Inhibition of flames

In addition to the chemical mechanisms of fire retardants, thermal or barrier-type mechanisms may be operative. Coatings may prevent oxygen from reaching the wood surface. Dilution of combustible gases by noncombustible gases and inhibition of flaming by free radicals can also be in effect. Therefore, fire retardancy of wood involves many complex reactions. The effectiveness of a particular fire retardant depends on the overall summation of these competitive and sequential reactions and the thermal and physical environment of the material. 

AnSwear and EP agents in non-crankcase lubricants ferrous metal passivator fluid base stock where inhibition of flame propagabon is desired. Liquid bps = 245-260° SG25 = 1.15 insoluble in H2O, soluble in organic solvents. Akzo Chemie. 

The participation of HX and RX in the inhibition of flame reactions has already been discussed in the chapter 3.1. The participation of antimony atoms in the inhibitor process occurs according to reactions (a) -(d) ... 

The amount and physical character of the char from rigid urethane foams is found to be affected by the retardant (20—23) (see Foams Urethane polymers). The presence of a phosphoms-containing flame retardant causes a rigid urethane foam to form a more coherent char, possibly serving as a physical barrier to the combustion process. There is evidence that a substantial fraction of the phosphoms may be retained in the char. Chars from phenohc resins (qv) were shown to be much better barriers to pyrolysate vapors and air when ammonium phosphate was present in the original resin (24). This barrier action may at least partly explain the inhibition of glowing combustion of char by phosphoms compounds. 

Removal of one of the eorners of the fire triangle normally results in extinguishment of a fire. Propagation of a flame ean also be stopped by inhibition of the ehain reaetions, e.g. using dry powders or organo-halogen vaporizing liquids. 

The production of ground-state gaseous atoms which is the basis of flame spectroscopy may be inhibited by two main forms of chemical interference (a) by stable compound formation, or (b) by ionisation. 

Creitz, E.C., Inhibition of diffusion flames by methyl bromide and trifluoromethy 1-bromide applied to the fuel and oxygen sides of the reaction zone, J. Res. App. Phys. Chem., 65, 389, 1961. 

Although there seems little doubt that antimony trihalides play a chemical role in inhibition of free radical chain reactions in the flame zone, a comparison... 

Research on water explosion inhibiting systems is providing an avenue of future protection possibilities against vapor cloud explosions. British Gas experimentation on the mitigation of explosions by water sprays, shows that flame speeds of an explosion may be reduced by this method. The British Gas research indicates that small droplet spray systems can act to reduce the rate of flame speed acceleration and therefore the consequential damage that could be produced. Normal water deluge systems appear to produce too large a droplet size to be effective in explosion flame speed retardation and may increase the air turbulence in the areas. 

Day, M. J., D. V. Stamp, K. Thompson, and G. Dixon-Lewis. 1971. Inhibition of hydrogen-air and hydrogen-nitrous oxide flames by halogen compounds. 13th Symposium (International) on Combustion Proceedings. Pittsburgh, PA The Combustion Institute. 705-21. 

Westbrook, C. K. 1980. Inhibition of laminar methane-air and methanol-air flames by hydrogen bromide. Combustion Science Technology 23 191-202. 

However, the question whether the combustion of oxidised or weathered pulverised coal would maintain a self-sustaining flame in a full-size industrial boiler at maximum load cannot be addressed within the present study. The inhibition of volatile matter release, due to the promotion of char condensation reactions during coal pyrolysis, suggests that this may not be the case, a point pertaining especially to the more severely oxidised coals (i.e. 373 K for 112 days). Clearly there is need for ture work within this area of pulverised coal combustion. 

Bardwell, J., Inhibition of Combustion Reactions by Inorganic Lead Compounds, Combustion and Flame, Vol. 5, No. 1, 1961, pp. 71-75. 

Tris (2-ethyl hexyl) phosphate (TOP) Tricresyl phosphate (TCP) Tributyl phosphate Triethyl phosphate Flame retardant plasticizers for inhibition of DB rocket propellants... 

It is, in fact, a combination of properties such as compatibility, tensile strength (TS), % elongation (E), bond strength (BS) with propellant and explosive plasticizer (NG)/non-explosive plasticizer (TA,DEP,DOA,DOP etc.) migration or absorption, heat resistance and flame retardance which makes a polymer suitable for inhibition of solid propellants. A compromise among these properties is made in such a way that the performance of inhibited propellants after conditioning at ambient, cold (-40 °C) and hot (+60 °C) temperatures is satisfactory during static evaluation. 

Flames. Reactions 6 and 7 must be largely responsible for inhibition in flames. They replace the highly reactive H and OH by a less reactive X. The loss in the concentration of H and OH would decrease the... 

Determine the amount of CO2 addition required to obtain a 10% decrease in the flame speed of an atmospheric, stoichiometric methane-air flame. Explain how CO2 inhibits the flame speed. 

M.D. Rumminger, D. Reineldt, V. Babushok, and G.T. Linteris. Numerical Study of the Inhibition of Premixed and Diffusion Flames by Iron Pentacarbonyl. Combust. Flame, 116 207-219,1999. 

The transfer of heat from layer to layer is a natural mechanism of flame propagation. The cooling of the combustion products which follows combustion does not by itself inhibit combustion. 

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