Fuel Oil day tank shall be located at a distance of not less than 15m from equipment except those facilities such as heat exchanger. Class-B or Class-C petroleum. g) Flash Point "Flash point" of any petroleum liquid is the lowest temperature at which the liquid yields vapour in sufficient concentration to form an ignitable mixture with air and gives a momentary "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices. a) Two road approaches from the highway / major road should be provided. In undulating areas.OISD-STD-118 4 -------------------------------------------------------------------------------------------------------------------------------------o) Future expansion should be assessed and (b) Process unit(s). Madras Refineries Limited. Cylinders shall be stacked vertically.OISD-STD-118 9 -------------------------------------------------------------------------------------------------------------------------------------- (h) Spillage collection shallow sump shall be located at a distance where the flames from sump fire will not impinge on the vessel. Tank farm for storage of crude / products. If the blow down drum is located underground / oil catcher is cover with vent to safe location. condensate etc. g) Rail spur shall be located close to the periphery of the plant to minimise road/pipe crossings and blockage of roads during shunting. p) Petroleum Refinery Petroleum Refinery is a plant where crude oil is received and processed into intermediates and finished products. Shri H.COMMITTEES ON LAYOUTS FOR OIL AND GAS INSTALLATIONS Second Revision – Month /Year LEADER Shri Vinay Kumar MEMBERS GAIL (India) Limited. . Cooling Towers should be located downwind of process equipment and substation so that fog developed will not cause corrosion or obstruct vision or short-circuiting." storage and blending of base oils & additives into finished Lube products. This should be closer to disposal point by the side of the boundary and at lower grade to facilitate gravity flow of effluent. Excluded Petroleum: Liquids which have flash point of 93 oC and above. the minimum separation distance shall be 30 meter. August 1999 Third Revision. construction. Hydrocarbons day tanks shall be provided with dyke in line section 7. column. • 120. (a) In a dyked enclosure where more than one tank is located. blended or stored at above its flash point. The following stipulations shall apply for the separation distances for above ground tanks storing petroleum: (a) For larger installation. operating and maintaining oil and gas installations. May Indicates provisions that are optional.C is likely to be refined. warehouse. sulphur handling etc) and cooling towers should be decided based on prevailing wind direction to avoid travel of hydrocarbon vapour over sources of ignition. The following are the key codes and standards requirements in India for tank farm design. Separation distances between the nearest tanks located in two dykes shall be equivalent to the diameter of the larger tank or 30 m. Shall be 60 m for non-blast construction and 30 m for blast resistant construction. transportation and distribution. Pump stations and piping manifold should be located outside dyke areas by the side of roads. Oil / Gas Production Plant Oil / Gas production plant is a plant where oil and/or gas is collected. Roads should be provided in a symmetric manner to serve all process areas requiring access for the operation. x) Tank height Tank height is the height from tank bottom to top kerb angle for cone roof tanks. Distances given are shell to shell in the same dyke. reactors. q) Process Unit A unit having integrated sequence of operation. e) In Table –4. Water spray deluge valve shall be minimum 15 m from equipment handling hydrocarbon.a) b) c) All distances are face-to-face clear minimum distances in meters. (i) Petroleum having flash point below 65 deg. These OISD standards are periodically reviewed to incorporate the latest technological. .Meteorological data. (c) Excluded petroleum should be treated as Class-C petroleum for the purpose of separation distances and Table – 5 shall be applicable for their separation distances. Vent from Blow down facility shall be minimum 6m above the highest equipment falling with in radius of 15 m from the vent stack. heater of a process unit remains an integral part of the process unit to which it is attached and in that case the inter equipment distances should be inline with Table –2. n) For construction activities. 1.05 Whether the location of halipad is safe and conforming to DGCA norms? intermediate pumping station / compressor station. Reactors with internals and / or containing catalysts. (c) "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices. vent stack Structural main – Technological platforms 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 x 15 15 15 22 15 15 20 15 15 15 x 18 6 30 15 15 2 2 6 8 7 15 7 7 4 3 15 5 3 15 3 15 2 3 4 7 5 15 5 5 2 3 15 3 3 15 3 15 6 4 2 8 5 15 4 4 2 3 15 3 3 15 3 22 8 7 8 3 7 15 7 7 7 7 15 4 3 20 7 15 7 5 5 7 1 7 1 1 2 2 15 3 x 15 x 15 15 15 15 15 7 T-5 15 15 15 15 15 15 x 15 15 20 7 5 4 7 1 15 1 1 2 2 15 3 x 15 x 15 7 5 4 7 1 15 1 1 2 2 15 3 x 15 x 15 4 2 2 7 2 15 2 2 2 2 15 2 2 15 x 15 3 3 3 7 2 15 2 2 2 x 15 2 x 15 2 x 15 15 15 15 15 15 15 15 15 15 x 10 x 15 5 18 5 3 3 4 3 15 3 3 2 2 10 2 3 15 2 6 3 3 3 3 x x x x 2 x x 3 x 15 x 30 15 15 15 20 15 15 15 15 15 15 15 15 15 x 15 15 3 3 3 7 x 15 x x x 2 5 2 x 15 x General notes to Table –2: "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices." Adequate drainage should be provided around such vessels. .Sr no. Plant layout arrangement should follow the general route of raw material to process unit(s) with tankages interposed as required followed by storage & despatch facilities. Fire station A building housing facilities of parking fire tenders and keeping other ready to use fire-fighting equipment for meeting plant emergencies. area should be earmarked. economy. Smoking booths should not be provided in the hydrocarbon industry. T4.0 4. Activities of OISD OISD consists of a small core group of technical experts of various disciplines from the industry. the following should be considered: (a) Layout of Blocks / facilities should be in sequential order of process flow. Between floating Roof Tanks Class A & B Between fixed Roof Tanks Class A &B TABLE– 4 Between Class C Petroleum Storage tanks (D+d) / 4 Min 10 m (D+d) / 4 (D+d) / 4 Min 10 m (D+d) / 3 (D+d) / 6 Min 6 m (D+d) / 4 General notes to Table – 3 & 4 a) All distances are in meters. (ii) The distances given in the brackets ( ) are from the shell of the Heater / Boiler / Furnace / Still. T7.0 5.0 8. LPG. However in case these tanks are provided with windows opening on the shell and these windows will not get blocked in any case. distances for 8. Visakhapatnam. Equipment should be arranged in logistic process sequence for optimum piping runs and operational and maintenance ease. thereby splitting the unit into two or more areas of equipment. For floating roof tanks. j) Hazardous Area An area will be deemed to be hazardous where. 10 out of these 60 OISD standards (OISD STD 105, OISD RP 108, OISD STD 114, OISD STD 116, OISD STD 118, OISD STD 128, OISD STD 129, OISD RP 149, OISD STD 150 and OISD GDN 178) are mandatory in nature by dint of their inclusion in various statutes like the Duliajan MEMBER-CO-ORDINATOR S K Aggarwal Oil Industry Safety Directorate.Shah Shri S. Shri Sunil Dewan. Manual whitelisting should be a thing of the past. Gas Processing Plant Gas processing plant is a facility where natural gas is received and processed to separate gas. slope. Piping connected to tanks should run directly to outside of dyke to the extent possible to minimise piping within the enclosures. Trucking traffic shall be smooth to avoid blocking/ obstruction for loading and unloading of cylinders. a) Table-6 is applicable for total storage of above 100 Tonnes. . Class-C petroleum should preferably be stored in separate enclosure. shall be as per Oil Mines Regulations Piping from / to any tank located in a dyked enclosure should not pass through any other dyked enclosure.1.000 cum whichever is lower.3 Fire walls.4 (a) (b) (b) (c) (d) (c) The minimum distance between a tank shell and the inside toe of the dyke wall shall not be less than half the height of the tank.0 8. Regulations . Full rake loading / unloading is shall be done on two separate rail gantries having a minimum distance of 50m.1. (b) Dyked enclosure shall be able to contain the complete contents of the largest tank in the dyke in case of any emergency. Class-A and / or Class-B petroleum may be stored in the samedyked enclosure. Note-7 The distances specified are for the elevated flare. maintenance and inspection of Terminal and Tank facilities. bitumen / asphalt etc and other open storage areas like scrap yards and dumping ground . Panipat Refinery. Adequate space should be provided around cold boxes for ease of operation and maintenance. structure. API Separators / Oil sludge pit 1 Note-1 Note-3 30 30 30 60 90 45 45 60 45 30 60 60 30 90 2 Note-3 x 3 30 Note-4 4 30 Note-5 Note-6 Note-6 Note-6 30 90 30 30 60 (90) 30 T3 30 30 50 5 30 30 Note-6 Note-6 Note-6 30 90 30 30 60 (90) 30 T3 30 30 50 6 60 60 30 30 30 T7 90 30 T6 90 (90) 30 T7 45 30 60 7 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 8 45 45 30 30 30 30 90 Note-8 Note-9 60 30 Note-10 T3 60 30 50 9 45 45 30 30 30 T6 90 Note-9 T6 90 (90) T6 T6 60 30 50 10 60 30 60 60 60 90 90 60 90 x 30 30 12 12 30 90 11 45 Note-3 (90) (90) (90) (90) 90 30 (90) 30 x 15 50 30 30 Note-12 12 30 x 30 30 30 30 90 Note-10 T6 30 15 x 30 6 15 50 13 60 30 T3 T3 T3 T7 90 T3 T6 12 50 30 x 6 30 50 14 60 15 60 30 30 45 90 60 60 12 30 6 6 x 30 50 15 30 30 30 30 30 30 90 30 30 30 30 15 30 30 x 15 TABLE – 1 16 90 30 50 50 50 60 90 50 50 90 Note12 50 50 50 15 x Note-4 Note-6 Note -5 Note-6 30 60 90 45 45 30 Note-3 x 30 15 30 30 Note-6 30 90 30 30 60 (90) 30 T3 60 30 50 General Notes to Table-1 . Standardization in design philosophies and operating & maintenance practices at national level was hardly in existence. 5 4.5 x x x 3 3 10 3 3 x 3 1.0 4 9 9 9 x 4.5D Min 3.5 D Min 4.5 6 9 9 9 3 9 9 9 5 9 0.5D 0.5 x 9 4.5 x 9 4.5 3 9 4.5D 0.5 D Min 4.5D / 6.5 x x 3 x x 11 15 4.5 3 0.5 4.5 3 x x x x 13 15 D Min 4.5 4.0 x 9 0.B Tank vehicle Loading / unloading Class .5 0.0 0.5 x 1.5D 9 4.0 9 4.5 4.5 1.0 0.5 x 9 4.5 4. stores.5D / 6.5D Min 3.5 D Min 3.5 4.5 3 9 4.A Tank vehicle Loading / unloading Class .5 9 x 4.5 x 9 4.5 x 9 4.0 9 0.5 x x x 0.5D / 6.5 4." This table is applicable where total storage capacity of Class-A & Class-B is less than 5000 cum and diameter of any tank storing Class-A and Class-B petroleum product does not exceed 9 meters." This document will be reviewed periodically for improvements based on the experience and better understanding. Roads separating the blocks shall act as firebreaks. firewalls of minimum height 600mm shall be provided to prevent spills from one tank endangering any other tank in the same enclosure. whichever is more. The separation distance shall be 50 m. However. Mumbai Refinery.S. OISD-STD-118 Revision - II FOR RESTRICTED CIRCULATION LAYOUTS FOR OIL AND GAS INSTALLATIONS OISD STANDARD 118 Revision II, September 2004 Oil Industry . operational and maintenance requirements. Moreover, OISD was also given responsibility of monitoring implementation status of these standards through safety audits. These documents are intended to supplement rather than replace the prevailing statutory requirements. (s) Stairways should be provided for the main access. Panipat IOCL Refineries HQ. A free board of 200 mm above the calculated liquid level shall be considered for fixing the height of the dyke.0 m and shall not be more than 2.2 (a) (b) (c) "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices. Rules . 14.0 Check for proper alignment 15.0 Check for tension free jointing of piping connected to pressure vessel 16.0 Check painting for Dry Film Thickness (DFT). Equivalent international standard for OISD -118 a234f56 (Mechanical) (OP) 7 Jul 11 05:46. Bombay. for installations in coastal areas. However. Filling machines and testing facilities shall be organized in sequential manner distinctly in a separate area.3 (a) LPG truck loading/unloading gantry shall be located in a separate block and shall not be grouped with other petroleum products. Bulk handling facilities.1." (k) The local control panel for soot blower control and flue gas analyzer only should be located on and near the process heater. Aggregate capacity of tanks located in one dyked enclosure shall not exceed following values: • 60. The minimum height of dyke wall in case of excluded petroleum shall be 600 mm. for a group of fixed roof tanks. Madras.. fired equipment etc should be located in such an area so to facilitate erection. Filled LPG cylinders shall not be stored in the vicinity of cylinders containing other gases or hazardous substances. these should be located in open area. For ground flare, these distances shall be 150 m. For Exploration & Production installations, this shall be in line […] OISD-STD-117 & OISD-STD-144 as the case may be. utilities. Today's trend of large and complex plants present substantial risk potential. Fire station should be upwind of process units and hydrocarbon storage area with straight approach to process units / other critical areas. 5 D Min 20 m 0. Spheres and bullets shall be treated as separate groups with 30 meters separation distance between two groups. whichever is more. (f) Towers / columns should be located along the pipe rack towards open areas for unobstructed erection as well as maintenance of internals at grade. i) General Classification Of Petroleum Products Petroleum products are classified according to their closed cup FLASH POINTS as given below: l) — Class-A Petroleum: Liquids which have flash point below 23oC. The height of tank enclosure dyke (including free board) shall be at least 1." OISD has issued approximately 110 Standards relating to installation, commissioning and operation of oil facilities in India. 7. Primary traffic roads in the installation should be outside hazardous areas.g. General.000 cum in capacity shall be treated as one tank for the provision of firewall. Attempts have been made to incorporate the latest technological changes. View Std-118 from GENERAL HUL461 at IIT Kanpur. . In Indian projects we adopt OISD 118. New Delhi BPCL. OISD, headed by an Executive Director, gets its directions and guidance from the Safety Council, the apex body consisting of senior officials of the Ministry of Petroleum and Natural Gas, chief executives of oil/gas companies and heads of the populated and hazardous areas.g. storage areas for solid products such as petroleum coke. w) Storage / filling shed Facility for storage and filling of packed (non-bulk) petroleum product. stabilized and despatched for further processing. f)For different combination of storage tanks.SEPARATION DISTANCES BETWEEN STORAGE TANKS WITHIN A DYKE Item 1 2 All tanks with Diameter upto 50 meters Tanks with Diameter exceeding 50 meters." Propylene etc. group of pressurized storage tanks. OISD-STD-120 Selection, Operation and Maintenance of Compressors Adequate spacing between equipment will help in minimizing the spread of fire. T5.0 3.0 Introduction Scope Definitions Plant Layout Philosophy Layout of Blocks/Facilities Layout of Process Units Layout of Storage Tanks Layout of LPG Facilities References TABLES T1. The capacity of the collection sump shall be as per OISD-STD–144. s) Service building A building housing facilities for inspection / maintenance / other "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices. (b) company standards. refer Table-1. API Standard 2610–Design. Boiler house or heater of a process unit is to be treated as a separate identity only for the consideration of surrounding blocks / facilities. oisd - std - 113 first edition for restricted circulation only classification of areas for electrical installations at oisd 118. oisd 117. list oisd. Corrugated Plate Interceptor (CPI). (d) There shall be access on all four sides of each dyke area and roads should be linked to minimize the effect if one road is cut off during the fire. OISD-STD-119 Selection, Operation and Maintenance of Pumps. purification. Propane." LPG Workshop B PCL Pune 6-7 March 2020. furnaces & Block layout should be adopted as far as possible. Where alternate distances are specified (like 0. if these are covered from the top and provided with adequate venting to safe location. Consideration should be given to access for fire fighting. 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. “x” indicates suitable distance as per good engineering practices to meet construction.a) b) c) d) e) f) g) All distances are in meter and the table specifies the minimum requirement.0).5 D / 6.6 "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices." (h) Vessels. In August 2000 it was amended inline with the recommendations of the High Power Committee. It is hoped that the provision of this document. "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices." For a control room attached to single process unit or a boiler or a heater. 2. grease manufacturing plants.OISD-STD-118 2 -------------------------------------------------------------------------------------------------------------------------------------- flash on application of a small pilot flame under specified conditions of test as per IS: 1448 (Part-I). maintenance and fire fighting. ... OISD-STD-118 Layouts for Oil and Gas Installations Rev.I. 3800 90 General Notes to Table-6 & Table-7.450 40 451-750 60 751 .20 15 21 .Capacity of Each vessel in Cum of water Distance in meters 10 . Our Gallery. information should be collected on the following aspects. LPG storage vessels shall not be located within the same dykes where other liquid hydrocarbons are stored. Fuel gas knock out drum shall be located at a minimum separation distance of 15 m from the heater. hazardous and populated areas. . Cylinder evacuation facilities Tank Truck Loading / unloading gantry Tank wagon gantry Rail spur Pump house / Compressor house (LPG) Fire Water pump house 1 2 3 4 5 6 7 8 Note-1 T7 30 30 50 30 15 60 T7 x 30 30 50 30 30 x 30 30 15 30 50 30 15 60 30 30 30 30 50 50 30 60 50 50 50 50 50 50 30 60 30 30 30 50 50 50 30 60 15 30 15 30 30 30 x 60 60 x 60 60 60 60 60 x TABLE– 7 SEPARATION DISTANCES BETWEEN LPG STORAGE VESSELS AND BOUNDARY WALL / GROUP OF BUILDINGS NOT ASSOCIATED WITH LPG FACILITIES "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices." The edge of the road shall not be less than 15 meters away from the edge of the unit. OISD-STANDARD-118 Third Revision FOR RESTRICTED CIRCULATION. (h) High Tension (HT) sub-station(s) should be located close to major load centers. Storage vessels should be located down wind of process units. installation. Storage vessels shall not be stacked one above the other.2 Separation Distances between tanks / offsites facilities. The table shall be read in conjunction with the notes specified with the table. separation. etc should be 2. r) Protection for exposure This refers to fire protection for structures on property adjacent to liquid storage. minimum separation distances shall be as specified in Table-5.1. Suggestions from industry members may be addressed to: The Coordinator Committee on Layouts for Oil and Gas Installation Oil Industry Safety Directorate 7th Floor. Main pipe racks / pipe track shall not be routed through process units. Pipeline installations / terminals. All process units and dyked enclosures of storage tanks shall be planned in separate blocks with roads all around for access and safety.OISD-STD-118 3 -------------------------------------------------------------------------------------------------------------------------------------- supporting services which are directly required for operation of the plant e. Erection methods shall be studied for all types of equipment / structures. Maximum number of LPG tank truck bays shall be restricted to 8 in one group. .1 meters. Both these approaches should be available for receipt of assistance in emergency. T2. For mounded LPG storage. storage. treating or storing crude oil and includes central tank farm. (t) Minimum headroom under vessels." d) e) Pedestrian pathways should be provided / marked alongside the primary traffic roads. 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 following article will provide a sample case study for Storage Tanks Layout or Tank Farm based on OISD-Standards-118. . the minimum thereof shall be used. Chemical / Toxic chemicals storage. Mumbai Kochi Refineries Limited. 36th OISD Foundation day. Liquefied gases including LPG do not fall under this classification but form separate category. flammable and Combustible Liquid Code. Marketing depots and terminals. Engineers India Limited. LAYOUT OF LPG FACILITIES General Considerations: LPG Storage. New Delhi Department of Explosives.P.G. and drainage . Grouping. oisd standard 117 oil industry safety directorate pdf Free access for oisd standard 117 oil industry safety directorate pdf from our huge library or simply read online from your computer instantly. . Shri S. Shri K.Banerjee Shri M. Shri D.Palnitkar. Class 'B' petroleum: Liquids which have flash point of 23 degrees C and above but below 65 degrees C. Layout of an installation shall be done in accordance with OISD-Standard-118 on Layouts. solid storage. Shri A.Maji.Lokhande.D. “x” means any distance suitable for constructional or operational convenience.a) b) All distances are in meters. With this in view. for a variety of reasons. for all other Hydrocarbons Heat Exchangers Air fin coolers for Hydrocarbons Fired heater Local control panel Pressure vessels / Drums of Hydrocarbons Main Pipe rack Blow down facility – Drum. .Sr no 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 From / To Fired Heater / Any fired equipment Reactors Distillation column Accumulators – Hydrocarbons Compressors Hydrocarbons Hot oil pump Fuel Oil / HCs day tank Pumps for class. Note 2 : Type of construction shall be as per OISD-STD-163. Pumps handling hydrocarbons above the temperature of o 230 C or C4 and Lighters should not be installed underneath the air fin coolers. OISD constituted number of functional committees comprising experts nominated from the industry to draw up standards and guidelines on various subjects. (e) Utility block(s) should preferably be located adjacent to unit blocks.) Gas compressors should have roofing and open from sides to avoid accumulation of heavier vapours/gases on the floor of compressor house. Oisd 118 Standard Pdf 4,4/5 4172 votes Dear Professionals, I need the following OISD standards Sr. Oisd 118 latest edition pdf March 21, 2018 Oisd 118 latest edition pdf Download >>Read Online >>oisd - std - 113 first edition for restricted circulation only classification of areas for electrical installations at oisd 118. The present document on Cross-country Natural Gas Pipelines and City Gas pipeline were prepared by the Functional Committee on Natural Gas Pipelines. The minimum distances recommended many years ago need review in the context of today's environment in the industry. LPG facilities. Separation distance between tank truck gantry and rail spur shall be 50 m. All distances shall be measured between the nearest points on the perimeter of each facility except (i) In case of tank vehicle loading / unloading area where the distance shall be from the center of nearest bay. (c) For excluded petroleum product storage. f) Fire Water pump house A building housing fire water pumps. Tank Farm Design Considerations and Layout In this article, we will learn the tank farm design considerations, storage tanks arrangement, tank farm length, and width calculation, and dyke wall height calculation. then these may be considered as floating roof tanks. concrete or solid masonry shall be designed to withstand the hydrostatic load. The Petroleum 2. and may involve preparation. (g) Thermo-siphon reboilers should preferably be placed close to their associated towers. LPG bottling facilities should be located at a safe distance from other facilities with minimum ingress to trucking traffic and downwind to storage. Separation distances specified in other OISD standards or elsewhere in this standard (other than Table –2) shall be followed as recommended. surge wave height etc. For ground flare, these distances shall be 150 m. For Exploration & Production installations, this shall be in line with Oil Mines Regulations. received / despatched by rail / road / pipeline and / or filled in cylinders. The distances recommended should be followed to the extent feasible. storage tanks. For Gas processing plants. As such variety of practices have been in vogue because of collaboration / association with different foreign companies and governments. OISD-STD-118 Revision - II FOR RESTRICTED CIRCULATION LAYOUTS FOR OIL AND GAS INSTALLATIONS OISD – STANDARD – 118 Revision – II, September 2004 Oil Industry Safety Directorate Government of India Ministry of Petroleum & Natural Gas 6. Although, these can vary based on geographical changes and local statutory requirements: OISD-118 (Layouts for Oil and Gas Installations) OISD-116 or 117 (For Fire Fighting requirements) .1 1 2 3 4 5 6 7 8 9 10 11 12 13 Storage Tank Class A Storage Tank Class B Storage Tank Class C Storage / Filling shed for petroleum Class -A Storage / Filling shed for petroleum Class -B Storage / Filling shed for petroleum Class -C Tank vehicle Loading / unloading Class .5D x 9 4.5 9 4.5 x 3 x x x 12 15 D Min 4.5 9 4.5 x 3 1.5D 0.5D / 6.5 4.5 3 4.5D x 6 1.5 4.C Flame proof Electric motors Non Flame proof Electric motors Office building. (j) (k) Storage tanks should be grouped according to product classification.Environmental considerations .0.Highest flood level in the area. This distance shall not be less than the diameter of the nearest vessel or 15 meters whichever is higher. Any vessel in one group shall be separated from a vessel in another group by a minimum distance of 30 meters. 7. storage tanks should be located at lower elevations (l) Truck loading / unloading facilities should be located close to product movement gate and should be oriented "OISD hereby expressly disclaims any liability or responsibility for loss or damage resulting from use of the OISD Standards/ Guidelines/ Recommended Practices.1 General consideration for the layout of blocks / facilities While locating the various facilities / blocks.Process units.