The development of a model for the prediction of polymer spontaneous ignition temperatures in high pressure enriched oxygen across a range of pressures and concentrations

High pressure enriched oxygen is used in a wide number of areas, including aircraft, medical breathing apparatus, diving, mining and mountaineering operations. It is also used for a number of industrial processes, but is most commonly used for combustion. Where the pressure or concentration of oxygen is increased well above that of atmospheric, oxidation reactions occur more readily, and at a faster rate, relative to those under atmospheric conditions. Thus the criteria used for polymer selection is key to preventing, or at least limiting, the possibility of a catastrophic oxygen incident which endangers both property and human life. In this work spontaneous ignition temperature (SIT) data obtained in high pressure enriched oxygen from both differential scanning calorimetry and oxygen bomb testing are compared. A model is derived to enable the calculation of a SIT of a non-metal at any pressure and oxygen concentration using existing test data from other pressures. This has been shown to work with reasonable success for most materials tested, being validated using the comparison of test data from the oxygen bomb test and Pressurised Differential Scanning Calorimetry (PDSC) testing. These results may indicate the suitability of a PDSC for safety testing in the future. Further work is needed to increase the data base of ignition test data from PDSCs, and thermodynamic constants to allow for the direct comparison, and to assess the suitability of this apparatus for safety testing of more materials.