The main objective of this project is the formulation of substitutes for the halons which have the best efficiency as chemical inhibitors of combustion and the lowest ozone depletion potential (O.D.P.).
Preliminary studies have indicated that viable alternative compounds will be found among the follwing type of compounds:
(a) the perfluoroalkanes - fully fluorinated compounds (FCs)
(b) the hydrofluoroalkanes - hydrofluorinated hydrocarbons (HFCs)
(c) patially chlorinated or brominated hydrocarbons such as the hydrochlorofluorocarbons (HCFs)
Compounds of type (a) and (b) are considered as suitable replacements since they contain no chlorine or bromine and will therefore have no effect on ozone depletion. Compounds of type (c) will have lower ozone depletion potentials since the presence of hydrogen in the molecule makes them susceptible to attack by OH in the lower atmosphere. This reduces their residence time in the atmosphere and a smaller fraction of the parent compound compared to the CFCs will therefore reach the stratosphere to cause ozone loss.
Therefore, with the purpose of formulating substitutes of halons which have optimal properties as fire-extinguishing agents, the main objectives of this project can be summarized as follows:
* Producing reliable experimental data concerning the ability of FCs, HFCs or HCFCs to inhibit oxidations, flames and detonations,
* Improving the understanding of the mechanism of the inhibition of combustions and oxidations by FCs, HFCs or HCFCs.
* Developing correctly validated mechanistic models aimed at the prediction of the inhibition induced by the addition of FCs, HFCs or HCFCs.
* Analysis of the potential atmospheric impacts of using the proposed replacements of halons, including experimental investigation of their reactivity with ozone to see whether this could represent a significant atmospheric loss process for the parent compound.
Funding SchemeCSC - Cost-sharing contracts
OX11 0RA Didcot - Oxfordshire