Using CO and HCN as surrogates for multiple gases in fire toxicity calculations

Abstract

Engineering analyses of fire toxicity are often limited to the production and transport of carbon monoxide and hydrogen cyanide, despite the broader range of gases in the Purser’s formulation for the fractional effective dose (FED). In this work, we show how these two gases can be used as surrogates for the other gases. We validate the method by measuring the yields of asphyxiant and irritant gases for five fuels, assigning them to a source of a small room fire and carrying out CFD predictions of FED using full and simplified schemes of gas species. Results indicate that replacing the full list of species with surrogates leads to less than 6 % relative error while simplifying the user input considerably and saving computational resources.