Smoke Component Yields from Room-scale Fire Tests

This report presents the methodology for and results from a series of room-scale fire tests to produce data on the yields of toxic products in both pre-flashover and post-flashover fires. The combustibles examined were: a sofa made of upholstered cushions on a steel frame, particleboard bookcases with a laminated finish, polyvinyl chloride sheet, and household electric cable. They were burned in a room with a long adjacent corridor. The yields of CO2, CO, HCl, HCN, and carbonaceous soot were determined. Other toxicants (e.g., NO2, formaldehyde and acrolein) were not found
concentrations below the detection limits were shown to be of limited toxicological importance relative to the detected toxicants. The toxicant yields from sofa cushion fires in a closed room were similar to those from pre-flashover fires of the same cushions in a room with the door open. The uncertainties in the post-flashover data are smaller due to the higher species concentrations and the more fully established upper layer from which the fire effluent was sampled. The uncertainty values are comparable to those estimated for the fractional effective dose calculations used to determine the time available for escape from a fire. The uncertainty in the yield data from the sofa, bookcase, and cable tests is sufficiently small to determine whether a bench-scale apparatus is producing results that are similar to or different from the real-scale results here. The use of Fourier transform infrared (FTIR) spectroscopy was shown to be a useful tool for obtaining concentration data of toxicants. However, its operation and interpretation is far from routine. The losses of CO, HCN, and HCl as they flowed down the corridor were found to be dependent on the combustible. The downstream to upstream concentration ratios varied from unity for some fuels to a factor of five smaller for others. The CO yield from two of the combustibles was significantly lower than the expected value of 0.2, which should be used in hazard and risk analyses. The accuracy of the results is verified, and a hypothesis is offered for the lower CO yield values.