A Comparison of the Gas-Phase Fire Retardant Action of DMMP and Br2 in Co-Flow Diffusion Flame Extinguishment
Gregory T. Linteris, Nicolas Bouvet, Valeri I. Babushok, Fumiaki Takahashi, Viswanath R. Katta, Roland Kraemer
Phosphorus-containing compounds are added to polymers as fire retardants, and they are believed to act in both the gas and solid phase. In gaseous flame studies, they have been shown to be very effective gas-phase flame inhibitors; however, their performance varies with flame type. In particular, their effectiveness in co-flow diffusion flames is much lower than in other flames. To understand this behavior, experiments are performed with dimethyl methylphosphonate (DMMP) added to the fuel stream of methane-air co-flow diffusion flames (cup-burner configuration). At low volume fraction, phosphorus (via DMMP addition) is shown to be about four times as effective as bromine (via Br2 addition) at reducing the amount of CO2 required for extinguishment; however, above about 5000 μL/L, the marginal effectiveness of DMMP is about 25 times lower. In contrast, the diminished effectiveness does not occur for Br2 addition. To explore the role of condensation of active phosphorus-containing compounds to the particles in the lowered effectiveness, laser-scattering measurements are performed. Finally, to examine the behavior of the flame stabilization region (which is responsible for extinguishment), premixed burning velocity simulations with detailed kinetics are performed for DMMP or Br2 addition to methane-air flames. Analyses of the numerical results are performed to understand the variation in the inhibition mechanism with temperature, agent loading, and stoichiometry, to interpret the loss of effectiveness for DMMP in the present experiments.
Combustion and Flame
Cup burner flame, Fire retardants, phosphorus, dimethyl methylphosphonate (DMMP), particle formation, Rayleigh scattering, bromine
, Bouvet, N.
, Babushok, V.
, Takahashi, F.
, Katta, V.
and Kraemer, R.
A Comparison of the Gas-Phase Fire Retardant Action of DMMP and Br2 in Co-Flow Diffusion Flame Extinguishment, Combustion and Flame
(Accessed December 2, 2023)