PNE00003
PNE00003
PNE00003
June 2013
PIP PNE00003
Process Unit and Offsites Layout Guide
PURPOSE AND USE OF PROCESS INDUSTRY PRACTICES
In an effort to minimize the cost of process industry facilities, this Practice has
been prepared from the technical requirements in the existing standards of major
industrial users, contractors, or standards organizations. By harmonizing these technical
requirements into a single set of Practices, administrative, application, and engineering
costs to both the purchaser and the manufacturer should be reduced. While this Practice
is expected to incorporate the majority of requirements of most users, individual
applications may involve requirements that will be appended to and take precedence
over this Practice. Determinations concerning fitness for purpose and particular matters
or application of the Practice to particular project or engineering situations should not
be made solely on information contained in these materials. The use of trade names
from time to time should not be viewed as an expression of preference but rather
recognized as normal usage in the trade. Other brands having the same specifications
are equally correct and may be substituted for those named. All Practices or guidelines
are intended to be consistent with applicable laws and regulations including OSHA
requirements. To the extent these Practices or guidelines should conflict with OSHA or
other applicable laws or regulations, such laws or regulations must be followed.
Consult an appropriate professional before applying or acting on any material
contained in or suggested by the Practice.
PUBLISHING HISTORY
December 1998 Issued as PNC00003
June 2007 Complete Revision and Renumbering
June 2013 Complete Revision
PIP PNE00003
Process Unit and Offsites Layout Guide
Table of Contents
1. Introduction.............................. 2 11. Equipment and Instrument
1.1 Purpose ....................................... 2 Access .................................... 12
1.2 Scope ........................................... 2 11.1 General ................................... 12
11.2 Fired Heaters and Furnaces ... 12
2. References ............................... 2 11.3 Towers and Drums.................. 12
2.1 Process Industry Practices .......... 2 11.4 Heat Exchangers .................... 12
2.2 Industry Codes and Standards .... 3 11.5 Pumps ..................................... 13
2.3 Government Regulations ............. 4 11.6 Compressors and Auxiliaries .. 13
11.7 Reactor and Dryers ................. 13
3. Definitions ................................ 4 11.8 Pressure Reliefs and
De-pressurizing Systems ........ 14
4. General ..................................... 5
12. Cooling Towers...................... 14
5. Site Plan Development ............ 6
13. Storage Tanks ........................ 14
6. Accessways, Platforms,
Fixed Industrial Stairs, 14. Gas Processing, Storage and
Fixed Ladders .......................... 7 Terminal Facilities ................. 14
6.1 Access and Egress ...................... 7 15. Miscellaneous Considerations15
6.2 Platforms ...................................... 8
6.3 Fixed Industrial Stairs .................. 8 Table 1 - Recommended Offsites
6.4 Fixed Ladders .............................. 8 Equipment Spacing ..................... 17
7. Roadways and Area Paving .... 8 Table 2 - Recommended Process
Unit Equipment Spacing ............. 18
8. Piping ..................................... 10
Table 3 - Minimum Access
9. Buildings ................................ 11 Provisions .................................... 19
10. Instrument and Electrical Table 4 - Minimum Clearance
Equipment .............................. 11 Dimensions .................................. 20
1. Introduction
1.1 Purpose
This Practice provides guidance for the design and layout of process units and
offsites. This guide should be used as a starting point for the development of plans,
electronic models, and working drawings for process units and offsites. This Practice
should be coordinated with the overall site and offsites layout for geotechnical,
grading, zoning, building codes, life safety code, fire codes, other regulatory
requirements, and owner’s and insurer’s risk assessment requirements.
1.2 Scope
This Practice describes the guidelines for the layout of plot areas, equipment, pipe
racks, piping, platforms, roadways, and other miscellaneous items.
Layout includes equipment location, access and egress for personnel safety, access
for operations and maintenance, and provisions for operational housekeeping and
constructability.
This Practice does not cover requirements for owner safety and property protection
needs (e.g., loss prevention, vapor cloud explosions, or environmental or flare/vent
stack requirements). Spacings shown in the “Recommended Equipment Spacing
Charts” in this Practice are based on industry experience predominantly from a fire
exposure/asset loss stand point and are generally applicable for facilities processing
flammable and combustible gases and liquids.
This Practice should be used by persons knowledgeable in the governing laws, codes
and regulations applicable to the specific facility to ensure that minimum
access/egress and equipment spacing is provided to permit compliance with safety
regulations. This Practice does not cover the requirements of laws, codes, and
regulations in detail, it only provides general guidance or as a pointer for more
information.
2. References
Applicable parts of the following Practices, industry codes and standards, and references
should be considered an integral part of this Practice. The edition in effect on the date of
contract award should be used, except as otherwise noted. Short titles are used herein where
appropriate.
3. Definitions
accessways: Travel ways that provide occasional access to equipment or congested areas of a
facility for maintenance, security, and firefighting vehicles. Also known as tertiary roadways.
constructability: Optimum use of construction knowledge and experience in planning,
design/engineering, procurement, and field operations to achieve overall project objectives
dirty service: Contains fluids that may contain particulates which can plug passages or cause
erosion or has materials for which containment must be provided in the event of a spill
fixed industrial stairs: This classification includes interior and exterior stairs around
machinery, tanks, and other equipment, and stairs leading to or from floors, platforms, or pits.
(OSHA 29 CFR 1910.24.a)
main operating levels: Areas which, during plant operation, require plant personnel to be
continuously present or to be scheduled for presence at least once every shift
means of egress: A continuous and unobstructed way of travel from any point in a building or
structure to a public way consisting of three separate and distinct parts: (1) the exit access, (2)
the exit, and (3) the exit discharge. Public way is considered as beyond the battery and/or unit
limit.
offsites: Equipment grouped outside a process unit battery limits (e.g., tanks,
loading/unloading facilities, cooling towers, flares, etc.)
primary roadways: Main traffic routes. Primary roadways provide access to product shipping
and receiving points and sufficient space for major maintenance vehicles to pass. Primary
roadways include all roadways typically used by large trucks and cranes.
secondary roadways: Secondary roadways provide access to equipment within plant areas by
maintenance vehicles (except cranes) and personnel vehicles. Secondary roadways are not
subject to high traffic loads.
4. General
4.1 Prevailing weather and site conditions should be considered in the development of
general plant arrangements.
4.2 Site topography, soil conditions and geology should be considered and used to
minimize earthmoving and foundation requirements. Multiple ground elevations may
be used in a plant to avoid extensive cut and fill.
4.3 Grade elevation should be referenced to a datum (e.g., Elevation = 100 feet) for
convenience in design and to establish a consistent elevation relationship between
design disciplines. Reference point or reference coordinates are necessary for
locating the plant relative to its surroundings.
4.4 The Process Flow Diagram, equipment list, and additional process information show
how the pieces of process equipment are interconnected and provide special required
elevation requirements.
4.5 Plant equipment should be located far enough from public areas and thoroughfares to
minimize risk to or from the public.
4.6 Applicable local zoning, building codes, and regulations for specific setback, type of
facilities permitted, and type of construction permitted should be obtained and
applied.
4.7 The process unit should be integrated within a common plant site such that
independent operating and shutdown requirements for maintenance of other process
units are not affected.
4.8 If independent operation and shutdown is required for maintenance of a process unit,
facilities should be provided for the isolation of the process unit.
4.9 Plant and equipment layout should ensure that a safe means of egress is provided for
personnel evacuation in the event of an emergency. Egress routes should be continuous
(not necessarily in a straight line), unobstructed, clearly marked, and lighted.
4.10 Any future plot needs, as required by the owner for process and supporting
equipment, should be considered early.
4.11 Process lines, utility headers, power and instrumentation services should be
supported on overhead pipe racks at elevations designated for each fluid service.
4.12 Fire and safety equipment should be located to maximize accessibility and minimize
exposure to fires, explosions, or releases.
4.13 Equipment noise levels should be considered during process unit location and layout.
4.14 Equipment that handles flammable liquids (e.g., light hydrocarbons) should be
located downwind, with respect to prevailing wind direction, of fired heaters, boilers,
and other equipment that may cause ignition.
4.15 Layout should permit full utilization of plant mobile handling equipment for
construction, servicing, and maintenance from roadways through or adjacent to the
unit.
4.16 Permanent handling equipment should be limited to specific items that cannot be
serviced manually or by plant mobile equipment.
4.17 If cost effective, equipment that shares common service should be grouped together.
4.18 Equipment containing hazardous materials should be grouped within a paved and
curbed area that is drained or transferred to waste neutralizing.
4.19 All special process requirements (e.g., gravity flow, self-draining, critical Net
Positive Suction Head, etc.) should be considered.
4.20 If possible, catch basins, floor drains, and other flammable fluid spill collection
points should not be located under fixed ladders, fixed industrial stairs, low
platforms, or flammable/heat-sensitive fluid storage equipment or close to egress
points. Consideration should be given to the location of drains with relation to fired
equipment.
4.21 Offsites and process units equipment spacing requirements should be in accordance
with Tables 1 and 2, respectively, of this Practice.
4.22 Constructability considerations for facilities should be in accordance with the
guidelines of PIP STE01100.
4.23 ADA considerations for facilities should be in accordance with DOJ-ADA 28 CFR
Part 36.
6.1.13 Elevators may be considered for maintenance and operations in tall structures
for moving small numbers of personnel and equipment. Elevators should not
be considered as a means of egress for emergency use.
6.2 Platforms
6.2.1 Platforms serving vertical and horizontal exchangers should not interfere
with removal of the channel end or bundle.
6.2.2 Platforms around furnaces should permit unobstructed access for plant
personnel at and around piping manifolds, instruments, and furnace
appurtenances.
6.2.3 The distance between the edge of equipment and the pipe rack should be set
to permit operator access to equipment and grade level instruments.
6.3 Fixed Industrial Stairs
6.3.1 Fixed industrial stairs should serve as the primary access and egress to main
operating levels in structures, industrial buildings, and furnaces for operation
or maintenance services if the maximum occupancy is expected to be more
than three persons at any time.
6.3.2 The number of fixed industrial stairs provided depends on the number of
occupants and the length of the egress route in accordance with NFPA 101.
6.3.3 Fixed industrial stairs should have sufficient clearance to permit unobstructed
passage for plant personnel. See Table 4 of this Practice for clearances.
6.3.4 Fixed industrial stairs or fixed ladders should be considered for access to
electrical equipment and instrumentation not installed at grade.
6.4 Fixed Ladders
6.4.1 Fixed ladders may be used as the means of access and egress to vessel
platforms, air cooler walkways, relief valves platforms, and all other areas
not defined as main operating levels provided the maximum occupancy is
expected to be not more than three persons at any time.
6.4.2 Fixed ladders may also be used as a secondary egress for not more than three
persons where fixed industrial stairs serve as primary egress for other
occupants. See NFPA 101 for more information.
6.4.3 Fixed ladders should not be used as work platforms for operating, reading or
maintaining instruments or other items unless three-point contact on the
ladder can be maintained.
7.3 Table 4 of this Practice describes minimum horizontal and vertical clearances to be
provided for roadways. Clearances required for the actual vehicles expected to use
the roadways should also be considered.
7.4 Access clearances and roadway geometry should be provided as follows:
a. Under pipe racks as required to permit access for routine maintenance and
removal of equipment
b. To reactors as required to permit catalyst transfer vehicles to reach the area near
catalyst unloading nozzles
c. At compressors as required to permit vehicles such as flatbed trucks to enter a
dropout area and remove components using mobile equipment or permanent
handling facilities
d. Around other equipment as required by owner
7.5 Concrete and area paving should extend as follows:
a. To the outside edge of the supporting column piers of equipment such as bottom
oil-fired or combustible-liquid-containing furnaces or elevated structures
supporting coke drums
b. Around catalyst-containing vessels
c. Around groups of two or more pumps located outdoors
d. Around compressors and related servicing equipment (e.g., lube oil consoles)
e. Around equipment in dirty service that requires frequent turnaround maintenance
f. Around equipment handling materials detrimental to the environment (i.e.,
hazardous gas/liquid/solid materials) to control spills
7.6 Containment curbs required to retain spilled materials should be specified to contain
the required spill volume but not less than 150 mm (6 inches) wide. Curb height
should be specified to contain the required spill volume of a single container: 100%
of container plus 10%.
7.7 Secondary containment requirements are addressed by EPA. RCRA requires
secondary containment in two different areas as follows:
a. Portable storage containers (e.g., 55-gallon drums) for hazardous waste (see EPA
40 CFR 264.175)
b. Large stationary containers (e.g., tank systems) for hazardous waste (see EPA 40
CFR 264.193)
7.8 Facilities that store hazardous materials may also be required to be in accordance
with either NFPA 1, UFC-06 60.3.2.8.3 or ICC, IFC-06 2704.2 depending on the
applicable code.
7.9 Strategies and plot plan areas for managing and containing contaminated fire water
volumes should be considered.
8. Piping
8.1 All piping should be routed considering the following:
a. Provide the shortest possible run while avoiding pockets and permitting thermal
expansion.
b. Group piping together to present a neat appearance, permit orderly branching to
various users, and use common supports.
8.2 Provision of a centralized pipe rack should be considered. Equipment can be located
on both sides of the pipe rack. The area under the pipe rack can be used to provide
access to properly maintain adjacent equipment.
8.3 Specific elevations for pipe running north-south and other specific elevations for
east-west piping should be selected.
8.4 Piping at ground level should be located a minimum of 30 cm (12 inches) off the
ground, and supported. Runs of lines located at ground level should not obstruct any
maintenance, operational accessways, and emergency egress/access. If crossing of
walkways is unavoidable, stiles should be provided.
8.5 Steam, instrument air, plant air, nitrogen, gas and vapor branch lines to/from main
headers should be connected at the top of the headers.
8.6 Discharge piping for relief valves should be connected into top of the relief header.
8.7 Steam and condensate piping should be arranged to permit expansion by using
vertical and horizontal offsets, loops, or expansion joints. The support system can
require anchors at certain places to control the direction and effect of expansion. Hot
lines requiring expansion loops should be grouped at one side of the pipe rack for
ease of support.
8.8 For a two level pipe rack, utility lines and service piping should be placed on the
upper level.
8.9 Space should be provided in pipe racks for instrument piping and electrical conduit.
8.10 Requirements for piping spacing around equipment should be considered in the
layout.
8.11 Additional insulation thickness should be considered in the requirements for piping
spacing.
8.12 Process piping should be located above ground.
8.13 Firewater mains, process sewer, sanitary sewer, and storm water drainage piping
should be located below grade.
8.14 Underground piping should have a minimum horizontal clearance from structures to
provide room for maintenance. Depth of piping burial should be determined based on
the following factors:
a. Commodity being carried
b. Whether flow depends on pressure or gravity
c. Traffic loads
9. Buildings
9.1 Buildings should be located in accordance with applicable zoning, building
regulations, API RP752, and the results of risk assessment analyses.
9.2 If feasible, buildings should be located upwind (based on prevailing wind direction)
of process units, or storage tank areas containing combustible or flammable gases,
liquids or solids.
9.3 Buildings should be located upwind or cross wind from cooling towers.
9.4 All drainage should be directed away from buildings.
9.5 Emergency evacuation and egress routes should be considered.
9.6 Portable occupied buildings should be located in accordance with API RP753.
10.8 Detailed minimum cover requirements for cables, conduits and duct bands should be
in accordance with NFPA 70, Table 300.50. See the IEEE NESC requirements for
additional information.
11.4.4 Air cooled heat exchangers may be located on the top level of pipe racks
provided that the pumps are located in accordance with Section 11.5.5.
11.4.5 Tubular heat exchangers should not be stacked higher than 4 m (12 feet) to
the top unit centerline.
11.4.6 If locating exchangers beneath other facilities cannot be avoided, the channel
should be clear of overhead obstructions and readily accessible for removal.
11.4.7 Access should be provided for exchanger cleaning and/or disassembly.
11.4.8 Bundle pulling methodology and equipment should be considered (e.g.,
bundle extractors or external anchorage).
11.5 Pumps
11.5.1 Access should be provided to pump auxiliaries (e.g., seal pots, starter button
stations, motor conduit connections, etc.)
11.5.2 Clearances and access should be provided for removal of pump, drivers,
pump rods, impellers, and other parts.
11.5.3 Access should be provided around and between pumps.
11.5.4 Vertical pumps should have appropriate overhead clearances for removal of
drivers, shafts, impellers and other parts.
11.5.5 For location of pumps relative to pipe racks, pumps should be located such
that the wet end is located outside the pipe rack and the driver should not
extend more than 0.76 m (2 ft-6 in) inside the center line of the pipe rack
column.
11.5.6 Pumps should be located close to and below their point of suction.
11.5.7 Pumps should be grouped for convenient operation and maintenance.
11.6 Compressors and Auxiliaries
11.6.1 Clearance should be provided so that compressors and associated auxiliaries
(e.g., lube oil consoles, large castings, rotating elements, and valves) are
readily accessible for maintenance.
11.6.2 Clearance and adequate laydown areas should be provided for maintenance
activity equipment (e.g., lifts for large compressor cylinders and pistons,
casing and impellers for centrifugal compressors, and rotors for large
motors).
11.6.3 All air compressor intakes should be located to avoid intake of contaminants.
11.6.4 Adequate space should be provided for personnel on compressor decks and
around compressor auxiliaries.
11.6.5 Lay down areas on compressor decks should be provided on elevated
structures.
11.7 Reactor and Dryers
Adequate space should be provided for handling drums and/or tote bags at dryers,
reactors, etc. that require frequent catalyst changes or raw material charging.
14.4 Coverage of LP-Gas systems at utility gas plants extends to the point where LP-Gas
or a mixture of LP-Gas and air is introduced into the utility distribution system.
14.5 NFPA 59A should apply to the following:
a. Facilities that liquefy natural gas
b. Facilities that store, vaporize, transfer, and handle liquefied natural gas (LNG)
c. The training of all personnel involved with LNG
d. The design, location, construction, maintenance, and operation of all LNG
14.6 LNG storage facilities should be in accordance with NFPA 59, ACI 376 and API 625.
14.7 Marine terminals handling liquefied gases should be in accordance with the
contingency planning described in the SIGTTO publication A Guide to Contingency
Planning for Marine Terminal Handling Liquefied Gases.
A A FIRED BOILERS
L 61 (200) 30 (100) A A 15 (50) 30 (100) 6 (20) 0 0 15 (50) A A LOADING AND/OR UNLOADING RACKS
N 15 (50) 30 (100) A A 30 (100) 30 (100) 8 (25) 30 (100) 30 (100) 30 (100) A 30 (100) 30 (100) 3 (10) PIPEWAYS (MAJOR)
O 6 (20) 6 (20) A A 6 (20) 8 (25) 0 6 (20) 0 6 (20) A 0 6 (20) 3 (10) A PUMPS (FLAMMABLE)
P 15 (50) 15 (50) A A 15 (50) 15 (50) 5 (15) 30 (100) 8 (25) 30 (100) A 30 (100) 30 (100) 15 (50) 5 (15) 1 (3) PUMPS (NONFLAMMABLE)
Q 8 (25) 2 (5) A A 0 A 5 (15) 5 (15) 5 (15) 0 A 5 (15) 5 (15) 3 (10) 0 1 (3) 1 (3) RAILROADS (MAIN LINES -R/W)
R 61 (200) 30 (100) A A 0 30 (100) 8 (25) 8 (25) 0 15 (50) A A 61 (200) 8 (25) 0 30 (100) 15 (50) N/A RAILROADS (SPURS-CENTER LINE)
T 30 (100) 61 (200) A A 46 (150) 30 (100) 15 (50) 30 (100) 15 (50) 61 (200) A 30 (100) 30 (100) 30 (100) 6 (20) 3 (10) 5 (15) 30 (100) 30 (100) 8 (25) SEWER MAINS (FLAMMABLE)
U 8 (25) 15 (50) A A 6 (20) 6 (20) 6 (20) 6 (20) 6 (20) 6 (20) A 3 (10) 3 (10) 3 (10) A 3 (10) 3 (10) 3 (10) 3 (10) 3 (10) A PLANT ROADS (EDGE)
Y 61 (200) 91 (300) A A 76 (250) 30 (100) C, D 61 (200) 30 (100) 91 (300) A 91 (300) 30 (100) 30 (100) 15 (50) C, D 8 (25) 61 (200) 30 (100) 61 (200) 15 (50) A B, C, D B, C, D B, C, D NFPA CLASS III LIQUID STORAGE
AA 61 (200) 61 (200) A A 61 (200) 61 (200) 8 (25) 61 (200) A 76 (250) A 61 (200) 46 (150) A 3 (10) A A 61 (200) A 61 (200) A A B, C, D B, C, D B, C, D B, C, D B, C, D PROCESS UNITS
BB 30 (100) 30 (100) A A 15 (50) 15 (50) 3 (10) 30 (100) 15 (50) 61 (200) A 30 (100) 61 (200) 30 (100) 5 (15) A A 30 (100) A 61 (200) 6 (20) 5 (15) 30 (100) 61 (200) 61 (200) A 46 (150) 15 (50)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 COLUMN
BLOWDOWN FACILITIES
(DRUMS, PUMPS, STACKS) Notes:
COMPRESSORS GAS 1. This table does not account for vapor cloud explosions, customer safety
A A and property protection, environmental or flare vent/stack dispersal
(NO IGNITION SOURCE) requirements.
CONTROL HOUSES 2. Distances are in meters (feet).
B 15(50) 3 (10) 3. Distances are from PIP Member Company input.
(FOR SINGLE UNIT)
4. "A" indicates that an engineering/ safety decision is required. For location
CENTRAL CONTROL HOUSES of buildings, refer to Section 9.1.
C A A A
(2 OR MORE UNITS)
DRUMS - CONTAINING
F 15 (50) 15 (50) A A 15 (50) A
FLAMMABLES
ELECTRICAL CONTROL AND
G 15 (50) 8 (25) A A 2 (8) 15 (50) 2 (5)
DISTRIBUTION CENTERS
ELECTRICAL SWITCH
H 15 (50) 15 (50) A A 15 (50) 15 (50) 15 (50) 1 (4)
RACKS, CRITICAL
EXCH'RS CONTAINING
I 15 (50) 8 (25) A A 5 (15) 5 (15) 5 (15) A A
FLAM/COMB LIQ
FURNACES (PROCESS FIRED
J 15 (50) 8 (25) A A 2 (8) 15 (50) 2 (5) 15 (50) 5 (15) A
EQUIPMENT)
K 30 (100)30 (100) A A 15 (50) 30 (100) 8 (25) 15 (50) 12 (40) 15 (50) 8 (25) PIPEWAYS (BETWEEN UNITS)
L 6 (20) 5 (15) A A A 8 (25) 2 (5) 3 (10) 0 1 (3) 8 (25) A PIPEWAYS (WITHIN UNITS)
N 15 (50) 8 (25) A A 8 (25) 15 (50) 2 (5) 15 (50) 8 (25) 2 (5) 15 (50) 1 (3) 0 1 (3) PUMPS (NONFLAMMABLE)
REACTORS (INTERNALLY
O 8 (25) 2 (8) A A A A 1 (3) 8 (25) 2 (8) 1 (3) 8 (25) 1 (3) 0 1 (3) 1 (3)
LINED & EXTERNALLY INS)
SEPARATOR UNIT(S) (LIGHT
P 15 (50) 8 (25) A A 3 (10) 15 (50) 3 (10) 15 (50) 5 (15) 3 (10) 8 (25) 3 (10) 2 (5) 3 (10) 2 (8) 3 (10)
ENDS)
SNUFFING STEAM OPERATING
Q 15 (50) 8 (25) A A 15 (50) 15 (50) 6 (20) 15 (50) 5 (15) 8 (25) 15 (50) 5 (15) A 3 (10) 1 (3) 15 (50) A
VALVE FOR FURNACES
STRUCTURES (EQUIPMENT &
R 15 (50) 15 (50) A A 6 (20) 15 (50) 6 (20) 1 (4) 1 (4) 6 (20) 15 (50) 0 0 6 (20) 1 (3) 15 (50) 9 (30) 0
PROCESS)
S 15 (50) 8 (25) A A A 15 (50) 1 (3) 15 (50) 5 (15) 1 (3) 15 (50) 0 0 2 (5) 1 (3) 6(20) 15 (50) 5 (15) 0 TOWERS (FLAMMABLE)
WATER SPRAY
T 15 (50) 8 (25) A A 2 (8) 15 (50) 2 (8) 15 (50) 5 (15) 2 (8) 15 (50) 2 (8) 2 (5) 2 (5) 2 (5) 3 (10) 6 (20) 8 (25) 2 (5) 2 (8)
DELUGE VALVES
U 15 (50) 15 (50) A A 8 (25) 5 (15) 8 (25) 1 (4) 1 (4) 5 (15) 15 (50) 0 0 8 (25) 1 (3) 15 (50) 6 (20) 0 0 8 (25) 0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 COLUMN
Access Clearance height for projections over platforms, working areas, 2290 mm (7.5 ft); 2030 mm
Walkways walkways (exit access routes) (6.75 ft) for bottom of valve
and Fixed handwheels or other
industrial projections from ceiling
stairs Minimum head room over stairs 2030 mm (6.75 ft)
Projections into stairs below handrail height 115 mm (4-1/2 inch)
Width of stairs serving < 50 persons 915 mm (36 inches)
Width of stairs serving > 50 and < 2000 persons 1120 mm (44 inchest)
Width of landings in direction of stairs, minimum Width of the stair
Length of landings in a straight run, maximum 1220 mm (48 inches)
Minimum Width of walkways (should be the width of the required
stair) 915 mm (36 inches)
Width of walkways for industrial equipment access < 20 persons 560 mm (22 inches)
Maximum vertical rise of one flight of stairs 3660 mm (12 ft)
Maximum horizontal distance from any point on platform to an
emergency exit 22 m (75 ft)
Maximum length of outdoor dead-end platforms and exit routes
(depends on occupancy class) 6100 mm (20 ft)
Fixed Maximum vertical rise of fixed ladders in a single run 9 m (30 ft)
ladders Maximum allowable slope of fixed ladders from vertical 15 degrees
Minimum toe clearance from centerline of rung to obstruction 180 mm (7 inches)
Electrical Maximum depth of bury to top of electrical duct banks 750 mm (30 inches)
Duct Banks Maximum depth of bury to top of direct bury electrical cables 900 mm (35 inches)
& Cables