LAUSR

The current study presents an improved test method for refrigerant flammability limit measurements. Such measurements are essential for determining refrigerant safety classifications. Predicated on expert interviews and experiments, several changes to ASTM E681 and related standards are recommended, as follows. The 12 L glass vessel should be replaced with transparent polycarbonate. The orientation of the electrode supports and the temperature probe should be changed from vertical to horizontal. All penetrations should be removed from the rubber stopper, it should be weighted for a total mass of 2.5 kg, and the initial pressure should be 90 kPa absolute. The flame angle should be plotted versus refrigerant concentration to obtain flammability limits. Finally, the vessel pressure should be measured during each test. These changes are relatively easy to implement and they will improve the test precision and reproducibility without significantly changing previously established flammability limits.