In-duct countermeasures for reducing fire-generated-smoke-aerosol exposure to HEPA filters. [High efficiency particulate aerosol]
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. In a ''forceful burn'' the crib of fuel is continuously exposed to an energetic premixed methane flame during the entire experimental period. This tactic serves two purposes: it optimizes the production of smoke rich in unburned pyrolyzates which provides severe exposure to the filters, and it facilitates the ignition and enhances the combustion of cribs formed with synthetic polymers. The experiments were conducted in an enclosure specifically designed and instrumented for fire tests. The test cell has a volume of 100 m/sup 3/ and includes instrumentation to measure the internal temperature distribution, pressure, thermal radiation field, flow fields, gas concentration, particulate size distribution and mass, fuel weight loss, inlet and exit air velocities, and smoke optical density. The countermeasure techniques include the use of passively operated sprinkler systems in the fire test cell, of fine and dense water scrubbing sprays, and of rolling prefiltration systems in the exit duct of the fire test cell. Of the countermeasures surveyed, the rolling prefilter system showed the most promise. This paper concentrates on the effect of control variables; i.e., enclosure air supply, fuel composition and crib porosity on the combustion response; i.e., crib burning rate, enclosure temperature rise, oxygen consumption, and CO, CO/sub 2/ and total hydrocarbon production. A discussion of the attempts to rationalize smoke aerosol properties will be included along with results from the effect of countermeasure application on HEPA filter lifetimes.
- Research Organization:
- California Univ., Livermore (USA). Lawrence Livermore Lab.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6691494
- Report Number(s):
- UCRL-80789; CONF-780819-19
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420600 -- Engineering-- Safety Engineering-- (-1987)
424000* -- Engineering-- Pollution Control Equipment-- (1980-1989)
AEROSOLS
CHEMICAL REACTIONS
COLLOIDS
COMBUSTION
CONTROL
DESIGN
DISPERSIONS
ENGINEERING
FILTERS
FIRES
FUELS
LIFETIME
MEASURING INSTRUMENTS
OXIDATION
POLYMERS
SOLS
TESTING
THERMOCHEMICAL PROCESSES