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DETERMINING MINIMUM IGNITION ENERGIES AND QUENCHING DISTANCES OF DIFFICULT-TO-IGNITE COMPOUNDS
Citation:
Smith*, N D., W A. Mitchell*, AND M. W. Tufts. DETERMINING MINIMUM IGNITION ENERGIES AND QUENCHING DISTANCES OF DIFFICULT-TO-IGNITE COMPOUNDS. JOURNAL OF TESTING AND EVALUATION (ASTM) 31(3):5 p., (2003).
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Description:
Minimum spark energies and corresponding flat-plate electrode quenching distances required to initiate propagation of a combustion wave have been experimentally measured for four flammable hydrofluorocarbon (HFC) refrigerants and propane using ASTM (American Society for Testing and Materials) Standard Test Method E582-88. Among the HFCs studied, the minimum ignition energies span a range of approximately 0.9 to 26,300 mJ. The minimum ignition energy of the most flammable HFC studied (HFC-152a) is approximately twice that of propane, while the minimum ignition energy of the least flammable HFC studied (HFC-32) is approximately 88,000 times that of propane. Attempts to establish the minimum ignition energy of HFC-245ca were unsuccessful due to the refrigerant's flammability dependence on the moisture content of the refrigerant/air mixture and associated experimental difficulties. Modifications to the ASTM procedure which were found necessary to measure ignition energies over the wide range exhibited by the HFCs are described, and additional refinements to accommodate moist gas mixtures are recommended.
