NIST Time|NIST Home|About NIST|Contact NIST

HomeAll Years:AuthorKeywordTitle2005-2010:AuthorKeywordTitle

Suppression Concentration of Clean Agents Exposed to a Continuously Energized Heated Metal Surface.


pdf icon Suppression Concentration of Clean Agents Exposed to a Continuously Energized Heated Metal Surface. (788 K)
Braun, E.; Womeldorf, C. A.; Grosshandler, W. L.

Fire Safety Journal, Vol. 33, No. 2, 141-152, September 1999.

Keywords:

cleaning agents; hydrocarbon fuels; autoignition temperature; NFPA 2001; fire extinguishing agents; experiments; inert gases; ignition; temperature

Abstract:

An apparatus for the determination of autoignition temperature of hydrocarbon fuels has been used to measure the change in ignition temperature of a stoichiometric mixture ofethene/ air with and without the addition of a suppressant: N2, IG-542, HFC-23, HFC-227ea, FC-218 or FC-3-l-10. When exposed to a heated metal surface of nickel, a fuel/air stream with clean agent added generally required higher temperatures to ignite than when no agent was present. For some agents at low concentrations, it was found that ignition occurred at temperatures lower than when no agent was present. As agent concentration was increased, ignition became harder, i.e., the temperature required for ignition was higher. For each of these suppressants, with foil temperatures approaching 100 dec C, the agent concentration necessary to prevent ignition of the ethene/air mixture exceeded the total flooding and met or exceeded the inerting design concentrations recommended in NFPA 2001, the Standard on Clean Agent Fire Extinguishing Systems.