FIRE SAFETY OF PETROLEUM INDUSTRIES By- Debapriya Biswas Additional Director General West Bengal Fire & Emergency Services
Petroleum industries are dealing with different hazardous materials starting from storing, processing and distributing the petroleum products These help us in moving wheel of prosperity, but it has a threat of doing harm through accident, fire, explosion, release of toxic gases and other physical hazards.
It is necessary to monitor/regulate safety measures through the Statutory Authorities /Govt. bodies.
Department of Explosive, Govt. of India (Explosive Act.) Chief Inspector of Factories for enforcing Factory Acts & Rules Oil Industry Safety Directorate The Petroleum Acts & Rules Indian Electricity Acts. Boiler Act. Static & Mobile Pressure Vessel Rule A P I Codes (American Petroleum Institute) National Fire Protection Association (NFPA Codes) Relevant B.I.S. Standards
Different standards & codes of practices are also to be taken care for isolation of hazards in petroleum industries.
As per Petroleum Act 1934:- Petroleum means any liquid hydrocarbon or mixtures of hydrocarbons any inflammable mixture (liquid, viscous or solid) containing any liquid hydrocarbon. 1) Petroleum class a means petroleum having a Flash point below 230C. 2) Petroleum class b means petroleum having a flash point of 230C and above but below 650C. 3) Petroleum class c means petroleum having a flash point of 650C and above but below 930C.
Fire or Combustion:- Combustion is chemical reaction which will create heat, light & sound. Combustion takes place in different way mainly in premixed condition where vapour air or gas air mixture travel to zone of combustion in premixed way which appears dangerous because combustion takes place with minimum energy. Ignition energy for hydrocarbon :- 0.22 to 0.25 milli-joule
The requirement for combustion are:- The sufficient time the complete chemical reaction. Sufficient temperature to heat the fuel through its various decomposition stages to ignite the carbon and hydrogen. Sufficient turbulence to mix the oxygen and fuel elements completely.
To initiate combustion the following condition must be fulfilled:- Temperature must be above flash point. The temperature must be equal or exceed the ignition temperature. The vapour air composition must fall between the limit determined upper & lower flammability.
Fire hazards in Petroleum Industries confined- Raw material i.e. Crude Oil Process (Plant)- High Temperature/High Pressure Products- Oil or Gaseous form
The Characteristics & Properties of these substances are:- (a) Huge quantity of fuel (b) Having Low Flash Point (c) Flammable in nature (d) High vapour density (e) Low Specific gravity (f) Hazardous reaction at high temperature and pressure. (g) Inherent quality to form combustible mixture. (h) Availability of source of ignition (flame, spark Etc).
Causes of Ignition:- Flame from cutting and welding Smoking material Spark from Electrical Equipment Static Electricity Pyrophoric Material Frictional Spark Combustion Engine Mechanical Spark Spontaneous Ignition Open flame Hot Surfaces
Hence Safety measure in petroleum industries depends on:- Planning in Safe Design. Selection of Safe Technology Proper lay out based on:- 1. Wind Direction 2. Orientation of the Plant 3. Safe Distance between Two Risks 4. Limitation of Risk 5. Proper roads, Approaches and Escape routes
Zones Classification:- Based on above classifications, the whole area is divided into 4(four) Zones. 1. Zone 0 area: The area in which flammable atmosphere is expected to be present continuously. 2. Zone 1 area: The area in which flammable atmosphere is likely to be present under normal operating condition. 3. Zone 2 area: The area in which flammable atmosphere is likely to be present only under abnormal operating condition of failure of rupture of equipment. 4. Safe area: There is no possibility of presence of flammable atmosphere.
Electrical Equipments for hazardous area: For specific classification of the hazardous area, electrical equipment of specific construction is to be used.
Zone Type Symbol Zone 0 - Intrinsic safety category ia i a -Other electrical apparatus specifically design for zone 0 - s Zone 1 Types of protection adequate for zone 0 - Flame proof enclosure d - Increased safety e Intrinsic safety category ib ib - Oil immersed o -Pressurization p - Sand filled q Other electrical apparatus specially designed for zone 1 s Zone 2 - Types of protection adequate for zone 0 or zone 1 -Non-sparking apparatus - n Pressurization P Hermetically sealed- H
The electrical machines and equipments are classified as per degree of safety as follows. 1) Ex i -intrinsically intrinsically safe (unable to produce spark which can ignite vapour-air air mixture) 2) Ex d -flame proof (strong enclosed in capable to communicate spark quenching distance ) 3) Ex p -pressurization pressurization (+ve pressure inside, so that no combustible mixture come in contact) 4) Ex e -machine with increased safety (does not produce arc, spark and excessive temperature)
5) Ex q - sand filled apparatus (protect spark to come out) 6) Ex o -oil oil immersed apparatus (protect spark to come out) 7) ex n - non-sparking apparatus (pneumatic, hydraulic) 8) Ex ia -intrinsic intrinsic safety category ia (incapable of causing ignition in normal operation or with any single fault or with any combination of faults applied with specified factor for current and or voltage) 9) Ex ib - with single fault applied with as a specified safety factor for current and voltage.
Maximum surface temperature has been classified in BIS-8239-1976. Temperature class maximum surface temp T1 450 0 C T2 300 0 C T3 200 0 C T4 135 0 C T5 100 0 C T6 85 0 C
Therefore the Marking will be Ex d IIB T3- In case of intrinsically safe Hazardous vapour liquid Gasor vapourgroup 1. Methane I 2. Ammonia, propane, butane, IIA 3.ethylene IIB 4.Hydrogen IIC
Permit to work System: As a preventive and protective measure against fire /Accident/Incident the following Type of Permit are being issued to perform any job/activity inside the Refinery. premises. Fire Permit Safety Permit Electrical Clearance Excavation Permit Road cutting Permit Dyke cutting Permit Working at Height Vessel Entry Permit
Welding & Cutting: 1. Use Work Permit System 2. Take Precautions Before / During / After Welding & Cutting 3. Create Enclosures with Metal Sheet 4. Implement safe Storage & careful Handling of Gas Cylinders
Oil Leakage: 1. Inspect Storages / Pipe Lines 2. Attend Leakages Promptly 3. Use Colour Code
Static Electricity: 1. Cotton waste soaked in oil / grease 2. Coal Storage 3. Proper House Keeping
Conclusion: Accident/Incident not just happens they are caused, they are caused by human being due to their unsafe activities or prevailing unsafe situation /condition. Similarly safety not just happen they are caused by human being by their consorted and preventive efforts so that the probability-of of harm to human or property is isolated. To achieve this it is necessary to promote the safety culture amongst the employees through effective training thereby sensitize them in fire safety practice.
There is a need to ensure that the specific duties, responsibilities and individual accountability in regards to fire safety are well defined. The actions to be monitored at various levels of hierarchy for effective maintenance, adherence to well defined procedures and completion of task within well defined time period.
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