An extinguishing of a hydrogen jet flame by a supply of a gaseous suppressant into fuel and oxidizer

An experimental determination of fire extinguishing concentrations of gaseous agents (CHF3, C2HF5, C4F10) in relation to a hydrogen jet flame in air at their simultaneous supply into a fuel and an oxidizer have been carried out. It was revealed that limiting contents of the agents exceed substantially the values calculated according to Le Chatelier rule. This result is interpreted on the basis of the concept of an active chemical influence of fluorinated hydrocarbons on a flame, and this influence can be not only inhibitive, but sometimes also promotive. Analytical estimation were made, which confirm a possibility of a substantial heat release at an interaction of hydrogen with the fluorinated hydrocarbons. It was found that the standard method of a determination of minimum fire extinguishing concentrations using the criterion of a time required for extinguishing (10+/-2) s gives a remarkable overestimation of the minimum fire extinguishing concentration in relation to the hydrogen jet flame.