A generalized relationship between the normalized yields of carbon monoxide and hydrogen cyanide

Experimental studies have demonstrated that there are close correlations between the normalized yields of carbon monoxide (CO) and hydrogen cyanide (HCN) from the combustion of materials containing nitrogen. In this paper, a generalized relationship using the stoichiometric oxygen to fuel mass ratio (SOFMR) is derived to represent these correlations. Using this generalized relationship, the predicted yields of HCN for nylon in tube furnace experiments and HCN concentrations in full-scale cable fire tests are in good agreement with the corresponding measured data. The derived relationship is used to analyse the contributions of CO from different materials in a complex fire reconstruction. The generalized relationship is then used to predict HCN concentrations in two full-scale nylon fires and the predicted concentrations are compared with both experimental data and predictions from a flamelet model. Finally, a method to incorporate the generalized relationship within CFD fire simulations to determine HCN (or CO) concentrations based on measurements of CO (or HCN) yields is presented