other HVM strategies such as architectural layout, technology systems, or
operations. Studies by CPNI have recommended to move the line of bollards outwards from any exits (at
least 3 m away) so that crowds have time to diffuse before having to move around the bollards.

JERSEY BARRIERS
Jersey barriers can be deployed quickly and easily with little construction time. Jersey barriers do not
provide an ASTM security rating and are not considered to be architecturally pleasing. However, they
do provide a baseline level of protection and are visual deterrents. These may be useful to deploy at
times of elevated threat, or as temporary solutions where a vulnerability has been identified but time is
required before procurement of a larger project can be undertaken.
Figure 4-17. Jersey Barriers
Source: bmk Engineering, perimeter security design project
CONCRETE PLANTERS AND KNEE WALLS

Concrete walls can be designed for any requirements and can be made to fit within the surrounding
architectural environment with stone facades. They are not pedestrian friendly and typically require deep
foundations, which are often a challenge at existing facilities. However, at airports they would be ideal
in locations where pedestrian flow is low, or if there is a highly vulnerable area such as a straight-away
road or an access point for large trucks.

Figure 4-18. Concrete Knee Wall
Source: bmk Engineering: design project: Bamako, Mali
WEDGE BARRIERS
Wedge barriers are operable and provide the maximum perimeter protection with a low-profile barrier.
The wedges are within the roadway, so they can present challenges in some weather conditions if not
maintained properly. Different systems have various foundation requirements. The shallow systems are
very extensive in horizontal area, while the deep systems do not affect the surrounding pavement. There
are also surface-mounted systems if needed for a high-profile event or on a temporary basis. Wedge
barriers are best suited at discrete locations such as an access control point to a loading dock or an
authorized taxi/shuttle bus entrance, if throughput times can be accommodated.

Figure 4-19. Wedge Barriers
Source: bmk Engineering, Inc. Construction project: Tiblisi, Georgia
DROP ARMS
Drop-arm-style barriers can be the least invasive on the roadway as their foundations are typically the
smallest. However, they take up the most real estate above ground and can be challenging to use across
multiple roadways. At airports, these are best utilized at staff parking, entrances to service yards, or
other areas where authorization is required for entrance.
Figure 4-20. Drop Arms
Source: bmk Engineering design and construction project: Gribble Gate, Alexandria, VA
4.1.6 Physical Measure Retrofits for Existing Airports

Existing airports may have been designed without structural blast enhancements or with blast
enhancements that are no longer best practice in airport design. Retrofitting landside areas of existing
airports is a routine occurrence and often provides an opportunity to invest in security. Existing airports

often contain legacy infrastructure that cannot be easily replaced without great financial cost or effort.
Such infrastructure may include the following:
• Elevated roadways and drop-off zones in close proximity to the terminal building.
• Structures and facades designed some time ago that incorporate older standards and have little
blast resilience.
• Existing/outdated CCTV systems and cabling.
• Terminal layouts that promote crowding at areas such as check-in, drop-off, and security
screening.
• Data centers and other functions critical to the airport’s operations.
Traditional blast-mitigation strategies for retrofit, in particular physical enhancements, come at a
financial cost and effort that is disproportionate to the risk, often stalling an airport’s plans to invest in
landside security. For that reason, an existing airport may have a blast-mitigation strategy with emphasis
on operational measures, which can be easily deployed across landside areas. However, operational
measures also come with substantial recurring costs and do not directly reduce the effects from a blast
itself.
In regard to retrofit of physical measures, depending on the blast DBTs and performance criteria, costs
and implications of retrofitting structures may become expensive and onerous to implement. However,
the risk reduction may be necessary to pursue. There are many retrofitting techniques that can be
employed, but given the nature of a retrofit, all will need to be customized to the unique conditions of
each airport and its particular risk-reduction needs. For most cases, a blast engineer will be needed to
help identify the most effective and feasible measures.
4.1.6.1 Structural Retrofits

Although not a structural retrofit by technical definition, structural performance can be enhanced
significantly by increasing standoff. Increasing standoff will almost always offer improved performance
to a DBT. In the case of close-in bombs, increase in standoff may trigger a global response mode (as
opposed to localized) that should be evaluated by a blast engineer; nevertheless, increasing standoff is
one of the most effective strategies. Increases in standoff should be considered before or in combination
with structural enhancement retrofits. For existing airports, increasing standoff may not be functionally
possible or is significantly more onerous than making structural enhancements. In this case, the
following are common retrofitting techniques that can be applied to an existing structure—all of which
require engineers’ evaluation:
Increased strength: Increasing the strength of the global or local structure can improve performance.
Effective performance enhancements can be achieved by increasing the section depth dimension of the
member, as this will reduce the final deformation and thus rotation.
Mass increase: Increasing mass is an economical and fairly straightforward method of increasing the
blast resistance. However, this method is only deemed suitable for elements subjected to impulsive
loading, and increasing the mass of the structure may negatively affect the foundation and other
structural members (e.g., the additional mass may overload existing structural components).
Boundary conditions modifications: Modifying the supporting conditions of a member can increase
the capacity of a member. For example, a slab that is spanning between two beams has a lesser load-
carrying capacity than a slab spanning onto four beams; an illustrated example is presented in Figure
4-21 and Figure 4-22. Careful consideration should be applied to the new load path distribution of the
modified members, as the redistributed load may overstress other structural components.

Figure 4-21. Two-Side Supported Slab Figure 4-22. Four-Side Supported Slab
(One-Way Spanning) (Two-Way Spanning)
Source: Arup Source: Arup
Span length reduction: Span length reduction can increase the stiffness of the member, effectively
increasing the load-carrying capacity. Significant attention should be paid to the end reactions of the
shortened members, as they may exceed the capacity of the supporting members.
In addition to the above-described techniques, careful consideration should be placed on strengthening
the existing structural components’ connections. Table 4-5 presents a selection of structural retrofitting
methods that can be adopted to increase the blast resilience of an existing structure.
Table 4-5. Example Structural Retrofitting Techniques
Most Applicable
Structural System Structural Modification
DBT
Metal decking over roof • Pour additional concrete and reinforcement*

VBIED
joists • Install lateral braces to bottom flanges of joists
• Increase section thickness and mass of member by pouring
RC slab or composite additional concrete and placing additional reinforcement*
PBIED metal deck support by • Install I-beam on top of existing slab, provide fixing in-
joists between existing joist and new I-beam, and pour additional
concrete over existing slab
• Install steel jacket on RC column; steel column can be
VBIED & PBIED Exterior column encased in concrete or web stiffeners can be welded to the
flanges
• Install new vertical beams in the walls
• Install high strength fiber-reinforced strips to the wall surface
• Increase the wall thickness by increasing the wall section (add
VBIED & PBIED RC wall concrete and reinforcement)*
• Install new blast-resistant wall behind; consideration should
be given to the impact of debris from the existing wall on the
new wall
• Install a new blast-resistant roof on top of the existing
VBIED Roof systems
structure*
Steel joists floor • Install lateral bracing angles to reduce joist effective length
PBIED
framing • Bolt or weld steel plate to the bottom flange of the joist
VBIED RC connections • Install additional steel angles tying RC members together

Most Applicable
Structural System Structural Modification
DBT
• Add web stiffeners near the supports to improve shear

resistance and avoid web buckling
VBIED & PBIED Steel connections
• Provide additional bolts and weld material to the connection to
allow transfer of moment forces
• Install cross bracing between structural bays
VBIED Frame
• Install new interior shear wall to resist lateral loads*
* Note: It should be considered that enhancements may trigger structural upgrades due to larger gravity loads that
are disproportionate to the retrofit intent.
When retrofitting of an existing building is considered, it is crucial that the advice and expertise from a
security/blast consultant and structural engineer is sought. Retrofits may impact the global response of
the building or have cascading consequences to other disciplines under conventional loading scenarios
such as gravity and wind.
4.1.6.2 Facade Retrofits

When considering retrofits to the facade, there are three main options:
1. ASF (i.e., daylight film/fragment retention window film)
2. Mechanically attached ASF
3. Replacement blast-resistant facade systems with laminated glass and blast-resistant frames
Also worth mentioning in this section is retrofit of other architectural features that may contribute to
hazards in a blast event if not properly anchored. Hazard-mitigating design details of typical interior
elements (including glazing) have been developed and professionally drafted. Refer to Appendix D for
the drafted book of details.
ANTI-SHATTER FILM (DAYLIGHT AND MECHANICALLY ATTACHED)
Implications of ASF as a retrofit were discussed previously in Section 4.1.4.1. Further to that discussion,
it should be noted that ASF is well known as a blast enhancement primarily because of its cost and ease
of implementation for existing systems, not its high performance. Test reports demonstrate that ASF can
provide enhanced performance under lower loads, but the performance is variable, and it is only a
marginal improvement over the existing glass. ASF is generally regarded as better than doing nothing;
however, a significant performance benefit would only come from installing a properly designed
laminated glass and an anchored blast-resistant facade.
Without attachment of the film to the frame (i.e., “daylight” application), under a large blast loading like
a VBIED at the drop-off curb, the entire pane is likely to come out of its frame. As discussed earlier, this
creates a hazard in its own regard, but is generally accepted to be a lesser hazard than the shattering that
would occur with glass left untreated. A catchment system could be provided behind the glass with
daylight film, but this would have aesthetic impacts and would also need to be anchored properly in
order to perform effectively, which in turn would impact the structural design.
There are two options for attaching the film to the existing frame: mechanically using screws or using
structural silicone sealant (SSS). Either option may provide superior performance to daylight film, but
only if the existing frame and anchorages are robust enough to transfer the additional load that is
imparted to the frame through the attachment; the facade system is only as strong as its weakest link.

It should also be noted that if existing glass is laminated, the application of ASF would not be an
effective use of resources, as the laminated glass accomplishes a similar result as the anti-shatter film.
4.1.6.3 Hostile Vehicle Mitigation Retrofits

A common site constraint for existing airports is one of minimal stand-off between roadways and the
terminal building. This exposes the terminal building and its occupants to severe effects from a VBIED.
Previously, the TSA had developed the “300-foot rule,” also known as the Special Category Airport 3
(SCA-3), which has been since rescinded. The rule was a ban on any unknown vehicle parking within
300 feet of the terminal building. In its place, the TSA instituted a series of operating procedures called
the Bomb Incident Prevention Plan (BIPP) to provide relief from the SCA-3. Each BIPP was required to
be based on an approved blast analysis performed by a certified engineering firm that would be
instituted when the DHS threat level was elevated to Orange. However, without analysis supporting their
BIPP, the 300-foot rule remained in effect for Category X airports.
Each airport’s approach to this flexible BIPP required approval by TSA. Although the alternative
operational measures are expensive to implement, some airports had elected to accept these
circumstances rather than constructing parking facilities 300 feet from the terminal. Some airports also
elected to reduce capacity in the garage to achieve the 300 feet instead of building 300 feet away.
Although the SCA-3 rule was rescinded, TSA still requires addressing the threat of a VBIED in the
airport’s TSA-approved Contingency Plan, especially for Category X airports. The threat can be
addressed by restricting parking and unauthorized vehicles within 300 feet of the terminal, or by
implementing alternate procedures that the airport has proposed and have been approved by the
TSA. For non-Category X airports, where a risk assessment may suggest a low risk of terrorism, a
Contingency Plan is still required, but the alternative procedures for VBIED mitigation may be less
strict. In both cases, in practice, the airport is responsible for determining appropriate standoff and
mitigation strategies, and a TSA audit will verify that the airport has a plan established.
As was the case with the 300-foot rule, traditionally the focus of an HVM strategy has been to protect
the terminal itself. It is important to note that recent attacks indicate that the target has shifted towards
crowded places, in general. Before specifying vehicle barriers, evaluation should be undertaken to
identify goals for protection and vulnerable areas of the airport, whether that be near the terminal or non-
terminal areas where people congregate. A holistic strategy for protection from hostile vehicles should
be developed, which includes:
• Definition of the protection objectives

o e.g., Protect the people or protect the structures
• Identification of the expected threats
o e.g., Abandoned vehicle in the parking garage, or a suicide VBIED attack on the terminal
• Criteria for evaluating the effectiveness of measures
o e.g., Is a visual deterrent (reduce likelihood) acceptable, or is a physical barrier (reduce
consequence) required?
• Identification of significant vulnerabilities
o e.g., Minimal standoff or publicly accessible roadways
• Guidelines for redevelopment to mitigate such threats
o e.g., Roadway rerouting, vehicle barriers, or screening checkpoints
Also of note is that an airport’s HVM strategy should encompass consideration for both VBIED and
vehicle ramming attacks, with the former being the focus of this guidebook.

For existing airports, the following measures may be implemented as part of an HVM strategy that
encompasses physical, technological, and operational measures:
1. Reduce speed limits
2. Increase curb height
3. Provide signage or physical height restrictions on roadways
4. Install landscaping or roadway impediments to slow vehicles
5. Disperse (i.e., separate and/or additional) drop-off and pick-up zones to reduce crowds and thus
reduce the vulnerability of any one area
6. Relocate drop-off and pick-up zones to less vulnerable areas
7. Implement video analytics to help detect illegally parked vehicles, stolen or unregistered cars,
etc. (refer to Section 4.2)
8. Provide physical barriers (i.e., bollards, planters, or drop-arms) to prevent vehicles from entering
the terminal building, bus plaza, or other identified vulnerable area
9. Screen vehicles prior to entering the terminal areas using a vehicle checkpoint
10. Reconfigure traffic lanes for authorized vehicles to be nearest the terminal or other vulnerable
areas, and unauthorized vehicles to be furthest away
4.1.6.4 Summary of Retrofits

An overall summary of physical retrofits and their applicability to VBIEDs and PBIEDs is shown in
Table 4-6.
Table 4-6. Summary of Retrofit Measure Applicability
Retrofit Measure VBIED Applicability PBIED Applicability
Yes, however the benefit may

ASF (Daylight Application) Yes
be small
Yes, however the benefit may
ASF (Mechanically Attached) Yes
be small
New/Replacement Blast-Resistant Laminated
Yes Yes
Glazing System
Enhancements to Overhead Equipment
Yes Yes
Anchorages
Structural Member Enhancements Yes Yes
Incorporation of Progressive Collapse Yes, but it is less likely to
Yes
Resistance be necessary
Hostile Vehicle Mitigation Yes No
4.1.7 Physical Measure Cost Estimations

Rough order-of-magnitude (ROM) cost estimates have been calculated for a number of blast-mitigation
measures. These costs are summarized in Table 4-7 for structural and facade enhancements, and in
Table 4-8 for HVM enhancements. The unenhanced costs are intended to be representative of a
conventionally designed system that has not considered blast. Details and assumptions of the ROM cost
estimate are provided in Appendix C; costs were developed in 2018. The default cost information from
the estimate is also included in the Excel-based tool that accompanies this guidebook to help identify
cost-effective measure combinations using the framework process.

Table 4-7. Summary of Physical Enhancement Options and ROM Costs
Enhancement Cost
Description ROM Cost Estimate
Type Premium
New Facade
Glass: IGU Outer: 3/8” (TT)/Inner 1/4” Glass: $45.00/ft2
Unenhanced* (HS)+0.03PVB+1/4” (HS) Framing: $30.00/ft2 Baseline
Mullion: 10x4x0.125” Aluminum extrusion Installation: $9.15/ft2
Glass: $33.00/ft2
Enhanced Framing: $77.00/ft2
Generic and proprietary 4 psi/28 psi-ms facade 1.4x
Option 1* Installation:
$10.30/ft2
Glass: IGU Outer: 3/8” (TT)/Inner 1/4” Glass: $65.00/ft2
Enhanced (HS)+0.06PVB+1/4” (HS) Framing: $89.00ft2
2.0x
Option 2* Mullion: 10x6x3/16” Aluminum extrusion + 9.5x1/2” Installation:
Steel stiffening Inserts $10.30/ft2
Glass: $51.00/ft2
Glass: IGU Outer: 3/8” (TT)/Inner 1/4”
Enhanced (HS)+0.06PVB+1/4” (HS) Framing: $132.00/ft2
2.3x
Option 3* Installation:
Mullion: HSS 12x4x1/4”
$11.30/ft2
Glass: IGU Outer: 1/4” (HS)+0.06PVB+1/4” (HS) Glass: $100.00/ft2
Enhanced Inner: 1/4” (HS)+0.06PVB+1/4” (HS)+0.06PVB+1/4” Framing: $197.00/ft2
3.7x
Option 4* (HS) Installation:
Mullion: HSS 16x8x1/2” $12.30/ft2
Existing Facade
Enhanced
ASF (Daylight Application) $4/ft2 Baseline
Option A
Enhanced
ASF (SSS Attachment) $5/ft2 1.3x
Option B1
Enhanced
ASF (Mechanical Attachment) $14/ft2 3.5x
Option B2
Enhanced ASF (Daylight Application) with Cable Catchment
$33/ft2 8.3x
Option C System
Columns
Unenhanced Materials and install:
Steel column: W12x106 Baseline
Option 1* $4,500/column
Enhanced Steel Column: W12 x 106 + 1” stiffener plates to Box Materials and install:
1.1x
Option 1A* section at column base + Grout-filled at column base $5000/column
Enhanced Steel Column: W12 x 106 + 20” Square Concrete Materials and install:
1.2x
Option 1B* encasement $5400/column
Unenhanced Concrete Column: 3’ Diameter + #4 hoops at 12” on Materials and install:
Baseline
Option 2* center + 16 x #10 longitudinal bars $1400/column
Enhanced Concrete Column: 3’ Diameter + #6 hoops at 6” on Materials and install:
1.7x
Option 2A* center + 16 x #10 longitudinal bars $2416/column

Enhancement Cost
Type Premium
Concrete Column: 3” Diameter + #4 Ties at 12” on

Enhanced Materials and install:
center + 1/2” full height steel jacket + 16 x #10 2.6x
Option 2B* $3700/column
longitudinal bars
Floor
Unenhanced Beam: W24 x 84 + Shear Studs Materials: $170.24/ft
Baseline
Option Floor Slab: 8” RC slab (#4 bars at 8” on center) Installation: $52.77/ft
Beam: W27 x 146 + Shear Studs
Enhanced Materials: $229.97/ft
Floor slab: 10” RC slab (#4 bars at 8” on center) + 1.3x
Option 1 Installation: $62.28/ft
enhanced connection
Beam: W30 x 116 + Shear Studs
Enhanced Materials: $301.70/ft
Floor slab: 12” RC slab (#5 bars at 8” on center) + 1.7x
Option 2 Installation: $70.70/ft
enhanced connection
Roof
W21 x 62 (primary Beams-32 ft span) + W21 x 50 Materials: $9/ft2
Unenhanced
(secondary Beams at 16 ft on center) + 6” cold formed Baseline
Option Installation: $15/ft2
Purlins (0.08”t) at 4 ft on center
Enhanced
(secondary Beams at 16 ft on center) + 8” cold formed 1.3x
Option 1 Installation: $19/ft2
Purlins (0.08"t) at 4 ft on center
Enhanced
(secondary Beams at 16 ft on center) + 10” cold 1.5x
Option 2 Installation: $22/ft2
formed Purlins (0.08”t) at 4 ft on center
Table 4-7 Notes:
PVB: Polyvinyl Butyral; HS: Heat Strengthened;

IGU: Insulating Glass Unit;
TT: Thermally Tempered;
HSS: Hollow Square Section; RC: Reinforced Concrete
* Indicates member is shown in Figure 2-6.
Table 4-8. Hostile Vehicle Mitigation (HVM) Enhancement ROM Costs
Enhancement Cost
Type Premium
Steel Bollards
Unenhanced Steel bollard, not rated $112/ft Baseline
Enhanced
Steel bollard, PU50-P1 rating* $3,129/ft 28x
Option 1
Enhanced
Steel bollard, M30-P1 rating $1,685/ft 15x
Option 2
Enhanced
Steel bollard, M40-P1 rating* $2,677/ft 24x
Option 3
Enhanced
Steel bollard, M50-P1 rating $2,167/ft 19x
Option 4

Enhancement Cost
Type Premium
Concrete Barriers
Enhanced
Raised Curb, not rated $14/ft -
Option 1
Enhanced
Jersey Barrier, not rated $117/ft -
Option 2A
Enhanced
Concrete Bench, not rated $191/ft -
Option 2B
Enhanced
Concrete Planter, not rated $238/ft -
Option 2C
Other HVM
Enhanced
Speed Humps, not rated $5,000/hump -
Option 1A
Enhanced
Height Restriction Bar over Road, not rated $7,006/barrier -
Option 1B
Enhanced
Gate Barrier, M50-P1 rating $28,000/barrier -
Option 2A
Enhanced
Wedge Barrier, M50-P1 rating $54,000/barrier -
Option 2B
Table 4-8 Notes: *Costs are unexpectedly high due to the limited availability of barriers tested and manufactured
to these ratings.
4.2 Technological Measures

This section describes common technological measures and how they can be adopted to mitigate blast
threats at landside areas of airports. Also discussed is application of technologies to existing or new
airports.
Although technologies are not perfect, they can supplement the role of operational security in being able
to monitor greater areas than would otherwise be possible with operations alone. Active monitoring is
expensive due to the operations personnel required behind the technology. As technologies are
constantly changing, airports should review their options regularly to evaluate their best options. Further
discussion on technology solutions is provided in Section 4.3, where the use of technology to support
operational measures is discussed.
4.2.1 Video Surveillance

Video surveillance camera technology has evolved alongside that of computers. With a majority of
current systems now using IP-based signal transmission, network video recorders are often able to
automatically act upon predefined algorithms identified within the camera feeds. This field is referred to
as video surveillance analytics.
A computer’s main purpose is to perform vast amounts of repetitive calculations that would take a
human much longer to achieve. Analytics aim to work in the same manner by relying on computer
vision, a field that has gained much advancement in recent years. Ideally, analytics can make sense of
the data in a video feed and relay it as a qualitative, actionable item for a staff member to carry out. For
example, if a person is recorded climbing over a fence into a secure area, the system can automatically

bring up the live video feed on a security guard’s workstation and/or mobile phone, sound a local alarm,
and turn on nearby lighting. This saves the employee from the mental fatigue associated with having to
stare at numerous camera feeds for many hours at a time.
The maturation of this field means that a system can identify possible problems before they happen
rather than just forensically determining what happened afterwards. Below are a few common video
surveillance analytics that can be used to help reduce the likelihood of a blast event; a more detailed list
can be found in Appendix A.
• Objects left unattended for a specified period of time

• People and objects crossing a predefined digital barrier or zone in the camera’s field of view
• Smoke detection, even outdoors
• Tracking a person or object through multiple cameras’ views
• Irregular behavior—compares the baseline footage of what a camera sees during a normal day
and flags if it detects an action it has not seen before
• Automatic identification of faces and license plates
Just like humans, analytics are not perfect. False positives can have a “boy who cried wolf” effect on
security guards, who lose faith in the system if they receive too many incorrect flags. A video
surveillance system designer must take into consideration a camera’s environment, resolution, frame
rate, and other factors to maximize effectiveness. For example, it is unwise to run facial recognition on a
180-degree camera that overlooks the entire check-in area from twenty feet above the floor. Like with
any computer, the more data being analyzed at any given time, the less performance will be available for
assessing situations in other feeds.
4.2.2 Emerging Technologies

Supplementary systems can be utilized to minimize false positives. One such method is by using the 3D
detection capabilities of light detection and ranging (LiDAR). Traditionally used to map an area or
building, LiDAR laser scanning has more recently seen use in autonomous vehicles to detect other
moving automobiles and pedestrians as well. This real-time 3D capture (up to 20 scans per second with
a range of 100 m) can be used to safely detect objects of a particular size and automatically aim and
zoom a pan-tilt-zoom (PTZ) camera to view them; a system configured to alert if a human-sized object
is climbing over a fence will not be triggered if a squirrel were to do the same (see Figure 4-23).
In addition to autonomous vehicles, autonomous surveillance robots are also beginning to emerge as a
method of seeing into places not normally visible to CCTV systems. Most of these are purely for
surveillance with some other features (i.e., two-way intercom, public announcement), but some
governments have taken steps to militarize their robotic security guards with stun capabilities. Once
purely science-fiction, this implementation is certainly not without controversy.
Leveraging the connectivity of the general public has also begun to aid security. Cloud-based systems
allow anybody with a smartphone to transmit live video feeds to an operations center, which can also be
coordinated with location tracking to determine the location of the event.
Companies are also using millimeter wave detection technology to modernize the standard metal
detector. This technology can make use of the naturally occurring radiation from the human body and
see where these signals are reflected, which beyond a certain threshold usually indicates some sort of
weapon. Using a touchscreen, security guards can then view a diagram of where on the person’s body
the potential weapon is detected and act accordingly. Some manufacturers also include cameras with
facial identification capability and integration with the building’s security network for optional record

keeping. The fact that this technology can be adjusted based on the site’s threat and risk assessment
means that they can be adjusted as needed; for an airport, these devices can be set to a threshold that
only detects large firearms and explosives at the airside entrance to increase speed at those locations,
knowing that a more thorough check will be performed at the TSA checkpoints into the sterile area.
Figure 4-23. LiDAR System Supplementing CCTV
Source: Arup
4.2.3 Technology Systems Cost Estimations

The following ROM costs have been approximated for CCTV, vehicle screening, and explosives
detection technologies. Note that the costs only include construction and materials, and do not include
staffing the security operations center or manning the security checkpoints, which adds significant cost
to the systems. Costs are based on 2018 pricing; further assumptions can be found in Appendix C.
Table 4-9. ROM Costs for Select Technology Systems
Enhancement Type ROM Cost Estimate Cost Premium
CCTV
Unenhanced:
$14,700/camera Baseline
CCTV
Enhanced Option 1:
$16,600/camera 1.1x
CCTV with Analytics
Enhanced Option 2:
$25,300/camera 1.7x
CCTV with LiDAR Analytics

Enhancement Type ROM Cost Estimate Cost Premium
Vehicle Screening
Enhanced Option 1:
$19,300/camera Baseline
ALPR
Enhanced Option 2:
$26,400/scanner 1.4x
UVVS
Explosives Detection
Enhanced Option 1:
$211,200/scanner Baseline
TSA mm-wave Body Scanner
Enhanced Option 2:
$256,200/scanner 1.2x
High throughput mm-wave Detection
4.2.4 Existing Constraints

From a technology standpoint, the most important element is the data network. Most devices can
transmit and even receive power over a standardized Category 5 or Category 6 cabling system for
telecommunications, which makes each data outlet largely interchangeable for connecting devices. Thus,
having a capable network provides room for expansion and modernization for future technologies as
well. Smart head-end equipment can enable systems to have a variable amount of integration with other
systems, something that has become increasingly necessary with multiple entities needing to operate in
the airport environment. For example, specific camera feeds can be made available to all entities’ video
management systems, while others can be restricted and viewed only by Customs and Border Protection.
Without a solid network backbone, many of the technologies discussed in this guidebook cannot be
implemented.
Smarter connectivity also brings with it cybersecurity considerations that must be addressed. More
connectivity often implies more points of entry for a malicious outside agent to access connected
systems. Firewalls and data policies are required to minimize the risk of breach.
Data devices are most optimally run over the latest standard Ethernet cable, and there are options for
running these signals over existing analog wiring. Media converters placed both at the edge and at the
system head-end can transmit data, and sometimes power, in cases where running new cable is not
feasible, or in locations surpassing the maximum distance limits of the data cable (in lieu of creating
another intermediate distribution frame). Wireless solutions are also available but are not as reliable as
their physically wired counterparts.
4.2.5 New Airport Considerations

The only sure thing about the future of technology is that it will always be changing, so the smartest
thing to do when designing a new airport building is to allow room for the network to expand. This can
involve purchasing more head-end equipment in the IT closets to create extra device ports and data
storage, running extra data cable to locations initially concealed above ceilings or behind walls for future
use, or running extra strands of fiber along the network’s backbone to link the distribution frames as
well as outside connections. As mentioned earlier, data outlets are often able to be repurposed and can
connect to different types of devices; for example, two outlets in a space that were originally supporting
three standard fixed dome cameras can be repurposed to now support one 360-degree camera, one
LiDAR detector, and one access point for Wi-Fi.

4.3 Operational Measures

The following common operational measures can be adopted to mitigate a blast threat:
• Patrols
• Explosives detection canines (EDC)
• Known vehicle regimes
• Vehicle checkpoints
• Advanced communication techniques
• Security management systems (SeMS)
Operational measures are critical to disabling and disarming the threat, which is something that neither
physical, technological, nor architectural measures can achieve. Therefore, to achieve a holistic security
strategy, operational measures should be included to cover this protection need. This principle is
reinforced in Section 5, whereby various measure types are combined to achieve a spread of protective
capabilities.
4.3.1 Agreement on Operational Measures

As discussed in Section 3.2, agreement on security measures is accomplished through a risk-mitigation
approach based on local and national risk assessments. Risk and threat mitigation may be defined in the
National Civil Aviation Security Program (i.e., 49 CFR) to some degree, but the application of each
measure will vary from airport to airport. Therefore, each airport determines which measures are most
appropriate to their risk environment under “business as usual” operations, what additional measures
should be implemented in heightened threat situations, and with whom the responsibility lies for each.
Airports implement operational security measures based on an operational requirement, which is a
statement of need based upon a thorough and systematic assessment of the security problem to be solved
and the desirable solutions. Defining the criteria below will inform the application of each operational
security measure.
Figure 4-24. Operational Requirements Criteria
Operational Requirements
• Site requiring protection
• Stakeholders
• Critical assets
• Threat and vulnerabilities
• Impact on site
• Proposed strategic security strategy
• Concept of operations
• Organizational constraints
• Implementation and integration
• Critical dependencies
• Costs and benefits
Source: CPNI Guide to Producing Operational Requirements for

Security Measures, 2016

The above criteria will aid the airport operator in determining which operational security measure to
implement based on the security function that is required to mitigate a particular threat scenario.
4.3.2 Operational Measures for Detection, Deterrence, and Prevention
4.3.2.1 Patrols
The main security function of patrols is detecting suspicious activity, but they may also serve as a
deterrent to security risks through the active deployment of airport security officers with high visibility
jackets. Further, unpredictable or random patrolling is also effective in reducing advantages potential
threat actors may have tried to gain through reconnaissance efforts to predict the best times to go
unnoticed. Patrolling involves surveillance of sites to monitor the following:
• The boundaries between landside, airside, and security restricted areas

• Areas of, and near, the terminal that are accessible to the public, including parking areas and
roadways
• The presentation and validity of persons’ identification cards in security restricted areas
• The presentation and validity of vehicle passes when airside
• Hold baggage, cargo and mail, in-flight supplies, and air carrier mail and material in critical parts
waiting to be loaded
It is a common practice for airports to have a combination of patrolling personnel such as airport
security personnel, law enforcement personnel, airport operations staff, and maintenance staff. Referring
to the developed framework (see Section 5), an effective patrolling process should ideally meet a
Platinum level of service to ensure a coordinated approach between different personnel groups. While
airport patrolling responsibility can lie with a variety of security-related stakeholders, the deployment of
any patrolling personnel should complement police patrolling strategies. Vehicle patrols can also be
utilized to deter potential threats by ensuring police vehicle presence at outer perimeters of terminals
such as pick-up and drop-off zones, vehicle checkpoints leading to airside, heightened points at the outer
perimeter, and areas identified by man-portable air-defense systems assessment.

Figure 4-25. Australian Police Officers at Airport
Source: Wikimedia Commons (CC 4.0)
4.3.2.2 Explosives Detection Canines

EDCs may be used to detect and indicate specified and higher individual quantities of explosive
material. An EDC and its handler should be approved independently and in combination as a team in
order to be used for screening. While canine olfaction (i.e., sense of smell) may be used to detect
explosives, illicit materials, or weapons in passenger baggage or on the passengers themselves, EDCs
should be single-purpose dogs specifically trained to detect explosives only, and not be subjected to
multiple training programs as protection dogs or for narcotics detection. EDCs’ detection capability of
explosives in terminals may be critical in preventing loss of life, but also plays a major role in reducing
the commercial impact on the airport’s business. An example of this is the 2017 bombing attempt at
Asheville Regional Airport in North Carolina, which was thwarted using the help of EDCs that signaled
to the airport security team the presence of dangerous materials in the suspect’s bag, preventing impact
to the airport, which serves approximately 50,000 passengers every month.

Figure 4-26. Free Running Explosives Detection Canine Accompanied by Handler
Source: Eglin Air Force Base Website

(CC 4.0)
Table 4-10 provides the two methods of security screening practiced by EDCs, with the FREDC method
being most applicable to the landside.
Table 4-10. Methods of EDC Security Screening
Free-Running Explosives Detection Canines

Remote Explosive Scent Tracing (REST)
(FREDC)
EDCs deployed directly in an operational environment

EDCs kept in sterile rooms
accompanied by handler, e.g., terminal
EDCs sniff extracted air samples from cargo
EDCs sniff items such as cabin baggage in terminal
containers at stations located in sterile rooms
While EDCs act as an effective detection measure, airport operators tend to procure EDC programs from
external providers as the costs of such programs are extensive, amounting to $35,000 USD for the EDC
and its training and $6,000 USD per annum for welfare costs. As EDCs can only be deployed for a
limited period of time without rest, and due to the high costs associated with this measure, a Silver level
of EDC service may be appropriate (see Section 5.3.3), where dogs are deployed sparsely within the
airport terminal, bus station, metro station, and other vulnerable areas to conduct random patrols.
Furthermore, the framework (see Section 5) provides a high scoring for combining EDCs with patrols,
which stems from the fact that patrolling personnel handling EDCs can act as a key deterrence measure.
EDCs give an alarm, in the form of a passive response, when they detect explosive materials, and in
order to fully resolve an alarm, a patrol officer may need to question a passenger about what they are
carrying.

4.3.2.3 Known Vehicle Regimes

There are certain landside areas of an airport that are dedicated to airport operations, and into which
entry is not permitted to passenger vehicles. These may include the following:
Police operation areas
Cargo pick-up/drop-off areas
Taxi operation areas
Bus operation areas
Traffic management operation areas
Perimeter patrol operation areas
While passenger vehicles are not permitted to enter these areas, the only measure used by some airports
to restrict access is signage. However, if a threat actor is planning a vehicle-based explosive attack,
traffic management rules like signage will not be followed. There are some operational measures used
by airports to mitigate this threat scenario to these types of landside areas, and to maintain airport-
supporting operations. For example, particular roads around Stansted Airport in the UK that are used for
the operations listed above are given a “controlled landside road” status, meaning that although it is not
airside or a security restricted road, limitations are placed on its use through vehicle access control
points (VACP) on each side of the road.
Instead of staffing the VACP, automatic license plate recognition (ALPR) can be implemented, which
uses video surveillance systems to screen the registration plates of all vehicles entering or leaving the
controlled landside road. This technology will only recognize license plates of vehicles used for airport
operations that require access to the roads. The implementation of ALPR by itself will only meet the
detection function and may not mitigate the deliberate breach of traffic management rules. Therefore,
ALPR should be used in combination with physical measures such as rated barriers that allow access
following approval from the ALPR.
Although ALPR can be easily implemented at existing airports, the use of a known vehicle regime is
more effective when introduced early in airport development. This is because sufficient space must be
allocated to install the VACP comprised of physical measures and an ALPR system. Furthermore, while
this system can detect and permit access to known vehicles only, the risk of an insider threat is not ruled
out. Although implementing this known vehicle regime early in airport development can ensure a
sufficient standoff distance is maintained between entry point for vehicles and any airport assets that
may be in close proximity to the VACP (therefore eliminating the risk of a blast affecting nearby assets),
it cannot validate capability and intent of an insider vehicle (i.e., a vehicle may be legitimate in the sense
that it is known but may still have an intent to cause damage, such as a VBIED).

4.3.2.4 Vehicle Checkpoints

Vehicle checkpoints should be deployed on approach roads and where road layout allows in order to not
disrupt the flow of traffic. These checkpoints are extremely effective in deterring threats, particularly for
heightened threat situations where an additional layer of protection is required. They are also a measure
that can be incorporated into an existing airport’s security program, requiring no refurbishment of any
infrastructure. A good example of this measure being implemented at an existing facility when threat
and risk context dictates is Brussels Airport, following the 2016 Brussels bombings. As additional
security requirements were imposed by the Belgian government, Brussels Airport managed to protect
and maintain its operational function while enhancing its security measures by deploying behavior
detection enforcement soldiers on Leopoldlaan Road, which leads to Pier A of the airport terminal. To
avoid traffic congestion, vehicles are required to drive slowly past the soldiers rather than come to a
complete stop, allowing the soldiers to conduct a quick non-stop visual inspection of the driver and the
vehicle, and to stop suspicious vehicles only.
Other examples of vehicle checkpoints include vehicle control posts (VCP) at airports, which are located
landside and are used by vehicles to access airside areas of airports. In the event of a blast at a VCP, the
operational functions of an airport can be severely affected, as VCPs allow the facilitation of airside
deliveries such as in-flight supplies/food and beverage, bulk liquids (e.g., aviation fuel and de-icer),
building materials (e.g., aggregates, concrete, and asphalt), and maintenance and construction materials.
Mitigating VCP blast scenarios can include the use of an under vehicle surveillance system (UVSS),
which enables the scanning of the underside of vehicles.
If the airport operator wishes to implement a Silver to Platinum tier of performance (refer to Section
5.3.3), UVSS can be integrated with an ALPR system in order to cross-check each vehicle against
airport databases to ensure all vehicles are approved to access airside or security-restricted areas. The
UVSS system can be implemented as shown in Figure 4-27. UVSS can be supplied in either static or
mobile configurations. Static systems tend to consist of a permanent deployment and are installed on or
below a road surface, whereas mobile systems are portable.
Figure 4-27. Implementing UVSS
UVSS
Static Mobile
On Road Below On Road

Road
ALPR

PERMANENT SECURITY CHECKPOINT – BEN GURION INTERNATIONAL AIRPORT, ISRAEL

Ben Gurion Airport has a road vehicle checkpoint one mile away from the main terminals where
vehicles and passengers are screened before they head to the airport. Speed bumps are present at the
checkpoint, reducing vehicle speeds as they are approaching, and armed guards stop, greet, and
question all drivers, gauging their mood and intentions and looking for suspicious behavior.
Major international airports tend to have a minimum of two main approach roads leading to
terminals, each with three or four lanes of traffic. Having a security checkpoint may not cause any
more congestion than toll booths. However, while Ben Gurion Airport claims that their vehicle
checkpoint does not lead to any major traffic delays, the airport handles approximately 11 million
passengers per annum as opposed to the bigger airports such as Chicago O’Hare, which handles
close to 77 million passengers per annum. Furthermore, it may be more appropriate to consider Ben
Gurion-like vehicle checkpoints when developing new airports, as the location and footprint of most
existing airports, especially at some older terminals, would not allow them due to space constraints.
The risk context for Ben Gurion is also unlike that of most airports worldwide.
4.3.2.5 Advanced Communication Techniques

This section provides a selection of communication techniques that can be utilized to deter a blast
scenario.
Figure 4-28. Types of Communication Techniques
Passive Communication Techniques Active Communication Techniques
• Vigilance posters • Advanced Passenger Information

(API)
• Vigilance leaflets
• Targeted passenger screening
• Security wallet cards
• Staff-passenger engagement
("Can I help you?")
ACTIVE COMMUNICATION TECHNIQUES

Active communication techniques are seen as more intrusive due to the element of singling out certain
passengers and subjecting them to enhanced screening. A method used by Ben Gurion Airport is a risk-
based approach to passenger screening. The system in place relies on identifying passengers who are
believed to pose a high risk and subjecting them to additional checks. Targeted screening of individuals
for landside security is made up of the three layers below:

Figure 4-29. Targeted Passenger Screening
Computer-Assisted Passenger Pre-screening System (CAPPS)

• Used by airlines
• Cross-checking passenger data with watchlists
• Searching for any unusual passenger activity (flight habits, method of ticket
purchase, car rentals, etc.) prior to travel
Pre-terminal entrance screening

• Vehicle checkpoint
• Vehicle trunk x-rays
• Vehicle undercarriage scanning
Face-to-face staff-passenger interaction

• Questioning starts at the vehicle checkpoint
• Risk-based screening consisting of questioning in the terminal before check-in
• Failure to answer questions may lead to pat down
Public knowledge of this degree of security implemented at Ben Gurion Airport serves as an effective
deterrent that discourages hostiles from targeting the airport. Although this measure is expensive to
operate and capital-intensive, it is highly effective in preventing loss of life, as the last notable incident
at the airport was in 1979, when an aircraft hijack was attempted. This measure is appropriate to Ben
Gurion as it is the only international airport serving Israel, allowing the country to focus all its effort and
expertise on this one facility.
PASSIVE COMMUNICATION TECHNIQUES
Less intrusive measures include passive communication techniques, which act as an extremely low-cost
deterrent that sends a subliminal message about the (high) level of security at an airport. Measures used
tend to be a part of a wider vigilance campaign that includes all airport staff playing their part in
maintaining an effective security culture. Vigilance posters such as those below can be put up in visible
places around the terminal to discourage any potential threat actors from carrying out reconnaissance.

Figure 4-30. Vigilance Posters
Source: This guidance/poster was created by the UK’s Centre for the Protection of National Infrastructure
(CPNI) and is subject to Crown Copyright. It is used with the permission of CPNI for our internal purposes.
Permission for any wider use should be obtained from CPNI.
Other staff-driven initiatives include carrying wallet cards that feature security/law enforcement
numbers that are visible on their person and are carried around with them when they are on and off site.
Also, handing out leaflets with security messages and placing them in passenger areas will serve to
reinforce the perception that staff are highly observant and vigilant.
4.3.3 Changing Passenger Habits

The implementation of various security measures mentioned thus far could be difficult due to
organizational constraints, costs, critical dependencies, and the need to retrofit or integrate into the
existing infrastructure. More creative methods can still be explored to improve blast-mitigation security,
and it starts with changing the way each passenger intends to travel and utilize airport facilities.
Changing passenger habits can make a significant difference in reducing the loss-of-life risk if the
airport manages to raise awareness about security and promote the mentality that every person has a
responsibility in ensuring security. In an operational setting, this may include exploring ways to reduce
queues and large gatherings of people in the landside/public area of the terminal.

Figure 4-31. Changing Passenger Habits to Achieve Risk Reduction
Increased use of self- • Fewer crowds at check-in desks

• Possible use of off-site hold
bag drop baggage check-in/drop-off
Increased use of • Hong Kong-like "in-town check-in"

• Checking luggage in town and
remote bag-drop proceeding to airport bag-free
Higher percentage of • Low-cost carrier model

discourages passengers from
passengers with cabin carrying hold baggage
baggage only • Fewer crowds at bag-drop desks
Source: Arup
The above procedures have been facilitated through the introduction of various technologies such as
online check-in and self-bag drop. Airports can contribute significantly to changing how passengers
travel by introducing incentives aimed at airlines and passengers. This may include revised procedures
for airlines in which certain airport charges are reduced if the airline can ensure that most passengers do
not travel with hold baggage. This would reduce crowding at check-in areas, facilitating passengers to
move airside as soon as they arrive at the airport. However, reducing queues from the ticketing area
does not necessarily eliminate all queues, especially if not managed properly. Management of crowds
and passenger flows are discussed further within Section 4.4.
Changing passenger habits requires a coordinated approach between all stakeholders such as airlines,
airports, and travel agencies. As these measures are customer service-driven, they do not guarantee that
security outcomes will be achieved. Furthermore, this type of measure will only reduce the loss-of-life
risk as opposed to protecting airport infrastructure.
4.3.3.1 Security Management System (SeMS)

An SeMS is a mechanism or management technique used to establish and maintain a security culture,
and integrate security into the airport’s business. The security culture is utilized to manage security
risks, while the inculcation of security into the business provides for more effective, efficient, and
sustainable security. The establishment and maintenance of an airport-wide security culture and the
integration of security into the airport’s business are achieved by establishing and maturing seven
elements that, when integrated with each other and the broader airport business, form an SeMS.
The figure below illustrates the seven elements, their relationships with each other, the governance and
quality assurance that underpins the system’s functionality, and their collective contribution to a positive
security culture.

Figure 4-32. SeMS Elements
Source: PARAS 0009
The security measures implemented at an airport will be informed by the SeMS. This is because the
SeMS serves as a tool for systematically incorporating security risk management into an airport’s day-
to-day operations. For an SeMS to be effective, it must be based on a continuous cycle that includes a
threat and vulnerability assessment; the identification, capture, and analysis of risk; and the generation
and continuous review of risk mitigation plans and the effectiveness of risk-reduction measures (refer to
PARAS 0009 for additional guidance).
4.3.4 Operational Cost Measures Estimations

The following ROM costs, shown in Table 4.11, have been approximated for operational security
measures. The costs are salary-based and do not include capital costs of materials required to support
operations (e.g., metal detectors are excluded). Section 4.4 offers further discussion regarding check-in
counter and TSA screening checkpoint staffing.

Table 4-11. ROM Costs for Operational Measures
Measure ROM Cost Estimate per year
Canine olfaction (Explosives $881,100

detection dogs) (5) 8-hr shifts, i.e., one person on-duty, 24-hour coverage
$1,090,300
Vehicle checkpoint staffing
(10) 8-hr shifts, i.e., 2 staff per checkpoint, 24-hour coverage
$597,300
Behavioral detection officers
(5) 8-hr shifts, i.e., one person on-duty, 24-hour coverage
$554,900
Airline check-in counter staffing
$2,147,600
TSA screening checkpoint staffing
(15) 8-hr shifts, i.e., 3 staff per checkpoint, 24-hour coverage
$530,100
Law enforcement patrols
$364,500
Private security patrols (unarmed)
$530,100
SOC staffing
4.4 Crowd Management

From an operations perspective, airports are considered large passenger-processing facilities, and
crowding is inevitable at peak times for busy airports. Air travelers expect queues in check-in halls and
at security checkpoints, as well as crowding around bag claim carousels and in arrival halls. These areas
of an airport are often non-secure, meaning the public can access them without going through the
security checkpoints.
These traits make non-secure areas particularly vulnerable to a blast attack, and therefore measures that
reduce the extent of crowding inherently reduce the total consequences of a blast event. Section 4.4.1
discusses the processes that typically generate crowds and potential mitigation measures.
Additionally, crowds of people are vulnerable to the effects of fragmentation hazards from an explosion.
Hazard-mitigating design details of typical interior elements (including glazing) have been developed
and professionally drafted. Refer to Appendix D for the drafted book of details.
This section discusses crowd-mitigation strategies related to blast risks. Refer to PARAS 0013 for other
crowd-mitigation strategies.

4.4.1 Crowding at Airports

Typically, the major non-secure areas that are prone to crowd accumulation from queuing include
departure halls, security checkpoints, domestic baggage claim halls, meet-and-greet areas, taxi queues,
and mixed-mode transportation hubs.
To subjectively assess the passenger experience at an airport, the International Air Transport Association
(IATA) and Airports Council International jointly provide metrics to determine the Level of Service of
an airport. The metrics are primarily based on the wait times and space provision at each facility. A
well-designed airport has properly sized facilities to process the passenger volumes in a timely manner
with acceptable queuing and accumulation, thus limiting crowds.
Table 4-12 and Table 4-13 show the metrics to measure Level of Service, as presented in IATA’s 9th
and 10th editions of the Airport Development Reference Manual (ADRM). In the remainder of this
section, any reference to passenger wait time limits and space requirements is based on these two tables.
Another level of service criteria also exists for passageway widths. Table 4-14 shows the Level of
Service standards for passageways, measured in passengers/meter of width/minute. This allows for the
required corridor width to be determined given the passenger flow.
Most airports aim to provide enough facilities to achieve Level of Service C, or optimum provision,
during typical peak hours. Using these standards results in different processor requirements, which are
dependent on the operating parameters at each airport that include peak hour volumes, processing rates,
and passenger composition.
Table 4-12. Waiting Time Standards (ADRM 9 and 10)
Level of Service Guidelines for Airport Terminal Facilities

Comparison ADRM 9th & 10th Edition
WAITING TIME STANDARDS FOR PROCESSING FACILITIES (Minutes)

Passenger Terminal
Economy Class Business Class/First Class
Processor
ADRM 9th Edition A B C D E A B C D E
Over Over
ADRM 10th Edition Optimum Suboptimum Optimum Suboptimum
design design
Self
Service
Boarding 0–2 >2 0 0–2 >3
Pass/
Tagging
Bag Drop
Desk
Check- (queue
in 0 0–5 >5 0 0–3 >3
width 1.4–
1.6m)
Check-in <12 >12 Business <3 >3

Desk <10 10–20 >20 Class <3 3–5 >5
(queue
width 1.4– First <3 >3
1.6m) Class 0 0–3 >3
1.8 2.4 3 0.6 0.8 1


Security Checkpoint
<5 5–10 >10 0 0–3 >3
(queue width 1.2m)
Emigration (Passport 3 4 5 1 1.3 1.7
Control)
(queue width 1.2m) <5 5–10 >10 0 0–3 >3
Immigration 4.2 5.6 7 1.4 1.9 2.3

(Passport Control)
<10 10 >10 <5 5 >5
(queue width 1.2m)
Transfers <5 5 >5 0 0–3 >3
Baggage Claim Area <12 >12 <12 >12
Narrow Body
<0 0–15 >15
Aircrafts 0 0–15 >15
Wide Body Aircrafts <0 0–25 >25

Table 4-13. Space Standards (ADRM 9 and 10)

Passenger Terminal Processor SPACE STANDARDS FOR WAITING AREAS (sf/pax)

ADRM 9th Edition A B C D E
ADRM 10th Edition Over design Optimum Suboptimum
33.4 29.1 24.8 20.5 16.1
Public Departure Hall
>24.8 24.8 <24.8
24.8 20.5 18.3 17.2 16.1
Self Service Boarding Pass/Tagging
19.4 14.0–19.4 14.0
24.8 20.5 18.3 17.2 16.1
Check-in Bag Drop Desk (queue width 1.4–1.6m)
19.4 14.0–19.4 14.0
24.8 20.5 18.3 17.2 16.1
Check-in Desk (queue width 1.4–1.6m)
19.4 14.0–19.4 14.0
Security Checkpoint 15.1 12.9 10.8 8.6 6.5

(queue width 1.2m) >12.9 10.8–12.9 <10.8
28 21.5 18.3 14 10.8
Baggage Claim Area
Narrow Body >18.3 16.1–18.3 <16.1
Wide Body
>18.3 16.1–18.3 <16.1
26.9 22.6 18.3 14 9.7
Public Arrival Hall
>18.3 16.1–18.3 <16.1
Table 4-14. Level of Service Standards for Passageways (Odoni 2003)

Level of Service Standard
Type of Passageway (passengers/meter/minute)
A B C D E F
Corridor (Regular Pace) 10 12.5 20 28 37 more
Stairs (Slow Pace) 8 10 12.5 20 20 more
For a given airport condition, pedestrian modeling combined with injury evaluation can be undertaken to
determine the volume of passengers that may be vulnerable to a blast event. For example, due to effects
of a blast wave itself (ignoring fragmentation), radii of casualties measured from the detonation point
would be expected as shown in Table 4-15 and Figure 4-33 below. These calculations are based on UFC
3-340-02, but are only approximations, as injury is highly dependent on the explosive, the environment
in which it detonates, and the body type. When overlaid on a pedestrian model, the reduction in
vulnerability that occurs in a crowd-dispersed area is evident.

Table 4-15. Example Radii of Casualties due to Blast Wave for Typical PBIEDs
Radius of 99% Threshold Radius of 50% Threshold

PBIED
of Lung Damage of Eardrum Rupture
10 lbs 2.3 ft 16.7 ft

25 lbs 4.6 ft 23.3 ft
50 lbs 6.9 ft 29.5 ft
75 lbs 9.1 ft 34.1 ft
100 lbs 10.8 ft 37.4 ft
Figure 4-33. Example Vulnerability of Crowding
Expected Casualties Expected Casualties in

in Crowded Area: Crowd Dispersed Area:
64 9
Global air traffic volumes are projected to double in the next 15 years (Airbus 2017). To meet the
increasing demand, airports and airlines are continuously adapting their facilities and introducing
innovative ways to process passengers. For some airports, it is simply a matter of providing more
counters or security lanes for processing passengers; for airports where space is limited, they must adopt
innovative and more efficient ways to process passengers.
4.4.1.1 Customer Service and Commercial Benefits

Passengers become dissatisfied and frustrated when they experience long wait times and crowding at
check-in, security, or baggage claim. In addition to reducing the attractiveness of the target and potential
of injuries and casualties from an attack or blast, reducing crowding in such areas makes for a better
passenger experience. This results in more satisfied passengers, which have a positive impact on sales at
retail offerings on the secure side of the airport. A study of over 300 airports showed that a 1% increase
in passenger satisfaction delivers a 1.5% increase in non-aeronautical revenue (Airports Council
International 2016).

A study carried out by DKMA concluded that by improving passenger experiences, passengers would
spend 10% more time at the airport, would be twice as likely to shop, and would spend 7% more on
duty-paid and 20% more on duty-free products.
4.4.1.2 Recommendations
The positive airport passenger experience is challenged by the security screening checkpoint, which is
usually rated as the most stressful part of the airport experience. In addition to screening passengers, a
secondary intention of the security screening process is to get people into the airside area as soon as
possible. The advantages of this are twofold: faster access to retail areas that generate airport revenue,
and the airside area is more secure than the landside areas of an airport. This can be achieved by
discouraging people from lingering in higher risk areas, such as the landside retail areas and creating
desire and incentives for people to move into the secured area.
Better passenger experience in the checkpoints can reduce levels of stress, which in turn can contribute
to passengers’ willingness to spend more money in retail areas, thereby generating higher non-
aeronautical revenues. In another study, ICF calculated that by increasing passenger dwell times in
airside areas by 10 minutes, the airport’s revenues would increase by 12%. This dwell time can be
increased in different ways; those relevant to this project are faster check-in and security screening
processes.
The potential for crowd mitigation to potentially improve customer service and increase airport
revenue is a key differentiator from traditional blast-mitigation strategies. It is recommended that
crowd mitigation techniques be incorporated to reduce blast risks as part of an airport’s holistic security
strategy. This includes decreasing queues, dispersing pick-up points, and re-working layouts for meet-
and-greet areas.
4.4.2 Departure Flow

The traditional check-in model consists of a group of staffed counters where passengers present
identification, select a seat, obtain a boarding pass, and check their luggage. This process typically takes
2-3 minutes per passenger. IATA standards recommend a maximum wait time of 20 minutes at these
counters for regular passengers, and under 5 minutes for premium passengers. For some low-cost
carriers, wait times of more than 30 minutes are not uncommon. In this model, each counter may have
ten passengers waiting during peak times.
The shift to automation has introduced self-serve kiosks to the check-in process. These kiosks can
perform many of the check-in tasks that are traditionally performed by airline staff at counters, including
seat selection and boarding pass printing. In an automated check-in process, only the passengers with
luggage or with difficulties at the kiosks would need to visit the staffed counters. To encourage kiosk
use, airlines often provide enough kiosks to maintain nearly free-flow conditions with close to zero
queue time at kiosks.
Some airlines and airports go one step further and allow printing of bag tags for checked luggage at
kiosks. Passengers then tag their luggage themselves and further reduce contact time at bag drop. Bag
drop contact time at the infeed belt is reduced to simply scanning the boarding pass/bag tag and then
placing the bag on the conveyor. This drastically reduces wait times and queuing, mitigating the risk of a
blast.

4.4.3 Security Checkpoints

Currently, TSA requires that passengers take off their shoes and unpack certain items from their bags.
To accommodate these requirements, there is a dedicated space in front of the x-ray machines for
passengers to unpack and place their items into bins. Passengers are processed in series with each
passenger waiting for the passenger in front to finish.
Automated screening lanes (ASL) differ from traditional lanes by providing multiple parallel divestiture
areas. This allows several passengers to unpack simultaneously, which reduces the amount of time
passengers need to wait before beginning the divesting process. In order to accommodate the multiple
divestiture process, ASL lanes need to have larger divestiture and recomposure areas, and some ASL
lanes are designed with additional tables or zones for recomposure. As a result, ASL lanes can reach up
to 80 feet, while traditional lanes are typically 54 feet long.
Consider a theoretical case study of two different screening options. The first option uses traditional
lanes and the second options uses ASL machines, both with a target of 10-minute maximum wait time.
The demand applied to both options is constant, and the number of required lanes open is determined by
a discrete event simulation. Passenger accumulation for option two is not lower than that of option one.
This is because a faster lane can process more people within the 10-minute period.
In summary, ASL can help, but to get significant reductions in passenger accumulation, the
maximum wait time target must be lowered.
4.4.4 Additional Crowd Reduction Measures
4.4.4.1 Staffing and Operations

Airport processors, such as check-in, bag-drop and security screening, are typically not fully staffed
outside of peak times. During off-peak times, it is common for only a small portion of the facilities to be
staffed. As peak hour approaches, staffing increases to respond to growing queues. However, this is
typically a reactive process, meaning that there may already be a significant queue present before the
passenger demand peaks. During the peak, queues may grow beyond the designated queuing space,
which results in overcrowded areas.
One way to avoid overcrowding is to proactively staff the processors before the peak occurs. This will
keep queues at a minimum before the peak hours, and the queues will remain within the designated
queue space. Simulation models can be used to study the demand profile at the various processors and
inform how to best balance passenger accumulation and staffing cost.
4.4.4.2 TSA PreCheck

At many airports, TSA PreCheck travelers can make use of dedicated security screening lines. TSA
PreCheck is a trusted traveler program in which the traveler applies online and undergoes a background
check. PreCheck passengers do not need to remove shoes, laptops, liquids, belts, and light jackets when
going through security screening. PreCheck travelers usually go through a dedicated security lane,
which can often achieve 250 passengers per hour, without requiring the larger ASL machines. This
means that as more travelers qualify for TSA PreCheck, the same security facility and staffing level can
achieve a higher passenger throughput.

4.4.4.3 Systems Approach with Passenger Simulation

Due to the nature of the airport system, many of the departure processes are coupled together.
Passengers flow from one set of processors to the next. For example, if the check-in facilities of an
airport are unable to meet the demand, there will be crowding in the check-in hall, and security will
experience a lower demand. When the airport and its operators invest in upgrading check-in capacity,
the crowding at check-in may dissipate, but security will experience a higher demand. Without a proper
analysis of the entire departure flow, congestion may simply move to a downstream process.
Proper facility requirements can be calculated through a simulation study of the entire departure flow. A
balanced facility can be designed to meet the passenger demand and manage crowding most effectively.
Simulation can also help determine the optimal staffing levels throughout the day, during both the peak
and off-peak hours.
4.4.5 Arrival Flow
4.4.5.1 Greeters Accumulation

Greeters are friends, colleagues, or family members of the travelers; they can also be limo drivers or
other designated personnel for a traveler. They often wait at the arrival hall of the airport to meet their
travelers. They accumulate in non-secured areas at the arrival levels of the terminal building and can
potentially form large crowds.
To mitigate concentrated crowding of greeters at the passenger exit doors, some large international
airports have installed displays in the arrival halls. These displays are linked to CCTV cameras that
monitor the passenger exits from the secure areas. Greeters can watch the displays, which can be
scattered in the arrival hall, rather than just at the passenger exits. This helps avoid large crowds in front
of the passenger exits and improves flow.
4.4.5.2 Domestic Baggage Claim Carousels

In the United States, domestic baggage claim carousels are typically in the non-secure areas of the
airport. Passengers typically wait up to 25 minutes at these carousels. Baggage claim is usually the only
task domestic passengers need to perform when arriving at an airport if they have checked luggage.
Domestic passengers will typically reach the carousels faster than their bags, which results in passengers
accumulating at carousels while waiting for their luggage. A faster bag delivery time can result in
passengers picking up their luggage more quickly, which would reduce crowding at the carousels.
Domestic baggage claim halls can be made more secure by limiting access to the public. For some
airports, this can be a simple matter of placing security agents at the exits of the baggage claim halls. For
others, it may require complex reconfiguration of the layout.
4.4.6 Traditional Analysis versus Passenger Simulation Model

Airport facility requirements can be calculated using traditional static calculation methods and planned
peak hour volumes. These traditionally served airport planners before airport simulation became
affordable. A thorough simulation of the departure and arrival flow of an airport can investigate the
following phenomena that were not viable using traditional static methods:

• The effect of peak spreading and residual queues

• Passenger surge demands (e.g., multiple aircraft de-boarding or train de-boarding)
• Variable staffing levels
• Check-in counter sharing
• Greeter-passenger and passenger-bag matching
Figure 4-34 and Figure 4-35 show the arrival and departure passenger volumes during a planning day for
a sample mid-sized airport.
Figure 4-34. Hourly Arrival Passenger Volume for Mid-Sized Airport
Arrivals Passenger Demand

Terminating Connecting Total Arrivals
6000
5000
Passengers per Hour
4000
3000
2000
1000
0
00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00
Figure 4-35. Hourly Departure Passenger Volume for Mid-Sized Airport
Departure Passenger Demand

Originating Connecting Total Departures
7000
6000
Passengers per Hour
5000
4000
3000
2000
1000
0
00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00
This type of demand reveals several characteristics about the airport:
• The airport predominantly serves its local population. The large percentage of Originating and
Terminating passengers shows that most passengers at this airport either began or ended their trip
at this airport. The other type of airport is a transfer hub airport, which serves mostly connecting
passengers. Atlanta’s Hartsfield-Jackson International airport is an example of a transfer hub

airport. An airport with more originating/terminating passengers will expect more landside and
non-secure traffic than a transfer hub airport of the same size.
• The main departure peak hour is in the morning. Many domestic US airports have a high
departure peak in the morning. Each morning, most airlines aim to have their flights take off as
soon as the flight crew is ready to fly, in order to achieve a high utilization ratio of their aircraft.
This results in a “rush hour” in the morning that lasts 1–2 hours. The morning departure peak at
this airport lasts over 3 hours. This may be an indication of a constrained operation, as there may
not be enough runway or aircraft stand capacity to accommodate the morning peak, pushing
departures into the late morning.
• There is a small arrival surge in the early morning, and this peak is mostly connecting
passengers. As such, the airport needs to be staffed to handle this traffic. If the arrivals are
international flights, transfer security and immigration need to be staffed to accommodate this
surge in the morning.
• There is a small departure surge late at night, indicating departures of overnight red-eye flights.
In the US, airports on the west coast tend to have a higher late-night departure peak, as they have
many red-eye departure flights heading to the east coast.
In a simulation model, the demand level of the planning day can be studied closely. Nuances in the
passenger demand and facility plans can be scrutinized to determine potential shortfalls in the facility.
Passenger crowd levels can be monitored in the simulation model, and the resulting level of service of
the facility can be predicted with sufficient time to adjust the plans and designs.
The planning day is often not the same as the busiest day of the year. Instead, the planning day
represents a typical busy day at the airport. Depending on the airport, the planning day may be the 95th
percentile in daily traffic, or it may be the day with the 30th busiest hour of the year. Airport planners
often use the planning day to design airport facilities, and accept a lower level of service during the
busiest days of the year (Thanksgiving, Christmas, and New Year’s Day). In these cases, passenger
simulation modeling becomes especially useful in predicting how the facility will perform and the
amount of crowding that will occur in various parts of the airport.
This leaves airports with greater vulnerability to attack on the busiest days, such as holidays. Airports
should offset this vulnerability by managing risks through other measures such as operations. This is one
of the key principles of the framework (explained in Section 5).
4.4.6.1 Ground Transportation

There are often many ways to access an airport, including personal vehicles, taxis, buses, subways, and
dedicated express rail. For the access modes provided by public transportation, there is a tendency to
design the stations and platforms like a typical terminal station. However, it is important to understand
that travelers at the airport often have carry-on and checked luggage, and passengers require more space
and are less maneuverable. The design parameters for the stations must reflect these realities.
For large airports, the vertical circulation cores connecting the ground transportation hub and the levels
of the terminal building can be complex. Pedestrian congestion models are useful in determining the
level of crowding within the ground transportation hubs and at critical vertical circulation cores. Using
these models, it is possible to determine which facility will experience passenger flow congestion, and at
what time of day it will occur. It is also possible to test any proposed solutions, which may be in the
form of additional escalators or elevators, widening of corridors and platforms, or relocating any of the
existing components. A passenger flow simulation model can be used to inform a holistic security

strategy whereby operations and technological measures are put in place to address predicted times of
heightened crowding.
4.4.6.2 Curbside and Vehicle Simulation

Airport groundsides are complex spaces with a wide variety of different vehicle types and users
interacting in a shared zone. During the planning of airport construction or refurbishment, vehicle
simulation is often used to plan lane access and allocation for various vehicles.
It is possible to test various design scenarios to determine vehicle queue lengths, delays, and likely
overflow space required. Solutions and mitigation strategies can then be tested. These vehicular
simulation models can also inform pedestrian models of groundside areas by determining likely crossing
delays.
4.5 Architectural Design Measures

Architectural design measures are best incorporated in new projects where designed-in solutions can be
more easily accommodated. This is most important for those strategies that are considered “big picture”
such as airport planning and layout; however, “small picture” considerations such as construction
materials and furniture selection can also reduce risk, especially for existing airports. This section
mentions a few of these architectural strategies that can help reduce blast risks.
Big picture considerations include:
• Roadway layout
o Design roadways with curves to limit the maximum speed that could be achieved by an
attacker.
o Separate roadways for the public and staff, as well as roadways for authorized vehicles
that need to access the loading dock. This way, appropriate access control measures can
be incorporated for different types of use.
• Do not locate critical utilities in landside areas vulnerable to explosive attacks, or otherwise
provide redundant systems. The minimum standoff distance from utilities to vulnerable areas
should be based on the specific DBTs for a particular airport, and the impacts to the construction
of that airport. Specifying a one-size-fits-all standoff distance could not ensure a specific
performance objective is achieved. There is guidance in government-based criteria, but this
guidance is based on the DBTs identified by those government agencies as risks to their
particular facility types.
• For a new build, the loading dock should ideally be isolated from the terminal building or
otherwise located to minimize impacts of an explosive incident on airport operations.
o However, in many cases of existing buildings or airports with space constraints, there are
many security measures that can be implemented (e.g., access control, vehicle screening,
visual inspections, etc.) to reduce risk such that it is possible for loading docks to be
located closer to or near critical assets. The framework process in Section 5 can help
identify measures for the loading dock, which may result in enough risk reduction that
location of the loading dock becomes less critical.
o It is typically good practice to include a frangible (i.e., allowed to fail) exterior wall on
the loading dock such that blast loads can dissipate rather than build up. This may not be
necessary if the DBTs identified for the airport in consideration are small enough, or the
construction of that particular loading dock can tolerate the blast loading.

• Terminal planning and layout, as they relate to crowd dispersal and management: greeter, check-
in, and baggage claim areas can be configured using pedestrian modeling to reduce choke points
where crowds or queues could be funneled.
Small picture considerations include:
• Ductile construction materials (i.e., metals instead of unreinforced masonry, laminated glass
instead of monolithic for interior glass partitions and handrails, etc.) can be used.
• Critical structural elements can be protected by wrapping them with architectural cladding or
furring to increase standoff against a PBIED (even a few inches provides benefit).
• Trash cans or other features that could conceal PBIED explosive devices should be located away
from critical structural elements.
• Furniture in non-secure areas should be selected and placed to allow for clear vision and
unobstructed lines of sight for patrols and CCTV to more easily detect suspicious objects. Design
measures to mitigate other security concerns such as active shooter incidents may have
conflicting requirements whereby locations for cover are needed; therefore, the risks of different
incidents should be compared and managed on a case-by-case basis.
• Landscaping that reduces the risk of both VBIED and PBIED incidents can be incorporated.
Landscaping should be integrated with the HVM strategy.
Refer to PARAS 0004 for additional considerations in terms of airport design for security purposes.
4.6 Elevated Threat Levels

There are some instances in which airport security must adapt to an elevated threat level. This could be
due to intelligence information at a particular airport through local law enforcement or the airport’s FBI
liaison, or when the National Terrorism Advisory System (NTAS) scale issues an elevated, intermediate,
or imminent alert.
Category X airports are required to have a TSA-approved Contingency Plan for VBIED threats. This
section discusses methods for developing those plans for Category X airports, and considerations for
other airports as to how to mitigate risks of elevated threat levels within their security strategy.
It is necessary to quickly deploy temporary solutions to mitigate the increased risk. Operational
measures are almost exclusively required for fast deployment, but some technological and physical
solutions can be incorporated relatively easily. To be prepared to respond quickly, airports should have a
plan in place to adapt to this heightened threat level.
Airports may consider performing a risk assessment that is based on a heightened threat level (i.e.,
likelihood of threats would be higher, threat scenarios might be different depending on potential
intelligence), and evaluating the threats and vulnerabilities that may exist in this heightened scenario.
Mitigations can then be theoretically developed for these higher risks. However, the mitigations selected
should be those that are needed to bring the airport from the current risk level to the higher risk level.
Therefore, they should not necessarily include physical enhancements that are implemented to achieve
that absolute level of risk mitigation, as these are permanent and may not be an efficient use of
resources.
In the context of this guidebook, the framework process described within Section 5 can be used to
support this effort. After mitigation measures have been selected based on the current risk assessment,
they can be assigned as a baseline and then supplemented with additional strategies to evaluate the extra
level of security that is achieved. It is most likely that this will result in an increase of performance tier

for the baseline operational strategies (e.g., adding more EDC patrols to move from Silver to Gold) or
the introduction of new operational strategies that are not incorporated into the baseline level of
operations (e.g., adding behavior detection officers, or adding vehicle screening checkpoints).
To mitigate risks of a blast threat on an immediate or imminent basis, the following strategies can be
considered in the airport’s elevated threat plan, or contingency plan:
For VBIED:
• Provide vehicle screening checkpoints with guards

• Reroute traffic lanes away from the terminal using temporary barriers and traffic officers
• Assign staff to actively monitor CCTV for suspicious or abandoned vehicles
• Perform additional EDC patrols in areas with vehicles
For PBIED:
• Perform additional EDC patrols in areas with vehicles

• Increase armed law enforcement patrols (i.e., high visibility as a deterrent)
• Incorporate additional screening of individual measures (e.g., random) before entering the
terminal
• Assign staff to actively monitor CCTV for suspicious persons or abandoned luggage
Add staff to check-in and screening to move passengers more quickly to the secure airside

SECTION 5: IMPLEMENTATION
This section examines the feasibility of the measures discussed in Section 4 and facilitates the
development of a blast-risk-reduction strategy consisting of a combination of blast-mitigation measures.
The following sections present a framework process to assist airports in evaluating these considerations.
Airports should follow the decision-making process outlined in Sections 5.2 through 5.5 to determine
which measures to implement and where. An Excel-based tool and corresponding instructions for
carrying out the framework accompany this guidebook. Furthermore, two case studies are presented
within Appendix B.
Once an implementation strategy is realized, the risk-reduction value can be observed. This will consider
both how much the strategy reduces the risk(s) and what the non-risk-related implications of measures
might be. Implications may include whole of life costs, disruption required to implement, time to realize
value, operational and infrastructure changes required to implement the measures, and impact on priority
business objectives like passenger experience and architectural objectives.
5.1.1 Framework Objective

The framework is a process for identifying cost-effective security measures that mitigate blast risks to an
acceptable level. Figure 5-1 shows how the framework process fits into an airport’s overall risk
management process and outlines the four steps of the framework.
The framework is to be performed after a risk assessment that has identified credible blast threats,
vulnerable locations to those blast threats, and the consequences of those threats. After using the
framework process to determine viable combined security measures, the reduced or residual risk when
the measures are implemented should be confirmed to be acceptable.
The framework is intended to be used following a robust security risk assessment process. It does
not provide a method to identify risks, but attempts to methodically break down the risks and
vulnerabilities identified and couple them with optimum mitigation measures.

Figure 5-1. Framework Process
Regulations Residual Risk

Implementation
and Risk Evaluation; Risk
(Framework)
Assessment Management
Step 2: List and

Step 1: Input critical
score existing and
areas and
potential mitigation
vulnerabilities
measures
Step 3: Gather cost Step 4: Calculate

estimations for effective
potential mitigation combination of
measures measures
5.1.2 Role of the Risk Assessment in the Framework

PARAS 0016 Airport Security Vulnerability Assessments is in progress as of the publication of this
document. A security vulnerability assessment is a prerequisite to the use of this framework. A simple
explanation and definition of the risk assessment process is included as part of this guidebook to provide
the context for the framework used in selecting blast-mitigation measures.
Decisions regarding site vulnerabilities are a required input. For the purposes of demonstrating this
framework, generalizations regarding vulnerabilities and risk appetite specific to life safety, commerce,
and operations have been made within this section. The intent of the framework is not to substitute for a
robust risk and vulnerability assessment undertaken by airports and relevant stakeholders.
When the risk assessment is conducted and it is agreed which risks need to be mitigated (based on risk
appetite), the measures that will be relevant and effective in reducing the risk(s) can then be identified.
In some cases, there may be more than one measure (or combination) that can reduce the risk, and a
decision will need to be made to determine the most appropriate measures. The following are
considerations that may be useful in making that determination:
• How much does each measure, or combination of measures, buy down the risk? (i.e., what is its
return on investment?) It may be that one measure reduces the risk more than others but the
reduction is far beyond what is necessary.

• Consider whole-of-life costs as well as the cost of other security resources/measures required to
realize this measure’s risk-mitigation value; e.g., active vehicle barriers will require operational
resources such as a static guard or electronic access control passes to operate the barrier.
• Subject to the airport’s financial management arrangements, funding may be sourced differently
based on the type of measure, e.g., capital expenditure versus operating expenditure or grant
versus self-funded. Additionally, and again subject to the airport’s financial arrangements, the
time at which the measure is needed versus the time within the financial year may be an
influencing consideration.
• Time to realize the measure’s risk mitigation value—in some cases, the implementation time is
not feasible relative to the current need. For example, installing blast film on a facade may take
up to six months (including procurement process), whereas the establishment of a standoff zone
could take less than four hours.
• Impact on other business objectives, e.g., architecture, passenger experience, airport image, and
non-aeronautical revenue.
• Impact on regulatory requirements, e.g., fire safety, health, and safety.
• Indirect benefits, e.g., improved wayfinding, pedestrian safety, reduced accidental incursion, and
architecture.
• Relative ease or “hassle factor” to implement, e.g., rerouting of traffic, use of scaffolding, after-
hours work, or incorporation into another project scope to enable works required.
• How available is the resource? Can the measure be achieved in-house or is external resourcing
required?
The value or weighting of each of these considerations will be different for each airport and most likely
in each circumstance. The framework is a process for decision-making that can be customized. This
guidebook makes assumptions about the inputs in order to demonstrate the process. These or other
factors can be customized into the framework process for a more unique assessment.
5.2 Step 1: Assessment of Vulnerabilities

As part of the risk assessment process, various landside areas of the airport may be identified as being
vulnerable to blast threats. Step 1 of the framework is to take these vulnerable areas and classify the
specific vulnerabilities into definitive categories. As a basis for demonstrating the framework process,
three vulnerability classifications that could be exposed from a blast threat are as follows:
• Life safety
• Commerce
• Operations
Ultimately, these vulnerability classifications for various areas will be used to identify mitigation
measures that have strengths for reducing a particular vulnerability type.
5.2.1 Life Safety

In most instances, life safety is the primary objective for the application of blast-mitigating measures in
most landside airport areas. Simply, it is the ability of mitigation(s) to reduce or prevent the number of
casualties or injuries from a potential blast attack. With regards to life safety specifically, the
vulnerability of an area can be assessed on the basis of the following:

• Number of people
• Concentration of people
• Predictability with which the crowded places occur
• Exposure of the crowd to potential PBIED or VBIED effects
5.2.2 Commerce
Airports are inherently businesses; the ability of mitigations to reduce the commercial impact on the
airport’s business is important in enhancing the resilience of the airport’s business. The commercial
vulnerability of an area is assessed on the basis of the following:
• Proximity to areas that generate airport revenue such as a parking garage, tenancies, shops, etc.
• Proximity of areas that contain or house infrastructure or equipment
• Reputational loss
• Financial replacement cost
5.2.3 Operations
While in some ways tied to the commercial aspect of an airport, the airport’s ability to restore its
operational function is a key objective following a blast event. Evacuation, rescreening, airport shut
downs, and flight delays have large economic consequences for the airport, airlines, passengers, and the
region. With regards to operations, the vulnerability is assessed on the basis of the following:
• Disruption to flight schedules – delay or cancellation of flights

• Proximity to critical infrastructure and equipment necessary for airport operation
• Proximity to airline areas of operation
• Disruption to transport modes to the airport
• Disruption of evacuation and recovery procedures for an airport
• Lack of redundancy of any area, system, or equipment critical to airport operation
5.2.4 Managing Vulnerabilities

Any decision-making process regarding the allocation of blast-mitigating measures should consider the
applicability of those measures to reduce the landside area’s vulnerability. The vulnerabilities of two
very different landside areas at a theoretical airport have been used as an example. These are theoretical
weightings, and it is expected that vulnerabilities for a particular airport would be based upon a risk
assessment process.
As shown in the example, the arrival and departure halls are largely vulnerable to life safety given the
density and frequency of crowds. However, the fuel farm is largely vulnerable to operational
considerations, with fuel a necessity for aircraft flight. It would therefore be expected in this instance
that mitigation measures for a blast would differ substantially between the two areas.
To complete Step 1, identify these weightings for each vulnerable area using ratios. Noting that the
example ratios can be modified to suit a particular airport, in the example above, this would be as
follows:

Table 5-1. Example Vulnerability Weightings for Theoretical Airport
Vulnerable Area Life Safety Weighting Commerce Weighting Operations Weighting
Arrival and Departure Halls 0.85 0.05 0.10

Fuel Farm 0.05 0.35 0.60
Table 5-1 demonstrates default vulnerability weightings for a number of landside areas of a theoretical
airport. These vulnerability weightings are used in the framework (Step 2) to identify mitigation
measures that have strengths in mitigating against certain vulnerabilities.
The vulnerability weighting of the arrival and departure halls and fuel farm have been graphically shown
within Figure 5-2.
Figure 5-2. Example Vulnerability Assessment, Arrival and Departures Hall (left); Fuel Farm (right)
Figure 5-3. Vulnerability Weightings for Various Areas of a Theoretical Airport

In addition to the landside areas shown in Figure 5-3, the following areas may be considered in the
airport’s risk assessment process:
• Emergency electrical or mechanical areas, e.g., generator or switchgear and cooling systems for
server rooms that support critical electrical systems
• Rental car facility
• Loading dock
5.3 Step 2: Assessment of Measures

Step 2 of the framework encompasses three parts:
• List: Cataloging a “shopping list” of security measures available to reduce the likelihood or
consequence of a blast attack at each vulnerable area.
• Classify: Classification of the listed measures under the previously defined vulnerability
categories: life safety, commerce, and operations.
• Score: Evaluation of existing-measure performance tiers and desired level of new-measure
performance tiers (if applicable).
5.3.1 List
Compile a list of measures applicable to each vulnerable area that ideally includes physical,
technological, operational, and architectural/crowd-management measures. Some example measures for
consideration on the list were discussed in Section 4. The lists should include measures that currently
exist, if any. The lists should exclude measures that are not feasible to implement or not applicable for a
particular area. For example, within the departure hall, an airport may exclude a new blast-resistant
facade or structural enhancements if terminal construction was just completed. As another example, an
airport would exclude a new blast-resistant facade from consideration at the fuel farm, where it is not
applicable.
5.3.2 Classify
This step will ensure that when combinations of measures are created in upcoming Step 4, measures are
selected based upon their suitability for mitigating the particular vulnerabilities of the area in question.
For example, this process will eliminate behavioral detection as a measure for fuel farm areas. To
complete the measure classification, classify each listed measure with respect to the three vulnerabilities
if it achieves one or more the following:
Life Safety: Mitigation measures should aim to reduce injuries and fatalities to passengers and
people within landside areas. This can either achieved by preventing the attack from occurring or
reducing the consequence of a blast event.
Commerce: Mitigation measures should aim to reduce the commercial consequences from a
blast attack such as investor value, cost of recovery, cost of operational disruption or opportunity
cost of future additional security measures. This can be achieved by either preventing the attack
from occurring or reducing the consequence of a blast event.

Operations: Mitigation measures should aim to reduce the period in which the airport is
operating in crisis-management mode and to improve the efficiency and effectiveness of the
recovery period before returning to normal operations following an attack. This includes
minimizing damage to assets, business continuity preparedness, incident management, and
assisting in the emergency response.
For example, EDCs are classified as a life safety measure because they aim to proactively detect
suspicious persons and neutralize them, thus potentially preventing an attack from occurring and
mitigating the life safety vulnerability. EDCs are typically deployed within areas of crowds and,
therefore, are not considered a commerce or operational-driven mitigation measure.
Table 5-2 lists and classifies mitigation measures under the vulnerabilities of life safety, commerce, and
operations.
Table 5-2. Mitigation Measure Classification
Life Safety Commerce Operations
• Terminal Finishes and Furniture • Hostile Vehicle • Hostile Vehicle Mitigation (HVM)
Mitigation (HVM)
• Hostile Vehicle Mitigation (HVM) • Evacuation procedures and
• Structural Hardening emergency response
• Structural Hardening
• CCTV • Structural Hardening
• Facade Enhancement
• Security Patrols • CCTV
• Security Patrols
• Vehicle Checkpoint and • Facade Enhancement
• Explosives Detection Canines
screening
(EDC) • Security Patrols
• Access control
• CCTV • Vehicle Checkpoint and
Screening
• Screening of Individuals
• Communication techniques
• Crowd Reducing Measures
• Security management systems
• Vehicle Checkpoint and
Screening • Business continuity preparedness
• Behavioral detection
• Changes to passenger behavior
and habits
• Evacuation procedures and
emergency response
• Advanced Passenger information
5.3.3 Score
Scoring requires evaluating the performance of each measure and assessing how its performance is
effective in mitigating a blast threat. This comprises two factors that are interrelated as shown in Figure
5-4.

Figure 5-4. Tiers of Performance and Scoring
Score particular
Identify tiers of strengths and
performance for a weaknesses for
given measure different tiers of
performance
Platinum Detect
Gold Delay
Silver Disarm / Disable
Bronze Inform
Crowd Reduction
Protect People
Protect Property
This step can be customized to identify performance metrics that are important to that airport. More
formally, to encompass the sliding scale of a measure’s performance, measures are divided into four
tiers — Bronze, Silver, Gold, and Platinum. Each tier of a measure is determined based on a subjective
incremental score for various security metrics (e.g., ability to detect, ability to protect, or aesthetics),
with Platinum levels representative of very best practice. It is expected that a Platinum level of
performance carries a higher cost than a Bronze level of performance.
The tier approach is intended to draw out the relative merits and implications associated with each risk
mitigation measure on the “shopping list” rather than an absolute and actual/guaranteed reduction in
risk. The model is purposefully idealized for ease of use, but with that comes the inability to capture all
the complexities associated with operating an airport in a rapidly changing threat environment. For
example, the effectiveness of a security guard measure is dependent upon organizational culture, which
will be unique to the airport, the guard company, and potentially the locations to which guards are
deployed (e.g., terminal versus fuel farm versus tenants). This will need to be considered by the airport,
hence the need for the airport to calibrate the framework model when using it. The model is designed to
provide airports with a greater insight into the implications and value of the various risk reduction
measures so they can in turn make investments that are better aligned to their risk appetite and business
objectives.
Following is a worked example of this step using HVM (as a stand-alone measure) and its effectiveness
across multiple security metrics shown graphically within Figure 5-5. In relation to the definition of

these levels for HVM, please refer to the broad definitions contained within Table 5-3. These definitions
have been formed by weighing cost and performance using professional opinion of already established
measures. It should be expected that a Platinum level of HVM performance carries a higher cost than a
Bronze level of performance. These tables have been developed for all proposed mitigation measures
and are shown in Appendix A.
Table 5-3. Definitions for the Various HVM Tiers of Performance
Hostile Vehicle Mitigation
Tier Description
Provides visual deterrent with limited vehicle physical impairment. Following impact with hostile
Bronze vehicle, vehicle speed largely consistent, leaving the vehicle drivable. Examples include
architectural bollards and raised curbs.
Provides visual deterrent with moderate level of vehicle physical impairment. Following a collision,
Silver a vehicle will sustain heavy damage but may still be drivable. Barriers are generally untested for
hostile vehicle impact. Examples include jersey barriers, trees, street poles, and street furniture.
Provides visual deterrent with high level of physical impairment. Barriers have been assessed using
Gold engineering calculations and analysis. Does not have the impact and penetration assurance
compared to a barrier that has been impact tested.
Provides visual deterrent and significant physical impairment. Barrier is impact rated to ASTM,
Platinum DOS, IWA, or any other industry-recognized standard. Barrier has a suitable vehicle penetration
performance.
Using the scoring metrics on the right side of Figure 5-4, Step 4 of the framework will select
combinations of measures that complement each other. For the framework to achieve this, measures
need to be assigned subjective values to distinguish their means of providing blast mitigation and their
impacts (i.e., ability to deter a threat, ability to detect a threat, adaptability/flexibility, aesthetics, etc.).
An example of what is required for each measure is shown in Table 5-4 and Figure 5-5 for HVM.
Table 5-4. Default Effectiveness Scores for the Various HVM Tiers of Performance
Crowd Protect Protect

Tier / Score Detect Deter Disable Inform
Reduction People Property
Bronze 0 5 0 0 0 5 10
Silver 0 10 5 0 0 10 15
Gold 0 15 10 0 0 15 20
Platinum 0 15 15 0 0 15 30

Figure 5-5. Scoring of Hostile Vehicle Mitigation as a Blast-Mitigation Measure
Additional default scores have been developed for several mitigation measures and are included in the
Excel-based tool that accompanies this guidebook. The scoring can be customized, but the default
scoring is based out of 100, whereby 0 means a measure has no contribution to the performance metric
and 100 means a measure completely achieves that performance metric (i.e., a Detect score of 100
would mean the threat is detected 100% of the time). Using this scoring system, none of the default
values inputted for measures exceed a score of 40. This is because none of the measures on their own
can achieve such high performance. This is an important realization of managing security mitigations
and should be considered carefully by the user before implementing.
5.4 Step 3: Financial Costs

Step 3 is to prepare a rough order-of-magnitude (ROM) cost estimate of the various mitigation
measures. To accurately compare capital and operational costs, these estimates should consider total life
costs. The estimate should account for the costs of the measure over all four tiers, or at minimum over
any tiers that the airport wishes to assess.
The aim of this exercise, together with the scoring of mitigations, is to provide airport operators or
stakeholders a methodology to put forward a simple business case to implement security measures. This
financial exercise is by no means exhaustive, and is targeted to make educated financial decisions
regarding security.
To compare the expense of measures that have capital costs (one-time investment) to measures that have
operational costs (recurring every year), Net Present Value (NPV) calculations should be performed. As
a default, the following assumptions can be used when combining the costs:

• Structural costs (assumed to recur every 25 years)

• Major capital costs (assumed to recur every 10 years)
• Minor capital costs (assumed to recur every 4 years)
• Operational costs (assumed to recur every year)
To apply costs to the framework, costs are only required for the measure tiers that the airport wishes to
consider in the process. However, it is beneficial to include more measures, tiers of measures, and
associated costs, as a greater number of measure combinations can be assessed during Step 4.
Example measure ROM costs are provided in Appendix C. The estimate is based on a medium-sized
airport and medium-sized city within the United States. This would include airports and/or cities like
Pittsburgh, Austin, New Orleans, etc. A factor can be used to translate the baseline estimate to large
cities (such as New York, San Francisco, Chicago, etc.) and conversely to small cities (such as Fresno,
Syracuse, Wichita, etc.) Factors for these examples are provided in Table 5-5. Because costs can vary
significantly by location, the relative cost difference of various measures should be assessed when using
the baseline data. The cost estimate does not include design costs, but only construction or operation
costs.
Also, note that this document is not dynamic; the cost data provided in this assessment was completed
during the beginning of 2018. There are many assumptions incorporated into the cost estimate. It is
meant to provide a relative reference between costs of different measure types, and it should not be used
to make explicit decisions about an actual project.
Table 5-5. Factors to Apply to Baseline Cost Estimate for Example Cities
Large City Airports Small City Airports
New York San Francisco Chicago Fresno Syracuse Wichita

155% 142% 130% 116% 94% 71%
In continuing with the above HVM example, Table 5-6 shows example ROM costs for constructing
HVM at a medium-sized airport. To determine this, a security or blast engineer and potentially civil
engineer would need to be consulted to identify which type of HVM measure is to be implemented,
where it should be implemented, and any construction issues.
Table 5-6. Example ROM Costs for HVM
Tier ROM Cost
Bronze $390,000
Silver $520,000
Gold $1,001,000
Platinum $1,300,000
5.5 Step 4: Effectiveness of Measure Combinations

Step 4 is the last step whereby all the information is consolidated for the purpose of decision-making.
Effective combinations of security measures are selected for review and cost comparison. Step 4 needs
to be completed separately for each vulnerable area in question.

Each time Step 4 is performed for a vulnerable area, each existing measure should be assigned the
appropriate tier for its current state. For example, when considering the departure hall, an airport may
have jersey barriers that separate the traffic lanes from the pedestrian space. The departure hall HVM
could be assigned a tier of Silver but no costs associated. For measures that are not currently existing but
are desired or known, a different tier can be selected and costs associated with it.
The calculation in this step will identify if effective measure combinations at the departure hall include a
Gold or Platinum level of HVM, thus indicating if improvements to the current state of HVM should be
considered.
While all of the mitigation measures presented within this section serve to reduce the blast risk, they do
so in various ways. Consistent with the traditional layered security approach, this proposed framework
attempts to capture a range of security objectives that act against the threat itself and/or its
consequences. The outcome of this methodology is to provide a basis for security investment spending
across multiple potential and feasible (for that airport) mitigations to achieve the desired security and
business outcome.
As the number of measures increases, an automated process is needed to support the model. The
accompanying Excel-based tool includes this process; customization of the tool is necessary. While a
qualitative approach has been used to calculate and illustrate the relative merits of security
measures, the resulting functional security score itself does not have quantifiable value. The
scoring instead keeps track of the qualitative assessments of measures.
Once the functional security scores are calculated, the decision-making can be evaluated. Figure 5-6
shows an example output of such an assessment. Each blue dot represents a combination of various
security measures for a particular vulnerable area. The combinations plotted in the lower left likely
include only one or two measures, so therefore they are relatively inexpensive and less functionally
effective (low functional security scores). On the other hand, the combinations plotted on the top right
are the most expensive, but also the most effective (high functional security scores).
Figure 5-6. Example of Combined Mitigation Measure Output
As an example exercise, if an airport has a budget of $60 million, the most cost-effective, relevant
measure combinations for the departure hall are shown graphically within the red circle in Figure 5-6,
acknowledging there is a degree of error and subjectivity to the measures rather than being an absolute

quantitative assessment. The airport would then evaluate the measure combinations within that red circle
to determine if any of them meet their blast risk objectives for the departure hall. Comparisons can also
be made between expenditure splits (physical, operational, and technology) of all measures under
consideration as shown within Figure 5-7.
Figure 5-7. Example of Expenditure Splits for Security Combinations under Consideration
Taking a broader view of the framework and applying it to various types of airports, relationships or
patterns can be made on the various optimum splits of combinations. For example, Figure 5-8 and
Figure 5-9 illustrate two theoretical outcomes for both an example new and an example existing airport.
For a given cost, two potential combinations of measures have been evaluated. While the new and
existing airports pose very different breakdowns of measures as would have been listed during Step 2,
their overall resulting functional security score is similar. Not surprisingly, the idealized new airport had
a higher weighting of physical measures, whereas the existing airport favored operational measures. It
should be noted that within the framework process, crowd-management techniques are considered to be
operational strategies.
Figure 5-8. Breakdown of Mitigation Measures (Vulnerability-Based): Example New Airport vs. Example
Existing Airport

Figure 5-9. Breakdown of Mitigation Measures (Metric-Based): Example New Airport vs. Example Existing
Airport
Once the effective measure combinations have been assessed, the airport would select which mitigation
measures to employ in that particular vulnerable area. This concludes the framework process (middle
box in Figure 5-10). Returning to the overall risk-based process, the airport would need to confirm that
the implemented measures have reduced the risks and have been managed appropriately.
Figure 5-10. Summary of Framework Relationship to the Risk Assessment Process
Residual Risk
Regulations and Implementation
Evaluation; Risk
Risk Assessment (Framework)
Management
The entire framework procedure (Steps 1–4) needs to be repeated for each vulnerable location in
consideration. Refer to Appendix B, which demonstrates a case study of the framework’s
application.
Not included in this process, but an important concluding note, is that identification of the security
strategy on paper is different from its actual implementation; by design, the strategy can only be as good
as how it is implemented by the responsible managers and staff. The framework process should provide
a sound basis to start from, but it does require some level of subjectivity by those implementing it;
refinement and modifications to the outcomes of the framework are undoubtedly required. Furthermore,
the strategy’s effectiveness in operation should be evaluated and re-evaluated on a regular basis to make
sure the strategy is working as intended.

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ABBREVIATIONS, ACRONYMS, & INITIALISMS

ADRM Airport Development Reference Manual
ASCE American Society of Civil Engineers
ASF Anti-Shatter Film
ASL Automated Screening Lanes
ASP Airport Security Program
CAPPS Computer-Assisted Passenger Pre-screening System
CCTV Closed Circuit Television
CFR Code of Federal Regulations
EDC Explosives Detection Canine
FAA Federal Aviation Administration
FBI Federal Bureau of Investigation
FHWA Federal Highway Administration
FoH Front of House
HVM Hostile Vehicle Mitigation
IATA International Air Transport Association
ICAO International Civil Aviation Organization
IED Improvised Explosive Device
IP Internet Protocol
IT Information Technology
FEA Finite Element Analysis
FOV Field of View
LiDAR Light Detection and Ranging
MDOF Multiple Degree of Freedom
msec Millisecond
ONVIF Open Network Video Interface Forum
PBIED Person-Borne Improvised Explosive Device

PVB Polyvinyl Butyral
Psi Pounds per Square Inch
PSIA Physical Security Interoperability Alliance
RC Reinforced Concrete
ROM Rough Order of Magnitude
SARP Standards and Recommended Practices
SDOF Single Degree of Freedom
SeMS Security Management Systems
SSS Structural Silicone Sealant
TATP Triacetone Triperoxide
TNT Trinitrotoluene
TSA Transportation Security Administration
TVRA Threat, Vulnerability, and Risk Assessment
UFC Unified Facilities Criterion
UVSS Under Vehicle Surveillance System
VACP Vehicle Access Control Points
VBIED Vehicle-Borne Improvised Explosive Device
VCP Vehicle Control Post
VMS Video Management System

EVALUATION OF MITIGATION MEASURES
ASSESSMENT OF VARIOUS MEASURES

Explosives Detection Canines
SUMMARY
Explosives detection canines may be used to detect explosives, illicit materials, or weapons within
passenger bags or on the passengers themselves. The process is undertaken using specially trained dogs
and handlers, and may be performed either by law enforcement agencies or by specialist contractors.
The provision of the service should be incorporated within the wider security operation plan. It should
be noted that when the service is provided by law enforcement agencies, it is they who dictate the
provision and scheduling of patrols. When a private contractor is used, the asset operator has control
over coverage and scheduling.
As a result of recent events, canines are being trialed by Istanbul Atatürk Airport to detect suspicious
behavior. While this is not yet proven as effective, it is worth considering as a future operation that
police may utilize.
There are more than 900 TSA canine teams deployed nationwide that are tasked with screening
passengers and cargo, and supporting other security missions.
• In 2016, there were more than 200,000 canine utilization hours throughout the nation’s
transportation system.
• Canine teams work at more than 100 of the nation’s airports, mass-transit, and maritime systems
CONSIDERATIONS
Asset owners may want to procure canine programs from external providers as the costs of such
programs are extensive: approximately $35,000 for the dog and training and $6,000 annual welfare
costs.
Key factors to consider when using explosives detection canines include:
• A single dog may operate for up to 8 hours per day with alternating on-duty/rest shifts of 30–90
minutes.
• Welfare and rest facilities (air conditioning, water, defecation) are required that may not be
available in transport areas.
• Dogs are trained to detect specific scents; programs may take 15 weeks for explosives and 25
weeks for a broader range of chemicals.
• Detection canines can either be trained to detect illicit drugs or explosives, but not both.
• Conventional explosives detection canine handlers undergo a 10-week training course. Passenger
screening canine handlers undergo a 12-week training course.
EFFECTIVENESS
• Dogs are able to detect explosive material through sense of smell rather than visual observations.
• Dogs can act as a deterrent.
• Explosives detection canines can be deployed on a risk basis and to new and existing terminals.
• Dogs can be deployed anywhere within the FoH areas.
• Dogs can be used for random searches.
Blast-Mitigation Strategies for Non-Secure Areas at Airports A-1

• Dogs are effective in areas of patrol, depending on the number and frequency of patrols.
• Canine detection can be subject to handler biases.
• Dogs are normally trained to detect commonly used explosives such as TNT, C4, commercial
dynamite and Semtex. As terrorists adapt with different devices containing household chemicals
(e.g., TATP), the challenge of detection becomes harder.
Millimeter Wave Detection

SUMMARY
Millimeter wave (MMW) scanning constructs 3D scans by measuring how much of the radio signal is
reflected. MMWs are able to penetrate through certain surfaces (such as clothing) and reflect off of
others (such as metals). MMW systems have been adopted for use at airport security checkpoints, where
a 3D body scan of a person may be captured without them having to remove their clothing. Some
manufacturers may use microwaves to accomplish the same thing.
CONSIDERATIONS
• MMWs are considered non-ionizing, which makes them safer than x-rays. While there are still
concerns about their overall safety given that they do slightly penetrate human skin, it should be
noted that even humans naturally produce MMWs, enough to the point where scanners are able
to now passively operate and not emit their own radiation.
• Earlier implementations of MMW scanners at airports would reconstruct an x-ray-like image of
the person passing through, which caused concern that essentially nude images were being
captured and stored. Current scanners forego complete reconstruction and instead usually only
show possible locations of detected objects on a generic human body outline so that officers can
further inspect.
• There has been work to extend the range of MMWs for use in surveillance cameras.
Considerations for this include the possibility of needing an active MMW source with no natural
emitting sources guaranteed to be in the camera’s field of view.
• Outside of security, MMWs are being sought for use in communications networks, including cell
phones and even autonomous vehicles. The reason for this is that the current bandwidth range is
nearing saturation as more and more connected smart devices come into existence, whereas the
MMW spectrum is relatively unused. There do not seem to be concerns over whether this will
interfere with the current security screening technology, as the specific frequencies at which
these different categories of devices operate can be regulated.
EFFECTIVENESS
• Along with the standard metal detectors, MMWs are commonly found at TSA security
checkpoints. While the agency has deemed the systems’ effectiveness to be suitable enough for
their standards, there have been reports of individuals being able to smuggle through prohibited
items.
• A new generation of devices aim to only detect large firearms and explosives while maintaining
a high throughput. These systems use passive MMW sensing and project any areas of sensed
disturbance onto an image captured of a person using a standard embedded RGB camera.

Stand-Off Explosive Detection and Mass Transit Metal Detection Equipment

SUMMARY
Walk-through equipment detects prohibited articles. Equipment is available that can detect anomalies on
the human body, whether metallic or not, including plastic explosives, hot or cold weapons, drugs of
various kinds, liquids, powders, gels, and other unauthorized items. The technology behind the
equipment may include MMW and micro-power non-ionized radio waves.
This type of equipment can also be integrated with threat analytics platforms, where alerts provide
assessment with classification information about the detected item overlaid on real time video, and
updates via the cloud. Also, these systems can be integrated with facial recognition systems to identify
known high-risk individuals.
Because there are no statutory requirements for screening at the terminal entrance, there is no legal
obligation for a person to submit themselves for screening. In the UK, private security guards do not
have authority to require persons to submit to a screening process or to undertake searches, so any
search would have to be conducted with explicit consent of the individual.
CONSIDERATIONS
• This technology is costlier than walk-through metal detectors, and given that it is primarily
intended for landside deployment, it is currently not required by regulators and therefore does
not meet any existing aviation screening regulations.
• Detection is not limited to metallic objects.
• There may be higher maintenance costs.
• The technology requires staff presence to respond to alarms.
• These systems may occupy significant space, or airport’s existing infrastructure may not allow
deployment.
• These systems require specific conditions to operate (e.g., operating temperatures), and therefore
should be deployed inside the terminal entrance.
• The equipment may have a high false alarm rate and may not be suitable for permanent
deployment at terminal entrance, where there is a high number of passengers.
• In poor weather conditions when passengers are wearing wet outer clothing, detection capability
can be impaired.
• The equipment tends to be deployed at the terminal entrance, and while there may be some
overlap with other security processes, the landside deployment is an additional layer that
supplements other security requirements, including those for the passenger checkpoint.
• The operation of the equipment needs to be considered in conjunction with other security
measures, and in particular with ConOps, which define the security process and the response to
any alarm. The technical system to screen persons entering the terminal, the exact approach to its
deployment, the role of security staff and law enforcement officers (LEO), in particular, relating
to alarm response should be covered in a detailed ConOps document, development of which
should involve all the relevant stakeholders.
EFFECTIVENESS
• 700 –800 pph throughput may be achieved.
• The systems provide ‘no pose’ screening, but the technology does not currently support multiple
passenger walk-through as stand-off detection.

• Compared with other pre-entry screening processes, it may eliminate long queues, as it allows
passengers to keep all their clothing on during the inspection—including coats, jackets, leather
items, etc.— without the need to remove those items before entering the system and then put
them back on after exiting.
• Most systems are portable and easy to install, and therefore can be effectively deployed on a
random basis to provide a deterrence and detection measure.
• The equipment supports a wide range of deployment scenarios that may be applicable to all types
of airports.
• Deployment of pre-terminal screening systems improves deterrence and detection capabilities,
while blast hardening mitigates the impact and consequence of any attack.
• These systems may be preferable to use for staff screening rather than passenger screening.
Passengers may carry other baggage that will trigger alarms if they go through the equipment.
Further operational evaluation and experience may be required to establish false-positive alarm
rates.
• The equipment provides an effective deterrence, but is unlikely to be a measure that can be
deployed 24/7 at all terminal entrances because it could cause unacceptable delays and also
create queues in public areas, which in itself would be a vulnerability.
• Some of the screening systems include facial recognition cameras. These can monitor persons
going through the system and then scan databases against a watch list or employee database. This
depends on the operator of the system having a suitable database with the right biometric, and/or
having access to such a database. In the case of an employer list (for example, at a staff access
post) this would probably be feasible, while in the case of a public entrance, owners of watch
lists or relevant databases may not be willing/able to share them (even assuming the database
includes the right biometric, such as facial recognition) and therefore, at this time, the potential
for finding known terrorist suspects could be limited by the availability of databases to the
system operators. However, the ability to integrate the screening process with a facial
recognition system does exist. If the equipment operator was an LEO, the ‘access to database’
obstacle may be overcome, at least in part. System integrators are analyzing the potential for real
time tracking of individuals through the terminal based on a range of biometrics, including facial
recognition, and physical characteristics, such as walking gait.
• Response to any alarm is critical and needs to be set out in a detailed ConOps, to clarify whether
the person should be stopped and the cause of the alarm verified, or tracked using technology or
Behavior Detection Officers.
• Theoretically, the system could be deployed without staff and could operate discreetly, with
alarms being sent to a control room and the person being tracked in the terminal, but this would
depend on false/false-positive alarm rates.
• It would also depend on the availability and proximity of response agencies.
‘Known’ Vehicle Systems

SUMMARY
There are certain landside areas of an airport, that are dedicated for bus, taxi, or cargo drop-off, and that
passenger vehicles are not permitted to enter. In some airports, the only measure in place to restrict
access is signage. However, if a threat actor is planning a vehicle ramming attack, there are no physical

or access control measures in place. An option using a combination of Automated License Plate
Recognition (ALPR) and physical measures to manage and mitigate this may be viable.
ALPR can record and display the registrations of all vehicles entering or leaving a site. Vehicle
screening system (VSS) cameras can record all other site activity, which can be viewed and controlled
from a single location.
ALPR could be used for loading docks and pre-authorized vehicles, but the technology will only identify
a specific vehicle registration. The vehicle and/or the driver/occupants may still present a threat.
Airport operators issue permits or passes to vehicles operating airside. Some airport operators may
implement a known vehicle process that may involve issuing a landside pass. This may provide a degree
of reassurance for vehicle status, but some airports do not recognize value in such programs on the basis
that the system may identify vehicles but not necessarily the threat they may pose.
CONSIDERATIONS
• ALPR VSS also include options for capturing image and vehicle registration details to keep on
record.
• ALPR will need to be used in conjunction with physical measures, such as hostile vehicle
mitigation road blockers, barriers, bollards, or gates, to ensure a physical barrier.
• Sufficient space must be allocated for installing physical measures as well as ALPR systems.
EFFECTIVENESS
• These systems may prevent VBIED in car parking through deterrence.
• Passengers are required to register details before arriving and parking their cars.
• All airport employee vehicle details can be stored in ALPR database. This can be effective in
preventing hostile vehicle ramming of critical infrastructure that employees can access.
• While ALPR can identify vehicles and individuals, it cannot validate capability and intent (e.g., a
vehicle may be legitimate in the sense that it is ‘known’ but still contain a viable VBIED).
Vehicle Checkpoints
SUMMARY
Below are some examples of vehicle checkpoints on approach roads:
• Brussels airport employed trained behavior detection enforcement officers/soldiers for spotting
suspicious vehicles on roads leading to the terminal drop-off.
• Ben Gurion Airport has a vehicle checkpoint.
• Other airports may also utilize vehicle checkpoints on approach roads, typically when threat and
risk context requires an additional layer of protection. An example was Belfast International
during the 1990’s when local PIRA activity posed a serious threat.
In these types of instances, the checkpoint may be manned by Police/LEO or military, and will be
located a significant distance from the airport terminal. The actual process may vary according to the
threat and risk (and also can be varied specifically to provide unpredictability), but may include:

• Driver and vehicle documentation checks

• Driver and vehicle searches (including underside and interior)
• Travel documentation
The process of searching vehicles is time consuming, so to process vehicles into airside, airport
operators often compartmentalize each vehicle into five areas such as trunk, under hood, interior, glove
box, and underside. This provides two variables to work with in changing threat and risk contexts: the
number of compartments to be searched and which compartments are searched for each vehicle.
Airports can use Under Vehicle Video Surveillance (UVVS):
• This practice involves scanning underneath vehicles.

• It offers stand-off identification of suspicious items/objects that are attached to vehicles.
• Some UVVS technologies take a snapshot of the undercarriage of each vehicle and compare it to
a database of undercarriages (based on model or previous snapshots of the same vehicle). If
something is out of place, an alarm will sound.
• Gatwick Airport uses UVVS for four new lanes leading to airside, but this represents only one
element of the vehicle security process. The technology can be integrated with ALPR so that
vehicle registrations are checked in real time against a database of known vehicles.
CONSIDERATIONS
Vehicle checkpoints on approach roads:
• Vehicles are required to slow down as they drive on Brussels airport approach road. This is to
allow officers/soldiers to carry out a non-stop visual inspection of the vehicle.
• If an officer/soldier notices anything suspicious, they can stop vehicle and ask for ID
documentation.
• This practice may slow down traffic and cause congestion.
UVVS:
• These systems may slow down traffic and therefore cause delay (but this can bring a security
benefit).
• A typical throughput speed is 18 mph.
• These systems can either be mobile, which may take around 20 minutes to deploy, or static,
which is installed in a small pit in the entrance road.
• UVVS can be integrated with ALPR.
EFFECTIVENESS
• Vehicle checkpoints are extremely effective in deterring a threat.
• From an operational point of view, UVSS and vehicle checkpoints will disrupt traffic flows and
may lead to congestion.
• Provision can be made for vehicle checkpoints on approach roads, and then they can be
operational on a random basis, or when required by threat and risk assessment.
• As first point of contact with the airport for many passengers, a vehicle security checkpoint can
be intimidating and create an adverse passenger experience.
• Vehicle checkpoints are facilitated if approach roads accommodate a dedicated lane for
processing any vehicles that require secondary inspection.

• Trace detection on vehicles is an effective detection process that could be introduced into the
vehicle checkpoint operation. (This is currently deployed at UK ferry terminals and the UK
Channel Tunnel).
• UVVS will not detect threat items within the vehicle.
• Depending on space capacity on approach roads, it can be easy to deploy temporary vehicle
checkpoints on approach roads (e.g., after March 2016 attacks, Brussels Airport deployed a
vehicle checkpoint on the approach road leading to the terminal, where vehicles were asked to
slow down and soldiers standing in between lanes visually inspected drivers to spot anything
suspicious).
• Vehicle scans can be performed in either static or mobile configurations. The static system is a
permanent deployment and is installed on or below the road surface. The mobile system is a
rapidly deployable portable version that is integrated into a heavy-duty rubber ramp assembly.
The static system is housed in a small pit in the road at the entrance to a security area. It can be
easily retrofitted into existing search bays and is non-intrusive to the driver. The mobile system
takes only 20 minutes to deploy. Durable and suitable for any temporary security measure, this
technology can also be used for permanent installations where alterations to the road surface are
not possible.
Advanced Communications Techniques

SUMMARY
The use of advanced messaging techniques can inform staff and passengers about security issues and
potentially send a subliminal message about the (high) level of security at an airport. Posters in
terminals/buildings with messages such as:
• “Undercover patrols are in use in the Terminal”

• “CCTV is working: if you can see this, we can see you”
• “This airport implements security measures that are both seen and unseen”
The use of coded messages and announcements encourages employees to be extra vigilant, without
alarming passengers; this method is employed by some airports very effectively.
Other related methods include running a staff vigilance campaign.
CONSIDERATIONS
• These techniques are an extremely cheap mitigation measure.
• They promote a ‘reporting’ culture where all airport staff feel involved in ensuring security.
• Advanced communication techniques should be considered as part of a wider security culture
initiative such as a Security Management System (SeMS).
EFFECTIVENESS
• These techniques may be extremely effective for deterring a threat.
• They can disrupt a hostile reconnaissance.

Security Management Systems (SeMS)

SUMMARY
This is more of a general security approach involving culture rather than a specific measure. A Security
Management System (SeMS) is described as an organized, systematic approach to managing security,
which embeds security management into the day-to-day activities of an organization. It provides the
necessary organizational structure, accountabilities, policies, and procedures to ensure effective
oversight. Its purpose is to enable an organization to identify and manage its security risks and be
assured right up to Board level that the security measures taken to manage those risks are effective.
CONSIDERATIONS
The key components of SeMS include:
• Management commitment
• Threat and risk management
• Accountability and responsibilities
• Resources
• Performance monitoring, assessment, and reporting
• Incident response
• Management of change
• Continuous improvement
• Training and education
• Communication
EFFECTIVENESS
For security management to be effective, it has to be a continuous cycle that includes a threat and
vulnerability assessment, the identification, capture, and analysis of risk, and the generation and
continuous review of risk-mitigation plans. Risk is a dynamic area and will require continual review
against an ever-changing threat landscape.
Changing Passenger Habits

SUMMARY
The aim of this approach is to look at methods to reduce queues and large gatherings of people in the
landside/public area of the terminal and adjacent areas. This may include revising procedures for
validating passengers for certain international destinations while waiting in the queue for check-in.
Airport authorities, such as operators or security personal, as well as airlines, can help reduce queues
significantly by reviewing and revising their procedures.
CONSIDERATIONS
The introduction of mobile technology means that more passengers are changing the way they plan their
travel.
• There is an increased use of internet check-in, potentially resulting in less crowding at check-in
desks as passenger go directly to the security checkpoint and into the airside area of an airport.
• There is an increased use of self-bag drop, which may mean there is less crowding at check-in
desks. Possible use of off-site hold baggage check-in/drop-off should be considered.

• There is an increased use of remote bag-drop. Hong Kong International Airport has an in-town
check-in. Airport Express travelers can check their luggage in town and then proceed to the
airport bag-free. In-town check-in service is provided for any passenger with baggage where the
total size does not exceed 58 inches (length) x 39 inches (width) x 33 inches (height) and weight
not exceeding 200 lbs.
• A higher percentage of passengers have cabin baggage only (due to airline fees for hold
baggage), which may mean less crowding at check-in/bag drop desks.
EFFECTIVENESS
• These techniques reduce the potential for mass casualties and deaths, as there is less crowding.
• These measures are more concerned with people security rather than airport infrastructure
security. Most of these measures are customer service-driven, but nevertheless introduce a
security benefit. All of these measures require airports, airlines, and other stakeholders to be
involved. Processes that take place off-site can reduce the risk exposure.
Security Patrols
SUMMARY
Perimeter patrols serve as a deterrent to breach attempts, allow for identification of persons on the
airfield who may have breached the perimeter, and enable inspection of the perimeter fence to locate
where breaches occurred or were attempted.
It is a common practice for perimeter patrol to be carried out by security personnel, LEOs, airport
operations staff, maintenance staff, or any combination of these groups. In some airports, operations
staff may carry out perimeter and airfield patrol duties, while in others, security staff and LEOs are
trained in and carry out some operations duties.
Where threat and risk context requires, airport operators will also arrange a security presence at
pickup/drop-off zones to ensure that vehicles are not left unattended. In the United States, this is usually
provided by airport staff, but may be supplemented by an LEO presence when required for traffic
management. Occasionally, patrols and security staff presence is supplemented by signage and
announcements to ensure that travelers are aware of the security requirements―but this is not always
the case.
CONSIDERATIONS
• The patrol of large airports may take several hours and require getting in and out of the vehicle to
ensure perimeter integrity. In some cases where airports use fencing that allows a vehicle to
breach under the fence, the fence may return to its normal position so that a breach may not be
noticeable.
• In some cases, portions of perimeter fencing must be inspected from landside due to factors such
as wetlands and wooded areas.
• Inspection of fencing around terminals and other busy areas where cargo containers and other
equipment are parked may require patrol observation from landside.
• In some very small airports, LEOs are required to be present at the passenger screening
checkpoint, to patrol inside the terminals, enforce the challenge program, monitor vehicles at
terminal curbsides, and patrol the Secured Area, which leaves little time for accomplishing
multiple perimeter patrols during an individual shift.

• The presence of security patrols walking or driving up and down the pickup/drop-off zones to
ensure that vehicles are not left unattended will add to the security costs of the airport. A more
cost-effective method would be to limit the space allocated for pickup/drop-off zones.
• Pickup/drop-off and loading zones should be set as far away from the terminal as practical to
minimize the blast effects of a vehicle bomb. Planners should consider the use of moving
sidewalks or access to luggage carts to help passengers bridge the gap.
EFFECTIVENESS
• Airports are always seeking to optimize the patrol mission, and often use increased frequency,
reconfiguration, and unpredictability of patrol tours in their efforts.
• Allocating enough space at pickup/drop-off zones to park a police car may act as a cheap measure of
deterrence.
Terminal Finishes and Furniture

SUMMARY
Consideration should be given to the materials used for fitting out terminals (furniture, signs, check-in
desks, etc.) to reduce potential damage in the event of an explosion. Heathrow’s new Terminal 2
designed, manufactured, and installed all check-in and associated desk/counter furniture taking blast
impact into account.
There should be no hidden places or corners where terrorists could place an IED (e.g., underneath or
behind seats and couches). The use of Tensa stanchions should be reviewed; these may become a javelin
in an explosion. Blast-proof protection may be built into separating walls and structures to reduce
injuries and provide protection from active shooters.
The type and style of commercial offerings should take into consideration security requirements. The
airport security and commercial departments should discuss the way the commercial offering is set up to
limit possible damage from a bomb blast.
CONSIDERATIONS
Planners must ensure that furniture fixtures and fittings are suitable with existing airport infrastructure
constraints.
EFFECTIVENESS
• Examples of these measures are compliant check-in counters and hybrid check-in counters, security
preparation (liquid/aerosol/gels), furniture, signage and beacons, wall linings, passport control
counters, retail frontages with bullet-resistant glazing screens, and immigration counters with swing
gates.
• Copenhagen Airport uses blast-proof trash cans.
• Bomb-resistant trash cans and suspect package isolation units used by Gatwick Airport (at the new
departure level).

Hostile Vehicle Mitigation – Physical Barriers

SUMMARY
Hostile vehicle mitigation is the practice of deploying measures to reduce risk of a vehicle-borne attack,
both vehicle ramming and VBIED.
Measures most often considered are physical barriers. Barriers are primarily installed for the following
objectives:
• Restrict vehicle access to authorized areas

• Prevent malicious vehicle ramming attacks on pedestrians or structures
• Maintain standoff when considering blast-load effects of a VBIED, thus reducing impacts to
structures and people
Barriers are commonly concrete-filled steel bollards or concrete knee-walls, with robust reinforced
concrete foundations. Other anti-ram features such as berms, planters, or trees may also be used, but
unless they are specifically designed to resist malicious vehicle attacks, they may only provide a visual
deterrent.
Crash-test certification standards, such as ASTM F2656, PAS 68 & 69, and IWA 14 are typically used
to specify the performance of the barrier. A barrier rating is based upon the vehicle size and approach
speed, its angle of impact with the barrier, and how far the vehicle can penetrate the barrier, if at all. An
engineering evaluation, often called a vehicle dynamics assessment, which takes into account achievable
radii of curvature for specified vehicle sizes, speeds, and road layouts, is typically performed.
Penetration is often restricted to 1 meter, and for trucks is based upon the distance that the front of the
cargo bed reaches past the original/reference point of the barrier at any time during the test.
In addition to physical barriers, a hostile vehicle mitigation (HVM) strategy may include operational and
technological methods that help detect or deter hostile vehicles. This can include measures such vehicle
screening and license plate video camera analytics. These measures are addressed separately.
Airports often implement HVM in some form, but a holistic strategy to address highest risk areas by
means of physical, operational, and technological measures may be overlooked.
CONSIDERATIONS
• Physical barriers as part of an HVM strategy may take away from the aesthetics of an airport
terminal.
• Typically, barriers are performance specified to be certified or to meet a crash-rating. Unless
conditions allow for deep foundations (i.e., no utility disruption or elevated slabs), installation
without any engineering analysis is difficult.
• Integration of HVM with site landscaping is imperative for using resources effectively (i.e., if the
landscaping considers HVM, explicit vehicle barriers may be redundant) and creating an
aesthetically-pleasing environment that is also secure.
• For elevated slabs such as at the raised departures-level viaduct of an airport, shallow-mount
barriers are required because standard depth excavation for the foundation is not possible.
• HVM is most applicable to terminal drop-off and pickup roadways.
• Placement needs to allow for vehicle doors to open and passengers to flow freely.

• Temporary/portable barriers may be deployed, but are less common and cannot achieve as high
of a crash-rating.
• Removable/operable barriers provide flexibility for use.
EFFECTIVENESS
• Physical HVM barriers do not have detection capabilities.
• HVM is an effective visual and physical deterrent.
• Little maintenance is required for physical barriers.
• No operational support is required for physical barriers.
• When specified and deployed appropriately, HVM is highly effective.
• HVM is sometimes deployed without consideration of a vehicle dynamics assessment, nor in a
holistic manner that considers other measures such as vehicle screening; this results in a less
effective design.
• Many HVM deployments are falsely assumed to be anti-ram or otherwise have unknown
performance (i.e., planters that are not crash-tested are often deployed in front of doors).
• HVM can be expensive.
• In large stretches of areas, barriers cannot be fully deployed due to limited resources; therefore,
this limits their effectiveness in certain scenarios.
• Barriers are generally permanent and thus not flexible to change with changing threat
environments or site reconfigurations.
• Failures may occur due to a vehicle being larger or having a greater speed than was determined
credible. Failures may also occur if removable bollards are used and the bollard is not replaced.
Failure may also occur due an improper assessment of where the barriers should be located.
Hostile Vehicle Mitigation – Roadways

SUMMARY
Roadways should be designed to reduce the speed of vehicles approaching the terminal: for instance,
having bends and corners so as not to allow a vehicle to build up speed. Management of flows of
vehicles entering/exiting the airport through separation of traffic by various configurations, including
arrivals/departures, public vehicles/taxis, and general/premium or valet, will also help minimize the
impact of a vehicle used as a weapon.
Structural Hardening
SUMMARY
The primary physical hardening objective for blast mitigation should be to limit structural collapse. This
will reduce risk of casualties. ASCE 59-11 defines reasons for blast enhancements in general.
Structural hardening is often provided to critical or primary structural elements, followed by secondary
structural elements, which may be allowed to experience slightly greater damage than primary elements.
Structural robustness is often included as a goal, which involves designing a structural system to sustain
local damage without failing to any great degree.

Hardening consists of increased shear and flexural strength as needed to withstand the loading
associated with the design basis threat. Additionally, increased capacity in connections is provided in
order to promote a ductile/flexural response rather than failure of members at their connection points.
CONSIDERATIONS
• Architectural furring or coverings may be installed on columns to reduce the effects of a PBIED.
• Locating high-risk areas for VBIEDs as far away from the building as possible will help reduce
the effects on structural hardening.
• Hardening of a parking garage against progressive collapse significantly increases the cost, and
is often not considered due to the lower occupancy and lower risk of downtime associated with
the loss of a parking garage.
• The minimum structural integrity provisions defined in US building codes, such as the IBC and
ASCE 7, provide a small degree of tying and otherwise include the general requirement that
collapse should not be disproportionate to the cause. Tying provides a minimum/baseline level of
robustness and is not based upon any specific initiating event (i.e., an explosion). Specific
progressive collapse analysis criteria to resist a design basis threat, such as an explosive event,
are not mandatory unless elected by the owner or authority having jurisdiction. There are a few
guidelines that are used as best-practice, primarily the UFC 4-023-03. Additionally, the
Structural Engineering Institute of ASCE is currently drafting a design standard. Using these
methods for blast resistance, a structure is explicitly designed to achieve an identified
performance after the loss of columns.
• Protection of critical infrastructure should be considered. A hardened envelope (i.e., reinforced
concrete walls) may be installed around fuel tanks or power supplies that are especially
vulnerable to PBIED or VBIED threats.
• The costs associated with structural hardening for an explosive event are often significant.
However, when considering the risks associated with costs of potential structural loss, downtime,
and casualties, it is often considered to some extent in terminal design.
• Retrofit of structural elements is difficult, but achievable.
EFFECTIVENESS
• Increasing the robustness of a structure is an effective means of preventing casualties
disproportionate to the event, but will not prevent casualties caused by the primary blast load
effects and fragmentation.
• Structural hardening will also reduce the risk of major downtime, such that only minor repairs
are required instead of major structural repairs.
• It is not economically feasible to harden a large structure like a terminal facility to prevent
damage in the event of all viable VBIEDs.
• Structural hardening is permanent and not flexible to change with a changing threat environment.
• These measures can incur large costs, particularly for retrofit activities.
Facade Enhancement
SUMMARY
The hazards created from glazing failure in an explosion are lethal. Monolithic glass is a brittle material
that fails suddenly and fragments are projected at high velocities. However, with a properly designed

blast-resistant laminated glass facade, the glass can respond in a ductile manner and the fragmentation
hazard can be reduced.
ASCE 59-11 recommends that exterior structural and non-structural elements be designed and detailed
to reduce the potential of a breach that would allow overpressures to enter the building. Additionally,
ASCE 59-11 recommends flying debris be minimized to reduce the potential for hazardous secondary
fragments.
Laminated glass with a polyvinyl butyral (PVB) interlayer used for blast resistance is highly ductile
when loaded at high strain rates, and will stay bonded to the glass after the glass has cracked.
Blast performance of glazing is typically based on the GSA Performance Condition scale, which is
based upon the distance glass fragments enter the space after an explosion (if at all). Ratings range from
Performance Condition 1 – No Breakthrough to Performance Condition 5 – Hazardous Failure. Typical
performance for a blast-resistant facade is between Performance Condition 2 and 3B.
Glass performance is also measured using ASTM F2912-17 hazard ratings. The hazard ratings are
measured H1 through H5, and have corresponding descriptions of glazing response from no glass
breakage through moderate hazards, similarly measured to GSA Performance Criteria via how far
fragments enter the space.
CONSIDERATIONS
• An essential part of laminated pane design is the detailing of the edge retention and frame and
fixings to support the glass. Laminated glass on its own may not provide appropriate
enhancement. The glass should be designed to remain in the frame and the frames should be
designed to carry the load of the glass.
• For retrofit, adhesive film can be applied to the inside surface of a pane to hold the glass
fragments together. A cable catchment system or mechanical anchorage of the film to the frame
may be warranted since proper detailing of the rebate in retrofit scenarios is not possible.
However, this may be a difficult retrofit for large airports that have large landside façades on
their terminals.
• Application of structural silicone sealant is required between the glass and the frame; otherwise,
large capture of the glass within the frame is required.
• The structural system needs to be designed to take the load from the facade.
• Glazing not only includes the exterior facade, but balustrades, handrails, smoke screens, and
overhead glass that may shatter.
• Maximum pane size may be limited; similarly, minimum pane size may be limited, especially if
there is a balanced design requirement.
• Balanced design is sometimes considered, where the frames and anchorages and supporting
structure are designed to withstand the maximum capacity of the glass, rather than the load that
is transferred as a result of the design basis threat. This provides some robustness in that it is
threat-independent; however, it can be a costly design requirement.
• US facade manufacturers have primarily blast-tested their products to prescribed government
criteria; deviation from this requires custom design by a blast engineer. Often, standard designs
do not fit within the aesthetic or architectural intent of an airport.

EFFECTIVENESS
• Properly designed glazing systems that achieve GSA Performance Conditions between 1-3B can
significantly reduce casualties in the event of an explosion and eliminate or reduce the blast
pressures that enter the building interior.
• Laminate can reduce fragments.
• Allowing a percentage of facade failure is often considered for economic reasons; this may
reduce the effectiveness of the mitigation in areas directly near the explosion.
• The measures, once installed, are permanent and not flexible.
• Failure can occur if the design basis threat is greater than what was designed, or if rebate
detailing was not specified properly.
• Failure can also occur if the supporting structure is not properly designed to withstand the greater
strength of the glass system. Blast-resistant facades are increasingly common at airports. The
cost is not insignificant; however, the cost-benefit is often judged to be worth the investment.
CCTV Analytics
SUMMARY
In the most basic sense, CCTV analytics are the application of computer vision on surveillance camera
feeds so that security guards do not have to stare at computer monitors for hours on end. The premise is
based on quantifying the events that may interest a security team (and others as well, such as
departments of transportation and retail, for example) so that a computer is able to then bring a particular
camera’s feed to the guard’s attention upon trigger.
The analytics most applicable to blast prevention are listed below. Each manufacturer may have
different names for their own implementations.
• Object left behind: Items such as bags and suitcases can be detected in feeds, especially when the
computer can compare to a baseline of the camera’s view (at a time with no people or other items
present). Settings can usually be set for how long an item can be in the scene unattended (when
no nearby person is detected) before alarm trigger.
• Virtual barrier: A line can literally be drawn on the feed of a camera so that the system is
triggered when a moving object is seen crossing that line.
• Smoke detection: Especially in outdoor areas, smoke can sometimes be detected through CCTV
feeds faster than by standard detectors.
• Person tracking: One person of interest will usually be captured by multiple cameras at slightly
different times. Some video analytic systems are able to detect the same person and/or item in
multiple feeds and automatically piece together a chronological montage of this footage, as long
as these feeds are synchronized properly. This can be used to actively or forensically track a
person and/or thing throughout an entire site automatically.
• Behavior: More advanced analytics are able to make use of machine learning to become more
robust over time. The computer is continuously establishing baselines depending on what is
captured by the camera during normal operations and is then able to detect abnormal behavior.
One example may be a camera that looks at a train tunnel where train exiting happens many
times a day, but the analytic is triggered if it notices a car going into the tunnel in the opposite
direction.

Other common analytics that can also play a role in blast prevention include more specific detection,
such as facial and license plate recognition.
CONSIDERATIONS
• As with general design of a video surveillance system, including both the head-end equipment
and the cameras deployed around a site, proper thought must be given to enabling each feed to
have sufficient definition in order to perform the desired analytic. For example, facial detection
analytics are often quoted to require higher than 60–80 pixels per foot at the target length away
from the camera, which is also subject to depth of field, lighting, and other conditions. For
applying analytics to a system of cameras that has already been installed, one must consider each
camera’s environment and specifications beforehand.
• Legacy CCTV systems are often able to be upgraded with analytic capability, even older analog
systems. There are certainly restrictions that vary by manufacturer, and the method of
implementation (whether the analytic is being run on the edge device out in the field or on the
head-end server) and different licensing models can also complicate things. Some companies
even sell small physical attachments that can be retrofitted into the transmitting wire of an older
CCTV camera to enable analytics on it. Whether the analytics are calculated on the edge or in the
head-end could have a large influence on the amount of data being transmitted over the network.
• Some analytics such as license plate reading may require the use of an additional server to store
and sort through the database(s) of records. If these servers are not on the same local network of
the video management system, further consideration into firewalling this connection is
necessary, especially if that database is hosted by external agencies.
• Different manufacturers have different ways of implementing the same analytic. Video
surveillance regulatory organizations such as the Open Network Video Interface Forum
(ONVIF) and the Physical Security Interoperability Alliance (PSIA) are mainly concerned with
ensuring that camera technology, including analytics, is able to work across multiple different
systems; these should not be mistaken as agencies that make sure the analytics meet any sort of
minimum performance criteria.
EFFECTIVENESS
• As is with most of the technology world, the field of CCTV analytics is rapidly changing; to take
a snapshot of its current effectiveness at any given time may not be indicative of even a few
months later. Most manufacturers do not publicize failure rates, which could include both false
positives and neglecting or missing the accurate identification of an item/person, but in their
defense, it is difficult to quantify this as a statistic independent of other factors or even against
rates of human monitoring. There seems to be a tendency in the airport industry to be hesitant to
trust a computer to conduct this type of work, but the independent testing organization IP Video
Market Info has shown at least some analytics use/acceptance steadily climb to north of 80%
among responders in 2016.
• Modern computer processing has turned analytics from what was mostly only able to be used as
a forensic tool into a live, real-time monitoring detection system. Even implementing basic
analytic functionality can allow for fewer guards to be needed in a security operations center,
which could in turn allow for them to be deployed on site. The fact that many video management
systems are embracing mobile device access enables guards to be instantly notified of events,
complete with location and video, right on their smartphones.

• A well-designed CCTV system that has both identification capability (resolution) at key points,
as well as overall awareness (coverage), can be enhanced with analytics without the need of
changing out the physical devices; remotely-deployed firmware upgrades allow for fast and
efficient system improvement.
LiDAR 3D Detection
SUMMARY
Light Detection and Ranging (LiDAR) projects a laser onto an object and measures the time it takes for
the beam to return to the source, after which the distance travelled by the light is used to determine
distance. When this laser is directed in many different directions via a rotating mirror, it is able to
reconstruct a 3D scan of a scene. Traditional LiDAR scanning can take many minutes as a scanner
rotates 360 degrees on a tripod to capture everything in high detail. However, lessening the detail
(amount of points captured per square meter, for example) can greatly speed up the process, enough so
that real-time 3D awareness can be attained. This use of the technology has its roots in autonomous
vehicles but the security industry is quickly realizing how it can be used for surveillance. A real-time 3D
map of an area can supplement CCTV analytics for further detection capability, especially in places with
low CCTV resolution and therefore lower analytic efficacy.
CONSIDERATIONS
• LiDAR is not able to detect 3D through physical geometry. In the 3D scanning sector, this fact is
overcome by simply moving a scanner to different points around a site and then stitching these
disparate scans together to reconstruct a cohesive overall scene. The solution for implementing
this in a real-time detection system is similar but instead of moving the scanner, a network of
different scanners can be planned and installed to cover for each other’s blind spots, as well as
have enough overlap with one another to capture the full area. Individual scanners typically have
a range of 100 meters; combining multiple scanners will extend this reach.
• Because enabling real-time scanning is achieved through the coarsening of resolution, LiDAR is
best used when supplementing another system such as CCTV analytics. This currently would
involve custom applications that make use of various software development kits given that the
technology is fairly new. LiDAR detection is able to classify objects based on their absolute size
(vs. 2D camera feeds that can only judge relative, pixel-based size) and can therefore filter out
objects smaller than, say, a small human before triggering alerts. The scanners themselves are
small devices that can be installed just like CCTV cameras. They rotate their laser emitter and
receivers at high frequency to capture at a 360-degree horizontal field of view (FoV) although
their vertical FoV is drastically reduced, which necessitates clever planning of the system’s
physical layout. Once set up, the technology requires no active human intervention.
EFFECTIVENESS
Even though it is in real-time (up to 20 frames/second), this low-resolution 3D scanning is not a security
solution until used in conjunction with something else, such as a video management system (VMS).
Upon recognition of a large enough object, the LiDAR system can transmit precise coordinates to the
VMS, which could in turn pan and zoom a camera to get a visual and bring it up on a security guard’s
screen and/or mobile device. The 3D nature of the scan is certainly more robust than using a tracking
CCTV analytic for this same purpose.

Unmanned Surveillance Touring

SUMMARY
As much as CCTV can be a cost-effective way to monitor large areas from a single central location, the
cameras are in fixed locations (even if they have PTZ capability). As versatile as security guards may
be, they are subject to human error, do not automatically document what they observe, and are much
more expensive than operating even a number of cameras. Leveraging the above topics of video
analytics and 3D detection are autonomous vehicles, and some have begun to apply these concepts to
using self-driving robots to conduct surveillance and even enforcement measures.
Utilizing self-driving robots also removes the security guard from potential physical harm.
CONSIDERATIONS
• Unlike dedicated bomb detecting and disarming robots, this technology has an implicit
dependency on the machine’s ability to make decisions, interpret human behavior, and self-
navigate using artificial intelligence. Because many jurisdictions have had to create legislation to
regulate autonomous vehicles, especially during the technology’s infancy, similar legislation
could be created regarding self-navigating security robots as well. Instances in the news
regarding autonomous vehicles and security robots getting into accidents, which have resulted in
human injury and even death, certainly make the public wary of implementing such a solution.
• There are also political ramifications to be considered, as some may see the adoption of such
machines as replacing jobs. Security guard unions, for example, could attempt to get legislation
passed to prevent transitioning jobs away from its unionized members.
• Whereas the artificial intelligence associated with more advanced CCTV analytics will usually
not be noticed by the public, this is not the case with security robots, especially at first due to
their novelty. Machines without enough intelligence could get lost or into accidents, and
machines with too much intelligence, while currently only realized in science fiction stories, is
something the scientific community has recently acknowledged as a potential real threat to
humanity.
EFFECTIVENESS
• Robots that function properly can offer a cost-effective way of actively preventing crime, and
they can extend the reach of monitoring systems into places that mounted CCTV cameras might
not be able to reach.
• There are many tests being done in academia with auto-piloted drones, but there do not seem to
be any actual products on the market quite yet. The very nature of an airport may prohibit the use
of any drone, automated or not.
• Alarming to many is the rather quick militarizing of these robots.
Mass Notification and Crowdsourcing

SUMMARY
In the smartphone age, at least one company has sought to leverage the general public’s proclivity to
photograph and record everything it sees by establishing a web platform where they can feed this data to
security centers in real-time. Essentially the modern day equivalent to calling 911, these systems can
enable live incident video sharing to entire workforces or even public populations. The GPS locations of
the phones are automatically shared with security so that response times can be shortened.

While not demonstrated, a system such as this and its Application Programming Interface (API) could
be leveraged for other uses such as people counting. In essence this can provide another Big Data source
that can be used for future planning.
CONSIDERATIONS
• While manufacturers will provide the supporting network infrastructure, there are too many
different models of cellular devices in circulation to guarantee that each is compatible with each
program’s mobile website and/or app. It is also subject to the network’s uptime and individual
cell connections of those devices.
• Pinpointing specific locations inside buildings is not attainable solely by using GPS and the
emergence of better technologies might be required to fully realize the benefits of these systems.
• When location tracking is functioning fully, these networks are able to locate any person on the
system. And even though there are assurances by manufacturers that this feature is disabled once
the app/site is closed, there will still undoubtedly be privacy concerns.
• Implementing these systems that are open to letting the public report suspicious activity can also
make them subject to being manipulated. Similar in concept to a Distributed Denial-of-Service
attack, a group of people can plan to disable the system by flooding it with massive amounts of
false data.

TIERS OF PERFORMANCE
Facade Enhancements
Level of Service Description

Reduces the extent of hazardous fragmentation for relatively small devices. An
Bronze
example is the application of anti-shatter film daylight-fixed to window glazing.
Laminated glazed facade with enhanced frame explicitly designed to maintain
Silver greater than 50% of the building envelope and reduce fragmentation for PBIEDs
or small-sized VBIEDs.
building envelope and reduce fragmentation for moderate-sized VBIED threats.
Gold
90% of the facade system achieves GSA Performance Condition 3B for a
moderate-sized threat.
building envelope and reduce fragmentation for large blast threats. An example
Platinum
is double-laminated glass panes. 90% of the facade system achieves GSA
Performance Condition 3B for a large-sized threat.
Structural Enhancements

Building structure designed to current structural design codes, incorporating
Bronze
ductility and robustness requirements in accordance with ASCE-7.
In addition to Bronze, in general, the structure has been designed for life safety
Silver
outcomes with respect to the identified blast threats.
In addition to Silver, the structure has been designed with progressive collapse
Gold
requirements stipulated within UFC 4-023-03, or equivalent methods.
The structure has been designed with progressive collapse requirements
stipulated within UFC 4-023-03, or equivalent methods. In general, the structure
Platinum
has been designed for property preservation or business continuity outcomes
with respect to the identified blast threats.

Crowd Mitigation

Consideration of flight schedules for airline, airport, and TSA staffing. Level of
Bronze
service equal to Level D in accordance with ADRM 9 and 10.
Majority of airlines incorporate technology for check-in processes and bag drops.
Consideration of flight schedules for airline, airport, and TSA staffing. TSA
Silver
PreCheck available. Airport Level of Service equal to Level C in accordance with
ADRM 9 and 10.
Almost all airlines incorporate technology for check-in processes and bag drops.
Gold
PreCheck used extensively. Airport Level of Service equal to Level B and space
and wait times in accordance with ADRM 9 and 10.
Almost all airlines incorporate technology for check-in processes and bag drops.
Platinum PreCheck used extensively. Airport Level of Service equal to Level A and space
and wait times in accordance with ADRM 9 and 10. Integrated Pedestrian
planning and modeling exercises undertaken for the majority of landside areas.
CCTV

CCTV system installed sparsely across landside areas. CCTV primarily used as
Bronze
deterrence.
CCTV installed with medium density across landside areas. CCTV monitored
Silver
with an adequately staffed control room.
CCTV installed with high density across landside areas. CCTV monitored with
Gold an adequately staffed control room with a moderate level of applied video
analytics.
CCTV installed, designed for 100% coverage at areas of high-risk on the
landside. CCTV monitored with an adequately staffed control room with a high
Platinum
level of applied video analytics. 3D scanning technology, thermal imaging, etc.
is also applied.

Screening of Individuals1

Screening of suspicious individuals in the terminal (or other high-risk landside
Bronze
area).
In addition to Bronze, implementing a policy of random screening of individuals
Silver
and their belongings entering the terminal (or other high-risk landside area).
In addition to Silver, implementing a non-invasive technology system capable of
screening some individuals (greater than random screening), but may be limited
Gold
in its deployment either due to location or staffing available to actively monitor
the system.
Implementing a non-invasive technology system capable of screening most
Platinum individuals in all high-risk locations, and adequately staffed to actively monitor
and resolve alarms.
1: This refers to screening of people entering landside areas (not passenger security screening to access the airside).
Although not currently deployed in US airports, technologies are currently being tested in US rail/metro stations and
internationally at airports that could be non-invasively and improve speed of screening. Therefore, this concept is a possible
category for consideration in the future, given emerging technologies may result in screening of people entering the airport
becoming feasible.

Bronze Canines deployed sparsely within the airport terminal.
In addition to Bronze, canines are deployed sparsely in other high-risk landside
Silver
areas including bus stations, rail stations, parking garages, etc.
Gold Canines deployed moderately within high-risk landside areas.
Platinum Canines deployed heavily in high-risk landside areas.
Security Patrols

Security patrols with a low level of training deployed sparsely throughout the
Bronze
airport terminal.
Security patrols with moderate level of training deployed sparsely throughout all
Silver
vulnerable landside areas.
Security patrols with high level of training deployed in moderate density
Gold throughout all vulnerable landside areas. Patrols are coordinated between
private security patrols and law enforcement/public safety officers.
Coordinated security patrols with high level of training and integrated with a
security management system. Patrols deployed in high density throughout all
Platinum
vulnerable landside areas. Patrols are coordinated between private security
patrols and law enforcement/public safety officers.

Vehicle Screening

Airport is capable of carrying out visual vehicle inspection on an ad hoc basis;
Bronze
operational plans to introduce a checkpoint are documented.
Visual vehicle inspection carried out by personnel on ad hoc basis in high-risk
Silver
curbside or parking areas.
In addition to Silver, ALPR is used to assist in the identification of high-risk
Gold vehicles. Under vehicle screening technology is capable of being deployed at the
checkpoint for times of elevated threat levels.
Visual vehicle inspection is carried out by personnel on a regular basis in times
of elevated threat levels. Checkpoints are adequately staffed to accommodate
Platinum increased screening frequency in high threat levels. Visual inspections are
compounded with active use of ALPR and under vehicle screening technology,
which is deployed at the checkpoint.
Resilient Finishes

Internal finishes designed in accordance with current design codes. Architectural
Bronze
items adequately restrained to the structure.
Internal finishes designed in accordance with current design codes. Architectural
Silver items and building services adequately restrained to the structure. Partition
glazing (i.e., single-story walls) within the landside area is laminated.
Internal finishes designed in accordance with current design codes.
Architectural items and building services restrained to the structure should be
Gold designed, detailed, and installed to substantially reduce the potential for
producing hazardous secondary fragments and debris. All glazing within the
landside area is laminated and silicone-fixed to robust supports.
In addition to Gold, explicit evaluation and protection for blast impacts to
Platinum architectural items or building services is provided, including materials and
anchorage.
Behavioral Detection

Bronze Few security officers have had training in behavioral detection.
A moderate proportion of security personnel have had training in behavioral
Silver
detection.
A high proportion of security personnel have had training in behavioral detection.
Gold Behavior detection officers are explicitly provided in terminal areas during high-
risk flight check-in, or in select crowded locations at peak-times.
A high proportion of security personnel and other airport employees have had
training in behavioral detection. Behavior detection officers are an explicit
Platinum
program at the airport, on duty on a regular, frequent basis, across all high-risk
landside areas.

CASE STUDY USING THE FRAMEWORK

Introduction
Existing airports often present significant challenges and restrictions to mitigation of blast threats.
Undertaking a substantial redesign of non-secure areas for the purpose of increasing the standoff
distance between blast threats and the terminal is often not possible for such locations. This fact signals
the importance of identifying logical retrofit options to address such threats. This case study
demonstrates how blast mitigation may be retrofitted to an existing example airport to address these
threats in the context of the existing site. Furthermore, the case study demonstrates the application of the
framework to prioritizing mitigations.
Airport Overview
The fictional airport considered for this case study is a major international airport, servicing
approximately 35 million passengers each year (for both domestic and international travel) with planes
departing every 2 minutes.
For the purpose of this case study, the airport is characterized by the following elements:
Characteristic Description
U-shaped A U-shaped roadway leads to the terminal pick-up/drop-off areas. This roadway is one-
roadway directional.
A multistory parking garage stands approximately 300ft away from the terminal, connected
Public parking
by a pedestrian walkway and road crossings.
Loading dock The loading dock is adjacent to the building at arrivals level.
The pick-up/drop-off areas are located outside the terminal entrances. Cars pull into parking
Pick-up/drop-
bays (with an unenforced time limit of 5 minutes) to drop off or pick up passengers. Bus pick-
off area
up zones are located in designated areas.
Terminal
The terminal has a glazed facade with automatic sliding doors to facilitate entry.
facade
The terminal entrances open into the check-in hall. Electronic check-in terminals are located
Check-in hall closest to the entrances, with a number of rental car tenancies occupying the wall-side of the
structure. A queuing area is facilitated by rope barriers.
Security Passengers for domestic flights proceed directly to security screening following their check-in
screening and then on to their boarding gate.
Baggage claim Arrivals head to the baggage claim hall that has approximately 12 baggage carousels.
Large cylinders containing jet fuel for flights are located landside approximately 150ft from
Fuel farm
the terminal structure.
Data centers are located within the terminal building. These are within the airport’s back-of-
Data centers
house area, segregated from the public area by a secure corridor.
Airport age Approximately 25 years.
The structural characteristics of the airport include: steel beams with concrete floor, steel roof
Structure and columns. The baseline structural design already considers design against
disproportionate collapse.
The airport is currently at a heightened threat level due to a recent bombing attack at an
Threat level
airport abroad. The selected mitigation measures reflect this threat context.
Blast-Mitigation Strategies for Non-Secure Areas at Airports B-1

Figure B-1 provides a general overview of the fictional airport’s layout.

Figure B-1. Airport Layout
Risk Assessment and Threat Profile

To demonstrate the implementation of the proposed framework, consider that a risk assessment
undertaken by the airport’s security team identified the blast threats requiring mitigation in Table B-1
and Table B-2. This is Step 1 of the framework process.
Table B-1. Airport-Specific Areas Vulnerable to a VBIED
Life
Location Description Commerce Operations
Safety
Roadway adjacent to Ramming attack through terminal facade

0.75 0.05 0.2
terminal followed by explosion
Table B-2. Airport-Specific Areas Vulnerable to a PBIED
Life
Location Description Commerce Operations
Safety
Terminal Arrival PBIED with explosive vest or backpack detonated

0.9 0 0.1
Hall in a crowded place

Case Study 1: VBIED

Effects of a VBIED in close proximity to the terminal building cannot be completely eliminated.
However, this section describes a process for addressing this threat scenario and adopting mitigation
measures that are proportionate to this threat.
Figure B-2. VBIED Risk
This section outlines the various operational, technical, and physical mitigation strategies that this
airport can implement to reduce the potential consequences of VBIED threats. The below sections
describe mitigation measures that could be applied to manage this risk.
Step 1 of the framework process has been completed during the risk assessment (see Table B-1). Step 2
incorporates listing the measures that can be used to mitigate this risk at this particular airport.
Physical
Physical mitigation strategies provide a passive benefit against a blast threat by directly mitigating the
effects that harm people and structures. Physical measures that may be implemented include:
• Impact-rated vehicle security barriers such as bollards. These barriers create standoff between a
VBIED and terminal facade, but also provide anti-ram capability, preventing a VBIED from
entering the building space

• Anti-shatter film (ASF) applied to glass panels to reduce fragmentation from entering the interior
terminal space from an outside explosion
• Installing replacement blast-resistant facade systems with laminated glass and blast-resistant
frames
• Enhancing existing overhead equipment anchorages to reduce overhead equipment falling from a
height
• Installing architectural furring and cladding around columns
• Installing fiber-reinforced polymer (FRP) wraps on concrete columns or concrete encasement
around structural steel columns.
Operational
There are several operational control measures that an airport can implement to reduce the impact of
VBIEDs. These measures generally do not reduce the effects of a blast, but predominately act as a
means of detection and deterrence, and potentially have the capability to disarm an assailant in some
instances. Operational measures often work best when implemented in tandem with technology.
• Patrolling the terminal roadway

• Vehicle screening
• Active monitoring of video surveillance within a control room.
Technology
Technological solutions can be used to enhance the effect of operational staff in detecting and deterring
blast threats. The following may be undertaken to enhance the airport’s electronic security systems, or
provide additional tools for operational staff to mitigate against the VBIED threat:
• Monitored CCTV surveillance of vehicles on and before the terminal roadway. This may be
supported by CCTV analytics to identify idle vehicles (or unusual vehicle behavior) in
designated areas. Note: CCTV cameras may need to be upgraded to a higher resolution to
support analytics software.
• License plate recognition systems to verify authorized vehicles for secure areas. This requires
coordination with authorities or agencies.
• Replacing fixed lens cameras with PTZ cameras or multi-imager cameras to facilitate an increase
to the potential field of vision provided by surveillance systems.
• Under vehicle screening devices used at checkpoints to thoroughly check a vehicle for explosive
materials.
Mitigation Assessment
Following a qualitative assessment of all the proposed measures to protect against the blast threats, the
following mitigations have been selected as potentially being able to be incorporated as part of the
holistic blast strategy. The extent of mitigations listed are for example purposes only, and mitigations
may vary depending on the risk assessment process and individual airport characteristics being
considered.
After further evaluation of the possible measures, the measures listed in Table B-3 have been identified
for moving forward with the framework process.

Table B-3. Individual VBIED Mitigation Measures Considered at the Example Airport
Mitigation Description
Vehicle Security Impact-rated vehicle security bollards installed 12 feet in front of the terminal facade.
Barriers
Vehicle Vehicle screening checkpoint with under vehicle screening technology. Inspections
Screening undertaken on a random basis.
Anti-shatter film installed on existing terminal facade. Provides improvement by reducing
Facade
glass fragments that enter the terminal building. Replacement of the facade was seen as
Enhancement
unfeasible in this specific example.
Additional taxi ranks provided to reduce the concentration of people along the roadway.
Crowd Reduction Ride-share pick-up locations spread over more terminal exit doors. General public pick-up
areas relocated to near bus zones.
An increase in the number of security personnel patrolling the roadway acting as a show of
Security Patrols
security presence and capable of detecting parked/suspicious vehicles.
Monitored CCTV with video analytics capable of picking up parked cars or suspicious
CCTV vehicles. License plate recognition linked with authorities capable of picking up suspect
vehicles.
Moving on to the scoring portion of Step 2, these mitigation measures have then been assessed against
metrics that achieve a security outcome. The scoring and metrics used in this example are summarized
in Table B-4. The list of security metrics and scoring was undertaken collaboratively with airport
stakeholders, airport management, and an external protective security professional. The scoring below is
for example purposes only, and may differ depending on individual airport characteristics and risk
profile.
Table B-4. Example Scoring of Mitigation Measures Against Proposed Security Metrics
Reduce Inform Law Protect Protect

Mitigation Detect Deter Disable
Crowds Enforcement People Property
Vehicle Security Barrier 0 30 20 0 0 30 30

Vehicle Screening 30 50 0 0 0 0 0
Facade Enhancement 0 0 0 0 0 30 0
Crowd Reduction 0 0 0 40 0 0 0
Security Patrols 10 30 0 0 10 0 0
CCTV 20 10 0 0 20 0 0
Step 3 of the framework includes developing ROM cost estimates. For this step, a blast engineer was
consulted for a nominal fee to develop conceptual ideas of the mitigations and where they would be
located. The airport’s cost estimator was used to develop annual costs, annualized over 15 years using
Net Present Value. The engineer would be retained to do a more detailed design once the airport has
considered which measures should be pursued after completion of Step 4.

Table B-5. Mitigation Measures and Listed Annual Financial Cost
Mitigation Annual Cost (annualized over 15 years)
Vehicle Security Barrier $1,200,000

Vehicle Screening $300,000
Facade Enhancement $350,000
Crowd Reduction $250,000
Security Patrols $900,000
CCTV $1,500,000
These mitigation measures, scores, and costs were inputted into the framework for evaluation of the
exterior drive-up area as it relates to the VBIED vulnerability. Figure B-3 shows the output from the
Excel-based tool for this case. The combinations within circles A, B, and C were independently selected
by the airport for evaluation, as they have the highest functional security score for a given financial cost
region.
Figure B-3. Output from the Excel-based Tool – Measure Combination Options
The airport’s assessment of the combinations within circles A, B, and C is summarized within Table
B-6.
Table B-6. Assessment Summary of A, B, and C Mitigation Combinations
Combination Groups
A When referenced back to the risk assessment, it was deemed that these were not adequate in reducing
risk to an acceptable level.
B These mitigations are to be considered for implementation and interrogated in more detail.
C Mitigation combinations are acceptable but expenditure is too high and not proportionate to risk.
The three measure combinations within circle B were further evaluated by reviewing the specific
measures in each combination along with their functional security scores and financial costs. A
summary of this assessment is shown in Table B-7. A summary of the breakdown of costs between

physical, operational, and technological was also investigated as shown in Figure B-4. The airport has
enough initial funding to make capital investments and would prefer this to longer-term operational
expenditures. Additionally, the airport is not comfortable with the first two options in terms of their
ability to meet their risk-reduction goals. Therefore, the last combination was chosen.
Table B-7. Comparison and Selection of Combination Measure
Functional Financial
Combination
Security Score Cost
Vehicle Security Barriers + Facade Enhancement and Vehicle Screening 200 $1,400,000
Vehicle Security Barriers + Vehicle Screening and Crowd Reduction 210 $1,500,000
Vehicle Security Barriers + Vehicle Screening and Crowd Reduction
240 $1,650,000
+ Facade Enhancement
Figure B-4. Expenditure Breakdown for Selected Combination of Measures
Design Process
This section briefly describes the design process for implementing the prioritized security measures.
Vehicle Security Barriers

The airport has hired a protective design consultant to assess the vulnerability of the airport to vehicle
ramming attacks and VBIEDs. The following attack paths were identified in the consultant’s report with
associated vehicle attack paths and mass. This allows the airport to select a specific barrier that meets
their protective needs. The design-basis vehicle selected by the airport was a large-duty vehicle
(approximately 15,000 pounds). The HVM consultant calculated a potential impact speed of 35 mph.
The maximum allowable penetration distance of the vehicle once it has contacted the bollard has been
specified as 12 feet, representing the distance between the barrier and the terminal facade.

Figure B-5. Attack Paths and Design Basis
Shallow mounted bollards have been selected due to the presence of underground services beneath the
footpath outside the entrances to the airport. These foundations (depth less than 12 inches) can sit atop
these services.
Therefore, the airport has implemented shallow-mounted bollards with a condition designation of M40
P2 (ASTM F2656-15).
Vehicle Screening
Due to the heightened threat level, the airport has decided to implement a vehicle-vetting procedure to
better control access of vehicles to its roadways. Authorized taxis and buses are permitted to enter the
lane closest to the terminal, and public drop-off/pick-up has been pushed back to the second lane. Doing
so has generated a further 25 m of standoff and added a level of screening to drivers using the roads
closest to the terminal. Passengers are also now spread across a large number of vehicle pick-up
locations, reducing the number exposed to a specific blast event.
Furthermore, delivery vehicles are to be screened further down the loading dock access road to allow for
greater standoff distance. This has been combined with a procedure whereby deliveries require prior
authentication, and driver identity is verified at the screening point along with the vehicle registration.

Figure B-6. Selected Vetting Points (Highlighted in Blue)
Crowd Reduction
With the objective of reducing crowd density outside the arrivals and drop-off halls, public pick-up and
drop-off zones have been located away from the terminal near the bus shelters, reducing the total
number of people along the terminal roadway. Through collaboration with ride-share services, pick-up
locations have been spread over a number of airport doors, spreading arriving passengers across the
terminal building to disperse crowds.
Facade Enhancement
The installation of ASF to the monolithic glass pane of the airport terminal facade will assist in holding
glass fragments together upon fracture under blast loads. It is not expected that this measure will
maintain the building envelope or reduce the expected hazard level of the glazing under blast, but it will
provide a nominal benefit.
This measure is seen as temporary until such time the airport undergoes major redevelopment and
replaces its glazed terminal facade.
Case Study 2: PBIED within Terminal

PBIEDs are a particularly challenging threat to mitigate against within non-secure areas. Given their
ease of concealment, these threats often go largely undetected until detonation. The focus of retrofit
items should therefore be:
• Identifying the threat (where possible)

• Responding to the threat
• Reducing its potential impact
The specific threat identified is located at the queuing area for passenger screening, as shown within
Figure B-7 below.
This section outlines the various operational, technological, and physical mitigation strategies that this
airport can implement to reduce the potential consequences of the identified PBIED threat. The below
sections describe mitigation measures that could be applied to manage this risk.
Figure B-7. Indicative Threat Areas: PBIEDs
Step 1 of the framework process has been completed during the risk assessment (see Table 5-8). Step 2
incorporates listing the measures that can be used to mitigate this risk at this particular airport.
Physical Measures

As with VBIED threats, there are several physical measures that have been implemented to protect
against PBIEDs.
• Adequate design and restraint of miscellaneous architectural components to reduce the effects of
fragmentation from a blast event
• The glazing treatments implemented to protect from VBIEDs provide additional protective
benefits in reducing the potential impact of PBIEDs detonated in close proximity to the terminal
facade
• Structural hardening of steel columns through concrete encasement to protect against progressive
collapse from a placed device
Operational Measures
Operational measures that could be considered to mitigate against a PBIED threat include:
• Increase in security patrols in front of house (FoH) areas to identify suspicious behavior and left
objects
• Patrolling activities enhanced by explosives detection canine patrols throughout the front of
house and drop-off/pick-up areas
• CCTV surveillance monitored 24/7 by operational staff within a control room
Technology
The airport has determined the following technology will be implemented to support the operational and
physical security elements:
• CCTV analytics to identify abandoned objects and to facilitate the tracking of suspicious persons
through the airport
• Controlled access (via an electronic access control system) to back of house (BoH) areas—
access to various BoH departments should be person-based rather than discipline-based—to
facilitate greater oversight and control of access to critical FoH areas
• Screening through the deployment of millimeter wave standoff explosive detection equipment at
terminal entrances
Mitigation Assessment
Following a qualitative assessment of all the proposed measures to protect against the blast threats, the
following mitigations have been selected as potentially being able to be incorporated as part of the
holistic blast strategy. The extent of mitigations listed are for example purposes only, and mitigations
may vary depending on the risk assessment process and individual airport characteristics being
considered.
Table B-8. Individual PBIED Mitigation Measures Considered at the Example Airport
Mitigation Description

Explosives Detection Canines trained in explosive detection deployed within the building terminal area to
Canines support security patrols
Additional staffed check-in lanes provided to reduce crowding within the security
Crowd Reduction
checkpoint
An increase in the number of security personnel patrolling the departure hall—some
Security Patrols
security staff are trained in behavioral detection
All miscellaneous glazing replaced with laminated glass and enhanced restraint to
Resilient Finishes
overhead equipment within the ceiling space
CCTV Monitored CCTV with video analytics capable of picking up unattended bags
The measure-scoring portion of Step 2 is shown in Table B-9, followed by the cost estimation for Step 3
of the framework process in Table B-10.
Table B-9. Example Scoring of Mitigation Measures Against Proposed Security Metrics
Reduce Inform Law Protect Protect

Mitigation Detect Deter Disable
Crowds Enforcement People Property
Explosives Detection Canines 40 40 20 0 15 0 0

Crowd Reduction 30 0 0 50 0 0 0
Security Patrols 15 30 20 0 15 0 0
Resilient Finishes 0 0 0 0 0 30 0
CCTV 20 20 0 0 20 0 0
Table B-10. Mitigation Measures and Listed Annual Financial Cost
Annual Cost
Mitigation
(annualized over 15 years)
Explosives Detection Canines $1,000,000

Crowd Reduction $2,500,000
Security Patrols $900,000
Resilient Finishes $850,000
CCTV $2,000,000
The outcome of using the Excel-based framework tool is shown in Figure B-8. The combinations within
circles A, B, C, and D were chosen, as they have the highest functional security scores for their
respective cost brackets.

Figure B-8. Graphic Representation of Combined Mitigations vs. Cost
The airport’s assessment of these four combinations is summarized within Table B-11. Combination B
was selected, as it provides an acceptable level of risk reduction within budget. The airport assessed that
they can achieve the budget required over the upcoming years for the operations costs required as
summarized in the expenditure breakdown of Figure B-9.
Table B-11. Assessment Summary of A, B, C, and D Mitigation Combinations
Combination Groups
When referenced back to the risk assessment, it was deemed that these were not adequate in reducing
A
risk to an acceptable level.
B This mitigation is to be considered for implementation and interrogated in more detail.
C Mitigation combination is acceptable but expenditure is too high and not proportionate to risk.
D Mitigation combination is acceptable but expenditure is too high and not proportionate to risk.
Table B-12. Summary of Selected Combination Measure (Combination B)
Combination Security Score Financial Cost
Security Patrols, Explosives Detection Canines, and Resilient Finishes 225 $2,750,000
Figure B-9. Expenditure Breakdown for Selected Combination of Measures
Design Process

This section briefly describes the design process for implementing the prioritized security measures.
Security Patrols
Security patrols are an integral component when implementing a security strategy. They can serve as a
deterrent and respond to a security event as it unfolds. Security patrols have some detection capability,
but are most effective when deployed in combination with supporting measures such as canines and
CCTV technologies. The number of security personnel patrolling the airport can also be readily
increased in an increased threat environment.

Trained explosives detection canines, along with trainers, are to be deployed within the terminal
building. Dogs are to be trained in explosive substance detection and used to sniff oncoming passengers
within landside terminal areas on a random basis. BoH areas to support canines are to be provided.
Resilient Finishes
Miscellaneous architectural items and building services are not usually designed for blast loads, and
therefore are likely to add to the level of fragmentation in a blast event. It is generally not practical to
enhance these items to directly withstand the blast overpressures; however, practical enhancements to
these elements can significantly reduce the risk to personnel.
As part of the project, a structural and a facade engineer have been asked to incorporate the following
within their design:
• All glazing within the terminal building to be replaced (if required) with laminated glass
• All glazing to be silicone-fixed with a minimum bite length
• Fixing of all miscellaneous architectural items (including glazing) and building services to the
structure is to be designed for a force equal to two times the items’ weight in all directions.
Examples of details incorporating the above are shown within Figure B-10 below.
Figure B-10. Example Details to Improve Finishes Resilience against a PBIED

COST DATA
1. Basis of Pricing
The rough order of magnitude (ROM) estimate is a Class 5 according to Arup’s estimate classification
matrix (Level 5), which was developed from the Association for the Advancement of Cost Engineering
(AACE) best practices.
The accuracy range is a gauge of likely bid prices if the project were issued to tender at the current
stage. The accuracy range of this estimate has been determined to be between -25% and +50%.
This document is based on the measurement and pricing of quantities wherever information is provided,
and/or on reasonable assumptions for other works not covered in the drawings and programs as stated in
this document. The unit rates reflected herein have been obtained from experience with projects of this
nature.
2. Scope of the Project

This exercise provides ROM costs for technological security measures (e.g., CCTV) and operational
security measures that might be used at airports. This work is for informational and comparison
purposes for National Safe Skies Alliance’s (Safe Skies) research study only; there is no actual
construction project.
The estimate is based on a medium-sized airport and a medium-sized city in the United States. Examples
of these airports/cities are Oakland, San Jose, Pittsburgh, New Orleans, Nashville, Milwaukee, etc.
This exercise provides factors that translate the medium/baseline costs to large city costs (e.g., New
York, San Francisco, Chicago, etc.) and one factor to translate the cost to a small/rural city cost (e.g.,
Fresno, Syracuse, Wichita, etc.)
3. Scope of Works
The scope of this cost estimate includes the following:
• Capital costs for different works, which will be applicable for locations within an airport
• Operational costs for different operational measures, which will be applicable for locations
within an airport
• Life cycle costs over a period of 20 years, including capital, maintenance, and replacement costs
4. Documentation
Documentation has been prepared by the project consultant, Arup, for developing this cost estimate:
PARAS 0014 Safe Skies Project, December 03, 2017.
5. Project Construction Schedule

An overall construction duration has not been calculated for this exercise.
Blast-Mitigation Strategies for Non-Secure Areas at Airports C-1

6. Other Costs
• Capital Cost
− An allowance of 20% from direct cost is considered a general requirement, which covers
costs related to general staff wages and fringes, site conditions, and temporary power
− Allow a project reserve of 15% from the total direct cost due to the project's uncertainty
− Allow 10% from the total cost for the contractor's overhead and profit
− Allow 2.5% from the total cost for the contractor's bonds and insurance
• Operational Cost
− Allow a project reserve of 15% from the total operational cost due to the project's uncertainty
− Allow 10% from the total cost for the contractor's overhead and profit
7. Escalation
• An escalation allowance is excluded for the capital cost
• An escalation of 3.5% per year is consider for the 20-year life cycle cost projection
8. General Assumptions
• The values are in US dollars
• The values are from the fourth quarter of 2017
• Material costs are calculated from databases such as RS Means, similar project costs, and
vendors
• Labor rates, fringes, and taxes are calculated based on data from the US Department of Labor,
Bureau of Labor Statistics
• Material, labor, and equipment rates are considered from an average of medium-sized airport
cities
• The medium-sized airport cities considered for this exercise are: Oakland, San Jose, Pittsburgh,
New Orleans, Nashville, and Milwaukee
• The location factor for the different cities was obtained from the portal of RS Means
• The operational cost estimate is not a life cycle cost, meaning that there might be other costs
involved to operate an airport
• The total first year investment is defined as the sum of the capital and operational costs
• A 5% preliminary engineering cost is suggested as part of the total price; however, it is excluded
• The structural, civil, and architectural costs are provided by the sub-consultant BMK
Engineering
9. Working Assumptions
• Capital Cost
− The total unit cost is compounded by material, crew, and sub-contractor overhead and profit
− Crews are composed of labor and equipment, and are defined based on similar project costs
and the RS Means portal
− A 150-foot length of cabling is considered per camera, scanner, and other security equipment
as part of its installation
− A 15% allowance of the material and crew cost is considered as sub-contractor overhead and
profit
− The security devices include the material, labor, and equipment needed to operate as a whole
system
• Operational Cost
− The operational costs are calculated for a year of operations, which is equivalent to 365 days
− Operations occur over 24 hours per day

− The operations define 12 hours for day time and 12 hours for night time
− The labor rates increase 25% for night time
− For officers/handlers/guard staffing, five workers are considered per day, one for each shift
plus two as a contingency. The frequency of each activity is considered based on similar
projects
− An allowance of security staff training is considered based on experience
• Replacement Cost
− It is assumed that a replacement cost per activity equals the capital cost of that same activity
− A replacement period of 10 years is considered for non-moving components
− A replacement period of 4 years is considered for moving components
− No replacement of civil, cable, or structural works is considered
10. Items Excluded from the Cost Estimate

• Costs or impacts of latent environmental issues that result in litigations or development delays
• Owner contingency
• Planning and enquiry costs, including legal expenses and fees
• Local planning obligations and agreements
• Site investigation
• Local taxes and duties
• Right-of-way and/or land acquisition costs
• Risk-based contingency analysis
• Tests and inspections performed by others, apart from that listed in the estimate
• Program management and construction management costs
• Compensatory costs to other interested parties
• Cost benefits and impacts associated with improvements in construction technology, more severe
regulatory requirements, and future construction that may impact the work contemplated under
this project
• Removal and disposal of hazardous materials, unless otherwise stated in the cost estimate
• Integration to the building management or communication systems unless otherwise stated
• Structural, civil, and architectural costs unless otherwise stated
• Consultant fees
• Owner costs
• Preliminary engineering costs
• Detailed engineering costs
• Escalation allowance
11. Items that May Affect the Cost Estimate

• Modifications to the scope of work included in this estimate
• Special phasing requirements
• Restrictive technical specifications or excessive contract conditions
• Any other non-competitive bid situations
• Bids delayed beyond the projected schedule
• Loss of labor productivity
• Future market conditions
12. Statements of Probable Cost

Arup has no control over the cost of labor and materials, general contractor’s or any subcontractor’s
method of determining prices, or competitive bidding and market conditions. This opinion of probable
cost of construction is made on the basis of the experience, qualifications, and best judgment of the
professional consultant familiar with the construction industry. Arup cannot and does not guarantee that
proposals, bids, or actual construction costs will not vary from this or subsequent cost estimates.









INDICATIVE BLAST-MITIGATION DETAILS
Blast-Mitigation Strategies for Non-Secure Areas at Airports D-1

























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PARAS PROGRAM FOR APPLIED

RESEARCH IN AIRPORT SECURITY

PARAS 0014 August 2018

Blast Mitigation Strategies for

National Safe Skies Alliance, Inc.

Sponsored by the Federal Aviation Administration

© 2018 National Safe Skies Alliance, Inc. All rights reserved.

Blast-Mitigation Strategies for Non-Secure Areas at Airports ii

NATIONAL SAFE SKIES ALLIANCE, INC.

Blast-Mitigation Strategies for Non-Secure Areas at Airports iii

PROGRAM FOR APPLIED RESEARCH IN AIRPORT SECURITY

PARAS PROGRAM OFFICER

PARAS 0014 PROJECT PANEL

Blast-Mitigation Strategies for Non-Secure Areas at Airports iv

Blast-Mitigation Strategies for Non-Secure Areas at Airports v

Blast-Mitigation Strategies for Non-Secure Areas at Airports vi

4.1.6 Physical Measure Retrofits for Existing Airports 54

Blast-Mitigation Strategies for Non-Secure Areas at Airports vii

EVALUATION OF MITIGATION MEASURES A-1

LIST OF TABLES & FIGURES

Blast-Mitigation Strategies for Non-Secure Areas at Airports viii

Figure 1-1. Overview of Guidebook Contents 1

Blast-Mitigation Strategies for Non-Secure Areas at Airports ix

Figure 4-19. Wedge Barriers 54

Blast-Mitigation Strategies for Non-Secure Areas at Airports x

The main concepts in this guidebook are as follows:

Blast-Mitigation Strategies for Non-Secure Areas at Airports xi

SECTION 1: OVERVIEW OF GUIDEBOOK

• Damage to be expected as a result of various threats (Section 2)

Figure 1-1. Overview of Guidebook Contents

Section 2: Section 3: Section 5:

Blast-Mitigation Strategies for Non-Secure Areas at Airports 1

1.2.1 Input from Airports

Table 1-1. Airports Interviewed

Airport Interview Department within

Dallas/Fort Worth International Airport

1.2.1.1 Experience Implementing Blast-Mitigation Strategies

Blast-Mitigation Strategies for Non-Secure Areas at Airports 2

Blast-Mitigation Strategies for Non-Secure Areas at Airports 3

1.2.1.2 Challenges of Incorporating Blast Protection

Blast-Mitigation Strategies for Non-Secure Areas at Airports 4

Blast-Mitigation Strategies for Non-Secure Areas at Airports 5

1.2.2 Gaps in Current Guidance

Blast-Mitigation Strategies for Non-Secure Areas at Airports 6

Blast-Mitigation Strategies for Non-Secure Areas at Airports 7

1.3 Guidebook Objective

Implementing appropriate blast-risk-mitigation strategies is the responsibility of the

Blast-Mitigation Strategies for Non-Secure Areas at Airports 8

SECTION 2: BACKGROUND INFORMATION

2.1 Basic Principles of Blast Loading

Blast-Mitigation Strategies for Non-Secure Areas at Airports 9

Figure 2-1. Simplified Blast Wave Interaction with Building

Source: bmk Engineering

Blast-Mitigation Strategies for Non-Secure Areas at Airports 10

2.2 Historical Explosive Events and Future Trends

2.2.1 Istanbul Atatürk Airport

Blast-Mitigation Strategies for Non-Secure Areas at Airports 11

Figure 2-2. Damage after Atatürk Explosion

Source: Associated Press