Flammability and explosion characteristics of mildly flammable refrigerants

The lab-scale tests showed that the laminar burning velocity was inversely correlated with the minimum ignition energy (i.e., higher burning velocities were more easily ignited by lower ignition energies), and as expected, strongly correlated to the deflagration index. Little to no correlation was found for auto-ignition temperature amongst the fluids. In addition, the lab results showed that mildly flammable substances: (1) had a lower probability of ignition from electrical sources (e.g., electrostatic discharge, arcing, etc.), whereby the ignition energies are roughly 1-2 orders of magnitude higher than extremely flammable fluids; (2) had a lower probability of forming a flammable mixture due to higher lower explosion limit levels; and (3) resulted in significantly lower deflagration consequences. The large-scale tests confirmed that peak pressures were significantly lower for mildly flammable substances and showed that these fluids have a much lower deflagration consequence in practical applications.