Start 
Ph. D. Anna A. Stec
Centre for Fire and Hazard Sciences, University of Central Lancashire, Preston, Wielka Brytania
Fire smoke has a highly variable composition which is dependent on several factors, including oxygen supply, heating rate, temperature and the chemical structure of the materials that are burning. One area that is particularly important is the determination of volatiles that can have a negative effect on the environment as well as posing a serious hazard to human health. Prediction of toxic fire hazard depends on two parameters: time-concentration profiles for major products. These depend on the fire growth curve and the yields of toxic products; toxicity of the products, based on estimates of doses likely to impair escape efficiency, cause incapacitation, or death. Toxic product yields depend on the material composition, and the fire conditions. The most significant differences in fire conditions arise between flaming and non-flaming combustion. The burning of an organic material, such as a polymer, is a complex process, in which volatile breakdown products react, to a greater or lesser extent, with oxygen, producing a cocktail of products. These range from the relatively harmless carbon dioxide (CO2) and water, to products of incomplete combustion, including carbon monoxide (CO), hydrogen cyanide (HCN), organoirritants etc. In addition, depending on the other elements present, halogen acids, oxides of nitrogen, and sulphur, may be formed. The fire toxicity of building materials were investigated under a range of fire conditions, oxidative pyrolysis (smouldering) and well-ventilated flaming to under-ventilated flaming. The yields of the major toxic products, carbon monoxide, hydrogen cyanide and irritant gases nitrogen dioxide, hydrogen chloride and hydrogen bromide together with polycyclic aromatic hydrocarbons are presented as a function of fire condition. The toxicities of the effluents, showing the contribution of individual toxic components, are compared using the fractional effective dose (FED) model and LC50, (the mass required per unit volume to generate a lethal atmosphere under specified conditions).
Keywords: fire smoke, toxicity, fire hazard.
Materiały Budowlane 10/2014, strona 32-35 (spis treści >>)
