The US-based Air Conditioning, Heating and Refrigeration Institute (AHRI) has released a test report that examines fire safety issues related to A2L (lower flammability) refrigerants.
The fire service requested that data be developed to identify hazards to fire service personnel when responding to fire events in occupancies with the new refrigerants.
Undertaken in cooperation with global safety certification company UL and the Firefighter Safety Research Institute (FSRI), the study tested and compared A2L refrigerants with A1 refrigerants (no flame propagation) in real-world situations.
“The phase-down and restriction of the most common and widely used refrigerants was initiated in the late 1980s and has spurred innovation, both for the alternative refrigerants that have been introduced as well as in the equipment that uses them,” says the study.
“Safety Group A2L refrigerants (lower toxicity and lower flammability) represent the most recent in the focus of deployable reduced GWP/zero ODP refrigerants.
“Studies conducted by the industry have shown that in order to reach the goals of the Kigali Amendment for global warming impact reduction it is likely that A2L refrigerants will be required.”
Five fire scenarios were designed based on objectives identified by the investigation. In most of the scenarios, the study found comparable results for both A2L and A1 refrigerants.
For example, the investigation for scenario one showed both A1 and A2L refrigerants generated hydrogen fluoride (HF) gas in quantities considered hazardous without personal protective equipment (PPE). There was not a significant relative difference in HF gas generation between R410A (A1) and other lower GWP refrigerants (A1, A2L) used in this investigation.
Scenario two examined conditions at a hallway entrance where firefighters were preparing to advance their attack on the room of origin. For both A1 and A2L refrigerants, heat flux exposure at the hallway entrance was less than 5 kW/m2 at the 3-foot level. This heat flux level is sufficient to cause pain to exposed skin within seconds.
Scenario five simulated a leak occurring in a basement utility room of a large residence that required a 5-tonne ducted AC unit and the associated charge needed to operate it. For the pool of A1 refrigerant (R410A) some flaming was observed at the igniters but did not lead to spread of flame in the room. The pool of A2L refrigerant (R32) was ignited by the fire source and spread away from the ignition source to other ignitable concentrations in the room
Levels of hydrogen fluoride (HF) gas, hazardous without PPE, were generated for both A1 and A2L refrigerants. The levels of HF from the A1 refrigerant were observed to be generated near the ignition source and developed at a much slower pace than the A2L refrigerant. The levels of HF from the A2L refrigerant were significantly higher and faster developing due to spread of the fire to the pooled layer in the room.
The data from the testing will be used by UL Fire Safety Research Institute (FSRI) to develop training materials for the fire service towards their tactical considerations.
To read the report, click here.