A study of fire-retardant mechanisms in the gas phase by FTIR spectroscopy

Abstract

This paper presents initial results of vapour-phase chemistry of volatile fire retardants, which may contain phosphorus, bromine or iron, in the presence of fuel from the burning material. Two studies have been carried out using an isothermal tubular-flow reactor. In the first study the influence of a flame-retardant ignition limits of fuel/fire-retardant additive at different temperatures has been determined. These results indicate that a commercial fire retardant (Reofos 95), a phosphorus-containing additive, and ferrocene, are effective gas-phase additives with isooctane, but that bromobenzene is not. With toluene, all additives have a negative effect on the ignition temperature of the fuel. In the second study, the gas-phase mechanisms of fire-retardant action have been studied using Fourier-transform infrared spectroscopy (FTIR). The FTIR study combined with target factor analysis chemometric software indicates that product and intermediate gas-phase species (H 3 PO 4 , (CH 3 O) 2 P(OH)O and CH 3 OP(OH) 2 O) can be detected over a wide range of temperatures (400-900°C).