Parametric Study of Hydrogen Fluoride Formation in Suppressed Fires.
Parametric Study of Hydrogen Fluoride Formation in
Suppressed Fires.
(1005 K)
Linteris, G. T.; Gmurczyk, G. W.
Halon Options Technical Working Conference.
Proceedings. HOTWC 1995. May 9-11, 1995, Albuquerque,
NM, 227-238 pp, 1995.
Keywords:
hydrogen fluorides; chemical inhibition; flame
chemistry; flame models; flame retardants; experiments;
halon alternatives
Abstract:
Some of the proposed replacements for CF3Br, the
fluorinated hydrocarbons, are required in higher
concentrations to extinguish fires and contain more
halogen atoms per molecule. Since they decompose in the
flame, they produce correspondingly more hydrogen
fluoride than CF3Br when suppressing a fire. Recent
laboratory experiments with burners using heptane,
propane, and methane have indicated that the amount of
HF formed in steady state can be estimated within about
a factor of two for diffusion flames and within 10% for
premixed flames based on equilibrium thermodynamics. In
this model for HF formation, the inhibitor molecule is
transported to the reaction zone by convection and
diffusion and is consumed in the flame sheet to form the
most stable products (usually HF, CO2, and COF2). In
the present work, the equilibrium model is used to
estimate the upper limit of HF formation in suppressed
fires. The effects of fuel and agent type, fuel
consumption rate, and agent injection rate are included
in the model, as are room volume, humidity, and
concentration of inhibitor necessary to extinguish the
fire. Results are presented for a range of these
parameters, and the predictions are compared, when
possible, with the results of laboratory and
intermediate-scale experiments.
