Safety Management Guide: Saudi Aramco
Safety Management Guide: Saudi Aramco
Safety Management Guide: Saudi Aramco
Table Of Contents
1. Purpose ........................................................................................................ 1
2. References ................................................................................................... 1
3. Definitions ..................................................................................................... 1
4. Before Work Starts........................................................................................ 3
5. Work Permits ................................................................................................ 4
6. Underground Utilities and Installations.......................................................... 4
7. Dewatering.................................................................................................... 5
8. Protection Against Sidewall Cave-In ............................................................. 6
9. Entry and Exit ............................................................................................... 8
10. Hazardous Atmospheres and Materials ........................................................ 9
11. Emergency Response................................................................................... 9
12. Edge Protection, Clearances, Barricades, and Fixed Lighting .................... 10
13. Roads, Streets, and Sidewalks ................................................................... 10
14. Inspections.................................................................................................. 10
15. Backfilling.................................................................................................... 10
Attachments
A1 Tables and Figures ..................................................................................... 11
A2 Excavation Safety Checklists...................................................................... 32
2. References
Saudi Aramco General Instructions (GIs):
GI 1021.000, Street and Road Closure, Excavation, Reinstatement and Traffic
Controls
GI 2.100, Work Permit System
Saudi Aramco Engineering Standards (SAES):
SAES-A-111, Borrow Pit Requirements
SAES-A-114, Excavation and Backfill
Saudi Aramco Safety Handbook
Saudi Aramco Standard Drawing (SASD):
AB-036899, Standard Specifications for Shoring Trenches
American National Standards Institute (ANSI):
ANSI/ASSE A10.12, Safety Requirements for Excavation
United States Code of Federal Regulations (CFR):
29 CFR 1926 Subpart P, Excavations (also cited as OSHA 1926, Subpart P)
3. Definitions
Benching – A method of protecting personnel from sidewall cave-in by excavating the
sides of an excavation to form one or more of a series of horizontal steps, with a vertical
rise between each step.
Competent Person – A person who has and is able to demonstrate the following:
1. Documented training, experience, and knowledge of:
a. soil analysis
b. use of protective systems
2. Ability to detect:
a. conditions that could result in sidewall cave-in
b. failures in protective systems
c. other hazards including those associated with confined spaces, dewatering; and
3. Written authority to take prompt corrective measures to eliminate existing and
predictable hazards.
Excavation – Any man-made cut, cavity, trench, or depression in an earth surface that is
formed by earth removal.
Excavation Box – A structure that protects personnel inside it by withstanding the forces
imposed by sidewall cave-in on four (4) sides.
Hydraulic Shoring – A pre-engineered shoring system of aluminum or steel hydraulic
cylinders (cross-braces) used with vertical rails (uprights) or horizontal rails (walers) and
designed specifically to support side walls of an excavation to prevent cave-in.
Protective Systems – Methods used to protect personnel from sidewall cave-in, materials
that could fall or roll into the excavation, or collapse of adjacent structures. Protective
systems include sloping, benching, and shoring.
Shoring – Hydraulic, timber, or mechanical systems that support the sides of an
excavation, which is designed to prevent sidewall cave-ins.
Sloping – A method of protecting personnel from sidewall cave-in by forming sides of an
excavation that are inclined away from the excavation. The safe angle of slope required
varies with different types of soil, exposure to the elements, and superimposed loads.
Soil Classification – A method of categorizing soil and rock deposits as Types A, B, and
C in decreasing order of stability (see definitions below). Soil type is determined by a
analysis of the soil's properties and how it performs under exposure to the elements and
superimposed loads. If the type of soil cannot be accurately determined, then Type C soil
is to be assumed for design of protective systems.
Stable Rock – Natural solid mineral matter that can be excavated with vertical sides and
remain intact while exposed. It is usually identified by a rock name such as granite or
sandstone.
Support System – Structures such as underpinning, bracing, and shoring that provide
support to an adjacent structure or underground installation.
Trench – A narrow excavation (in relation to its length), where the depth is greater than
the bottom width.
Trench Shield – A structure that protects personnel inside it by withstanding the forces
imposed by sidewall cave-in on two (2) sides.
Type A Soil
Cohesive soils with an unconfined compressive strength of 1.5 ton per square foot (tsf)
(144 kPa) or greater are classified as Type A. Examples of cohesive soils are: clay, silty
clay, sandy clay, clay loam, and, in some cases, silty clay loam and sandy clay loam.
Cemented soils, such as marl, are also considered Type A. However, no soil is Type A if
one or more of the following conditions are true:
• The soil is fissured.
• The soil is subject to vibration from heavy traffic, pile driving, or similar effects.
• The soil has been previously disturbed.
• The soil is part of a sloped, layered system where the layers dip into the
excavation on a slope of four horizontal to one vertical (4H:1V) or greater.
• The material is subject to other factors that would require it to be classified as a
less stable material.
Type B Soil
Soils classified as Type B are:
• Cohesive soils with an unconfined compressive strength greater than 0.5 tsf (48
kPa) but less than 1.5 tsf (144 kPa).
• Granular cohesionless soils including: angular gravel (similar to crushed rock),
silt, silt loam, sandy loam, and, in some cases, silty clay loam and sandy loam
clay.
• Soil that meets the unconfined compressive strength or cementation requirements
for Type A, but is fissured or subject to vibration.
• Dry rock that is not stable.
• Material that is part of a sloped, layered system where the layers dip into the
excavation on a slope less steep than four horizontal to one vertical (4H:1V) but
only if the material would otherwise be classified as Type B.
Type C Soil
Soils classified as Type C are:
• Cohesive soils with an unconfined compressive strength of 0.5 tsf (48 kPa) or
less.
• Previously disturbed soil (e.g., fill) is to be considered as Type C soil.
• Granular soils, including gravel, sweet sand, desert sand, and loamy sand.
• Submerged soil or soil from which water is freely seeping.
• Submerged rock that is not stable.
• Material in a sloped layered system where the layers dip into the excavation or a
slope of four horizontal to one vertical (4H:1V) or greater.
5. Work Permits
5.1 Saudi Aramco (SA) work permit(s) shall be obtained from the appropriate issuing
authority as required before excavation work is started. Refer to GI 2.100 for Saudi
Aramco’s work permit requirements. It is the responsibility of the SA Work
Permit Issuer to ensure that underground utilities/installations have been located
and marked (e.g., by flags or chalk) before excavation activities begin.
5.2 For grassroots projects, Project Management is to develop and implement its own
work permit procedures until such time as the SA work permit system goes into
effect. These work permit procedures are to incorporate the excavation safety
provisions and checklists from this guide.
5.3 For other work sites not covered by the SA work permit system (e.g., non-restricted
areas), the SA proponent organization is to develop and implement excavation
safety procedures in accordance with this guide. Development of these excavation
safety procedures is to include participation by Utilities, Communications, Power
Distribution Department (PDD), Pipelines, etc., as applicable.
5.4 As per GI 2.100, a properly completed Confined Space Entry Permit is required to
enter excavations equal to or greater than 1.2 m (4 ft) deep.
7. Dewatering
7.1 Employees are not to work in excavations where there is pooled water, or in
excavations in which water is accumulating, unless adequate precautions have been
taken to protect employees. The necessary precautions vary with each situation, but
are to include water removal to control the level of accumulating water (e.g., by
pumping) and may also include special support or shield systems to protect from
cave-ins.
7.2 If water is controlled or prevented from accumulating by the use of water removal
equipment, the water removal equipment and operations needs to be monitored by a
Competent Person to verify proper operation. The Competent Person may be an
individual other than the Competent Person for the excavation.
7.3 If excavation work interrupts the natural drainage of surface water (such as
streams), diversion ditches, dikes, or other suitable means need to be used to
prevent surface water from entering the excavation and to provide adequate
drainage of the area adjacent to the excavation.
7.4 Excavations that have been subject to runoff (e.g., from a rain storm) need to be
inspected before use by the excavation Competent Person in accordance with
section 14.
F. Vertical spacing of cross braces and stringers (wales) down the sidewall of the
excavation is not to exceed 1.2 m (4 ft). However, a maximum vertical
spacing of 1.5 m (5 ft) for braces and stringers may be acceptable in some
situations (see Tables 6 to 8, or SA Standard Drawing AB-036899). Cross
braces need to always be used with stringers (wales).
G. Horizontal spacing of cross braces (e.g., along the length of a trench) is not to
exceed 1.8 m (6 ft). However, a larger horizontal spacing for cross braces
may be acceptable in some situations (see Tables 6 to 8, or SA Standard
Drawing AB-036899). At least 2 cross braces (upper and lower) are to be
used at each bracing location.
8.5 When used, excavation screw jacks are to be installed in accordance with Figure 11
and the manufacturer’s instructions.
8.6 Scaffold tubing, with compatible screwjacks and baseplates, may be used as cross
braces for excavations not over 1.2 m (4 ft) wide and not more than 2.4 m (8 ft)
deep. For excavations between 1.8 m (6 ft) and 2.4 m (8 ft) deep, scaffold tubing
cross braces are to be horizontally spaced not more than 1.2 m (4 ft) apart. For
excavations less than 1.8 m (6 ft) deep, scaffold tubing cross braces are to be
horizontally spaced not more than 1.8 m (6 ft) apart. Scaffold tubing used as cross
braces for shoring is to have at least a 4.0 mm wall thickness and be permanently
embossed (stamped) before galvanizing with “BS 1139” or “EN39 - 4” (Type 4) as
per the Saudi Aramco Scaffold Safety Handbook, paragraph 9.7.2.
8.7 The top cross brace is not to be more than 0.6m (2 ft) below the top of the
excavation, and the lowest cross brace is not to be more than 0.6 m (2 ft) above the
bottom of the excavation.
8.8. Steel sheet piling or any other comparable material used as shoring is to be
designed by a degreed civil/structural engineer.
8.9 A minimum clear space of 0.6 m (2 ft) wide is to be maintained on all sides of an
excavation, in order to provide workers a flat surface to walk on next to the
excavation and to keep rocks from falling on workers inside the excavation.
8.10 Where personnel, equipment, or members of the general public are allowed to cross
an excavation, a tightly planked bridge or walkway with standard guardrails needs
to be provided and kept clear of excavated materials or other tripping hazards.
14. Inspections
Documented inspections are to be performed by a Competent Person before workers are
allowed to enter the excavation each morning or after a change in site conditions (e.g.,
rain storm, groundwater infiltration, sidewall deterioration, adjacent ground fissuring).
An excavation safety checklist is to be used to document these daily inspections. See
Attachment A2 for a sample daily excavation inspection checklist that is to be completed
and signed each day by the excavation Competent Person. If there is an unsafe condition,
workers are not to be allowed to enter the excavation. Attachment A2 also contains a
sample excavation safety pocket card that may be used by others at any other time (e.g.,
Work Permit Issuers/Receivers, Saudi Aramco and contractor employees who work in or
near excavations, Project Management and proponent personnel).
15. Backfilling
Backfilling and removal of shoring is to be accomplished first by backfilling up to a level
allowing for the removal of the lower braces. Another layer of backfill is to be
positioned in the excavation up to the next layer of braces to be removed. Removal of
shoring is to progress together with the backfill from the bottom to the top of the
excavation. In unstable soil, ropes are to be used to pull out the jacks or braces from
above after all employees have exited the excavation. All excavations are to be
backfilled and completed, and the surface left in good condition.
Attachment A1
NOTES:
1. Numbers shown in parentheses next to maximum allowable
slopes are angles expressed in degrees from the horizontal.
Angles have been rounded off.
All simple slope excavations made in Type A soil that are 6 m (20 ft) or less in
depth are to have a slope of not greater than 3/4 horizontal to 1 vertical.
All benched excavations made in Type A soil that are 6 m (20 ft) or less in depth
are to have a maximum allowable slope of 3/4 horizontal to 1 vertical and
maximum bench dimensions as follows.
SIMPLE BENCH
MULTIPLE BENCH
All excavations made in Type A soil that are 6 m (20 ft) or less in depth, which
have vertically sided lower portions that are supported or shielded, are to have a
maximum allowable slope of 3/4 to 1. The support or shield system must extend
at least 0.45 m (18 in) above the top of the vertical side.
All simple slope excavations made in Type B soil that are 6 m (20 ft) or less in
depth are to have a slope of not greater than 1 horizontal to 1 vertical.
SIMPLE SLOPE
All benched excavations made in Type B soil that are 6 m (20 ft) or less in depth
are to have a maximum allowable slope of 1 horizontal to 1 vertical and
maximum bench dimensions as shown below. Benched excavations that are
unsupported or unshielded are permitted only in cohesive soils.
SIMPLE BENCH
MULTIPLE BENCH
All excavations made in Type B soil that are 6 m (20 ft) or less in depth that have
vertically sided lower portions are to be shielded or supported to a height at least
0.45 m (18 in) above the top of the vertical side. All such excavations are to
have a maximum allowable slope of 1:1.
All simple slope excavations made in Type C soil that are 6 m (20 ft) or less in
depth are to have a slope of not greater than 1-1/2 horizontal to 1 vertical.
All excavations made in layered soils that are 6 m (20 ft) or less in depth are to
have a maximum allowable slope for each layer as set forth below.
FIGURE 10: GUIDE TO SAFE DISTANCE BACK FROM TOP OF SLOPE FOR
STORAGE OF MATERIALS OR PLACING EQUIPMENT (TYPE A SOIL)
Hydraulic Cylinders
Width Of Excavation
Hydraulic Cylinders
Width Of Excavation
OVER 20 AN EXCAVATION PLAN TO BE PREPARED BY A DEGREED CIVIL/STRUCTURAL ENGINEER AND REVIEWED BY CSD
* Mixed oak or equivalent with a bending strength of not less than 850 psi.
** Timber sizes shown are actual (not nominal) sizes. Manufactured members of equivalent
strength may be substituted for wood.
Note: Maximum spoils height is 0.6 m (2 feet) within a horizontal distance away from the edge
of the excavation equal to the depth of the excavation.
* Mixed oak or equivalent with a bending strength of not less than 850 psi.
** Timber sizes shown are actual (not nominal) sizes. Manufactured members of equivalent
strength may be substituted for wood.
Note: Maximum spoils height is 0.6 m (2 feet) within a horizontal distance away from the edge
of the excavation equal to the depth of the excavation.
Note (1): Member sizes at spacings other than indicated requires an excavation plan to be
prepared by a degreed civil/structural engineer and reviewed by CSD.
* Mixed oak or equivalent with a bending strength of not less than 850 psi.
** Timber sizes shown are actual (not nominal) sizes. Manufactured members of equivalent
strength may be substituted for wood.
Note: Maximum spoils height is 0.6 m (2 feet) within a horizontal distance away from the edge
of the excavation equal to the depth of the excavation.
Note (1): Member sizes at spacings other than indicated requires an excavation plan to be
prepared by a degreed civil/structural engineer and reviewed by CSD.
Attachment A2
Excavation Safety Checklists
PRE-EXCAVATION CHECKLIST
PROJECT OR WORK EXCAVATION
ORDER NUMBER LOCATION
______________________________ _______
PROPONENT
Depth of excavation: _______ meters / feet Width of excavation: _______ meters / feet
YES NO N/A
Has a Pre-Excavation Checklist been completed and is it available on site?
Have all relevant departments been notified?
Are underground utilities, cables, and pipelines located and marked?
Is a Work Permit required, issued, and available on site?
Is a Confined Space Entry Permit required, issued, and available on site?
Is gas testing required and performed; e.g., excavations deeper than 1.2 m (4 ft)?
Is a Stand-by Man and/or Fire Watch required and available on site?
Are pedestrian crossovers required and provided (with guardrails and toeboards)?
Is access to plant equipment maintained?
If excavation is near a roadway, are flagmen with bright orange vests present?
Are shoring/sloping/benching acceptable to prevent sidewall cave-in?
Is shoring material in sound condition and free of damage/defects?
Is shoring installed/maintained by qualified personnel?
Are adequate ladders provided within a travel distance of 7.5 m (25 ft)?
Are ladders properly secured and do they extend 1 m (3 ft) above the surface?
Is excavation free of tension cracks or other evidence of sidewall failure?
Is excavation free of water, hydrocarbons, or other toxic substances?
Are materials and spoils set back at least 0.6 m (2 ft) from excavation edge?
Are underground utilities and piping located, marked and protected from damage?
Are pedestrian barricades/lights placed at least 1 m (3 ft) from excavation edge?
Are hard barricades for vehicles placed at least 2 m (6.5 ft) from excavation edge?
Are cranes not closer than the depth of excavation to the edge of the excavation?
Are scaffolds erected no closer than 1.5 times the depth of excavation from edge?
Are overall conditions acceptable and safe for work?
All deficiencies will be corrected immediately.
PLANNING For sloping when excavation depth < 6 m (20 ft), use the
following maximum allowable sidewall slopes for the type
Has a Pre-Excavation Checklist been completed & on site? of soil, where “d” is the depth of the excavation.
Have all relevant departments been notified?
Are utilities, cables, and pipelines located and marked? • Stable Rock - Natural solid mineral matter that can
Was an excavation plan (calculations & drawing) prepared be excavated with vertical sides, such as sandstone.
by a civil engineer if excavation > 6 m (20 ft) deep?
Has the soil type (see back) been determined by a soil
analysis or by a “Competent Person”?
Is a Confined Space Entry Permit required and on site?
CONSTRUCTION
Is only excavating/backfilling equipment allowed within 2 m • Type A Soil - Previously undisturbed cohesive or
(6.5 ft) of the excavation and are the following clearances cemented soil, such as clay or marl.
maintained (unless properly designed shoring is used):
• Vehicles/cranes/heavy equipment more than the depth
of excavation away from excavation (2 m [6.5 ft] min.),
• Scaffold posts > 1.5 times depth of excavation away?
Has one or more of the following methods of protection
against sidewall cave-in been used and has it been done
per the excavation drawing? • Type B Soil - Less cohesive soil, such as a mix of
• Benching sand, rocks, and clay.
• Sloping (see back)
• Shoring (including trench shields, etc.)
Are spoil piles placed > 0.6 m (2 ft) away from excavation?
Are pedestrian barricades erected > 1 m (3 ft) away?
Are blinking warning lights installed and used?
Is a documented inspection performed daily by a • Type C Soil - Least cohesive soil. Examples are:
“Competent Person”? gravel, sand, muddy or freely seeping soils,
PERSONNEL ENTRY submerged rock that is not stable, or a layered
Do only authorized personnel enter the excavation? system. Previously disturbed soil is Type C soil.
Is any water in the excavation controlled by pumping?
Are gas tests conducted (e.g., low oxygen, toxic gases)?
Is a ladder or other access available within 7.5 m (25 ft)
travel distance (e.g., ladders spaced < 15 m [50 ft] apart)?
Is emergency rescue equipment available?
RESTORATION If a Pre-Excavation Checklist is not on site,
Has the work area been restored? contact your Saudi Aramco Representative
Are the walking surfaces level?