Flammability limits — a new technique

Abstract

A technique has been developed to study the extinguishment of premixed laminar flames. The technique utilizes a steady state burner with a tent flame surrounded by a separate stream of ignition gases, which are the product gases of another premixed flame using the same fuel. Extinguishment is determined by observation of the shape of the tent flame as the composition of the test mixture of fuelsuppressant-air is changed so as to move toward a composition region of extinguishment. Results are reported for five methane-air flames and methanesuppressant-air flames containing the suppressants Helium, Argon, Nitrogen, carbon dioxide and Halon 1301 (CF 3Br). The technique yields a slightly broader flammability region than other techniques previously used. The relation between the results of this technique and the standard flammability techniques is discussed.