Fire & Gas (F&G) Mapping Standards Comparison

Fire& Gas mapping study provides a systematic approach in identifying the possible leak sources for the early detection of flammable and toxic release in order to save the personnel and the Assets.

iFluids Engineering has successfully completed Fire & Gas mapping study for the overall Numaligarh Refinery Limited, adequacy check of F&G detectors in Ulfa EPF etc.

Following are the general standards used for Fire & Gas Mapping study:

  • OISD – 116 Fire Protection Facilities for Petroleum Refineries and Oil/Gas Processing Plants
  • OISD – 117 Fire Protection Facilities for Petroleum Depots, Terminals, Pipeline Installations and Lube Oil Installations.
  • ISA TR 84.00.07-2010 Guidance on the Evaluation of Fire, Combustible Gas and Toxic Gas System Effectiveness

Each of the standards mentioned above provide specific guidelines on placing the Gas/Fire detectors, hazard identification, overall approach for the study, classification of petroleum products and implementation of Detection and Alarm system.

Guidelines on Detection System Installation as per OISD – 116

  1. Following areas to be provided with hydrocarbon gas detectors
  • Light hydrocarbon pumps in process units
  • Process cooling tower top platform in the units having pressurized cooling waterreturn.
  • Fuel gas knock out drum
  • Suction side of forced draft air blowers if located where hydrocarbonvapors can be present.
  • Light hydrocarbon pump stations if located below grade level.
  • LPG Horton spheres
  • LPG pump house
  • LPG bulk truck loading area
  • LPG bulk wagon loading area
  • LPG bottling, storage, repair sheds.
  • Gas compressor
  • Near all potential leak sources of class – A e.g. tank dykes, tank manifolds, pump house manifold etc.
  • Air-intake point for control room, in line with OISD-STD-163.

Hydrocarbon detector of proper type shall be selected and also shall be proof tested and maintained in good condition.

  1. Following areas shall be provided with Smoke/Flame/Heat detectors with alarm and/or system to actuate relevant fire suppression system:
  • LPG spheres
  • LPG filling sheds
  • LPG pumps/compressors
  • LPG loading/unloading, both in tank truck and tank wagon gantry

Guidelines on Implementation Schedule of Detection and Alarm System as per OISD – 116 (Clause 14.1.3)

  • Hydrocarbon Detectors shall be provided progressively within 24 months from October, 2010 for existing locations.
  • For new/upcoming locations it shall be implemented along with commissioning of the facilities.

Guidelines on Hazardous Area Classification as per OISD – 117

  1. An Area will be deemed hazardous (as per clause 3.1.5) where
  • Petroleum having flash point below 65 oC or any flammable gas or vapor in a concentration capable of ignition is likely to be present.
  • Petroleum or any flammable liquid having flash point above 65 oC is likely to be refined, blended or stored at above its flash point.
  1. Classification of Petroleum products (as per clause 3.2.1, 3.2.2)

Petroleum means any liquid hydrocarbon or mixture of hydrocarbons and any inflammable mixture (liquid, viscous or solid) containing any liquid hydrocarbon. Flash point of a material is the lowest temperature at which it yields a vapor that gives a momentary flash when ignited.

Petroleum products other than LPG which is a separate category are classified according to their closed cup Flash Point as follows:

  • Petroleum Class A – Petroleum product having flash point below 23 o
  • Petroleum Class B – Petroleum product having flash point of 23 oC and above but below 65 o
  • Petroleum Class C – Petroleum product having flash point of 65 oC and above but below 93 o
  • Excluded Petroleum – Petroleum product having flash point above 93 o

Guidelines on Evaluation of Fire, Combustible Gas and Toxic Gas System Effectiveness as per ISA – TR84.00.07-2010

The standard explains the impact of detector coverage and mitigation effectiveness on the integrity of FGS functions. The concepts underlying a performance-based approach (clause 6) are suitable to the analysis and design of FGS, and these principles can be used effectively in conjunction with other good engineering practices.

Other guidelines specific to the material and type of installation:

  • OISD – 150 Design and Safety Requirements for Liquefied Petroleum Gas Mounded Storage Facility (Clause 8.1, 8.2).
  • OISD – 114 Safe Handling of Hazardous Chemicals (Clause 6.1.3).
  • OISD – 113 Classification of Areas for Electrical Installations at Hydrocarbon Processing and Handling Facilities (Clause A-5).
  • OISD – 244 Storage and Handling of Petroleum Products at Depots and Terminals Including Standalone Crude Oil Storage Facilities (Clause 6.4.5, 9.3 A).
  • OISD – 156 Fire Protection Facilities for Ports Handling Hydrocarbons (clause 5.1, 5.5, 8.5).
  • OISD – 173 Fire Prevention and Protection System for Electrical Installations (clause 4.5, 6.0).
  • OISD – 195 Safety in Design, Operation, Inspection and Maintenance of Hydrocarbon Gas Compressor Stations and Terminals (clause 4.5.3, 5.5).
  • OISD – 236 Design, Layout, Operation & Maintenance of Refrigerated LPG Storage (clause 7.4).