Abstract
Fire tests were conducted in one of the first floor rooms of a fire resistant 2-story house to investigate the evolution of toxic gases and the toxicity of atmosphere in its 2nd floor room. Natural polymer contents only or both synthetic and natural polymer contents were combusted repeatedly in the burn room under the different opening conditions.
Major toxicants were found to be CO and HCN. HCN evolution was greater from the fires involving synthetic polymers, although the same amount of nitrogen-containing materials were contained in both types of contents, Generally, the total toxicity index, Σ(Ci/Cfi), was higher for fires involving synthetic materials as much as the difference in toxicity index of HCN between the fires of the two types of contents. In the 2nd floor room, toxic gases concentrations began to rise about 1 minute after flashover in the burn room, and were faster to rise as the opening facing outdoor of the burn room was smaller. The analyses of the blood of rabbits which died or incapacitated after exposed to the 2nd floor room gases showed that CO-Hb levels were higher for fires of natural polymers than fires involving synthetic polymers. This indicates that greater evolution of HCN in the latter fires contributed to death or incapacitation of rabbits to some extent. A comparison between the total toxicity index and the lethal temperature has revealed that death due to gas poisoning is greater than death due to heat in the 2nd floor room.
