OPTICAL MEASUREMENT OF TOXIC GASES PRODUCED DURING FIREFIGHTING USINGHALONS

Several optical techniques (FT-TR emission and absorption spectroscopy ;, mid- and near-infrared tunable diode laser absorption spectroscopy) have been used to measure toxic gases produced during inhibition of f lames by halogenated hydrocarbons (Halons). Fire types studied include low-pressure premixed flames, counterflow diffusion atmospheric-press ure flames, open-air JP-8 (turbine fuel) fires, and confined JP-8 fire s, Spectra are presented and analyzed for these fires inhibited by CF3 Br (Halon 1301) and C3F7H (FM-200). For low-pressure premixed flames, spectra are presented which show production of the CF3 radical in meth ane/oxygen/Ar flames inhibited by CF3Br. For large-scale fire testing, it is shown that the type and amount of toxic gases produced during f ire inhibition are highly dependent on fire conditions and temperature s and that some species not considered important (CF2O) are often prod uced in significant amounts, Finally, it is shown that HF production, during inhibition of vehicle fires using FM-200, is highly dependent o n time to suppression.