According to newer regulations, the maximum allowable GWP for a refrigerant will be 700. This has led to ASHRAE redefining its refrigerant safety classifications to enable the adoption of A2L refrigerants. This classification previously categorized refrigerants into six buckets defined by: ■ A letter: where A denotes low toxicity and B means highly toxic. ■ A number: where 1 means not flammable, 2 is flammable and 3 denotes highly flammable.
Thus, refrigerants were easily identified to be flammable and/or toxic based on their classifications: A1, A2, A3, B1, B2, or B3. The redefined classification adds a second letter and two more buckets: A2L and B2L. Here, the L denotes that the refrigerant is flammable but with a low burning velocity. A few A2L refrigerants are vying to become the new standard refrigerants in the industry — based on their GWP. The current top contenders are R-32 with a GWP of 675 and R-454B with a GWP of
The history of HVAC refrigerants and their effects on the environment A substance’s impact on global warming is calculated relative to the greenhouse effect of carbon dioxide (CO2). Thus, the GWP of one ton of CO2 is one ton of CO2-equivalent, often shortened to just: 1. The global warming potential of R-410, a popular refrigerant scheduled to be phased down, is 2,088. In other words, the impact of one ton of R-410 released into the atmosphere would be equal to releasing 2,088 tons of CO2.
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