Fire Safety Science Digital Archive

Alternatives to halon 1301 are sought which are effective fire suppressing agents and which do not create unacceptable safety, environmental, or systems compatibility problems. Investigations of eleven chemical compounds using a deflagratioddetonation tube have revealed a great potential for the technique to study the fire suppression process. The facility is used to evaluate new suppressants, establishing their dynamic characteristics as well as elucidating complex suppression mechanisms occurring in fires under highly dynamic conditions typical of fast turbulent flames, explosions and detonations. A primary feature of the set-up is that the conditions of the ignition event do not affect the suppression process itself. Also, because an agent of interest is premixed with the fuel and air in a section of the tube divorced from the ignition event, the influences of ignition and entrainment of the agent into the flame are minimized. The tube is closed to allow the increase in pressure to influence the gas dynamics and chemistry. The deflagratioddetonation tube arrangement has been successfully employed to clearly discriminate among the dynamic characteristics of the eleven alternative agents, revealing new unexpected effects. The results have been used to help select among the alternatives for full-scale testing in simulated aircraft dry bay fires.