Fire Safety Science Digital Archive

The soot and hydrocarbon generation behaviour from four common polymers has been investigated under different fire conditions using different bench scale apparatuses. While well-ventilated flaming typically has high CO2/CO ratios and high combustion efficiency, in under-ventilated flaming, higher yields of the many products of incomplete combustion are generally observed, including carbon monoxide, soot and hydrocarbons. Hydrocarbon and soot production from polyethylene, polystyrene, polyamide and polyvinyl chloride were investigated using the steady state tube furnace (ISO TS 19700) under well-ventilated, small under-ventilated and large under-ventilated fire conditions; and in the smoke density chamber (ISO 5659-2) under the three standard test conditions; and the results have been compared to published data from the fire propagation apparatus (ASTM E 2058). The steady state tube furnace and the fire propagation apparatus show good agreement, for hydrocarbon and soot yields. Conversely it proved impossible to identify correlations with these tests for the soot and hydrocarbon yields in the smoke density chamber. To investigate the soot generation further, the particle size distribution was determined using a cascade impactor. This showed the predominance of 1-5 ?m particulates for all polymers, except PVC, in under-ventilated conditions, and a smaller yield and a more even particle size distribution for well-ventilated burning. For PVC, no significant difference was observed for different fire conditions, with no clear trend of particle size distribution.