Diode Laser-based Measurements of Fuels, Oxidizers, and Combustion Products during Fire Suppressant Testing

Near infrared tunable diode laser (NE-TDL) spectroscopy is used to quantify HF gas produced during fire suppressant testing of halon alternatives. Results of comparisons with other techniques for measuring HF gas concentrations are discussed. Measurements of HF gas produced in laboratory and real-scale fire suppression testing are presented. The necessity for time-resolved measurements during testing of suppression systems designed to scavenge HF gas is demonstrated. INTRODUCTION Fire and explosion suppression is of critical importance on board land combat vehicles. Currently, Halon 1301 (CF3Br) is employed to suppress fires and explosions in most military vehicles. However, due to its high ozone depletion potential (ODP), Halon 1301 was banned from production by international agreement [l] as of 1 January 1994. A current, service-wide program [2] is underway to identify near-term, environmentally acceptable halon alternative technologies. Important properties for successful Halon alternatives are high suppression efficiency, low ODP, low suppressant residue after use, low electrical conductivity, stability under long term storage, and non-toxicity prior to and during dispersion. Recent work [3] has shown that hydrogen fluoride gas (HF) is the principal toxic gas produced during fire suppression by Halon 1301 and by fluorocarbon-based fire suppressants. Therefore, for fluorocarbon-based halon alternatives, minimization of HF gas production during fire suppression is an important criterion. The work presented here describes our efforts using near-infrared tunable diode lasers (NIR-TDL) to measure HF gas produced during fluorocarbon-based chemical suppression of laboratory and real scale fires.