The California Fire Service March-April 2023

18 • THE CALIFORNIA FIRE SERVICE MAGAZINE • MARCH/APRIL 2023 here is a vast array of gases available for use in mechanical refrigeration systems and air-conditioning equipment. The California Mechanical Code recognizes over 150 different materials used as refrigerants. Some of these gases are classified as highly flammable; some are classified as highly toxic; and some are neither flammable nor toxic. See Table 1 for a breakdown of refrigerant classifications. The classification of hazard will dictate the type of refrigeration system, and the type of occupancy where each of these different refrigerants can be used. While each refrigerant has different characteristics with regard to flammability and toxicity, they also have different characteristics when considering environmental impacts and global warming. We have seen in the past, environmental restrictions affecting the use of Halon as a fireextinguishing agent, we are now experiencing restrictions of certain refrigerant gases because of their impact on global warming. U.S. Environmental Protection Agency (EPA) has established limits on the use of refrigerants based on their global warming potential (GWP). The end result, is that traditional refrigerants linked to ozone layer depletion and global warming are no longer allowed for use in new refrigeration or cooling systems. As the refrigeration industry develops new refrigerants to comply with the EPA rules, some of these new refrigerants present a low level of flammability. Refrigerants with a lower flammability have resulted in the new classification of Safety Group A2L (shown in Table 1). Several new refrigerants that meet the EPA and California Air Resources Board (CARB) T criteria and guidelines for protection of the environment fall into the Group A2L classification. Group A2L refrigerants present a higher flammability than the traditional Group A1 refrigerants which have been used in residential systems for years. To comply with the EPA, and more importantly in California, the CARB requirements new installations of air conditioning systems in residential occupancies and homes could involve the use of these lower flammability refrigerants, referred to as Group A2L refrigerants. The reality is that Group A2L refrigerants are in use today. They can be found in window mount air-conditioners, the air-conditioning system in automobiles and other refrigeration systems. The change is that they will soon be used in residential buildings, including dwellings. Currently, over 80% of new vehicles sold in the United States contain Group A2L refrigerants. In 2018, over 26 million Heating, Ventilation, and Air-Conditioning (HVAC) units were sold and installed across the globe containing Group A2L refrigerants. Group A2L has been chosen as the next best solution to address the global warming issues where refrigerants are used. Some Group A1 refrigerants currently or previously utilized in air-conditioning systems can burn under the right conditions. R-410A refrigerant has been the primary choice for air-conditioning systems for several years. Even though it is classified as Group A1, under elevated temperatures it can ignite and burn. The description for Group A2L refrigerants in Table 1 indicates they are hard to ignite. This means that a strong ignition Fire Prevention by Kevin H. Scott Understanding flammable refrigerant gases