SP12 2YY PI SP 999 029 D2[1] Spacing Creteria

8/17/2019 SP12 2YY PI SP 999 029 D2[1] Spacing Creteria

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Document No : SP12-2YY-PI-SP-999-029-D2

Date : 23th

June, 2010

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This Document is the property of N.I.O.C. Any unauthorized attempt to reproduce it, in any form, is strictly prohibited.

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TABLE OF CONTENTS

1. SCOPE ................................................................................................................. 4

2.

DEFINITIONS ....................................................................................................... 4

3. PURPOSE ............................................................................................................ 5

4. GENERAL CONSIDERATIONS ........................................................................... 5

5. TECHNICAL DEFINITIONS ................................................................................. 6

5.1 Flash Point .................................................................................................................... 7

5.2 Auto lgnition Temperature AIT ....................................................................................... 7

5.3 Sources of ignition ......................................................................................................... 7

6. INTERNATIONAL STANDARDS AND CODES ................................................... 7

7. THE SOUTH PARS 12 PLOT PLAN .................................................................... 8

8. THE AREA ALLOCATED FOR EPC CONTRACTORS ..................................... 10

9. SPACING OF UNIT AND AREAS ...................................................................... 11

9.1

Process Unit ................................................................................................................ 11

9.2

Process Area ............................................................................................................... 11

9.3

Process Block .............................................................................................................. 11

9.4 Tankage Block ............................................................................................................. 11

10. ON SITE SPACING ............................................................................................ 16

11. OFFSITE SPACING ........................................................................................... 25

12. TANKAGE .......................................................................................................... 30


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1. SCOPE

This specification covers the basic design, equipment spacing criteria and standards to beused in the layout of plant and equipment for the South Pars Gas Field DevelopmentPhase 12, Gas Plant, Gas Compression and Facilities. The spacing standard is applicableto the following installations: -

Process and Utility Plant

Tank Farms

In case of any conflict between this document and the Consequence Analysis, SP12-2YY-HS-NC-999-001 it shall be noted that the Consequence Analysis takes precedence on allmatters regarding unit layouts.

2. DEFINITIONSWithin this specification the following definitions shall apply:

COMPANY : Shall mean Petropars Limited.

CONTRACT : Shall mean the Agreement between the COMPANY and theCONTRACTOR and includes documents referred to therein.

CONTRACTOR: Shall mean the party, which has been entered under a CONTRACT or Agreement with the COMPANY for the execution of design, engineering, procurement ,construction, pre-commissioning, commissioning and start up of the Onshore Facilitiesregarding the South Pars Field Development Project, Phase 12.

CONSULTANT: Shall mean WorleyParsons resource and energy, engaged by theCOMPANY to perform Basic Design and FEED services.

INSPECTION AGENCY: Shall mean the inspection bodies which work under thesupervision of the COMPANY or CONTRACTOR. In some cases the COMPANY may alsoact as the INSPECTION AGENCY.

OWNER: Shall mean the National Iranian Oil COMPANY (NIOC)

PLANT: Shall mean permanent facilities designed, constructed and completed as a result

of execution of the WORK under the CONTRACT, located at the Tombak region of IRAN,on the Persian Gulf coast, in Bushehr Province.

SITE: Shall mean the premises and places on, under, in, over or through which the WORKis to be executed or carried out including CONTRACTORs engineering office and thePLANT.

SUPPLIER: Shall mean any person, firm or business which manufacture or supplymaterials, equipment or services for the performance of any item of WORK.

VENDOR or MANUFACTURER: Shall be considered to be synonymous with the termSUPPLIER as defined above.


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WORK: Shall mean all and any of the works and / or services and/or materials required tobe provided by the CONTRACTOR under the CONTRACT with COMPANY.

3. PURPOSEThe recommendations are based on current practice within the industry and are intended,as a minimum, to satisfy the requirements of all relevant Government safetyrecommendations.

Where applicable this standard is to be read and utilised in conjunction with relevantNational mandatory standards, listed codes and regulations which also apply to the locationof the project and the Safety Consequence analysis.

In the event of any conflict, CONTRACTOR shall seek clarification from the COMPANYbefore proceeding. Generally, the most stringent requirements shall apply.

This standard is not applicable for the following: -

Toxic Materials Handling Plant

Explosives Plant

Nuclear Plant

Pharmaceutical Plant

Equipment within Enclosed Buildings

4. GENERAL CONSIDERATIONS

The objective of the spacing recommendations is to ensure that maximum economical use

is made of available plot areas, compatible with the safety of personnel and vulnerability ofplant.

In achieving this end, consideration must be given to:

(a) Accessibility for normal operation and maintenance.

(b) Accessibility for fire fighting.

(c) Accessibility for emergency shutdown.

(d) Accessibility for evacuation of personnel.

(e) Segregation of high-risk facilities and sources of ignition.

(f) Protection of critical emergency facilities.

(g) Protection of adjacent facilities in event of fire.

(h) Security of installations from outside hazards.

(i) Minimising danger and inconvenience to personnel and property beyond theboundary fence.

(j) Ergonomic Factors


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(k) Escape access ways should be as straight and obstruction free.

(l) Hazardous area classification.

(m) Ensuring that flammable vapour generated from one facility will diffuse to aconcentraion well below the lower explosive level (LEL) before it reaches any otherfacility or area where a source of ignition may exist.

(n) Providing a reasonable degree of protection (distance) against heat radiation.

4.1 Circumstances will arise where it will be difficult to adhere to the minimum spacingrequirements; e.g. where there are severe limitations on plot availability. In such casesa reduction of minimum spacing (less than 10%) may be acceptable, after agreement atthe plot plan review. Any significant reductions in the proposed distances between

equipment should be discussed with the Design Safety Engineer involved, who maybeable to justify the proposed reduction by performing a Risk Assessment or Hazard Analysis. In this case some extra safety features such as Firewalls, Sprinklers,Emergency Shutdown Facilities etc., may be incorporated into the design in order tocompensate for the reduction in the distances between the equipment. Such reductionswill generally require the sanction of the COMPANY.

4.2 Other factors may require spacing greater than minimum recommendation of thisStandard. In this category consideration should be given to:

(a) proximity of adjacent property and the consequential environmental and publicrelations effects

(b) Special process hazards, which may necessitate increased spacing.

(c) Special plant maintenance or installation considerations.

(d) Future development plans both inside and outside the boundary fence.

(e) Topographical features of site and direction of prevailing winds.

(f) Political security factors.

(g) Special hazard zoning plans for existing plant areas.

4.3 A Safety Consequence Analysis study report will be prepared and issued. This ocumentprovides the minimal distances and leads to specific prevention and protectionmeasures to ensure that the impacts are within acceptable limits.

5. TECHNICAL DEFINITIONS

The following definitions are used throughout the standard.


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5.1 Flash Point

The flash point is the lowest temperature at which a product gives off sufficient vapour toform a mixture with air that can be ignited by a flame or spark.

5.2 Auto lgnition Temperature AIT

The auto-ignition temperature is the temperature at which a product will burn withoutapplication of any other form of ignition.

The AIT of most petroleum products is between 250ºC and 500ºC.

In general the AIT of petroleum hydrocarbons decrease with higher boiling fractionswhereas flash points increase.

5.3 Sources of ignition

Possible sources of ignition include the following:

5.3.1 ELECTRICAL

Sparks or arcs may occur when current carrying contacts are separated or through staticelectricity discharge.

5.3.2 NAKED LIGHTS

E.g. fired heaters, fires, smoking, hot work, gas welding, etc.

5.3.3 INTERNATIONAL COMBUSTION ENGINES

Spark-ignition systems, exhaust hot spots.

5.3.4 SPONTANEOUS COMBUSTION

Pyrophoric materials, vapour leakage at temperatures above AIT.

5.3.5 FRICTIONAL IGNITION

Grit blasting, power tool grinding, mechanical failure of rotating machinery.

5.3.6 HIGH TEMPERATURE SURFACES

Transfer lines, HP steam lines, and other hot surfaces.

6. INTERNATIONAL STANDARDS AND CODES

The plant layout spacing specification is based on the following international codes andstandards:

Institute of Petroleum Model Codes of Safety Practice, Part 3, 1981

LP GAS Association Code of Practice 1

Institute of Petroleum Model Codes of Safety Practice, Part 9, LPG Area Classification Code for Petroleum Installations,(IP15) Model Code of Safe

Practise in the Petroleum Industry Part 15,1990,


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NFPA-30 (Flammable & Combustible Liquids Code)

NFPA-59A (Storage and Handling of LNG)

European Standard EN 1473:1997 Installation and equipment for LNG – Design ofonshore installations.

European Model Code of Safe Practices in the Storage and Handling of PetroleumProducts. Part 1, Operations.

API Standard 2510 – Design and Construction of LPG Installations, 7th Edition May1995.

HSE Guidance: Storage of Flammable Liquids in Tanks [TBA Draft] (ReplacesHS[G] 50 & HS[G] 52)

Note: Reference should be made to these documents when producing the optimum layoutof the relevant plant facilities.

7. THE SOUTH PARS 12 PLOT PLAN

(See FIG. 1)

7.1 The Plot Plan has been prepared using the following information provided by theCOMPANY PPL

Site plans, survey and topographical drawings.

Site boundary coordinates.

A service road giving access to the site from the plant north.

The burn pit location. Location of the emergency gates and sulphur export gate (agreed with PPL).

The flare stacks are to be located a minimum distance from the plant south shoreline.

The location of IGAT 5 and 6 pipelines.

7.2 The Unit and building locations

7.2.1 The Main gatehouse, Administration building, Canteens, Security building, Mainworkshop, Indoor/outdoor warehouses and the car/truck maintenance buildings have allbeen located within a fenced area at the north west corner of the plot at grade elevation

119000. This fenced area has an internal gatehouse for access into the main processplant. The location of the above buildings gives a minimum distance and good access tothe local service and main roads and allows for car and bus parking outside of the maingate. The location is also a safe distance from the plant process equipment.An area forfuture use has been allocated to the west side of the fenced area.

7.2.2 The Main Control Room has been located inside the main process plant at gradeelevation 119000 and has a local access gate into the fenced administration area. TheMain Control Room is also located at a higher elevation than the main processequipment.

7.2.3 The Firewater unit/station 130 is located at grade elevation 116000 and at the north ofthe plot at a safe distance from the main process equipment.

7.2.4 The diesel and chemical storage units 131 and 146 are located at grade elevation116000 and at the north of the plot to enable tanker loading within a short distance from


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the north gatehouses with no need for the tankers to enter the main process areas. Anarea has been allocated for chemical storage.

7.2.5 The condensate storage tanks, unit 143 have been located at grade elevations 125000and 119000 the highest elevations of the plot within a bunded area, this gives NPSH forthe condensate pumps which are located at a minimum of 10 metres below. The storagetanks are located at the north east corner of the plot a safe distance from thesurrounding buildings and equipment.

7.2.6 The six Gas Treatment trains consisting of units 101, 104, 105, 107 and 111 are locatedat elevation 109000 with a main central pipe rack. The Gas trains will be identical withno mirror images.

7.2.7 The four Sulphur Recovery/Tail Gas trains, units 108 have been located at elevation106000 and to the east of the plot. The Sulphur solidification unit 144 is located in thesouth east corner of the plot and south of the 108 units. The location of these unitsenables the sulphur loading trucks to enter/depart the north east gate with minimum

access into the main process plant. An area west of unit 144 has been allocated forsulphur storage.

7.2.8 The gas compression unit 106 is located at grade elevation 106000 and is at a minimumdistance from the gas treatment trains and the boundary tie-in.

7.2.9 The sour water stripper unit 109 is located at grade elevation 106000.

7.2.10 The propane storage unit 145 is located at grade elevation 106000 and at the south ofthe plant. The tanker loading will be from the south road using the north east gatehousewith minimum access into the main process plant.

7.2.11 The fuel gas unit 122 is located at grade elevation 106000 within its own area andsurrounding roads. The unit is a minimum distance from the boundary fuel gas tie-in, the

sulphur recovery units 108 and the gas compression unit 106.7.2.12 The power generation unit 120 is located at grade elevation 106000 and close to the

centre of the plot and local to the main north/south pipe rack. The main sub station is tothe south of unit 120.

7.2.13 The blowdown/drains units 140, 141, 142 are located at grade elevation 106000 and atthe south of the plot local to the main north/south piperack and a minimum distance fromthe offshore flares.

7.2.14 The steam, air and nitrogen unit 121, 123 ,124 are located at grade elevation 106000 tothe south of the plot and local to the main north/south piperack.

7.2.15 The seawater desalination units126, 127, 128, 132 are located at grade elevation

106000.

7.2.16 The waste effluent disposal and storm basin unit 129 are located at grade elevation106000 and at the south of the plot close to the shore line. The outfall lines will berouted a safe distance offshore.

7.2.17 The Gas receivers unit 100 are located at grade elevation 106000 at the west side of theplot connecting with the three gas pipelines from offshore which are routedunderground.

7.2.18 The slug catcher unit 100 is located at grade elevation 114000 at the south west cornerof the plot and slopes from north to south down to grade elevation 104700 and is local tothe three gas receivers .

7.2.19 The three stabilization units 103 and the back-up stabilization unit 110 are located atgrade elevation 106000 to the west side of the plot and local to the slug catcher and theoff-spec and pre-treatment storage tanks.


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107, 111, the condensate pumps unit 143, four trains of sulphur recovery/tail gas units108 also units 106, 109, 122, 144, 145 and as fully described

9. SPACING OF UNIT AND AREAS

9.1 Process Unit

A process complex consists of a combination of plants, each carrying out a specificprocessing duty. These plants are defined as PROCESS UNITS.Equipment items within the process unit limits are referred to as „on-site equipment‟.On-site Spacing Chart, Fig. 4, gives the recommended spacing between these items ofequipment.Equipment limits are determined by an imaginary line drawn around the outer edge ofequipment within the Process Unit.

9.2 Process AreaSeveral process units may be combined to form a PROCESS AREA. These units maybe integrated, i.e. by no spacing between units other than basic equipment spacing, ormay be laid out as separate units with spacing between equipment limits (as definedabove) based on fire fighting access, process hazard or separate shut-downrequirements; depending on overall plant philosophy.

9.3 Process Block

A number of process areas may be combined to form a PROCESS BLOCK

9.4 Tankage Block

Fig. 3 shows the basic minimum spacing between bunded areas for a TANKAGEBLOCK.


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Fig. 1 South Pars 12 Plot Plan


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Fig. 2 EPC Boundary Definition


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Fig. 3 Typical Tankage Block

Dimensions are from the inside of the top bund wall. Bund should not be less than 15mfrom the outer boundary of the installation or the protection belt. This is to allow for anaccess for fire fighting and also to create a safe distance from the boundary.

30m 30m

ACCESSROAD

30m


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Fig. 4 – „On Site‟ Spacing Chart

This chart to be used with „On-site‟ spacing guide.

Note: All distances in metres

N.A. – Not applicable.

X – Provide spacing based on access for operation and maintenance.

Y – As required see „On-site‟ spacing guide.

Basic spacing is the recommended distance required between a given facility andother general processing equipment. This spacing is not required between items insimilar service, (i.e. pumps and spare etc).

See notes in section 10.1: „On-site‟ spacing guide.

7.5 7.5 7.5 7.5

3 4.5 4.5 1.5 4.5

7.5 7.5 7.5 N.A. 15 N.A. 7.5 7.5 7.5 7.5 X X X N.A. 7.5 X X

EMERGENCY VALVES FOR SHUT-

OFF, ISOLATING, SNUFFING ETC

X

EMERGENCY VALVESETC

X

7.5

4.5

4.5 4.5 1.5 3 6 4.5 3 1.5 4.5 4.5 X 7.5 4.5 4.5

ON SITE PIPE RACKS

MAIN EQUIPMENT STRUCTURES

X

15

15

30

X

10.5

4.5 4.5 X

15 15 15

22.5 X 4.5 X X 15 15 4.5 3 7.5 X X 30

22.5 15 15 15 15 15 15 15 15 15 X X X

15 15 15 22.5 15 15 15 15 15

30 30 30 30 30 30 30 30 30

4.5 4.5 X X X 4.5 X X 4.5

4.5 7.5 10.5 22.5 15 4.5 10.5 10.5 7.5

15 15 15 15 15

30 30 30 30 30

X 4.5 X X X

15 4.5 10.5 X X

15

X X

15 X

X X X

X X

X

7.5 7.5 7.5 7.5 22.5 15

3 4.5 7.5 3 22.5 7.5

4.5 4.5 7.5 4.5 22.5 15

7.5 7.5 7.5 22.5

4.5 3 3 15

4.5 4.5 4.5 7.5

15 15 15 15 22.5 15 15 15 15 30

15 4.5 7.5 15 22.5 15

3 4.5 7.5 3 22.5 7.5

1.5 4.5 7.5 1.5 22.5 7.5

7.5 15 15 Y

4.5 3 X

4.5 1

15 7.5 7.5

15 4.5 1

15 1.5

X

X

4.5 4.5 7.5 4.5 22.5 15

7.5 15 15 7.5 22.5 X

22.5 22.5 22.5 22.5 10

1

1.5 4.5 7.5 1.5

7.5 7.5 1.5

4.5 1.5

3

ELECTRICAL SUBSTATION

UNIT CONTROL HOUSE

CENTRAL CONTROL HOUSE

EQUIPMENT HANDLING NON-

FLAMMABLES

COMPRESSOR DRIVERS (OTHER

THAN STEAM OR MOTOR)

GAS COMPRESSORS AND EXPANDERS

HANDLING FLAMMABLE MATERIALS

PUMPS HANDLING FLAMMABLE

MATERIALS

PUMPS ABOVE AIT

COOLING TOWERS

FIRED HEATERS

AIR FIN COOLERS

EXCHANGERS OPERATING BELOW

AIT

EXCHANGERS OPERATING ABOVE

AIT

BLOWDOWN AND DISENGAGING

DRUMS

ON-SITE PRESSURE STORAGEVESSEL

DRUMS

REACTORS ABOVE AITINTERNALLY INSULATED

REACTORS ABOVE AITEXTERNALLY INSULATED

N.A.

15

15

30

X

10.5

7.5

3

4.5

15/30

15

3

1.5

4.5

7.5

22.5

1.5

7.5

4.5

1.5

RT1

RR1

RS1

RQ1

RP1

RO1

RN1

RM1

RL1

RK1

RJ1

RI1

RH1

RG1

RF1

RE1

RD1

RC1

RB1

RA1

RU1

RV1

22.5

ITEM

REF

BASIC SPACING

TOWERS


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10. ON SITE SPACING

The recommended spacing for on-site equipment is indicated in “On-site Spacing Chart”Fig. 4.

The information on this chart is supplemented by explanatory notes which are contained inSection 10.1 “On-Site Spacing Guide”.

It is essential that reference is made to Section 10.1 when using “On-Site Spacing Chart”Fig. 4.

Against each type a basic spacing dimension is quoted. This basic spacing is therecommended distance in metres between the item and other general process equipment.The recommended spacing between different items is given at the intersection of the

horizontal line for one item and the vertical line from another. In general, this shall be thegreater of the basic spacing dimensions for the two items. Explanatory notes can be foundin Section 10.1.The spacing between two similar items is given in the first box adjacent to the item. Notethat basic spacing is not required between items in the same service.

10.1 On-Site Spacing Guide (Use with on-site spacing chart Fig. 4)

10.1.1 Ref: RA1 Towers

(Basic Spacing 1.5 metres)

The basic spacing of 1.5 metres provides access for operation and maintenance. Thedistance between two towers is twice the basic dimension. This provides someadditional access for fire fighting and clearance for non-coincidental platforms.

10.1.2 Ref. RBI Reactors

(Above AIT – externally insulated) (Basic spacing 4.5 metres)

The basic spacing of 4.5 metres provides access for fire fighting and minimises damageto other equipment. The external insulation protects the reactor shell from fires on otherequipment.

Reactors may be grouped together; in which case operational and maintenance accessof 1.5 metres between shells is satisfactory.

Reactors operating below AIT may be regarded as drums, i.e. drum spacing recommendations will apply (see Ref. RD1).

Spacing from Ref. RF1 is in excess of the greater basic dimension as the Reactor isregarded as high-risk equipment.


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Since the Reactor is operating above AIT, other sources of ignition are not a spacingconsideration and basic reactor spacing of 4.5 metres will apply, e.g. items Ref. RJ1and R01.

10.1.3 Ref. RC1 Reactors

(Above AIT – internally insulated. Basic spacing 7.5 metres)

The basic spacing of 7.5 metres provides access for fire fighting, minimises damage toother equipment in event of reactor fire, and protects exposed shell.

N.B. Internally lined reactor shells are more susceptible to fire damage than unlinedvessels. Reactors may be grouped together; in which case operational andmaintenance access of 1.5 metres between shells is satisfactory.

Reactors operating below AIT may be regarded as drums, i.e. drum spacingrecommendations will apply (see Ref. RD1).

Spacing from RF1 is in excess of the reactor after basic dimension as the reactor isregarded as high-risk equipment.

Since the reactor is operating above AIT, other sources of ignition are not a spacingconsideration, basic reactor spacing of 7.5 metres will apply, e.g. items RJ1/R01.

Spacing from Refs. RP1, RT1, RU1 – these items are not regarded as fire hazardous – the spacing of 4.5 metres will give these items protection in the event of reactor fires.

10.1.4 Ref. RD1 Drums


The basic spacing of 1.5 metres access for operation and maintenance. Spacing fromRU1 is the basic drum spacing as the piperack is not considered fire hazardous. Drumsshould not be located under pipe racks.

10.1.5 Ref. RE1 On-site Pressure Storage Vessels


The basic spacing of 22.5 metres minimises exposure of unit equipment to a potentialsource of severe fire, and blast damage in the event of an explosion.

Pressure storage in on-site locations should be avoided wherever possible. It issometimes necessary, e.g. in solvent propane dewaxing and deasphalting units toprovide pressure storage facilities on-site; in such instances the inventory should beheld to a minimum and the storage vessel located at the unit battery limit and as far aspossible from fired heaters and other source of ignition.

For pressure storage vessels, in the same service provide a minimum of one diameterbetween shells for operational and maintenance access.


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Spacing from RU1 pipe racks is not considered as fire hazardous- spacing of 4.5 metersaffords protection to these items in the event of storage vessel fire.

10.1.6 Ref. RF1 – Blow-down and Disengaging Drums

(Basic spacing 7.5 metres)

The basic spacing of 7.5 metres provides protection to the Drum in the event of firewithin the unit.

For high-risk equipment the spacing should be increased to 15 metres. High riskequipment includes reactors, exchangers and pumps, operating above AIT, firedheaters, gas compressors and expanders, and their drivers, e.g. items Ref. RB1, RC1,RG1, RL1, RN1, R01.

Spacing from Ref. RU1 – pipe racks are not regarded as fire hazardous – spacing of 4.5metres affords protection to the pipe rack in the event of blowdown drum fire.

10.1.7 Ref. RG1 Exchangers

(Operating above AIT) (Basic spacing 4.5 metres)

The basic spacing of 4.5 metres minimises damage to other equipment in event of fire.Exchangers operating above AIT are high-risk items with greater probability of fire thanfor exchangers operating below AIT.

Exchangers above AIT in the same service, i.e. connected by a common processstream, may be spaced 1.0 metres apart; for other exchangers basic spacing of 4.5metres should apply.

Spacing from Ref. RJ1 – since the fluid in the exchanger is already above its AIT, thefired heater, in this case, does not represent a source of ignition. However, a heater fireis considered likely to be more severe than other plant fires, so spacing greater thanbasic is applied to minimise damage to the exchanger in the event of a heater fire.

Spacing from Ref. R01 – since the fluid in the exchangers is above its AIT, thecompressor driver does not represent a source of ignition. Therefore, exchanger basic

spacing of 4.5 metres applies.

Spacing from RF1 is in excess of the greater basic dimension as the exchanger (above AIT) is regarded as a high-risk item.Spacing from ref. RP1 protects equipment from a high fire risk system.

10.1.8 Ref. RH1 Exchangers

(Operating below AIT) (Basic spacing 1.5 metres)

The basic spacing of 1.5 metres provides access for maintenance and operation. There

are no limitations on spacing exchangers from pipe racks – exchanger spacing applies.


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10.1.9 Ref. RI1 Air Fin Coolers

(Basic spacing 3 metres)

Air fin coolers by virtue of their design and operations are particularly vulnerable to firehazard.

For this reason grade mounted units isolated from other equipment are preferred.However, because of restrictions on area availability, it is common practice to mount air

fin coolers on top of the pipe rack (see Engineering Standard 50A1). In such casesconsideration must be given to the following:

Air fin coolers must not be mounted over pumps, compressors, drums or heatexchangers, containing flammable materials.

There must be no flanges or valves in any hydrocarbon lines on the rack beneath an airfin cooler.

Horizontal spacing requirements of “on site” spacing chart, Fig. 4, must be met.Support legs for the air fin cooler must be fireproofed in accordance with the ProjectSepcification.

Access must be provided for tube bundle removal by mobile equipment.

The basic spacing of 3.0 metres (horizontal) minimises exposure to fire hazard – air finsare more vulnerable to fire damage than shell and tube exchangers.

Ref. RU1 – the basic spacing of 3.0 metres is applicable to grade mounted air fincoolers only.

10.1.10 Ref. RJ1 Fired Heaters


A fired heater by its nature is a permanent source of ignition while operating. A heaterfire is likely to be of maximum severity. The basic spacing of 15 metres separatesequipment handling flammable vapours from a permanent source of ignition and affordsprotection in the event of a major heater fire. Heater location will sometimes bepredetermined by the requirement of grouping to a common stack with heaters fromother process units.

Where such restrictions are not applied, the heater location should be selected on thewindward side of the unit with reference to the prevailing wind, close to the battery limitand as far as practicable from other equipment. Consideration must also be given to theproximity of plant and equipment outside the unit battery limit.

When the heater has an individual stack, the top of the stack should be at least 3 metreshigher than equipment within a horizontal distance of 15 metres and at least 3 metreshigher than any operating platform within a horizontal distance of 65 metres.


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Ref. RJ1 - If all heaters in a group shutdown together at plant turnaround, spacingbetween shells can be for normal maintenance only. If heaters are required toshutdown individually, spacing of 7.5 metres between shells is required for LPoperation (less than 7 kg/cm2g) and 15 metres between shells for HP operation (7

kg/cm2

g and above).

Refs. RB1, RC1, RG1, RL1 are items operating above their AIT and in these cases thefired heater is not considered to be the primary source of ignition, spacing is based onaffording protection in the event of heater fire.

For reformer heater/reactor installations, where vapour only is present in heater tubesand reactors, spacing may be further reduced to 3 metres in the case of Ref. RB1 and5 metres in the case of Ref. RC1.

Ref. RN1 – the compressor area is regarded as a special risk area in view of thepotential release of large vapour quantities. Spacing greater than the basic dimensions

are required.

Ref. R01 – the compressor driver is not considered a source of ignition in this case.The spacing of 7.5 metres minimises damage to the compressor driver in the event ofheater fire.

Ref. RP1 – a spacing of 4.5 metres minimises damage in the event of the heater fire.For equipment higher than 3 metres, spacing should be increased to 7.5 metres fromheaters with liquid in their tubes. Reduced spacing is permitted because there is noflammable material release in the event of damage.

Ref. RU1 – because of severity of heater fire, spacing to pipe racks is greater thanbasic.

N.B. This does not apply to heaters‟ own pipe rack.

10.1.11 Ref. RK1 Cooling Towers

(Basic spacing 15 and 30 metres)

Basic spacing of 15 metres applies to equipment lower than the cooling tower; basicspacing of 30 metres to equipment higher than the cooling tower.

The cooling tower becomes a source of hazard in the event of tube failure in a watercooler. Basic spacing provides for dispersion of hazardous vapours, minimisescorrosive effects of spray impingement and visibility problems from exhaust plume.

The cooling towers should be located on the leeward side of a process unit withreference to the prevailing wind.

Ref. RU1 – the factors above are not considerations in the case of a pipe rack. Piperack basic spacing will apply.

10.1.12 Ref. RL1 Pumps (Above AIT)



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Pumps operating above AIT are a high fire risk. Basic spacing of 4.5 metres providesfire-fighting access and minimises damage to other equipment.

Ref. RF1 – because of the high fire risk, spacing greater than basic should be provided

from this item.

Ref. RJ1 – the fired heater is not considered a source of ignition in this case. Spacing of7.5 metres is provided between two high-risk items.

Ref. RL1 – pumps in the same service may be spaced at 1.5 metres. For pumps indifferent services basic spacing of 4.5 metres applies.

Ref. R01 – the compressor driver is not considered a source of ignition in this case.Basic spacing for pump applies.

Ref. RP1 – a spacing of 4.5 metres minimises damage in the event of a pump fire.

Ref. RU1 – spacing is horizontal from edge of rack to pump stuffing box.

10.1.13 Ref. RM1 Pumps handling Flammable Materials


The basic spacing provides for fire fighting and minimises damage in the case of fire.Pumps in the same service may be spaced at 1 metre, which provides access foroperation and maintenance.

Ref. RU1 – spacing is horizontal from edge of rack to pump stuffing box.

10.1.14 Ref. RN1 Gas Compressor and Expanders


When there is more than one compressor on a process unit, it is usual to locate these,together with their auxiliaries, in a designated area. Basic spacing is not appliedbetween the compressors or their auxiliaries, access for operation and maintenance isprovided.

Compressors are costly items so basic spacing is greater to allow additional protectionin the event of a fire.

Small compressors (200 HP and less) may be treated as pumps for spacing purposes.

Ref. RF1 and RJ1 - spacing greater than basic is provided because of the high-risknature of these items.

Ref. RU1 is not a hazard producing item. The basic spacing of 4.5 metres providesprotection in the event of compressor fire.

10.1.15 Ref. R01 Compressor Drivers (Other than steam or motor)



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Basic spacing is not applicable between Compressor and driver. Gas turbine, gasengine or internal combustion engine drivers are sources of ignition. Basic spacing of10.5 metres affords safe spacing from a source of ignition.

For items RB1, RC1, RG1, RL1, which are operating above AIT, the driver is notconsidered to be the primary source of ignition. The basic spacing for these itemstherefore applies.

Ref. RJ1 – spacing of 7.5 metres protects driver in event of heater fire.

Ref. RF1 – spacing greater than basic provides additional protection to critical item.

Ref. RU1 – the pipe rack is not a hazard – rack basic spacing applies.

10.1.16 Ref. RP1 Equipment Handling Non-Flammables

(Spacing provided for operational and maintenance access)

Ref. RB1, RC1, RG1, RJ1, RL1 – spacing of 4.5 metres provides protection toequipment in the event of fire at likely sources of ignition.

10.1.17 Ref. RQ1 Central Control House


Basic spacing of 30 metres affords protection to personnel and critical control equipmentfrom plant fire or explosion hazard. Consideration may be given in specialcircumstances to blast-resistant design of building.

Ref. RU1 – on site pipe racks should not generally be nearer than 30 metres to theControl House. Provided lines are fully welded with no valves or flanges, a pipe rackmay be brought to 7.5 metres from one side only of a central control house.

10.1.18 Ref. RR1 Unit Control House


The location of a unit control house is obviously less critical than a central control house.It should be located at the battery limit adjacent to a roadway. Basic spacing minimisesrisk to personnel and equipment in the event of a unit fire.

Ref. RU1 – pipe rack basic spacing applies provided lines are fully welded withoutvalves or flanges.

10.1.19 Ref. RS1 Electrical Sub-station



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Electrical sub-stations are located close to the battery limit and near to a roadway. Thebasic spacing is fixed by Area Classification considerations and provides protection tothe electrical equipment in the event of unit fire.

Ref. RU1 – pipe racks do not present a major hazard. Basic rack spacing applies.

10.1.20 Ref. RT1 Main Equipment Structures

(Basic spacing – not applicable)

Sufficient spacing should be allowed from ignition sources of high-risk RC1 items toprevent damage to structure in event of fire or explosion. Items RB1, RC1, RE1, RG1,RJ1, RL1, RN1 are in this category. In most other cases the equipment in the structurewill govern its location with respect to other equipment.

10.1.21 Ref. RU1 On-site Pipe Racks


Pipe rack basic spacing gives protection to the pipe rack in the event of equipment fireswithin a process unit. Items Ref. RB1, RC1, RE1, RG1, RK1, RN1 and R01 are locatedon this basis.

Item Ref. RJ1 – fired heater is a possible source of a major fire. Spacing greater thanbasic is required in this case.

N.B. This limitation does not apply to the pipe rack serving the heater area.

The piperack in itself is not considered highly hazardous. In general equipment which isnot hazardous may be located on access and operability considerations relative to thepipe rack. Items Ref. RA1, RD1, RH1, RI1 (grade mounted) are in this category.

In special cases where the hazard from the pipe rack must be minimised, fittings andflanges which could be sources of leakage must be eliminated from the pipe rack in thevicinity, e.g. from pipe racks under air fin exchangers and from pipe racks in the vicinityof control houses, i.e. items RI1, RQ1 and RR1.

Pumps are also considered as a special case as, for layout purposes, access andoperability, it is usual to have pumps in close proximity to the pipe rack, e.g. items Ref.RL1 and RM1 – spacing is horizontal distance from pump stuffing box to edge of piperack.

10.1.22 Ref. RV1 Emergency Valves for Shut-off, Isolation, Snuffing, etc.


The basic spacing is the distance between the emergency valve and the equipment itcontrols. It can be located adjacent to other equipment.

Ref. RE1 and RJ1 are exceptionally hazardous items. The basic spacing for theseitems there applies.


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Where it is necessary for reasons of plant layout to locate emergency shut-off valvemanifolds closer to a heater than 15 metres, a fire wall shall be provided between themanifold and the heater at a minimum distance of 7.5 metres from the heater.

10.1.23 Roads of width 6 metres or more

Maintain a minimum of 10m between roads and any hydrocarbon containing equipment.

Fig. 5 – „Off -Site‟ Spacing Chart

This chart to be used with „Off -site‟ spacing guide.

Note: All distances in metres

N.A. – Not applicable.

X – Provide spacing based on access for operation and maintenance.Basic spacing is the recommended distance required between a givenfacility and other general processing equipment.

7.5

See notes in section 11.1: „Off -site‟ spacing guide.

30

45

15

45 30 60 45 45 45 45 45 4.5

45 45 45 45 45 45 45 45 4.5

7.5 15 15 7.5 7.5 45 N.A. 4.5

45 45 30 60 15

45 45 30 60 30

45 N.A. 15 N.A. N.A.

30 N.A.

X

30 7.5 30 60 7.5 7.5

30 45 15 15 45 45

45 X 30 60 X X

7.5 60 45 7.5

30 45 15 4.5

X 45 45 4.5

45 60 30 60 45 45 45 45 45 4.5

6 15 4.5 X 7.5 4.5

45 60 30 60 45 45

45 45 45 60 45 45

4.5 45 15 N.A.

45 45 N.A.

45 N.A.

60 N.A. 45

15 45 X

45 N.A.

N.A.

15

30 X 15 60 X X

30 X 15 60 X N.A.

X X 45 60 X

X

60 60 60 N.A.

30 45 X

30 X

X

FACILITIES FOR HEAT SENSITIVE

MATERIALS EG TEL. & TML.

MAIN EFFLUENT TREATMENT

PLANT RAIL FACILITIES

RAILWAY MAIN LINES

MAJOR PUMP AREAS

BOUNDARY FENCE

PROCESS AREAS

MAJOR OFFSITE PIPE TRACKS

LOADING RACKS FOR LOW FLASHPRODUCTS

FIRE TRAINING AREA

MAIN FIRE WATER PUMPS

FIRE STATION

MAIN ELECTRICAL SUB-STATIONS

JETTIES (LOADING ARM MANIFOLD)

COOLING TOWERS

BUILDINGS, MAIN OFFICES, WORK-SHOPS, LABORATORIES, ETC

30

45

15

60

15

45

45

4.5

45

45

45

45

45

60

15/30

45

30

RR2

RQ2

RP2

RO2

RN2

RM2

RL2

RK2

RJ2

RH2

RG2

RF2

RE2

RD2

RC2

RB2

RA2

FACILITY

REF

BASIC SPACING

BOILER HOUSES AND POWERSTATIONS

50

100 50 50 50 100 100 100 50 50 50 100 50 100 100 50 100 N.A

PIGGIN FACILITIES 50

RR2


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11. OFFSITE SPACING

Facilities outside the confines of a Process Block, e.g. boiler houses and power stations,administration offices, workshops, effluent treatment, flare stacks, jetty and rail loading,blending facilities etc., are referred to as “off -site facilities”.

It is customary to combine the utility type facilities, e.g. steam generation, water treatment,plant air etc., within a utility area or block.

Effluent treatment, flare and similar high hazard off-site facilities are generally locatedremote from process facilities, utility areas and administration areas.

Spacing of flare stacks requires special consideration based on relief loads and thermalradiation levels. Reference must be made to the Process Engineer.

The recommended spacing off-site equipment is indicated in “Off -site Spacing Chart”, Fig.5.

The information on this chart is supplemented by explanatory notes contained in Section11.1 “Off -site Spacing Guide”.

It is essential that reference is made to Section 11.1 when using “Off -site Spacing Chart”,Fig. 5.

Against each item a basic spacing dimension is quoted. This basic spacing is therecommended distance in metres between the item and other equipment/facilities. The

recommended spacing between different items is given at the intersection of the horizontalline from one item and the vertical line from another.

In general, this shall be the greater of the basic spacing dimensions for the two items,otherwise explanatory notes can be found in Section 11.1.

The spacing between similar equipment/facilities is given in the first box adjacent to theitem.

11.1 Off-site Spacing Guide

(Use with off-site spacing chart Fig. 5)

11.2 Ref. RA2 Boiler Houses and Power Stations


The basic spacing protects critical equipment from fire or explosion in processequipment.

Ref. RB2 – buildings are not considered hazardous to boilers and generating plant andvice versa. Therefore, spacing less than basic for buildings is acceptable.


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Ref. RK2 – spacing protects pipe track from possible fire in boiler house.

Ref. RO2 – railway main lines are not at risk from facilities and do not present a risk tofacilities. Boiler basic spacing applies.

Ref. RP2 – rail sidings present a minimum risk to facilities. Siding basic spacing applies.

Note that steam generators forming an integral part of a process unit are considered asfired heaters. In such cases, on-site basic spacing will apply.

11.3 Ref. RB2 Buildings, Main Office Block, Workshops, Laboratories etc.


The basic spacing protects personnel from fires and explosions in process equipment.

For high hazard process equipment, spacing in excess of basic is applied.

Items Ref. RD2, RJ2, RL2 fall into this category.

Items Ref. RA2, RK2, RO2, RP2 are not considered high-risk items. Spacing less thanbasic building space is applied.

11.4 Ref. RC2 Cooling Towers

(Basic spacing 15 metres and 30 metres)

Two basic spacings are given for Cooling Towers.

The lower basic spacing is for equipment that is lower than the cooling tower.

The higher basic spacing is for equipment that is taller than the cooling tower and whereit is necessary to minimise the corrosion, visibility and ice formation problems, resultingfrom the impingement of the cooling tower exhaust plume.

A cooling tower can become a source of hazard due to release at atmosphere offlammable vapours, caused by tube failure in water cooled exchangers. The higherbasic spacing distance is considered adequate for dispersal of these vapours.

Spacing greater than cooling tower basic is applied from highly hazardous sources, e.g.items Ref. RD2 and RH2.

Items Ref. RF2, RG2 and RO2 do not present a hazard to these cooling towers.Cooling tower basic spacing is therefore applied.

Items Ref. RJ2 and RL2 are possible sources of fire. Higher cooling tower basicspacing is applied to these items.

Items Ref. RM2 and RO2 do not present a hazard to the cooling tower. Cooling towerhigher basic spacing is applied for environmental considerations.


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Item Ref. RK2 – the cooling tower is not considered to be at risk from the pipe track.Pipe track basic spacing is applied.

11.5 Ref. RD2 Jetties

(Loading arm manifold – basic spacing 60 metres)

The basic spacing protects facilities from fires at loading manifolds or on tankers andvice versa.

Items Ref. RN2, RP2, RQ2 are not considered as sources of hazard. Basic spacing forthese items will apply.

11.6 Ref. RE2 Main Electrical Sub-stations


The basic spacing protects electrical equipment from explosion or fire in process areas.By using blast resistant construction, this basic spacing may be reduced.

Items Refs. RK2, RO2, RP2 are not considered as major sources of hazard. Spacingless than basic is allowed.

11.7 Ref. RF2 Fire Station


The basic spacing provides protection to the fire station and equipment in the event offire in the process areas.

Items Ref. RA2, RC2, RK2, RO2 and RP2 are not considered as major sources ofhazard. Spacing less than basic is allowed.

Items Ref. RB2, RE2, RG2 and RM2 are not hazardous to the fire station. Location isdetermined by access and maintenance considerations.

11.8 Ref. RG2 Main Fire Pumps


The basic spacing provides protection to prevent loss of pumps from fire exposure.Items Ref. RA2, RC2, RK2, RN2, RO2 and RP2 are not considered sources of majorhazard. Spacing less than basic is allowed.

Items Ref. RB2, RE2, RF2 and RM2 are not hazardous to fire pumps. Location is

determined by access and maintenance considerations.


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11.9 Ref. RH2 Fire Training Area


The basic spacing protects vulnerable process equipment from a source of ignition.Spacing also allows smoke dispersal.

11.10 Ref. RJ2 Loading Racks


The basic spacing is considered adequate for the dispersal of spillage or vapourreleases. During unloading it also protects the equipment in the event of fires at processareas and vice versa.

In locating main loading racks, consideration must be given to access from outside andto minimising the flow of traffic through process areas.

Spacing must be sufficient to allow the safe manoeuvring of road tankers and for railsidings where applicable.

Items Ref. RC2, RK2 and RN2 are not considered hazardous with respect to the loadingarea. Spacing less than loading rack basic is acceptable in these instances.

For item Ref. RB2 spacing greater than basic is applied to reduce hazard to personnel.

11.11 Ref. RK2 Major Off-site Pipe Tracks


The basic spacing of 4.5 metres minimises hazard to off-site piping in the event of firesat major plant areas.

For items Ref. RC2, RF2, RL2, RM2, RN2, RP2, RQ2 and RR2, this criterion applies.

For items Ref. RA2, RB2, RE2, RH2, RJ2 and RO2 greater spacing is applied forcommodity criticality or personnel hazard requirement.

11.12 Ref. RL2 Process Areas


The basic spacing minimises damage to other areas or equipment in the event of fire orexplosion in the process area and vice versa.

For item Ref. RB2 spacing greater than basic is applied to reduce hazard to personnel.

Items Ref. RC2, RK2 and RN2 are not considered at high hazard from process areas.The basic spacing for these items is therefore applied.


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A process to process area spacing of 15 metres is considered sufficient to permitindependent shutdown at turnaround.

In the case of light end units this should be increased to 25 metres. Where several

process units are integrated, the internal spacing should be based on maintenance,operational and fire fighting access.

11.13 Ref. RM2 Boundary Fence


The basic spacing provides protection to personnel and property outside the boundaryfence in the event of explosion or fire. It also protects the facilities inside the fence fromexternal hazard.

Item refs. RC2 and RK2 are reduced hazard items. Spacing less than the basicboundary spacing is acceptable in these instances.

Item refs. RB2, RE2, RF2 and RG2 are not hazardous. Spacing from boundary fence isbased on access or environmental consideration.

11.14 Ref. RN2 Major Pump Areas


The basic spacing affords protection to pump areas in the event of fire or explosion inprocess facilities and allows access for fire fighting.

Pump areas, because of their low inventory, do not present a major hazard to otherequipment.

Spacing less than basic item spacing is therefore permitted from these items, e.g. itemsRef. RD2, RG2, RJ2, RL2, RO2 and RQ2.

11.15 Ref. RO2 Railway Main Lines


The basic spacing protects personnel and railway property from fire or explosion insideplant.

Items Ref. RA2, RC2, RJ2 and RN2 present a reduced hazard to railway property.Spacing less than basic is permitted in these cases.

11.16 Ref. RP2 Rail Sidings



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A rail siding can be considered as a source of ignition from a locomotive engine. Thebasic spacing protects flammable equipment or sources of vapour emission from thishazard.

Items Ref. RC2, RD2, RN2 and RR2 fall in this category.

Non-hazardous items may be located at less than the basic spacing. Items Ref. RB2,RE2, RF2, RG2 and RK2 fall in this category.

For item Ref. RQ2, additional spacing is required to permit dispersal of vapours.

11.17 Ref. RQ2 Main Effluent Treatment


A basic spacing of 45 metres from process areas or other sources of ignition allows fordispersal of vapours, which are likely to be emitted at a separator.

Items Ref. RA2 to RJ2, RL2, RM2 and RR2 fall in this category.

Lower risk facilities, not representing a source of ignition, may be located not less than30 metres from a separator. Items Ref. RN2 and RP2 fall in this category.

Item Ref. RK2, off-site pipe tracks, is a minimum risk item. Its basic spacing applies.

11.18 Ref. RR2 Facilities for Heat Sensitive Materials


Heat sensitive materials are liable to decomposition explosions on prolonged exposureto heat. The basic spacing of 30 metres protects the facilities from such exposure.

Items Ref. RK2 and RP2 are not sources of fire. Spacing less than basic 30 metres willbe acceptable in these instances.

11.19 Ref. RS2 Pigging Facilities

The barrel of the pig launcher and receiver „closure end‟ must point away from anyfacility.

12. TANKAGE

This section gives basic guidance for the spacing and bund capacities of storage tanks,storage spheres and cylinders. For specific spacing direction refer to the relevant listedstandard(s).

Other types of bulk storage, e.g. underground caverns, are not covered by this standard.


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12.1 Flammable Liquids

Petroleum products by their nature are potentially hazardous, the degree of hazardbeing directly related to their volatility and flash point.

These are classified:

Class 0 Liquified petroleum gas

Class I Liquids having flash points below 21ºC

Class II (1) Liquids with flash points from 21ºC to 55ºC

stored below flash point

Class II (2) Liquids with flash points from 21ºC to 55ºC

stored at or above flash point

Class III (1) Liquids with flash points from 56ºC to 100ºC

stored below flash point

Class III (2) Liquids with flash points from 56ºC to 100ºC

stored at or above flash point

Unclassified Liquids which have flash points above

100ºC

12.2 Types of Tankage

The type of tank used to store a particular product is generally specified byCOMPANY‟S requirements. In the absence of such requirements, type selection shouldbe referred to the Process Design Co-ordinator.

12.2.1 Fixed or Cone Roof Tanks (CR)

For the storage of Class III (1) and Class III (2) and Unclassified products. Other classesof product may be stored in this type of tank, provided that the vapour pressure atstorage temperature is less than atmospheric pressure (e.g. refrig. atmosphere storageof LPG/LNG).

12.2.2 Floating Roof Tanks (FR)

For the storage of Class II (1) and Class II (2) flammable products in the middle flashpoint range.

12.2.3 Spheres and Cylinders (SP and CYL)

For the storage of Class 0 and Class I highly flammable products, which have flashpoints below 21ºC, e.g. pressure storage of LPG products.


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12.2.4 Table 1

This table gives typical examples:

Product Type of Tank orVessel

Class Comments

C3 CYL 0 Pressure Storage

C4 SP 0 Pressure Storage

C3 CR 0 Refrig. Atmos. Storage

C4 CR 0 Refrig. Atmos. Storage

LPG/LNG CR 0 Refrig. Atmos. Storage

Benzene FR I

Xylene FR I

Reformate FR I

Gasoline FR I

Naphtha FR I

Kerosene FR II (1)

Jet Fuel FR II (1)

Crude Oil FR II (2) Boil/roll Over Tendencies

Gas Oil/Diesel FR III (1)

LFO CR III (2)

MFO CR III (2)

HFO CR III (2)

Heavy Oil/Residue CR III (2)

Asphalt/Bitumen CR Unclassified

Note: Certain produce classifications may change if operational temperatures areincreased.

12.3 Definitions

12.3.1 Bund or Firewall

A wall of pre- determined height constructed of concrete, earth, or any other suitablematerial and designed to confine spillage of tank contents.

12.3.2 Bunded Area

An area bounded by bund walls to confine spillage.

12.3.3 Exposed Bunded Area


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The net effective area bounded by a bund wall after the deduction of tank areascontained within the bunded area.

12.3.4 Secondary or Intermediate Bunds

As for bund above, but usually no higher than 600mm in order to contain local spillagewithin a sub-area of the main bunded area.

12.3.5 Bund Capacity

The volume in cubic metres that can be contained within the exposed bunded area.

12.3.6 Tank Group

A number of tanks contained within a common bund.

12.3.7 Small Tanks

A tank of 10 metres diameter or less and capacity of 8000 cubic metres of water or lessis deemed to be a small tank.

12.4 Grouping and Spacing of Tanks

12.4.1 It is desirable to group tanks for the storage of the same products in one group within abund area, subject to the prescribed limitations of the bunded capacity.

12.4.2 It is desirable that LPG or other liquefied flammable gases should be stored remote fromother products.

12.4.3 Intermediate and component tankage should be located in areas local to their respective

units where possible so that lines can be kept to a minimum length.

12.4.4 Account should be taken of the possibility of storing more than one class of material incertain tanks or of changing the tank service at some future date. Where future changesof service of the storage tanks are anticipated, the layout and spacing should be for themost stringent case.

12.4.5 Wherever possible storage tanks should not be located on high ground overlooking thefacilities, unless the spillage is protected by bund walls. This prevents spillage offlammable liquid flowing downhill and endangering the operating plant.


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12.4.6 For fire fighting reasons there should be no more than two rows of tanks betweenadjacent access roads.

12.4.7 Intermediate bunds may be provided to divide the tankage into groups of a convenientsize so as to contain small spillage and act as firebreaks.

12.4.8 For Class III (1) and Unclassified petroleum stocks spacing of tanks is governed onlyby constructional and operational convenience.Note that the spacing of Class III (1)tankage from Class I, II or III (2) tankage is governed by the latter.

12.5 Sizing of Bunds

12.5.1 Tank bund volumes must comply with the requirements summarised below: 110% of thecapacity of the largest storage vessel located within the bund after deducting the volumeup to top of bund height of all other tanks in the same bunded area. (HSE ref.)

12.5.2 The effective height of the bund used in calculating the capacity of the enclosure shallbe the constructed height less an amount sufficient to allow for future consolidation,settlement and possible erosion of the fill. This “freeboard allowance” shall be:150mmfor 0.6 to 1.2 m effective height225 mm for 1.5 m effective height300 mm for 1.8 m

effective height, plus 50 mm for each 0.3 m of height over 1.8 m.

12.5.3 Bund Walls shall generally be constructed using earth embankments having a crest of600-mm minimum width.

12.5.4 For bunds over 1.2 m in height, stairs should be provided for personnel.

12.5.5 In the event that there is inadequate space for construction of earthen bund walls due torestricted site dimensions, the use of reinforced concrete retaining walls will be

permitted.


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Example 1 Cone Roof Tanks (CR)

Tanks greater than 10 metres diameter Class II and III (2) Storage

Maximum Total Tankage Capacity of Group:

60,000m3 should not be exceeded (HSE ref)

Minimum Bund Capacity:

See Paragraph 9.5

Spacing

„A‟ to suit construction and operating conditions but not less than half tank height.

„B‟ The least of (i) half the diameter of largest tank (ii) diameter of the smaller tank. -Must be minimum of10 metres and need not exceed 15m

„C‟ & „D‟ See Table „2‟.

A

‘B’

‘D’ ‘C’

INSIDE TOPOF BUND

EQUIPMENT/FACILITY REFERENCE LINE. SEE TABLE

‘A’ ‘A’

‘A’ A ‘A’

‘A’ ‘A’

‘B’

‘B’

‘B’ C RC R

C R C R


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Example 2 Floating Roof Tanks (FR) Class I, II and III (2) Storage

Maximum Total Tankage Capacity of Group

120,000m3 should not be exceeded. (HSE ref.)

Minimum Bund Capacity

See Paragraph 9.5. For tanks larger than 60,000m3 not more than 2 tanks in samecompound.

Spacing

„A‟ to suit construction and operating conditions but not less than half of tank height.

„B‟ 10 metres for tanks up to and inc. 45m dia. For tanks above 45m dia., half thediameter of largest tank or the diameter of smaller tank - but not less than15 metres(HSE ref.)



A

‘B’

‘D’ ‘C’

INSIDE TOPOF BUND‘A’ ‘A’

‘A’ A ‘A’

‘A’ ‘A’

‘B’

‘B’

‘B’ F RF R

F R F R


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Example 3 Cone Roof (CR) and Floating Roof (FR) in a Common Bund Class I and II

Maximum Total Tankage Capacity of Group

No of FR Tanks x 60,000 +60, 000m3

No of Tanks in group


See Paragraph 9.5.

Spacing„A‟ Distance equal to not less than ½ height of tank .„B‟ The least of (i) half the diameter of largest tank (ii) diameter of the smaller tank. Mustbe minimum of10 metres and need not exceed 15m



A

‘B’

‘D’ ‘C’

INSIDE TOPOF BUND‘A’ ‘A’

‘A’ A ‘A’

‘A’ ‘A’

‘B’

‘B’

‘B’ F RF R

C R C R


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Example 4 Cone and Floating Roof Tanks not exceeding 10 metres diameter Class Iand II.

Fixed or floating roof tanks not exceeding 10 metres diameter may be grouped togetherup to a total of 8000m3 and treated as one tank if grouped with other tanks. Total overalltank capacity including other tanks in common bund not to exceed 60,000m3 if othertanks are fixed roof type, or 120,000m3 if other tanks are floating roof type.

(HSE ref.)

Spacing

„A‟ to suit construction or operating requirements

„B‟ Half the diameter of larger tank but not less than 10 metres and need not be morethan 15 metres.

GROUP OF TANKSNOT EXEEDING

8000m3 TREATED AS ONE TANK (ref.HSE doc.)

INSIDE TOP OFBUND

OTHER TANKAGE INCOMMON BUND

‘A’

‘A’ ‘A’

‘A’

‘B’

‘B’


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Example 5 Refrigerated Storage (LPG Products at low temperatures) Fixed Roof Tanks(CR) not more than 3 tanks in one compound.

No refrigerated LPG storage tank shall be located within a bund enclosing any othertank. Each refrigerated storage tank shall have an individual bund unless spills can bedirected safely away from adjacent tanks and equipment by means of drainage anddiversion walls (as required) to an impounding basin located within the site boundary.

Double containment storage tanks do not require a bund except for local containment of

leakage from pipework, valves etc.

Total recommended maximum tank capacity for bund not greater than 60,000m3 .


See Paragraph 9.5.

Spacing:„A‟ Minimum 30 metres

„B‟ (Dia. of large tank + dia. of small tank) divided by two.

„C‟ & „D‟ See Table „2‟

‘A’

‘B’ ‘A’

‘A’

‘A’

‘B’ ‘B’

C R C R

‘D’ ‘C’

INSIDE TOP OFBUND

EQUIPMENT/FACILITY REFERENCE LINE. SEE

C R

‘A’


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Example 6 Group of LPG pressure storage vessels (Class „0‟ products) Bullets andSpheres

Notes:

Horizontal LPG tanks with capacities of 45 cu.m or greater shall not be formed intogroups of more than six tanks each. Horizontal vessels used to store LPG should beoriented so that their longitudinal axes do not point towards other containers, processequipment, control rooms loading or unloading facilities, or flammable or combustibleliquid storage facilities located within the vacinity of the horizontal vessel.

Grading of the area under and surrounding the vessels shall direct any leaks or spills toa remote impoundment area. The remote impoundment area shall be located at least 15metres from the vessels draining to it and from any hydrocarbon piping or otherequipment.

Maximum number of vessels in any one group 6. Recommended maximum capacity ofall vessels within one group = 3 times capacity of largest vessel with in the group.

Spacing:

„A‟ = ¼ sum of diameters of 2 adjacent tanks, but not less than 2 metres, for bullets.(Reference IP LPG Vol1. Model Code of Safe Practice, Part 9)

„D‟ See Table „2‟

‘A’ ‘A’

d 1

‘D’

d 2

d 1

‘A’

B

SP

E UIPMENT/ FACILITY REFERENCE LINES. SEE TABLE 2

‘D’

BL BL

SP

d 1

3 m (API 2510)EDGE OF CATCHMENT

AREA


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Example 7 Group of fixed roof refrigerated atmospheric storage tanks containing LNG (Class „O‟ product) - Double Containment Tanks

Single Containment Tanks shall have a bunded [impounding] area. Minimum distancefrom tank to bund not to be less than: height of liquid level +LP gas pressure – bundheight (See NFPA 59A).

Spacing

„A‟ = Minimum distance to give a max. thermal radiation flux = 32 kW/m2 in the event offire (approximately equivalent to 30m).

„D‟ See Table „2‟

‘A’

‘D’

d 1 d 2

EQUIPMENT/FACILITY REFERENCE LINE. SEE TABLE 2


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Table 2 Minimum Tankage Spacing (Dimensions in Metres) (see tankage spacingexamples 1,2,3,4,5,6 &7)

Dimension „C‟ is a dimension from facility/equipment reference line to inside top of tankbund.

Dimension „D‟ is a dimension from facility/equipment reference line to tank shell.

Examples 5,6 &7: Refer to the listed Standards for more detailed spacing requirementsregarding spillage catchment (impounding) areas and drainage. Spacing will need to beconsidered for individual cases.

EXAMPLES1,2,3,4

EXAMPLE 5(note „d‟)

EXAMPLE 6(note ‟e‟)

EXAMPLE7 (note„ f‟)

FACILITY/EQUIPMENT „C‟ „D‟ „C‟ „D‟ „C‟ „D‟ „C‟ „D‟

BOUNDARY FENCE 15 30 30 90 NA 90 NA 100

EQUIPMENT LINE – PROCESS AREA

15 30 30 50 NA 50 NA 50

BUILDINGS 15 30 30 60 NA 60 NA 60

FIXED SOURCE OFIGNITION

15 30 30 60 NA 60 NA 60

HAZARDOUS

FACILITIES(e.g. Jetty, Loading)

15 30 30 90 NA 90 NA 100

PUMP AREAS „a‟ 15 30 50 NA 50 NA 50

TANK SHELL (adjacentgroup)

15 30 30 50 h NA 50 NA 50 h

REFRIG. FIXED ROOFTANKS

15 50 „d‟ 30 NA 30 NA 30

PRESSURE STORAGELPG „b‟

15 NA „c‟ 30 NA 25 NA 30

EDGE OF SITE ROADS 15 30 30 60 NA 60 NA 60

CRITICAL AREAS 15 30 30 90 NA 90 NA 100

Notes:

„a‟ To suit maintenance and operation requirements

„b‟ Assumed fitted with water deluge system.

„c‟ See notes on example 6

„d,„ „e‟ & „f‟: The equipment spacing listed for pressure or refrigerated storage of LPG and


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the refrigerated storage of LNG, within this standard, is for initial layout purposes (seealso notes for examples 5, 6 &7). The detail design spacing will be a function of theallowable thermal radiation flux values (permitted for fire protection) and a hazardous

assessment review. A summary of values and typical distances (in brackets), based ona 10m height above grade from liquid product containment, is as follows:

„d‟ Typical maximum thermal radiation flux values* for refrigerated storage of LPG are:

The outer surfaces of adjacent refrigerated storage vesselsor surfaces thermally protected. =32 kW/m2 (30m)

Outer surface of adjacent storage thermally protected tankscontaining flammable products. =32 kW/m2 (30m)

Unprotected metal surfaces of adjacent storage tanks,pressure vessels and process facilities = 8 kW/m2 (50m)

Protected work area, filling/discharge points = 8 kW/m2 (50m)

Urban areas, work area = 5 kW/m2 (60m)

Critical areas = 1.5 kW/m2 (90 m)

(* Reference IP LPG Vol1. Model Code of Safe Practice, Part 9)

„e‟ Typical maximum thermal radiation flux values for pressure stored LPG are:

The outer surfaces of adjacent pressure storage vessels orsurfaces thermally protected. =44 kW/m2 (25m)

Outer surface of adjacent storage thermally protected tankscontaining flammable products =32 kW/m2 (30m)

Unprotected metal surfaces of adjacent storage tanks,pressure vessels and process facilities = 8 kW/m2 (50m)

Protected work area, filling/discharge points = 8 kW/m2 (50m)

Urban areas = 5 kW/m2 (60m)

Critical areas = 1.5 kW/m2 (90m)

(

Reference IP LPG Vol1. Model Code of Safe Practice, Part 9)

„f‟ Typical maximum thermal radiation flux values for LNG storage are:

Concrete outer surface of adjacent storage tanks orsurfaces behind thermal protection =32 kW/m2 (30m)

Unprotected metal surfaces of adjacent storage tanks,pressure vessels and process facilities =15 kW/m2 (45m)

Control rooms, workshops, laboratories and warehouses = 8 kW/m2 (50m)

Administration building, work area = 5 kW/m2 (60m)

Urban areas = 3 kW/m2 (66m)

Critical areas = 1.5 kW/m2 (100m)

( Reference EN 1473:1997 for LNG storage- distances based upon IP LPG Vol1.Model Code of Safe Practice, Part 9)


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„h‟ Where multiple groups are required, each group shall be separated from unprotectedadjacent groups by a minimum horizontal shell-to-shell distance of 50 metres for heightsup to 10m (increase to 60m for unprotected items above 10m).

General:Where space is limited in tank layout areas, the use of firewalls, thermal protectionscreens, etc. may be considered.

Special spacing is required between the listed items and oxygen and/or gaseoushydrogen storage. Refer to the relevant standard or guide.

Documents

SP12 2YY PI SP 999 029 D2[1] Spacing Creteria