ves-1200 plant layout and spacing

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VES-1200 Plant Layout and Spacing

TS-ENC-STD-0005

VICO Indonesia


Author A.R. Thanura(Discipline Engineering Section Head)

Reviewer A.Rastiarsa (E&C Manager)

Approver

P.Stegers (Technical Support Vice

President) / Vania De Stefani

(Engineering Authority)

VMS Primary

Element Reference11.3

VMS Secondary

Element Reference

Date of Issue 31-Jul-2013 Next Review Date 31-Jul-2016

Revision Number B.01 Document Level 2 - Standard

NOT CONTROLLED WHEN PRINTED OR DOWNLOADED



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TS-ENC-STD-0005

VICO Indonesia

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Amendment

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VES-1200File:F:\WPDATA\NEWVES\2002\VES-1200 Rev. 4, 11/02

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VICO INDONESIA

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DOCUMENT

NUMBER

TITLE

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:

:

VICO ENGINEERING STANDARD

VES-1200

PLANT LAYOUT AND SPACING

4 11/02 Changed Virginia Indonesia Company toVirginia Indonesia Company LLC and changedBPPKA to BP MIGAS

Isdiarso K. Sukiswanto

3 4/93 Converted from Word Processor No. 333 toWord Perfect 5.1

Djarot S.S. Lukman M.

2 4/90 Changed HES to VES Herriwanto D.S. Newson

1 1/89 Revised Mutiara Project Specification to HuffcoEngineering Standard

B. Gadjuli D.S. Newson

0 2/27/88 Original Issue R. DURFEE M. HENDRIKSON

NO. DATE REVISION ENGINEER APPROVED BY

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VES - 1200PLANT LAYOUT AND SPACING

TABLE OF CONTENTS

PAGE

1.0 SCOPE 3

2.0 APPLICABLE CODES, STANDARDS AND SPECIFICATIONS 3

3.0 DEFINITION OF TERMS 4

3.1 Critical Area 43.2 Spacing 4

3.3 Battery Limits 4 3.4 Property Limits 4 3.5 Tank Diameter 4 3.6 Tank Spacing 4

3.7 Main Sewer 4

4.0 BASIC DESIGN CONSIDERATIONS 5

4.1 Objectives 5 4.2 Minimum Spacing Requirements 5

5.0 DEVIATION FROM SPACING STANDARDS 6

5.1 Reduced Risk 65.2 Basis for Deviation 6

6.0 CLEARANCE AND ACCESSIBILITY 7

6.1 Horizontal Clearances 76.2 Vertical Clearances 76.3 Access Platforms, Stairs and Ladders 76.4 Access for Maintenance 9

7.0 GENERAL LAYOUT 10

7.1 Major Facilities Spacing 107.2 Spacing Within Process Units 167.3 Miscellaneous Spacing Requirements 20

8.0 ATMOSPHERIC STORAGE 22

9.0 TRUCK LOADING 22

10.0 ROADWAYS 23

11.0 GENERAL RECOMMENDATIONS FOR PLANT SPACING 23

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1.0 SCOPE

This standard defines the minimum requirements for plant layout and spacing with guidelines tominimize the risk of catastrophic loss due to explosion and/or fire within the plant process areasThe guidelines provide adequate access for fire fighting, operation, maintenance and protectioof personnel and equipment in consideration of proximity to adjacent properties and facilitieslocation of accessways, direction of prevailing wind, and site topography.

2.0 APPLICABLE CODES, STANDARDS, AND SPECIFICATIONS

The codes, standards and specifications listed below are cited in this document. Most codeand standards cited are of Indonesian or U.S. origin. The applicable sections of the codes anstandards cited below (including revisions, addenda, and references) are to be considered aan integral part of this standard. The citations are to the latest edition except where a specifiedition is cited. Conflicts in specifications must be brought to Company's attention for resolutionbut generally the more restrictive specification shall govern. On projects where a desigcontractor is involved, he will be responsible for ensuring that all designs meet all applicablspecifications.

Government Regulation of the Republic of Indonesia No. 11, Labor Safety in Oil and Natural GaRefining and Processing Site American Petroleum Institute:

RP 520 (Parts I and II), Recommended Practice for the Design and Installation oPressure-Relieving Systems

RP 521, Guide for Pressure-Relieving & Depressuring Systems

RP 2001, Fire Protection in Refineries

RP 2510, Design and Construction of LP-Gas Installations at Marine and Pipelin

Terminals, Natural Gas Processing Plants, Refineries and Tank Farms

Industrial Risk Insurers:

"General Recommendations for Plant Spacing"

National Fire Protection Association:

Standard No. 30, Flammable & Combustible Liquids

Occupational Safety and Health:

Section 1910.106, Flammable & Combustible Liquids

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3.0 DEFINITION OF TERMS

3.1 Critical Area

Critical areas, as used herein, include process units, utility plants, high occupancbuildings (such as laboratories, shops, offices), public roads, and property lines adjacento land which is developed or could be built upon.

3.2 Spacing

The clear, horizontal distance between adjacent edges of equipment or boundarieexcept as otherwise noted.

Following are some definitions of particular spacings:

- Where tanks or drums of different diameters are considered, the larger diameter shagovern in setting spacings determined by diameter.

- Spacing to pipe racks is the horizontal distance between the edge of an overhea

pipe rack and the equipment under consideration.

- Spacings to pumps and compressors shall be measured to the stuffing box where firhazard controls or to pump base where mechanical interference is of concern.

3.3 Battery Limits

The extreme projection of any equipment or proposed future equipment within a processutility or storage unit or area.

3.4 Property Limits

The boundaries of the property adjacent to adjoining land which is or might be developed

or a public thoroughfare which includes public roads and navigable waterways.

3.5 Tank Diameter

Where tank spacing is expressed in terms of tank diameter, the following are used:

- If tanks are in similar services (type of tank and stock), the diameter of the largestank is used.

- If tanks are in different services, the diameter of the tanks which requires the greatespacing is used.

3.6 Tank Spacing

Tank spacing is the unobstructed distance between tank shells, or between the tanshells and the nearest edge of adjacent equipment, property lines or buildings.

3.7 Main Drains

Those drains serving more than one process area or unit. Main drains which handlhydrocarbon liquids or which may receive flammable liquid spills should have a wateseal and vent extending 3050 mm (10 feet) above grade.

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4.0 BASIC DESIGN CONSIDERATIONS

4.1 Objectives

The objectives of the spacing recommendations in this standard are as follows:

- To permit access for fire fighting.

- To ensure that critical emergency facilities are protected appropriately from firdamage.

- To permit access for operators to perform necessary emergency shutdown actions ia fire situation.

- To avoid danger or significant nuisance to persons or property beyond adjacenproperty lines.

- To segregate toxic or highly reactive materials and high risk facilities, to separat

continuous ignition sources from probable points of release of flammable materialsand to minimize involvement of other plant property.

- To provide adequate separation of employees, and persons and property beyonadjacent property lines from potential environmental or health problem generators.

- To permit access for normal operation and maintenance.

- To ensure site security.

4.2 Minimum Spacing Requirements

The equipment spacing distance in this standard are recommended minimum acceptablrequirements which will satisfy the objectives listed below in most cases.

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5.0 DEVIATIONS FROM SPACING STANDARDS

5.1 Reduced Risk

Where spacing is reduced significantly below the minimum distance recommended in thi

standard, it is usually necessary to compensate for the increased degree of risk incurredThis can often be done by providing more extensive safety features, such as fireproofingwater sprays, firefighting equipment, emergency shutdown facilities, emergency conditiodetectors, etc. Reductions below minimum recommended spacings must not be madwithout Company review and written approval.

5.2 Basis for Deviation

Factors which affect layout and spacing and which may justify deviations include thfollowing:

- Basic Assumptions - Informed basic assumptions, carefully made, covering the size

shape and installation of all major items of equipment in a project are critical to goodesign spacing. Frequently good design spacing cannot be maintained during projecdevelopment because of faulty assumptions in the preliminary plot plan from whicestimates are made and funds appropriated. Where preliminary design anestimates are prepared by contractors, design coordinators must be highly sensitivto this concern to protect the spacing integrity of the final project.

- Special Conditions - Increased spacing may be justified where unusual hazards oincentives to minimize fire losses apply or where continuity of operations is aoverriding consideration.

- Flexibility - Space may be required for expected future expansion. This may be

complete unit or individual equipment items.

- Onstream Maintenance - Access is required for personnel and equipment tindividual items of facilities which may be shut down for maintenance while adjacenfacilities remain in operation.

- Topography - A major factor to provide for safety in the design of sloped areas, foexample, location of separators depends on drainage. The possibility of major tanspills gravitating downhill to process areas must be avoided.

- Local Conditions - May dictate that site security be grater than normal, requirinincreased spacing between the plant facilities and the property line.

- Safety and Public Relations Factors - Associated with the type of adjacent propertmust be taken into consideration. Distance from the plant facilities to the property linmust be sufficient to prevent danger or nuisance to neighbors and vice-versa. Thspacing required depends on the type of plant nearest to the boundary and the natureof the adjacent property; e.g., industrial or residential. In residential areas, additionaspace for screening may be required. Generous spacing would also be advisablwhere the adjoining land is undeveloped but is subject to future development.

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6.0 CLEARANCE AND ACCESSIBILITY

6.1 Horizontal Clearances

Equipment, structures, platforms, piping and supports shall be arranged to provid

minimum horizontal clearances as follows:

Insulation requirements must be added to clearances stated below.

- The clear width of aisles between shells of adjacent vessels shall be 1525 mm (feet) unless specified otherwise.

- The clear width of operating and servicing areas around compressors and any othemajor mechanical equipment shall be 2624 mm (8 feet). Where truck access irequired, the maintenance aisle width shall be 3050 mm (10 feet) minimum.

- The clear width of operating aisles between pumps, exchangers, small vessels, an

piping manifolds shall be 1220 mm (4 feet).

- Clearance in front of inspection, cleanout and manways shall be a minimum of 91mm (3 feet).

- Minimum passageway at grade and on elevated platforms shall be 760 mm (2.5 feet)

6.2 Vertical Clearances

Equipment, structures, platforms, piping and supports shall be arranged to providminimum overhead clearances as follows:

- The clear headroom over platforms, walkways, stairways, and over all passagewayand working areas shall not be less than 2135 mm (7 feet). The lateral limits owalkways shall be kept clear of valves or valve operating mechanism.

- The clear headroom over service and operating areas where small mobile equipmenmay be required for maintenance shall not be less than 3050 mm (10 feet).

- The clear headroom under main pipeways within the unit shall not be less than 305mm (10 feet), and under secondary pipeways shall not be less than 2440 mm (8 feet)

- The clear headroom over main road crossings and over areas where major mobilequipment may be required for maintenance shall not be less than 6100 mm (2feet). Clearance over secondary roads shall be 4875 mm (16 feet) minimum.

6.3 Access Platforms, Stairs and Ladders

6.3.1 Platforms shall be provided at all access and inspection openings in vessels anequipment; at control and safety valves, instruments, etc., which require serviceor attention during operation and where local storage of small quantities ochemicals and other operating materials are required during operation.

6.3.2 Platforms are not required for service or inspection openings when the bottom o

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such openings are located 3660 mm (12 feet) or less above grade, where a fixedladder is provided.

6.3.3 Portable ladders shall be considered acceptable for access to valves, line blindsetc., which do not require periodic service or attention during normal operation oroutine maintenance. Portable ladders shall be used only at grade.

6.3.4 Major operating platforms servicing several pieces of equipment shall b

provided with at least two exits and placed in such a manner as to provide escapefrom either end. Where a platform is attached to and serves only that equipmenone exit only may be provided.

6.3.5 Stairways shall be provided as the main access to major operating platforms oplatforms of frequent use. All other platforms shall be accessible by cageladders only. Stairways shall be 760 mm (2.5 feet) minimum width for single-watraffic and 1220 mm (4 feet) minimum width for two way traffic.

6.3.6 Platforms shall be located about 915 mm (3 feet) below the centerlines of a vessemanway. There shall be a minimum clearance of 230 mm (0.75 feet) from lowesedge of manway flange to platform.

6.3.6.1 Platforms for vessels, air coolers, etc. shall be a minimum of 915 mm(3 feet) wide.

6.3.6.2 Platforms on vertical vessels shall conform to the curvature of thvessel.

6.3.7 Connecting walkways and access platforms for servicing other parts oequipment shall not be less than 760 mm (2.5 feet wide).

6.3.8 Ladders shall be "side step-off" unless approved otherwise and shall extend thheight of the handrail above the platform.

6.3.8.1 Ladder access openings shall be provided with a self closing device.

6.3.8.2 Ladders shall not exceed 9145 mm (30 feet) of straight run and shabe provided with intermediate landings at a maximum of every 914mm (30 feet) except on flare towers. Ladders higher than 3050 mm(10 feet) above grade or platform shall have a safety cage installedThe safety cage above a platform must start at the handrail height anextend to the handrail of the next higher platform.

6.3.9 Stairways, platforms, and walkways for large volume storage vessels and tankshall be provided in accordance with the industry standards for the design osuch vessels and tanks.

6.3.10 Two means of access shall be provided at:

- Elevated platforms 3050 mm (10 feet) or more above grade serving three or morvessels, when lack of such means might prevent escape of personnel.

- Any platform serving fired process equipment. - Any platform serving two or more pieces of equipment which are concurrentl

maintained or operated. - Large elevated structures, if any part of platforming has more than 22,860 mm

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(75 feet) of travel from a single access.

6.4 Access for Maintenance

6.4.1 In general, all mechanical equipment such as pumps, turbines, compressors, acoolers, etc. shall be arranged to permit access by mobile equipment fomaintenance, removal and reinstallation. Permanent handling facilities shall b

provided only where such equipment is not accessible from grade with mobillifting equipment.

6.4.2 Clear access, both vertical and horizontal will be provided under main pipewayfor truck and mobile equipment to service pumps. Pump drivers should blocated adjacent to the access.

6.4.3 Vertical vessel platforms, manholes and piping shall be arranged to provide cleadropping areas adjacent to accessways for lowering of internals, catalystsvalves, etc.

6.4.4 Pressure relief valves and control valves 3 inch inlet size and larger which ar

located 9150 mm (30 feet) or more above grade shall be provided with davits anddropping area. Such relief valves located below this height should be accessiblto mobile equipment.

6.4.5 A clear area at grade on the access side of structures shall be provided for lowering andsetting elevated equipment by mobile equipment or permanent handling facilities.

6.4.6 Concrete paving is required under any equipment where flammable or hazardous liquidsmay be spilled during routine operating or maintenance function. This includes areasunder pipe racks where low point draining, sampling, insertion of blinds, etc. arefrequently carried out. Paved areas must be graded and drained.

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VES-1200File:F:\WPDATA\NEWVES\2002\VES-1200 Rev. 4,11/02

7.0 GENERAL LAYOUT

The location of the major facilities should be designed not only in accordance with thespacing standards, but also with consideration of proximity to adjoining facilities, locationof roadways, prevailing wind direction, site topography, etc. Control rooms should belocated convenient to a roadway and only separated from it by parking or other openarea. Consideration should be given to greater spacing for multi-unit control rooms. Therouting of pipe racks closer than 15,250 mm (50 feet) from control rooms should be

minimized, but this spacing may be reduced on one side of the control room only,subject to a minimum of 7620 mm (25 feet), if the lines are all-welded without flanges orvalves within 15,250 mm (50 feet) of the control room.

The overall layout of the process area must be designed with accessways for firefighting, maintenance and turnaround isolation, in accordance with the following:

- Accessways are also required for entrance into the unit site and within the site asrequired for movement of maintenance equipment. All accessways designed toaccommodate trucks, motorized cranes and other road-traveling vehicles shall have6100 mm (20 feet) overhead clearance. Equipment shall be positioned formaximum use of motorized maintenance equipment.

- Emergency valves for shutoff and isolation should be located a minimum of 7620mm (25 feet) from the most probable point of fire involvement of the particularequipment. Where remote actuation for such valves is provided, the point ofactuation should be 15,250 mm (50 feet) from the most probable point of fireinvolvement. Water spray valves should be at least 15,250 mm (50 feet) from theequipment to be protected since such valves often must be operated with a firealready in progress.

7.1 Major Facilities Spacing

In developing the overall layout of a process plant, it is important to consider froma fire protection standpoint, the location, spacing, and arrangement of all thevarious facilities. The facilities should be arranged so that, in the event of a fireor explosion, adjacent facilities and neighboring property will not be endangered

and the potential for personnel involvement is minimized.

The spacing between units should take into account the maintenancerequirements of one facility while an adjacent one is operating. Adequatespacing is needed to permit unrestricted hot work in the facility that is beingmaintained.

It is preferable for process units to be placed on high ground to avoid major spillsfrom storage areas. At locations where prevailing winds exists, the processareas and pressure storage should be downwind from ignition source, such asengine driven compressors and generators.

High-occupancy buildings such as laboratories, shops and change houses and

the like should not be located near hydrocarbon processing areas. Powerhouses and electrical generating and stations should be located to minimize thespread of fires that may occur in the process, or other areas handlinghydrocarbons. The following Table 7.1 indicates the basic minimum horizontaldistance between the outer extremity of major facilities or areas, taken from theIndustrial Risk Insurers' recommendations for plant spacing. It also givesguidelines and considerations for deviation from the recommended spacing.

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TABLE 7.1

o Service Buildings

Those buildings, such as offices, laboratory, change house warehouse, repair shops, etc. which housepersonnel not immediately involved in process or mechanical operation.

FACILITYDISTANCE mm (ft)(from edge of area) REMARKS

Basic 30,500 (100) Protect critical power facilities feeding majorportions of the plant from fire or explosionhazard.

From Fire Pump,Utilities, MCC,Generators.

Space for maintenance and convenience ofoperation as these do not present a major firerisk to each other.

o Generator and Utility Plants


Basic 30,500 (100) Protect critical power facilities feeding mportions of the plant from a possible fireexplosion on equipment handling phydrocarbons.

From MCC, FirePumps

6,100 (20) Provides access for operation maintenance. Generators and electrdistribution centers may be located in the saarea with no basic spacing between simfacilities. Fire pumps may also be locatedthis area.

From utilities, ServiceBuildings, Unit ControlHouse

9,150 (30) Generating stations constitute only a minorto facilities which do not represent a significhazard to power facilities; hence, reduspacing is acceptable.

o Process Unit


Basic 15,250 (50) Spacing between process units proviaccess for fire fighting and maintenance.

From Fire Pump,Building, Utilities

30,500 (100) Protects personnel and equipment in low for explosion in process unit.

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Central Control Room


Basic 30,500 (100) Central control house serving multiple umay require greater separation from hhazard units and possibly less separation flow hazard units.

o Motor Control Centers (Including Buildings)

Circuit breakers, switches, etc. for a process unit are normally grouped together in a load center. Locationshould be at the edge of the unit. Climate-controlled on-site buildings may be required to house minicomputers, transducer banks and other instrument interfaces.


Basic 15,250 (50) Spacing may increase or decrease with speexposures as defined in general specificat

"Electrical Area Classifications".

o Fired Equipment

Where practical and economical, fired equipment from multiple units should be grouped together in anisolated fired equipment area. If grouping is impractical, the unit heaters should be isolated near the uniboundaries with roadway access for fire fighting and maintenance. Prevailing winds should be consideredand fired equipment should be located upwind from equipment handling light hydrocarbons to minimize thepossibility of vapors being carried toward open flames.


Basic 30,500 (100) Provides isolation for possible auto-ignitionleaks or spills at the heater.

From Process Unit 15,250 (50) Associated equipment may be consideredone fire risk

From Heaters 7,625 (25) Provides maintenance access and sodegree of isolation in case of small involving spills or leaks.

o Gas Compressor House

Where there are several large compressors in a unit it is usually economical for operation and maintenance tolocate them in one area. Associated intercoolers, knockout drum, etc., may be located in the compressoarea and need not comply with 30,500 mm (100 feet) spacing to non-associated equipment, provided thatthey do not restrict access for fire fighting and maintenance. Compressors shall be oriented as follows:

- Longitudinal axis of reciprocating cylinders shall not be pointed toward control houses, control centersor service buildings.

- The plane in which centrifugal parts (rotors, turbines, etc.) rotate shall not be in line with control houses

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control centers, or service buildings.

Access for fire fighting must be available on at least two sides. Compressor orientation should consider thepossibility of massive mechanical failure in relation to surrounding equipment.

Compressors handling inert gases or air may be spaced closer than is shown for gas compressors unlessthey are in a service critical to plant operations, such as main plant instrument and industrial air system.


Basic 30,500 (100) Protect high investment compressor equipmfrom fires involving other equipment. Smelectric motor driven compressors may treated as pumps for spacing and locatpurposes.

From Gas Compressor 3,050 (10) Compressors may be grouped in the same area.

From AssociatedEquipment

4,575 (15) Intercoolers and scrubbers, etc. consideredrisk with compressor.

o Atmospheric Storage Tanks (Hydrocarbon)

Equipment other than pumps and associated piping must not be located within the dikes of storage vessels.Tanks operating above the flash point of the product stored should be considered in the same manner as lowflash tanks. Open-top floaters are somewhat less hazardous than cone roof tanks in the same low flashservice.


Basic 61,000 (200) Provides spacing to contain a tank fire

prevent involving other facilities or person Also protects tankage in case of fire at ofacilities.

o Flare Stack

A flare stack may create problems of noise, luminosity, smoke, toxic vapor release, radiated heat, and flamingliquid carry-over. Minimum spacing set at 61,000 mm (200 feet) can be recommended only for flares up toabout 61,000 mm (200 feet) in height, or for higher stacks only when they are preceded by a cooling and/orcondensing facility. Many flares will require spacing of at least 91,450 (300 feet) from the other items in orderto minimize risk from carry-over of flaming liquid. Spacings set by radiant heat effects will be a function of themaximum heat release and height of the flare. Toxic vapor releases or unburned combustible should be animportant factor in setting stack height, which can then affect allowable spacing needed to control radiant heaeffects. Parameters for radiated heat are listed as follows:

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Heat Intensity Remarks

500 BTU/hr/ft2 Personnel may work in area up to 8 hours.

1,600 BTU/hr/ft2 Personnel must leave area in 5 minutes.

4,300 BTU/hr/ft2 Damage to electrical and instrumentation.

6,000 BTU/hr/ft2 Damage to process vessels and equipment.

10,000 BTU/hr/ft2 Combustible material ignites in 1 minute.

For recommended design flare radiation levels and radiation calculations to determine the height and spacingof flares where thermal radiation exposure on personnel and equipment is a limiting factor see API RP 521,"Guide for Pressure-Relieving and Depressuring Systems." An alternative method of calculating radiationlevels may be used if specified or approved by Company.

Drums, exchangers, pumps, etc., associated with the flare stacks are considered one risk with the stack andneed spacing only sufficient for maintenance. However, these items shall observe at least standard minimumspacings to all other facilities and to each other.

Where there are multiple flares that are to be taken out of service independently for maintenance, spacingbetween the flares should be at least 152,400 mm (500 feet). Platforms and ladders should be shielded topermit escape from the direct effects of radiant heat from a potential large release from flares which are inservice.


Basic 61,200 (200) Basic spacing is designed to protect adjacentinterests from flares of height of 61,000 mm(200 feet) or less. Where greater heights are

used, increase spacing should be consideredfor certain types of stacks.

From ServiceBuildings, ProcessUnits, Storage

76,200 (250) Greater than basic spacing for these exposuresis highly desirable.

o Major Pipe Racks

Major pipeways shall be sized and designed to provide 25 percent excess for future lines. Ample space shalbe provided for instrument and electrical conduit along with process and utility piping. The area directly ovethe pipe support column shall be left open for extending the column for future decks.

Piping above grade shall be consolidated into pipe racks and routed through the unit area in such a manneras to offer minimum obstruction to maintenance operations and fire fighting. Piping from other process unitsor offsite operating areas shall not be routed on onsite pipe racks unless they terminate at the unit served bythe onsite pipe racks. Internal unit piping should not be run on offsite racks.

Lateral pipe racks interconnecting two parallel pipe racks shall be at least 24,400 mm (80 feet) apart if thelaterals cross major accessways. This provides space for raising and lowering crane booms.

Pipe racks shall be located outside of areas enclosed by fire walls or spill walls.

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The area under onsite pipe racks shall be kept clear for fire fighting and other access and shall not beencroached upon even though other equipment spacing standards might still be met. Drain catch basins shalnot be located under or within 3050 mm (10 feet) of pipe racks.


Basic 3,050 (10) Provides spacing from pipe racks to equipmfor operations, maintenance and to redinvolvement from adjacent fires. Procequipment should not be located under on-spipe racks.

From Process Pumps 1,525 (5) There are no limitations on spacing pudrivers from pipe racks, except those providfor access for mobile equipment.

o Main Fire Pumps


Basic 76,200 (250) Provides spacing between fire pumps major plant equipment in hydrocarbon servto prevent loss of fire pumps from exposure. Special purpose fire pumps, e.g.specific plants, may be spaced closer to related facilities.

From Process Pumps 30,500 (100) Fire in these areas is probably less sevhence, spacing may be reduced.

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7.2 Spacing Within Process Units

A primary consideration in the arrangement of items of equipment within aunit is to provide an economical facility, safe and easy to operate andmaintain. The arrangement shall favor compactness and consolidation ofequipment for short and direct pipe routing but still providing flexibility andfree access.

The spacing and arrangement of equipment within a process unitdepends on the type of equipment, the kinds of material handled, thedesign philosophy, and the method of operation in the particular unit. Inconsidering the layout, safety, efficient erection, maintenance andoperation, in addition to accessibility for fire fighting and a degree ofisolation to prevent fire spread should be provided.

In determining the location of equipment, consideration should be given tothe kind of material to be handled. Hydrocarbon gases that are heavierthan air are more likely to reach an ignition source than lighter air vapors.Equipment such as pumps and compressors, that may be a source of

leakage, should be located as far as possible from ignition sources whenvolatile hydrocarbons are handled. Unit heaters and other open flamedevices are sources of ignition and should be located upwind of a unit atthe plot limit taking into consideration the type of adjacent units.

Equipment handling material above auto ignition temperature should beisolated and accessible to fire fighting, as any leaking hydrocarbon willautomatically ignite. Hot pumps and exchangers require particularattention and should not be located near critical equipment where fireinvolvement could result in expensive downtime for the unit. However,such hot equipment can be located closer to heaters or other ignitionsources since ignition by an external source would not be a factor should

leakage occur.

The vulnerability of certain types of equipment to fire damage is also animportant layout consideration. Air coolers represent a greater degree ofvulnerability than shell and tube exchangers. Electrical equipment, cableand conduit, as well as instruments and instrument tubing are quicklydamaged if involved in a fire. To reduce the chances of fire involvement,the location of unit switchgear and control house as well as theaboveground routing of banks of cable and tubing through the unit shouldbe carefully examined. Below grade trenches and compressor or pumppits in the process unit should be avoided as these areas presenthousekeeping problems and provide a place for accumulation offlammable vapors. Section 6.0 of this specification considers accessibilityfor operations and maintenance. The following Table 7.2 providesadditional guidelines for equipment spacing for fire protection.

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TABLE 7.2

o Process Train (Towers, Drums, Exchangers)


Basic 3,050 (10) Provides isolation for containment of smfires.

From Exchanger 915 (3) Exchangers in same service may be grouptogether as one unit providing only operation and maintenance.

o Process Pumps


Basic 3,050 (10) Provides access for fire fighting to minimdamage in case of local fire. Pumps handlhydrocarbons below auto-ignition temperatudo not represent as great a fire risk as thooperating above auto ignition temperatuReduced spacing may be considered pumps handling high flash materials temperature below their flash point becausuch services represent a minimum fire risk.

From Associated Vessel 1,525 (5) Pump suction lines should be as short a

direct as possible, still providing flexibility aaccess for operation and maintenance. In tcase the vessel and pumps must considered one fire risk.

From Process Pumps 1,525 (5) For pumps in different service, unless onboth are operating above auto igntemperature in which case the basic spacinrequired and should be provided. For pumthe same or similar service and for spare puthe spacing may be reduced providing acfor maintenance and operation is provided.

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o Unit Control Rooms

Location should be at unit battery limits, next to a roadway.


Basic from ProcessUnits, Heaters,Compressors

15,250 (50) Spacing is required to minimize exposurepersonnel and equipment in control house explosion or fire risk. Since the control roois associated with a single unit, less spacerequired compared to control centers. For lrisk units, e.g., those handling high-flastocks below their flash points, reducspacing may be allowed.

Main Piperack 7,620 (25) Unit control rooms may be closer to pipe racthan to general process equipment, providthat the lines are all-welded without flangesvalves.

o Critical Electrical Switch Racks


Basic 4,575 (15) Provides space to minimize damage to critiswitch equipment that has relatively litresistance to fire exposure. Moderate fwould damage this type of equipment quickly

reduced spacing can be considered for con-critical racks based on the merits of t

individual case

o Unit Fired Equipment

Fired heaters and other open flame equipment, which for practical reasons cannot be located outside aprocess unit, should be separated as much as possible from other process equipment handling flammableproducts. Unit fired equipment should be located at the edge of the process unit with accessway fomaintenance and fire fighting equipment. Consideration should be given to the prevailing wind direction andspacing requirements in relation to the heater and equipment in the adjacent unit.

Controls for emergency fuel shutoff valves or other fire suppression systems should be located a safedistance from the heater and in a safe area.

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Basic 30,500 (100) Provides isolation from equipment or arewith vapor hazard and protects othequipment from risk of fire spread from theater.

From Control House,Process Unit, Utilities,Emergency Controls

15,250 (50) Protects unrelated equipment from risk of fin the heater area and provides access for ffighting equipment.

From Heaters relatedEquipment

7,625 (25) Provides maintenance access. Relatequipment with this or less separation must considered at risk with the fired equipment.

o Air Coolers

Air cooled heat exchangers with their extensive heat transfer surfaces are highly vulnerable to failure undefire exposure. They should not be located over any of the following:

- Pumps or compressors handling flammable materials.

- Drain manholes and catch basins.

When air coolers are located over major pipe racks, the following requirements must be applied:

- There should be at least 2135 mm (7 feet) of head room between the lowest part of the cooler, includingdriver and platform, and the top of the piperack.

- Normal horizontal spacing requirements from both the air cooler and the pipe rack to adjacent equipmen

must be met.

- Access must be provided for mobile equipment for removal and replacement of air coolers.

- Supports for the air coolers and pipe rack must be fireproofed. Air discharged from coolers should nocreate operating or maintenance problems on other equipment.

- Drain catch basins should not be located under or within 3050 mm (10 feet) horizontally of air coolers.


Basic 6,100 (20) Minimizes damage to air fins, since theymove vulnerable to damage from fire exposthan shell and tube exchangers.

Form Piperack, Associated Equipment

3,050 (10) Provides operation and maintenance accand protects tube fins from small fires

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7.3 Miscellaneous Spacing Requirements

7.3.1 Portable Gas Cylinders - The vulnerability to fire exposureof portable gas cylinders located in plant area must beconsidered in selecting their location. Depending on localregulations, gas cylinders are not always provided withoverpressure protection or fusible plugs. Cylinders should

be located as follows:

- High-risk cylinder installations (volatile, flammable ortoxic liquids, e.g., Cl2, NH3 and multiple flammable gascylinders, e.g., H2) should be located at the edge ofthe plant area, 7625 mm (25 feet) from other processequipment, with good access for firewater cooling.General storage of such cylinders should beminimized, and they should be located in a remoteoffsite area.

- Lower-risk installations (single cylinders containing

flammable or inert gases, e.g., H2, N2 ) should belocated at the edge of a fire risk area, and at least7625 mm (25 feet) from high fire risk equipment suchas pumps and furnaces.

7.3.2 Safety Showers - In areas where corrosive chemicals(which can cause skin burns or eye injury) are handled andpersonnel exposure may occur, safety showers with eyebaths shall be provided. They should be located so thatany equipment is no further than 15,250 mm (50 feet) froma safety shower.

7.3.3 Engine Exhaust - Atmospheric exhausts from gas turbinesand internal combustion engines should be located suchthat they do not present a hazard to personnel on adjacentworking platforms. They should be at least 3050 mm (10feet) higher than any platform or accessway within ahorizontal distance of 7625 mm (25 feet).

7.3.4 Drain Vents - Should be located with respect to ignitionsources as required.

7.3.5 Air Intakes - Air is drawn from the atmosphere for variousprocess or equipment uses, including:

- Combustion air for gas turbines and internalcombustion engines (gas engines, diesels).

- Air for ventilation, pressurization or air conditioning ofcontrol houses and substations, and for cooling oflarge electric motors.

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- Instrument air distribution headers, compressorstarting air systems and compressed air utilityheaders. The latter may be used for variousmaintenance tools, driving of pipeline pigs, tankmixing, etc., as well as for supplying some of the

consuming processes.

The potential for contamination of the air drawn from theatmosphere for these purposes introduces the possibility ofinternal explosion if a flammable vapor/vapors enter aforce-ventilated working space. The locations of airintakes in relation to adjacent equipment (safety valve andother vents, exhaust from engines, air coolers, equipmentliable to uncontrolled release such as pumps, etc.) musttherefore be carefully selected, taking into account factorssuch as prevailing wind direction, probable horizontal andvertical dispersion patterns, and the degree of hazard

which would result from contamination.

As a minimum requirement, the location of any air intake ina facility should be in an "unclassified" or "safe" area asdefined by the electrical area classification procedure.

- Air intakes to gas turbines, internal combustionengines, air compressors or other equipment locatedwithin enclosed or partially enclosed buildings shouldbe located outside the building.

- Air intakes which supply breathing air such as to

control house pressure ventilation and airconditioning systems should be located in a carefullyselected safe area based on vapor dispersioncalculations, where the recommended minimumspacing is held; safe location may normally be foundat some elevation directly above the control room.

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8.0 ATMOSPHERIC STORAGE

The location and arrangement of atmospheric storage tanks will generally begoverned by topography, the character of nearby facilities, the type of product tobe stored and shipping facilities. Exposure of atmospheric storage tanks toadjoining property should receive the same consideration with respect to fireprotection as the facilities within the process plant. It is advisable to locate tanksa reasonable distance from the boundaries of adjoining property where futureconstruction may occur.

The natural slope of the ground may be used effectively in development of adrainage system to prevent the spread of fire. Where the site is such thatdiversion dikes or ditches can be employed to divert spills away from the tanksinto an impounding area, this system may be safer and more economical than

complete tankage enclosure. On level ground, adequate protection by means oftank spacing, drainage and diked enclosures will be required. Products thatcould boil over in the event of a fire should have dikage as well as diversionaryditches and impounding basins to divert the boil over wave to a safer location.Refined products are not usually subject to boil over so these storage tanks needto be spaced only to protect against possible ignition from an adjacent tank fireand to provide sufficient space for manuvering of fire fighting equipment.

The grouping of tanks in like service in one enclosure is common practice and ifthe tanks are small, a single peripheral dike may suffice for the group. Wherelarger tanks are grouped, it is generally desirable to install intermediate spill wallsor drainage channels between the tanks. It is advisable to develop a means of

controlling drainage from the diked areas. Pipe connections through the dike,valved on the outside of the dike and discharging into a drainage ditch or piped toa remote holding pond should be provided.

Atmospheric storage tanks for hydrocarbon liquids shall be arranged and spacedin accordance with the recommendations of NFPA Standard No. 30, "Flammableand Combustible Liquids Code."

9.0 TRUCK LOADING

Truck loading should be located near an entrance into the site to avoidunnecessary vehicle traffic through the plant. Loading facilities handling volatilehydrocarbons should be located downwind of ignition sources. The mostimportant aspect in controlling fire in the loading area is stop the product flow tothe rack. Some method must be devised to block off the product lines to the rackat a remote location. These methods may be remote pump shutdown, remotelyoperated block valves or manually operated block valves located a safe distancefrom the loading facility.

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VES-1200

10.0 ROADWAYS

Access should be assured to all plant areas for emergency vehicles. Roadswithin the process units should be wide enough for two way traffic. Because itmay be necessary to block certain roads in case of fire or other emergency, twoor more approaches to each area are desirable. The relative location of roads,including roads on adjacent property to equipment handling volatile hydrocarbonsshould be considered because motor vehicles can be an ignition source.

Adequate turning radii should be allowed for mobile crane to clear pipe racks andequipment.

11.0 GENERAL RECOMMENDATIONS FOR PLANT SPACING

The Industrial Risk Insurer's general recommendations for spacing in refineries,petrochemical plants, gasoline plants, oil and gas pumping stations and terminals arebased primarily upon composite experience of a large number of hydrocarbon handlingand processing operations. Plant layout personnel should give particular attention to thenotes and remarks included on the individual tables.