Hot surface ignition test method and date for class 2L refrigerants.

The need for environmentally sustainable substances is rapidly increasing due to societal demands and, associated regulatory pressures as noted in EC 842/2006 (2014). Many low global warming potential (GWP) refrigerants are ISO 817 “class 2L” refrigerants and exhibit reduced flammability properties versus class 3 refrigerants (ISO 2014). Class 2L refrigerants are not easily ignited due to high minimum ignition energy (MIE), and high lower flammability level (LFL) compared to class 3 refrigerants ASTM (2013). Heating/ventilation/air-conditioning/refrigeration (HVACR) standards have focused on LFL and autoignition temperature (AIT) as the basis for equipment safety design (IEC 2018, ASTM 2015). However, AIT might be overly conservative for class 2L refrigerants. A more relevant test is the hot surface ignition temperature (HSIT), where the 2L refrigerant is released onto a hot surface and monitored for subsequent ignition or non-ignition under dynamic conditions (Koban 2016). Therefore, this work highlights recent HSIT test method improvements and data for various 2L refrigerants using the improved HSIT test equipment (Coughlan et al. 2018).