IN-DUCT COUNTERMEASURES FOR REDUCING FIRE-GENERATED-SMOKE-AEROSOL EXPOSURE TO HEPA FILTERS.

An experimental program was conducted to assess the endurance and lifetime of HEPA filters exposed to fire-generated aerosols, and to reduce the aerosol exposure by installing engineering countermeasures in the duct between the fire source and HEPA filters. Large cribs of wood and other potential fuels of interest were ″forcefully burned″ in a partially ventilated enclosure. This paper concentrates on the effect of control variables; i. e. , enclosure air supply, fuel composition and crib porosity, and on the combustion response; i. e. , crib burning rate, enclosure temperature rise, oxygen consumption, and CO, CO//2 and total hydrocarbon production. A discussion of the attempts to rationalize smoke aerosol properties, i. e. , aerosol mass-and-size distribution on filter plugging phenomena is included along with results from the effect of countermeasure application on HEPA filter lifetimes.