Ignition sources control

Ignition of flammable Provide safe separation distances release resulting in fire. Develop appropriate area electrical or explosion. classification Provide ignition source control Place ignition sources in positive pressure enclosure and buildings Provide adequate ventilation API RP500 BS 5345 BS 5958 NFPA-70 NFPA-77... 

Design to contain overpressure where practical Maintain ignition source control Maintain use of inert atmosphere Provide automatic isolation via quick closing valves of manifold duct system on detection of fire/flammable atmosphere or overpressure in duct system... 

Provide ignition source controls (e.g., permanent grounding/bonding, nonsplash filling, etc.)... 

Ventilation of buildings and enclosed structures Piping redesign Mechanical flow restriction Ignition source control... 

Detonation arresters are typically used in conjunction with other measures to decrease the risk of flame propagation. For example, in vapor control systems, the vapor is often enriched, diluted, or inerted, with appropriate instrumentation and control (see Effluent Disposal Systems, 1993). In cases where ignition sources are present or pre-dic table (such as most vapor destruct systems), the detonation arrester is used as a last-resort method anticipating possible failure of vapor composition control. Where vent collec tion systems have several vapor/oxidant sources, stream compositions can be highly variable and... 

Ignition Sources Normally it is best practice not to base explosion safety solely on the presumed absence of an ignition source. Explosion control should be based on prevention or protection techniques, or both. Even so, all reasonable measures should be taken to eliminate ignition sources. 

Tayout also has a significant role in minimizing the probability of ignition of a flammable release. Area electrical classification provides the basis for the control of electrical ignition sources. This classification is also used to determine the areas that require protection from vehicular access, etc. Frequently, highly hazardous processes that can result in overpressure (e.g., hydrogenation) are placed behind blast resistant structures/walls. 

Potential ignition sources that cannot be controlled adequately, such as ... 

Ignition of flammable atmosphere for open filters or solvent may be above flash point with air present when cleaning or unplugging closed filters. This may necessitate tight control of ignition sources to prevent a fire/explosion. 

A battery backed-up d.c. source of control supply is provided for the AMF panel and engine ignition. The control scheme, as illustrated, generally eonsists of a 220 or 240 V a.c. source of supply, with a transformer rectifier unit, to provide a 24 or 48 V d.c. control voltage, to charge the battery as required and a battery back-up of suitable capacity. 

Controlled release to the atmosphere should be at least 15 m from any continuous ignition source. 

Fire hazards are minimized by minimum inventories of chemicals. Control or miniini/e ignition sources, provide a confining area, reduce the temperature of the material as much iis possible, blanket the material to eliminate air contact. Have available fire protection equipment breathing apparatus, and protective clothing for the fire fighters. Use several hour fire walls to prevent the spread of fire to other process areas. 

If LNG were released and cloud ignited the accident would be serious. If the cloud did not ignite on site but drifted to a populated area and then ignited, the number of casualties would be be much greater, Ignition sources are strictly controlled at the terminal so on-site ignition w a.s not considered... 

The ignition sources described above cannot be eliminated, but tliey can be controlled by careful layout of tlie plant, proper design and maintenance of equipment, and tlie use of trip systems. 

Fire precautions including control of ignition sources, e.g. smoking, maintenance activities, vehicular access (see Chapter 6) and limitation of combustible materials, e.g. packaging. 

A segregated area adequately spaced from ignition sources, etc. with provision for spillage control and with appropriate protection from vehicle impact. 

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