Why is hfo-1234yf is classified as A2L- mildly flammable?

HFO-1234yf is classified as A2L, indicating it is mildly flammable, due to its low flammability and moderate toxicity. This classification is based on its flash point, which is higher than that of more flammable substances, but still poses some flammability risk under certain conditions. A2L refrigerants are designed to be safer alternatives to higher global warming potential (GWP) substances, making them suitable for use in air conditioning and refrigeration while adhering to safety standards. The "L" designation signifies that it has a lower toxicity compared to A2 refrigerants.