OISD

OISD-STANDARD-118 Amended edition FOR RESTRICTED CIRCULATION

LAYOUTS

FOR

OIL AND GAS INSTALLATIONS

OISD-STANDARD-118 First Revision, July 1995

Amended edition. August 2000

Oil Industry Safety Directorate Government of India

Ministry of Petroleum & Natural Gas

OISD-STANDARD-118 First Revision, July 1995 Amended edition. August 2000 FOR RESTRICTED CIRCULATION

LAYOUTS

FOR

OIL AND GAS INSTALLATIONS

Prepared By :

COMMITTEE ON LAYOUTS

OIL INDUSTRY SAFETY DIRECTORATE 2ND FLOOR, KAILASH

26, KASTURBA GANDHI MARG NEW DELHI-110 001

"OISD hereby Expressly Disclaims any liability or Responsibilities for Loss or Damage Resulting from the use of the OISD Standards/Guidelines."

NOTE OISD publications are prepared for use in the oil and gas industry under Ministry of Petroleum and Natural Gas. These are the property of Ministry of Petroleum & Natural Gas and shall not be reproduced or copied or loaned or exhibited to others without written consent from OISD. Though every effort has been made to assure the accuracy and reliability of the data contained in these documents, OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from their use. These documents are intended only to supplement and not to replace the prevailing statutory requirements.

Note1 in superscript indicates the modification/changes/ addition based on the amendments approved in the 17th Safety Council meeting held in July, 1999.

Note 2 in superscript indicates the modification/changes/addition based on the amendments approved in the 18th Safety Council meeting held in August, 2000.


iii

FOREWORD The Oil Industry in India is over 100 years old. As such various practices have been in vogue because of collaboration/association with different foreign companies and governments. Standardisation in design philosophies and operating and maintenance practices at a national level was hardly in existence. This coupled with feed back from some serious accidents that occurred in the recent past in India and abroad, emphasised the need for the industry to review the existing state-of-the-art in designing, operating and maintaining oil and gas installations. With this in view, the Ministry of Petroleum and Natural Gas in 1986 constituted a Safety Council assisted by the Oil Industry Safety Directorate (OISD) staffed from within the industry for formulating and implementing a series of self regulatory measures aimed at removing obsolescence, standardising and upgrading the existing standards to ensure safer operations. Accordingly, OISD constituted a number of functional committees comprising of experts nominated from the industry to draw up standards and guidelines on various subjects. The experience and knowledge gathered over the years and the various national and international codes and practices are taken into consideration. The first edition of the document on "Layouts for Oil and Gas Installations" was prepared by the Functional Committee and published in November 1988. This document of July 1995 is the first revision prepared by the Functional Committee. This document will be reviewed periodically for improvements based on the experience and better understanding. Suggestions from industry members may be addressed to:

The Coordinator Committee on Layouts

Oil Industry Safety Directorate 2nd Floor, Kailash

26, Kasturba Gandhi Marg New Delhi-110 001


COMMITTEE ON LAYOUTS (First Edition - November 1988)

NAME ORGANISATION Leader

Shri R.P.Bhatla Engineers India Ltd., New Delhi Members

Shri K.K. Arora Oil & Natural Gas Corpn. Ltd., Bombay

Shri S.K. Mukherjee Hindustan Petroleum Corpn. Ltd. (R), Bombay

Shri V.K. Raina Bharat Petroleum Corpn. Ltd. (M), Bombay

Shri K. Ravi Kumar Madras Refineries Ltd., Madras Member Coordinator

Shri B.K. Trehan Oil Industry Safety Directorate, New Delhi

COMMITTEE ON LAYOUTS (First Revision - July 1995)

Leader

Shri R.P. Bhatla/ Engineers India Ltd., New Delhi

Shri M.M. Kapoor

(since February, 1995) Members

Shri S.K. Mukherjee Hindustan Petroleum Corpn. Ltd. (R), Bombay

Shri K.K. Arora Oil & Natural Gas Corpn. Ltd., Bombay

Shri V.K.Raina Bharat Petroleum Corpn. Ltd. (M), Bombay

Shri S. Pandarinathan Madras Refineries Ltd., Madras Member Coordinator

Shri B. Sadhukhan/ Oil Industry Safety Directorate, New Delhi

Shri S.N. Mathur

(since April, 1995) (In addition to the above, several other experts from the industry contributed in the preparation, review and finalisation of this document.)


v

LAYOUTS FOR OIL AND GAS INSTALLATIONS

INDEX

SECTION CONTENTS

1.0 Introduction 2.0 Scope 3.0 Definitions 4.0 Plant Layout Philosophy 5.0 Layout of Blocks/Facilities 5.1 General Considerations 5.2 Inter-distances 6.0 Layout of Process Units 6.1 General Considerations 6.1.1 Process Equipment 6.1.2 Control Room and Sub-Station 6.2 Equipment Spacing within Process Units 7.0 Layout of Storage Tanks 7.1 General Considerations 7.2 Inter-distances between Tanks / Offsite Facilities 8.0 Layout of LPG Facilities 8.1 General Considerations 8.1.1 LPG Storage 8.1.2 LPG Bottling 8.1.3 LPG Bulk Handling 8.2 Inter-distances for LPG Facilities 9.0 Layout of Utility Stations 9.1 General Considerations 9.2 Inter-distances 10.0 References TABLES

1. Inter-distances between Blocks/Facilities 2. Equipment Spacing within Process Units 3. Inter-distances between Storage Tanks/Offsite Facilities (for Small Installations) 4. Inter-distances between Storage Tanks/Offsite Facilites 5. Inter-distances between Storage Tanks 6. Distances from Boundary Fencing 7. Inter-distances for LPG Facilities 8. Inter-distances between LPG Storage Vessels and Boundary/Property Line/ Group of Buildings not associated with LPG plant. ANNEXURE 1 : TYPICAL LAYOUT OF LPG STORAGE VESSELS


LAYOUTS FOR OIL AND GAS INSTALLATIONS

1.0 INTRODUCTION Hydrocarbon processing and handling plants are inherently hazardous. Today's trend of large and complex plants presents substantial risk potential. At times plants are modified to operate at higher capac ities or efficiencies necessitating larger storage requirements than contemplated earlier. For these reasons, initial site analysis for the proposed new construction or addition should be done carefully while considering the space allocation to the various facilities.

The hydrocarbon industry over the years learnt lessons from fires and explosions throughout the world and has been up-dating plant safety norms including inter-distances between facilities and their relative locations. The minimum distances recommended many years ago need review in the context of today's environment in the industry.

It is not intended that requirement of this standard should be applied rigidly to existing premises where for a variety of reasons, it may not be practicable to comply with. This standard will however create awareness and help in selective implementation of the recommen-dations at existing installations. 2.0 SCOPE

This document lays down minimum requirements of layouts within the plant boundary for petroleum refineries, Oil/Gas production and processing plants, LPG filling plants and other petroleum storage installations. The requirement of green belt/buffer zone beyond the plant boundary is outside the scope of this standard. Such provision may be considered based on local environmental/ security requirements. 3.0 DEFINITIONS

(i) PETROLEUM REFINERY

Petroleum Refinery is a plant where crude oil is received and processed into intermediates and finished products.

(ii) OIL/GAS PRODUCTION PLANT

Oil/Gas production plant is a plant where oil and/or gas is collected, stabilised and despatched for further processing. Drilling activities and facilities upstream of the christmas tree of a well are not covered under this definition.

(iii) GAS PROCESSING PLANT

Gas processing plant is a facility where natural gas is received and processed to make gas, LPG, condensate etc.

(iv) LPG FILLING PLANT

LPG filling plant is a plant where liquefied petroleum gas (LPG) is received/despatched by rail, road and pipeline and filled in cylinders.

(v) OTHER PETROLEUM STORAGE INSTALLA-TIONS

Other petroleum storage installations include:

- Crude oil gathering stations

- Coastal storage installations for crude oil and petroleum products

- Marketing depots and terminals

- Aviation storage and fuelling stations

- Pipeline installations/terminals. (vi) FLASH POINT "Flash point" of any petroleum liquid is the

minimum temperature at which the liquid yields vapour in sufficient concentration to form an ignit-able mixture with air and gives a momentary flash on application of a small pilot flame under speci-fied conditions of test as per IS:1448 (Part-I).

(vii) GENERAL CLASSIFICATION OF PETROLEUM

PRODUCTS Petroleum products are classified according to

their closed cup FLASH POINTS as follows:

Class "A" Petroleum: Liquids which have flash point below 23 oC.

Class "B" Petroleum: Liquids which have flash point of 23 oC

and above but below 65 oC.

Class "C" Petroleum: Liquids which have flash point of 65 oC

and above but below 93 oC.

Excluded Petroleum: Liquids which have flash point of 93 oC

and above. Liquefied gases including LPG, do not fall under

this classification but form separate category.

OISD-STD-118 Revision -II


3

In the following cases, above classification do not

apply and special precautions should be taken as required:

(a) Where ambient temperatures or the handling temperatures are higher than the flash point of the product.

(b) Where product handled is artificially heated to a temperature above its flash point.

(viii) TANK HEIGHT

Tank height is the:

- Height from tank bottom to top kerb angle for cone roof tanks

- Height from tank bottom to top of tank shell for floating roof tanks

(ix) STABLING LINE

It is an additional railway line/spur reserved for additional rake/stabling.

4.0 PLANT LAYOUT PHILOSOPHY A petroleum installation may be broadly considered as a group of one or more of the following units/facilities:

- Crude oil storage

- Intermediate and finished product storage

- LPG storage and handling facilities

- Process units and control room

- Product loading/unloading facilities (Rail, Road and Pipelines)

- Utilities generation and distribution centers

- Blow down and flare system

- Waste water treatment facilities

- Administrative and service buildings (ware-house, workshop, canteen, fire station, laboratory, first aid, parking lot etc.)

Following points shall be kept in mind while developing overall plant layout of any installation.

(i) BASIC INFORMATION (a) Information on following items should be

collected before proceeding with the development of overall plot plan:

- Process units and their capacities

- Process flow diagram indicating flow sequence

- Utility requirements

- Storage tanks list

- LPG storage vessels and their sizes

- Product despatch and mode of transport (rail, road and pipeline)

- Warehouses, open storage areas

- Number of flares

- Operating and maintenance philosophy for grouping of utilities

- Plant and non-plant buildings

- Environmental considerations

- Scrap yards and dumping ground

- Fire station and fire training ground

- Chemical/Toxic Chemical storage

- Storage areas for solid products such as petroleum coke, petroleum wax, coal, bitumen and asphalt

(b) Data on following infrastructural facilities

should be collected before detailed layout activity is taken up and due consideration should be given for the same while deciding plant layout:

- Site location map

- Prevailing wind direction

- Area topography contour map

- High flood level in the area

- Source of water supply and likely entry point

- Electric supply source and direction of entry point

- Crude oil entry point

- Storm water disposal point and effluent disposal point

- Railway entry point and marshalling yard location

- Approach roads to main plant areas

- Inward/outward product movement by rail/ road and pipelines.

- Surrounding risks (ii) BLOCKS

(a) In any process installation, it is recommen-ded that plant layout arrangement should follow the general route of raw material to process unit (s) with tankages interposed as required followed by despatch facilities.

4 OISD-STD-118 Revision - II


(b) Block layout should be adopted as much as possible. The entire area should be sub-divided into blocks. Maximum size of a block should be established based on tank farm layouts.

(iii) ROADS

(a) All process units and dyked enclosures of storage tanks shall be planned in separate blocks with roads all around for access and safety. Primary traffic roads in the installation should be clear of hazardous classified areas. Roads separating the blocks shall provide fire breaks and have facilities for fire fighting activities.

(b) Alternative access should be provided for each facility so that it can be approached for fire fighting/maintenance/construction in the event of blockage on one route.

(c) Road widths and turning radii at road junctions shall be designed to facilitate movement of the largest fire fighting vehicle in the event of emergency.

(d) Rail spur shall be located close to the periphery of the plant to minimise road crossings and blockage of roads during shunting.

(e) Layout of the facilities shall be made to minimise truck traffic ingress in the plant.

(f) Two road approaches from the highway should be provided, one for employees and other for product movement. Both these approaches should be available for receipt of assistance in emergency. However, for smaller installations, this requirement may be relaxed if not feasible.

(iv) LOCATION

(a) Process unit(s) should be located on high ground to avoid flooding.

(b) Presence of ignition source shall always be contemplated beyond the boundary wall of the installation.

(c) Orientation of flares,furnaces/heaters, dusty operations (e.g. sulphur handling) and cooling towers should be decided based on prevailing wind direction.

(V) ERECTION AND MAINTENANCE

(a) Erection methods shall be anticipated for all types of equipments. Towers, reactors and

fired equipments should be located away from congested areas to facilitate erection at any stage.

(b) Maintenance methods for each type of equipment shall be identified in advance since these affect the requirements for layout. Equipment requiring frequent atten-tion shall have easy accessibility. For equip-ments having removable parts, wherever possible, arrangements shall be made to facilitate their removal without dismantling long lengths of piping. Free access shall be provided for hoisting the equipment.

(vi) FUTURE EXPANSION

Future expansion shall be assessed and space provision for known and unforeseen needs shall be made. Orderly future expansion shall be affected by providing space adjacent to similar type of facilities for expansion. Extension of pipe sleepers and pipe way, road crossings for yard piping shall be given due consideration. Care shall be taken to facilitate future expansion without any interferene to plant on-stream.

5.0. LAYOUT OF BLOCKS/FACILITIES

An installation may consist of one or more of the following basic blocks/facilities:

- Storage tanks/offsites - LPG storage and filling facilities - Process units - Utilities and effluent disposal facilities 5.1 GENERAL CONSIDERATIONS

While locating the above blocks/facilities and further sub blocks/facilities within them, following items should be considered :

(i) Layout planning should be in sequential order of process flow.

(ii) Orientation should be to suit wind direction to avoid travel of hydrocarbon vapour over sources of ignition.

(iii) Process units should be centrally located with straight approach from main gate. Orientation of process units should follow process flow in sequential order so that piping runs are also minimum.

Location of tall columns and furnaces should be

close to road side for ease of construction and maintenance.

OISD-STD-118 Revision -II


5

(iv) Storage tanks should be grouped according to product classification. In undulating areas, storage tanks should be located at lower elevations.

(v) Utility blocks should be located adjacent to unit

blocks. (vi) Main power receiving station should be close to

the fence line with minimum overhead power transmission lines passing through the installa-tion.

Overhead power transmission lines shall not pass

over process units, storage tanks, offsite and utility areas. Wherever these lines are passing through plant premises adequate safety distances shall be kept.

(vii) H T sub-station should be located close to major

load centres. One or more sub-stations could be provided to limit distances.

(viii) L T sub-station should generally be located at

load centres in such a way that the distance between distribution transformer and farthest motor is minimum.

(ix) Gas/Oil based power plants should be located

close to process units/utility blocks and closer to Main Receiving Station, as far as possible. Coal based power plants should be located away from criticalfacilities like air separation plants, electri-cal installations etc. to avoid problems due to coal dust and ash.

(x) Flare should be located upwind of process units.

Height of flare and its distance from operating facilities shall be decided based on heat radiation considerations and other considerations like ground level concentration, cold venting etc.

Area around flare should be paved to avoid

growth of grass/vegetation which can otherwise provide combustible material for fires. (Ref. section 8.0 of OISD-STD-106 on "Process Design and Operating Philosophies on Relief and Disposal systems").

(xi) Truck loading facilities should be located close to

product movement gate. Rail loading facilities should suit rail siding layout and preferably be located along periphery of the installation.

(xii) Effluent Treatment Plants should be located

minimum one block away from unit area, down wind of process units and important areas to avoid odour problems. They should be closer to

disposal point and at lower grade to facilitate gravity flow of effluent.

(xiii) Sulphur recovery unit and sulphur loading area

should be located close to product movement gate and away from hazardous and populated areas. A minimum distance of 50m is recommen-ded between sulphur storage/handling and any building or boundary wall.

(xiv) Petroleum coke/coal storage and handling

facilities should be located as far as possible away from process units, air separation plants, populated and hazardous areas.

(xv) Sufficient open areas should be left where

construction activities can be undertaken. Requirements for erecting tall structures should be studied before finalising the layout.

(xvi) Fire station should be located close to main entry

gate with straight approach to process units/other critical areas. Fire station and fire water pump house shall be located at a safe place away from hazardous areas. Fire station includes fire tenders, foam equipments and fire fighting accessories.

(xvii) Fire water storage and pumps shall be located at

a minimum distance of 60 m from hydrocarbon storage and process units. However for petroleum depots and terminals, it shall be as per clause 4.3.5(V) of OISD-STD-117.

5.2 INTERDISTANCES Interdistances between various blocks/facilities described above shall be as per Table-1.



TABLE - 1 (NOTE1)

MINIMUM INTERDISTANCES BETWEEN BLOCKS/FACILITIES

S.No. From \ To 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

1. Process Units 36 *** 30 45 30 60 90 150 45 60 45 30 60 60 30 90

2. Process Control *** - ** 45 30 60 90 150 45 30 30 - 30 15 30 30 Room

3. Storage Tank 30 ** T3 & T3 & T3 & 30 90 150 30 60 90 30 T6 60 30 50 Class A T5 T5 T5

4. Storage Tank 45 45 T3 & T3 & T3 & 30 90 150 30 60 90 30 T6 30 30 50 Class B T5 T5 T5

5. Storage Tank 30 30 T3 & T3 & T3 & 30 90 150 30 60 90 30 T6 30 30 50 Class C T5 T5 T5

6. Storage Vessels 60 60 30 30 30 T7 90 150 30 90 90 30 T8 45 30 60 (Pressure) LPG/Other

7. Flares-elevated 90 90 90 90 90 90 90 150 90 90 90 90 90 90 90 90

8. Flares-ground 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150 150

9. Bulk loading racks 45 45 30 30 30 30 90 150 T7 90/60 30 T7 T6/T760 30 50 (rail/road) LPG/POL

10. Fire stations/ 60 30 60 60 60 90 90 150 90/60 - 30 30 12 12 30 90 First aid centre

Contd...

OISD-STD-118 Revision - II


7

TABLE - 1 (Contd..)

S.No. From \ To 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

11. Boiler House/ 45 30 90 90 90 90 90 150 30 30 - 15 50 30 30 90 heaters 12. Rail spur 30 - 30 30 30 30 90 150 T7 30 15 - 30 6 15 50 13. Boundary fence 60 30 T6 T6 T6 T8 90 150 T6/T7 12 50 30 - 6 30 50 around installation 14. Service buildings 60 15 60 30 30 45 90 150 60 12 30 6 6 - 30 50 15. Cooling towers, 30 30 30 30 30 30 90 150 30 30 30 15 30 30 - 15 water storage, nitrogen plant 16. API Separators/ 90 30 50 50 50 60 90 150 50 90 90 50 50 50 15 - oil sludge pit

** Distance will be 30 meters in case Control Room is blast proof and 60 meters in case it is not blast proof. *** Refer OISD-STD-163 on Process Control Room Safety Notes : 1. All distances are in metres.

2. All distances shall be measured between the nearest points on the perimeter of each facility except in case of tank vehicle loading/unloading area where the distance shall be measured from the centre of each bay.

3. "T" indicates the table to be referred.

4. Where distances have not been specified, it shall be decided based on construction,operation & maintenance requirements.

5. API/CPI, open oil separators/oil collection sumps shall be categorised under the same risk and shall be located at 90m distance from heaters/boilers. However, if these are covered from top and provided with adequate venting to safe location, the minimum safe distance can be reduced from 90m to 30m.

6. Distance between bulk loading racks and fire station shall be : (i) For LPG Gantry - 90 m &



ii) For POL Gantry - 60 m.

7. Definitions :

Process Unit - a unit having integrated sequence of operation , physical and chemical, and may involve preparation, separation, purification, or change in state, energy content or composition. Service building a building housing facilities for inspection/maintenance/other supporting services which are directly required for operation of the plant. Fire station a building housing facilities of parking fire tenders and keeping other ready to use fire fighting equipment for meeting plant emergencies, fire control room with required communication facilities/mimic panel.

Fire pump house a building housing main fire water pumps, jockey pumps, communication and alarm system, instrumentation and the required operating & supporting personnel.



9

6.0 LAYOUT OF PROCESS UNITS 6.1 GENERAL CONSIDERATIONS 6.1.1 PROCESS EQUIPMENT

(i) Process flow sequence and operating procedures shall be thoroughly understood so that equipment arrangement in the plot plan is functional. Equipment shall be arranged in logistic process sequence for short piping runs and operational ease.

(ii) It is recommended that the unit pipe rack be kept in the centre, thereby splitting the unit into two or more areas of equipments.Pumps may be arranged in two rows close to and on either side of the central pipe rack. Heat Exchangers and vessels should be grouped together forming outer rows on both sides of the rack. Fired heaters should be kept at open end of the unit upwind from the remaining plant equipments.

(iii) Spacing between battery limits of individual pieces of equipment shall be adequate for undertaking maintenance jobs.

(iv) Spacing between two process units in a complex should be decided based on shut down philosophy for maintenance of the units. If the shut down of the units are expected at different occasions, then inter distances may be increased.This will facilitate ease in maintenance and minimise risk from/for operating units due to hot jobs in the units under shut down.

(v) Heat exchangers should be located perpendicular to the pipe rack on the outer row to facilitate pulling of tube bundles with mobile crane or by other means.Shell and tube heat exchanger should have a longitudinal clearance of at least one metre plus the length of removable bundles.

(vi) Air fin coolers should be installed above the pipe rack. Pumps handling hydro-carbons and materials above the temperature of 230 degree C should not be installed underneath the air fin coolers.

(vii) Cold boxes should be located on grade or on separate elevated structures. Adequate space should be provided around cold boxes for ease of operation and maintenance.

(viii) Vessels having large liquid hold-up should be installed at lower heights and preferably at grade. Adequate drainage should be provided around such vessels. Where process requirement dictates their installa-tion above grade, these should be located in open area.

(ix) Towers/columns should be located along the pipe rack towards open areas for unobstructed erection as well as maintenance of internals at grade. Tall towers require frequent operating attention at upper levels. Hence they may be located at one place so that common connecting platform can be provided.

(x) Thermo-siphon reboilers should preferably be placed close to their associated towers. Reboiler should be mounted on the tower so that vertical expansion will be uniform, piping system design is simplified and inlet/outlet piping is minimised. Clearance shall be provided for movement between reboiler and tower.

(xi) Gas compressors should be located down wind from heaters so that leaked gases will not drift towards the heater. Gas compressors should have roofing and open from sides to avoid accumulation of heavier vapours/gases on the floor of compressor house. Compressor house should be located near the battery limits to facilitate ease in maintenance and operation.

(xii) Heaters should be located up wind at one corner of the unit. Space should be provided for removal and cleaning of heater tubes besides approach for crane. Areas around the heaters shall be graded for guiding spills away from process equipment. FD fans shall be located away from process equipment from where they arelikely to suck hydrocarbon vapours.

The local control panel for soot blower control and flue gas analyser shall only be located on and near the process heater. The rest of controls shall be taken to central control room.

(xiii) No other tankage except day tanks shall be

provided within battery limits of any process unit.

(xiv) Flare knock out drum of the closed blow

down system should be located at battery limit of the unit.



(xv) Blow down facilities/burried drum shall be

located at one corner of the plant farthest from furnace or any fired equipment and on the lee-ward side of the unit.

Vent from Blow down facility shall be

minimum 6m clear off the air fin coolers. It shall be minimum 6m above the highest platform if horizontal distance of 15m from process equipment is not possible.

6.1.2 CONTROL ROOM AND SUB-STATION

(i) Control room should be located distinctly in the process block or in the adjoining block. It should be at a safe distance where protection to instruments and personnel is ensured and non-hazardous electrical area classification is permitted. It should have alternate means of exit with doors opening towards outside. Doors should be made of fire proof material.

(ii) Control room should be designed to cater

for minimum occupancy.

(iii) Transformers should be located in open area on the rear side of sub-station.Each transformer shall be isolated from the other by a brick masonary wall. Approach road to sub-station and transformer bays should be provided to facilitate crane movement for erection and maintenance.

(iv) Electrical sub-station should be located

adjacent to the control room building and should meet the requirements of electrical area classification.

6.2 EQUIPMENT SPACING WITHIN PROCESS

UNITS Interdistances betweenvarious equipments in

process units shall be as per Table-2.



11

TABLE-2

MINIMUM INTERDISTANCES BETWEEN EQUIPMENTS WITHIN PROCESS UNIT This table could be used by the oil companies as a guideline for their projects. These could be suitably modified as required to suit space constraints and relevant engineering practices. NOTE 1

S.No. From \ To 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

1. Fired heaters/ - 15 15 15 22.5 15 15 20 15 15 15 16/30 15 - 18 15 6 30 15 15 any fired equip.

2. Reactors 15 2 2 6 8 7 15 7 7 4 3 16 - 15 5 15 3 15 15 3

3. Distillation 15 2 3 4 7.5 5 15 5 5 2 3 20 - 15 3 15 3 15 15 3 columns

4. Accumulators 15 6 4 2 8 5 15 4 4 2 3 20 - 15 3 15 3 15 15 3 (Hydrocarbon)

5. Gas compressors 22.5 8 7.5 8 3 7.5 15 7.5 7.5 7.5 7.5 16 - 15 4 15 3 20 15 7.5 (Hydrocarbon)

6. Hot oil transfer 15 7 5 5 7.5 1 7.5 1 1 1 2 2 16 - 15 3 15 - 15 15 - pumps

7. Fuel Oil Day tank 15 15 15 15 15 7.5 2 15 15 15 15 16 - 15 15 15 - 15 15 15

8. Pump for Class A & 20 7 5 4 7.5 1 15 1 1 2 2 16 - 15 3 15 - 15 15 - all products above auto-ignition temp.

9. Pumps - other 15 7 5 4 7.5 1 15 1 1 2 2 16 - 15 3 15 - 15 15 - Hydrocarbon

10. Heat Exchanger- 15 4 2 2 7.5 2 15 2 2 2 2 16 - 15 2 15 2 15 15 - Hydrocarbon

11. Air Fin Coolers- 15 3 3 3 7.5 2 15 2 2 2 - 16 - 15 2 15 - 15 15 2 Hydrocarbon

12. Control room 16/30 16 20 20 16 16 16 16 16 16 16 - 16 20 16 - 16 16 5 16

13. Snuffing/purging 15 - - - - - - - - - - 16 - - 2 - - 15 5 - steam isolation valve

14. Fired heaters - 15 15 15 15 15 15 15 15 15 15 20 - - 10 15 - 15 15 5 control panel (local) Contd....



TABLE - 2 (Contd...)

S.No. From \ To 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 15. Pressure Vessel/ 18 5 3 3 4 3 15 3 3 2 2 16 2 10 2 15 3 15 15 2 Drums (Hydrocarbon)

16. Fire water 15 15 15 15 15 15 15 15 15 15 15 - - 15 15 - 15 15 - - hydrants/monitors

17. Pipe rack (main) 6 3 3 3 3 - - - - 2 - 16 - - 3 15 - 15 15 -

18. Blow down facility 30 15 15 15 20 15 15 15 15 15 15 16 15 15 15 15 15 - 15 15 (pumps, drums, stacks)

19. Water spray 15 15 15 15 15 15 15 15 15 15 15 5 5 15 15 - 15 15 - - Deluge valve

20. Structural main 15 3 3 3 7.5 - 15 - - - 2 16 - 5 2 - - 15 - - (Technological platforms) Notes: 1. All distances are face to face clear minimum distances in meters. 2. Distance between equipments not covered herein & equipments handling non-hydrocarbons shall be as per good engineering practices. 3. From control room to heater, safe distance shall be 16m if the control room is for one unit and shall be 30m, if it is for two units. For gas

processing plants, it shall be 30m irrespective of whether the control room is for one or more units. 4. Distances between the reactor and furnace when directly connected process-wise, can be relaxed to 5m. 5. Only distances indicated from fired heaters (1) Fuel oil day tank (7), Control room (12), Fired heater local control panel (14), Fire water

hydrant/monitor (16), Blow down facility (18) and water spray deluge valve (19) are by safety considerations. Other distances indicated are recommended from erection, operation and maintenance safe guards.

6. The local control panel meant for soot blower control & fuel gas analyser shall only be located on and near the process firedheater. The rest of controls shall be taken to central control room.

7. Safety distances as per preceeding Table-2 for blow down facilities are for open pit location. If the blow down drum is located underground, the distance from fired heater shall be reduced from 30m to 15m.

8. Steam snuffing/purging valve shall be located minimum 15m from only those equipments which are served bythe steam valve. 9. Fuel Oil day tanks shall be located at a safe distance of 15m from equipment except those facilities such as heat exchanger, pump connected

directly with the Fuel Oil system. (Refer Table-5 for interdistance between tanks). 10. Distance between fired heater and distillation column shall be increased to 22.5m in case of light ends such as Naphtha stabiliser. 11. Minimum distances between equipment shall not be applicable for package items and their related appertenances.



13

7.0 LAYOUT OF STORAGE TANKS 7.1 GENERAL CONSIDERATIONS (i) DYKED ENCLOSURES

(a) Petroleum storage tanks shall be located in dyked enclosures with roads all around the enclosure. Aggregate capacity of tanks located in one dyked enclosure shall not exceed following values :

For a group of floating roof tanks : 120,000 cu.m. For a group of fixed roof tanks : 60,000 cu.m. If a group of tanks contains both fixed and

floating roof tanks, thenit shall be treated as a group of fixed roof tanks for the purpose of above limits.

(b) Dyked enclosure should be able to contain

the complete contents of the largest tank in the tank farm in case of any emergency. Enclosure capacity shall be calculated after deducting the volume of tanks (other than the largest tank) upto the height of the enclosure. A free board of 200 mm above the calculated liquid level shall be considered for fixing the height of the dyke.

However, for excluded petroleum, the

capacity of the dyked enclosure should be based on spill containment but not for containment on tank rupture.

(c) The height of tank enclosure dyke shall be

at least one metre and shall not be more than 2.0 m above average grade level inside. However, for excluded Petroleum, the minimum height of dyke wall shall be 600 mm.

(d) Interdistance between the nearest tanks

located in two dykes shall be equivalent to the largest tank diameter or 30m, which-ever is more.

(e) The tank or tanks shall be supported on

well designed foundations and shall be either buried underground or installed in the open and surrounded by wall or embankment not more than two meter high and made of earth, concrete or solid masonry capable of withstanding fully hydrostatic load. Earth wall of over 1 meter

high shall have not less than 0.6 meter wide flat section on top. Note 2

(f) Pump stations should be located outside dyke areas by the side of roads.

(g) Tanks located overhead for process

considerations shall meet safety distance and shall also have dyked enclosure of RCC construction and provided with drain valves at suitable height for easy operation.

(ii) GROUPING

(a) Grouping of petoleum products for storage

shall be based on the product classifi-cation. Class "A" and/or class "B" petro-leum can be stored in the same dyked enclosure. Class "C" petroleum should preferably be stored in separate enclosure. However, where class "C" petroleum is stored in a common dyke along with class "A" and/or class "B" petroleum, all safety stipulations applicable for class "A" and/ or class "B" respectively shall apply.

(b) Excluded petroleum shall be stored in a

separate dyked enclosure and shall not be stored along with class A, B or C petroleum.

(c) Tanks shall be arranged in maximum two

rows so that each tank is approachable from the road surrounding the enclosure. However, tanks having 50,000 cu.m capacity and above shall be laid in single row.

(iii) FIRE WALLS In a dyked enclosure where more than one tank is

located, fire walls of 600mm should be provided as explained below: (a) Any tank having a diameter more than 30m

should be separated with fire walls from other tank.

(b) Fire walls should be provided by limiting

the aggregate capacity of each group of tanks within, to 20,000 cu.m.

(iv) GENERAL

(a) The tank height shall not exceed one and half times the diameter of the tank or 20m whichever is less.



(b) Piping from/to any tank located in a single dyked enclosure should not pass through any other dyked enclosure. Piping connected to tanks should run directly to outside of dyke to the extent possible to minimise piping within the enclosures.

(c) No fire water/foam ring main shall pass

through dyked enclosure. (d) The minimum distance between a tank

shell and the inside toe of the dyke wall shall not be less than one half the height of the tank.

7.2 INTERDISTANCES BETWEEN TANKS / OFF-

SITE FACILITIES The following stipulations shall apply for the inter distances for above ground tanks storing petroleum:

(i) Inter distances shall be as given in Table-3 for tanks storing class "C" petroleum; or

class "A" and "B" petroleum products with total storage capacity not exceeding 5000 cu.m at one installation.

(ii) Inter distances shall be as given in Table-4

for tanks storing class "A" and class "B" petroleum products with total storage capacity exceeding 5000 cu.m

(iii) Interdistances between tanks and fencing

shall be as given in Table-6 for tanks storing Class "A", Class "B" and Class "C" petroleum products with total storage capacity of class "A" and class "B" petroleum stored exceeding 5000 cu.m

(iv) Interdistances between tanks storing

excluded petroleum will not be governed by Table-3 and 4 and should be decided on construction, operation and maintenance requirements.



15

TABLE - 3 (NOTE1)

INTERDISTANCES BETWEEN TANKS/OFFSITE FACILITIES (For small installations)

S.No. From \ To 1 2 3 4 5 6 7 8 9 10 11 12 13

1. Storage tank for 0.5 D 0.5 D 0.5 D 9 9 9 15 15 15 3 15 15 15 petroleum class A or 6 or 6

2. Storage tank for 0.5 D 0.5 D 0.5 D 9 0.5 D 0.5 D 9 4.5 4.5 3 4.5 D D petroleum class B or 6 or 6 min.4.5 min.4.5

3. Storage tank for 0.5 D 0.5 D - 9 0.5 D - 9 4.5 - - - 0.5 D 0.5 D petroleum class C or 6 or 6 min.3 min.3

4. Storage / filling shed 9 9 9 - 4.5 6 9 9 9 3 9 9 9 for petroleum class A

5. Storage / filling shed 9 0.5 D 0.5 D 4.5 - 1.5 9 4.5 4.5 1.5 4.5 4.5 4.5 for petroleum class B

6. Storage / filling shed 9 0.5 D - 6 1.5 - 9 4.5 - - - 3 3 for petroleum class C

7. Tank vehicle loading / 15 9 9 9 9 9 - 9 9 3 9 9 9 unloading area for petroleum class A

8. Tank vehicle loading/ 15 4.5 4.5 9 4.5 4.5 9 - 4.5 1.5 4.5 4.5 4.5 unloading area for petroleum class B

9. Tank vehicle loading/ 15 4.5 - 9 4.5 - 9 4.5 - - - 3 3 unloading area for petroleum class C

10. Flame-proof electric 3 3 - 3 1.5 - 3 1.5 - - 3 - - motors

Contd...



TABLE - 3 (Contd...)

S.No. From \ To 1 2 3 4 5 6 7 8 9 10 11 12 13

11. Non-flameproof 15 4.5 - 9 4.5 - 9 4.5 - 3 - - - electric motors

12. Office building, stores, 15 D 0.5 D 9 4.5 3 9 4.5 3 - - - - amenities etc. within min. 4.5 min. 3 installation

13. Boundary fencing 15 D 0.5 D 9 4.5 3 9 4.5 3 - - - - around installation min. 4.5 min. 3

Notes: 1. All distances are in metres.

2. Above table is applicable for installations where

i) Only petroleum class C is stored.

ii) The total quantity of petroleum class A and class B stored above ground in bulk does not exceed 5000 cu.m.

iii) The diameter of any tank storing petroleum class A or petroleum class B does not exceed 9m.

3. Interdistances given for tanks are shell to shell in the same dyke.

4. All distances shall be measured between the nearest point on the perimeter of each facility except in the case of tank vehicle loading/unloading area where the distance shall be measured from the centre of each bay.

5. Where alternate distances are stipulated, maximum thereof shall be observed.

6. Notation :

"D" diameter of the tank

(-) a distance suitable for constructional and operational convenience.



17

TABLE - 4

INTERDISTANCES BETWEEN STORAGE TANKS/OFFSITE FACILITIES

S.No. From \ To 1 2 3 4 5 6 7 8 9

1. Storage tank for petroleum T5 T5 T5 15 15 15 15 8 15 class A

2. Storage tank for petroleum T5 T5 T5 15 15 15 15 8 15 class B

3. Storage tank for petroleum T5 T5 T5 15 - 8 - - - class C

4. Storage / filling shed for 15 15 15 - 8 15 15 8 15 petroleum class A or class B

5. Storage/filling shed for 15 15 - 8 - 8 - - - petroleum class C

6. Tank vehicle loading/ 15 15 8 15 8 - - 8 15 unloading area for petroleum class A or B

7. Tank vehicle loading/ 15 15 - 15 - - - - - unloading area for petroleum class C

8. Flame proof electric pump 8 8 - 8 - 8 - - 8 motor

9. Non-flame proof electric 15 15 - 15 - 15 - 8 - pump motor

Notes : 1. All distances are in metres.

2. Above table is applicable for installations where total quantity of petroleum class A and class B stored above ground in bulk exceeds 5000 cu.m or where the diameter of any such tank for the storage of petroleum exceeds 9 m.

3. All distances shall be measured between the nearest points on the perimeter of each facility except in the case of tank vehicle loading/unloading area where the distance shall be measured from the centre of each bay.

4. Notation:

(-) any distance suitable for constructional or operational convenience.

T5 Table-5 shall be referred.

5. This table is applicable for class C petroleum storage also alongwith class A & B petroleum as per limits specified under note-2 above.



TABLE - 5

INTERDISTANCES BETWEEN STORAGE TANKS

Sl. Item Floating Roof Fixed Roof Class C No. Tanks Tanks (Class Petroleum A & B Petroleum 1. All tanks with diameters (D + D) / 4 (D + d) / 4 (D + d) / 6 upto 50 metres 2. All tanks with diameters (D + d) / 4 (D + d) / 3 (D + d) / 4 exceeding 50 metres

Notes :

1. This table is applicable for installations where aggregate storage capacity of class A and class B

petroleum stored above grade exceeds 5000 cu.m. or where the diameter of any such tank for the storage of petroleum exceeds 9 m.

2. Distances given are shell to shell in the same dyke. 3. Notation: D diameter of larger tank in metres d diameter of smaller tank in metres 4. If the interdistance (for class A & B) calculated as above are less than 15m,then minimum of 15m or 0.5

D or d shall be followed. 5. Interdistance between class A/B storage tanks and classC storage tanks shall not be less than 6 metres.



19

TABLE - 6 (NOTE1)

DISTANCES FROM BOUNDARY FENCING

Minimum Distance from Boundary S.No. Installation fencing around Installation

1. Storage tank for Pet roleum Class A ** 2. Storage tank for Petroleum Class B ** 3. Storage tank for Petroleum Class C ** 4. Storage/filling shed for Petroleum 15 Class A or Class B 5. Storage/filling shed for Petroleum 10 Class C 6. Tank vehicle loading/unloading area 20 for class A & B petroleum 7. Tank vehicle loading/unloading area 10 for class C petroleum

Notes :

1. All distances are in metres. 2. This table is applicable for facilities in an installation where total quantity of petroleum class A & B stored

above ground in bulk exceeds 5000 cu.m. or where the diameter of any such tank for the storage of petroleum exceeds 9 m.

3. Notation: "D" diameter of larger tank in metres. 4. Above table is based on the assumption that property beyond the boundary line is either protected or

adequate green belt is provided as a safety buffer where no structure exists. Property beyond property line is deemed protected if it is within the jurisdiction of public Fire Brigade or plant's own Fire Brigade.

** (I) Distance from Floating roof tank to boundary fencing for stable and boil-over liquids, having

protection for exposure shall be D/2 (minimum 20m).

(ii) For tanks with weak roof-to-shell joint :

The above distance shall be D/2 (minimum 20m) for tanks having approved foam or inerting system and the tank diameter not exceeding 50m.



8.0 LAYOUT OF LPG FACILITIES

8.1 GENERAL CONSIDERATIONS

8.1.1 LPG STORAGE (i) GROUPING Vessels shall be arranged into groups each

having a maximum of six vessels. Capacity of each group shall be limited to 15000 cu.m. Each group shall be provided with a curb wall.

Any vessel in one group shall be separated from

a vessel in another group by a minimum distance of 30m.

Spheres and bullets shall be treated as separate

groups with 30m safety distance between two groups. Separate dedicated manifold shall be provided for each group.

ii) LOCATION (a) Longitudinal axes of horizontal vessels

(Bullets) should not point towards other vessels, vital process equipments and control room.

(b) Storage vessels should be located down

wind of process units, important buildings and facilities.

(c) LPG storage vessels shall not be located

within the same dykes where other flammable liquid hydrocarbons are stored.

(d) Storage vessels shall be laid out in single

row both in case of the spheres and bullets. Storage vessels shall not be stacked one above the other.

(iii) SPILLS AND LEAKS (a) Spillage collection shallow sump shall be

located at a distance where the flames from sump fire will not impinge on the vessel. This distance shall not be less than the diameter of the nearest vessel or 15m whichever is higher. The capacity of the collection sump shall be as per drawing enclosed at Annexure-1. However in case of one sphere, the sump size shall be equal to layout of two spheres.

(b) Curb wall around the storage tank shall have a minimum height of 30cm. However

it shall not exceed 60cm at shallow sump position, as otherwise evaporation of spilled LPG may get affected.

(c) There shall not be any depressions, large

ditches and low lying areas around LPG storage as the leaked gas can accumulate, being heavier than air. Top surface of the vessels installed in a group should be on the same plane so that safety blowout from one vessel does not affect the other vessel. This will also minimise the chances of overfilling of adjoining vessels due to gravitation.

(d) A typical layout plan of LPG sphere area

with major safety requirements of distan-ces, drainage sump, pump station location etc. is enclosed at Annexure-1 for general guidance.

8.1.2 LPG BOTTLING (i) LOCATION LPG bottling facilities should be located at a safe

distance from other facilities with minimum ingress to trucking traffic and downwind to storage as far as possible.

There shall not be any deep ditches in the

surrounding area to avoid LPG settling. (ii) CONSTRUCTION Bottling section shall be of single storey having

roofing and open from sides for adequate ventilation so that leaked gas can drift away. RCC roofing should not be used to the extent possible.

(iii) OPERATION (a) Stacking areas for empty and filled

cylinders should be located separately. Cylinders shall be stacked vertically. Filling machines and testing facilities shall be organised in sequential manner distinctly in a separate area.

(b) Filled LPG cylinders shall not be stored in

the vicinity of cylinders containing other gases or hazardous substances.

(c) Storage shall be kept on or above grade and never below grade in cellar or basement.



21

(d) Trucking traffic shall be smooth to avoid blocking/ obstruction for loading and unloading of cylinders.

8.1.3 LPG BULK HANDLING (i) LOCATION (a) LPG truck loading/unloading station shall

be located in a separate block and shall not be grouped with other products.

Maximum number of LPG tank lorry bays

shall be restricted to 8 in one group. The bay should be designed in such a way that the driver's cabin will be facing the exit direction and shall have no obstruction.

(b) LPG rail loading/unloading station shall be

located on a separate rail spur and shall not be grouped with other products.

(c) LPG loading/unloading rail gantries shall be

separated from other rail shunting facilities by a minimum distance of 50m, except relating to service for the same gantry.

(ii) Rail loading/unloading of LPG should be restricted

to a maximum of half rake, presently capacity of which is 500 MT. If full rake loading/unloading is envisaged, this shall be done on two separate rail gantries having a minimum distance of 50m. In case of 8 wheeler wagons half rake unloading/ loading capacity shall be 600 MT.

8.2 INTERDISTANCES FOR LPG FACILITIES Interdistances for LPG facilities shall be as given

in Table-7.



TABLE - 7

INTERDISTANCES FOR LPG FACILITIES

S.No. From \ To 1 2 3 4 5 6 7

1. LPG Storage vessels * T8 30 30 30 15 60 2. Boundary/property line/ T8 - 30 30 30 30 ** group of buildings, not associated with LPG plant 3. Shed-LPG/Cold repair shed/ 30 30 15 30 30 15 60 cylinder evacuation facilities 4. Tank Wagon Gantry 30 30 30 50 50 30 60 Tank Truck Gantry 5. Rail spurs 30 30 30 50 50 30 60 6. Pump house/Comp. 15 30 15 30 30 - 60 house(LPG) 7. Fire Pump house 60 ** 60 60 60 60 -

Notes :

1. All distances are in metres. 2. Notation: T8 Refer Table - 8 * 1/4 of sum of diameters of adjacent vessels or half the diameter of the larger of the two adjacent

vessels whichever is greater. ** Any distance for operational convenience. 3. Distance of stabling line shall be as per minimum Railway Standards.



23

TABLE - 8 (NOTE1)

INTERDISTANCES BETWEEN LPG STORAGE VESSELS AND BOUNDARY / PROPERTY LINE / GROUP OF BUILDINGS

NOT ASSOCIATED WITH LPG FACILITIES

Capacity of S.No. Each Vessel Distance (Cum.M. of water)

1. 10 - 20 15 2. 21 - 40 20 3. 41. 350 30 4. 351 - 450 40 5. 451 - 750 60 6. 751 - 3800 90

Note : All distances are in metres.



9.0 LAYOUT OF UTILITY STATIONS 9.1 GENERAL CONSIDERATIONS Boiler House, Air compressors, fuel oil facilities (for generation of steam) shall be located in separate block adjoining the process unit blocks. The steam generation facilities block should preferably include boiler feed water pump, chemical block for boiler house etc., which form the integral part of the steam generation facilities. The plant air compressors and drying units should preferably be located in the boiler house unit block. Fuel oil heating and pumping facilities may also be located within the boiler house unit block. These may be located in the boiler house unit block to minimise the spreading ofvarious utility blocks around the process unit, to facilitate ease of operation. ( i) ELECTRICAL Electrical generation facilities should be located

near the process unit block because such electrical generation units normally supply steam to the process units e.g. Cogeneration. When external power grid is interconnected with plant power generation facilities, either the power plant shall be located at the side of boundary wall or the external power transmission lines shall be taken underground upto the interconnection grid inorder to minimise the length of overhead transmission lines within the plant.

(ii) COOLING TOWERS Cooling towers should be located away from

process unit area, preferably downstream direction of wind to avoid corrosion of the equipments in process areas.

(iii) WASTE DISPOSAL FACILITIES Separate collection system should be provided for

different types of waste generated in the process plant such as oily water, cooling tower blowdown, caustic and acidic effluents, sludge, fecal etc.

The waste disposal facilities like effluent channels, land fill areas for disposing off solid waste etc. should preferably be located by the side of boundary wall, but down stream of wind direction so that the foul odour that may be present at times does not affect the plant personnel and neighbourhood areas. Locating the waste disposal facility near the boundary wall also eliminates the vehicular movement in process areas in case solid wastes are to be taken out of installation for disposal.

iv) SMOKING BOOTHS Smoking booths should not be provided in

hydrocarbon industry. However if it is necessary to provide smoking booths, these should be located at a safe distance of :

(i) 30m from hydrocarbon source in case of oil

refinery/storage installation.

(ii) 60m from hydrocabon source in case of LPG/Gas Processing Plants.

9.2 INTERDISTANCES Interdistances between various utility stations

and other facilities shall be as given in Table-1.

10.0 REFERENCES

1. OISD-STD-106 on Process Design and Operating Philosophies on Relief and Disposal Systems.

2. OISD-STD-144 on LPG Bottling and Distribution.

3. NFPA Standard No.30 "Flammable and Combus-tible Liquids Code".

4. Petroleum Rules - 1976.

5. OISD-STD-117on Fire Protection facilities for Petroleum depots and terminals.

6. OISD-STD-116 on Fire Protection facilities for Petroleum Refineries/process plants.

7. SMPV Rules - 1981.



25

ANNEXURE - 1



27

NOTES



NOTES



29

NOTES

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