Детальная информация

Smoke inhalation is a major cause of civilian and firefighter deaths during a fire incident. To characterize effluents from burning or pyrolyzing wood, real-time measurements of the smoke obscurity (the specific optical density), the concentrations of particulates, and toxic gases in a standard smoke density chamber have been made with a tapered element oscillating microbalance (TEOM) dust monitor and a Fourier transform infrared (FTIR) gas analyzer. The FTIR analyzes a total of 21 gases, including both asphyxiants and irritants. In addition to the smoke characteristics, the temperature in the interior of the specimen under selected conditions are measured by thermocouples to study the heat transfer and pyrolysis processes. Common building materials, i.e., selected woods at various moisture contents, are used. A specimen, placed in a vertical or horizontal orientation, is exposed to an incident radiant flux of 25 kW/m2 for a flaming or non-flaming case. The effluent concentrations depend significantly on whether or not the flame exists and the specimen orientation as they influence the gas-phase reactions and the convection around the specimen. The non-flaming case in the horizontal configuration produces the highest smoke and toxicants (CO, formaldehyde, and acrolein) concentrations due to partial oxidation, while the flaming and horizontal case generates the lowest because of high-temperature oxidation (to form CO2 and H2O) in a flame with a longer residence time.