Deliberate Ignition

Deliberate ignition of a release in which the material is both toxic and flammable is a means of mitigation. But this approach may only be appropriate in a few select material-specific and facility-specific cases. Certain materials may well represent a toxicity hazard greater than the flammability hazard. Moreover, the combustion of the vapor cloud may be incomplete or generate toxic products (Husa and Bulkey, 1965). The facility itself, the layout of the processes, other hazardous materials, property lines, and prevailing weather conditions all are of critical importance when a vapor cloud is ignited. 

Timely ignition is critical, so there is a need for immediate or continual activation of the system being used. Devices that can be used for remote ignition include flare pistols, electric ignition devices, and propane burners. The location and spacing of the devices are typically functions of the material and facility however, it is critical that a release does not go undetected by the gas detectors (if there is no continual ignition source) or by the ignition system itself. 

American Industrial Hygiene Association. 1992. Emergency Response Planning Guidelines for Air Contaminants. Fairfax, VA American Industrial Hygiene Association, May. ANSUL. 1991a. Spill-X-A Acid Neutralizer Data Sheet. Marinette, Wisconsin ANSUL Fire Protection. 

Spill-X-C Caustic Neutralizer Data Sheet. Marinette, Wisconsin ANSUL Fire Protection. 

CCPS (Center for Chemical Process Safety) 1988a. Guidelines for Vapor Release Mitigation. New York American Institute of Chemical Engineers. 

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Countermeasures Water sprays Water curtains Steam curtains Air curtains Deliberate ignition of explosive cloud Dilution Foams... 

As for the deliberate ignition of the fleuumable mixture formed downwind of an H2 leakage, and unlike the situation with CH/, we obtained ignition in each of about 10 tests carried out. 

The acceptance of deliberate ignition as a viable strategy is based in part on a couple of controversial assumptions in the hydrogen rule. The TMI-2 accident did not result in vessel breach, and only about half of the available zirconium was oxidized. Therefore, the hydrogen rule was set up to address only degraded core accidents and not full scale... 

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