Hydrofluoroalkanes

Hydrofluoroalkanes (HFAs) are a class of chemical compounds composed of hydrogen, carbon, and fluorine, with no chlorine or bromine. They are a subset of hydrofluorocarbons (HFCs). HFAs are typically saturated compounds used as refrigerants, blowing agents for foams, and as propellants in aerosol products. They were developed as alternatives to ozone-depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs).

Many HFAs have become common refrigerants in air conditioning and refrigeration systems (for example HFA-134a) and blowing agents for polyurethane foams. Other members serve as propellants in metered-dose inhalers and other spray products. Their advantage is zero ozone depletion potential, but their climate impact varies and can be substantial due to high global warming potential.

Environmental and regulatory status: Under the Montreal Protocol framework, CFCs and HCFCs were phased out; HFAs are not ozone-depleting but are potent greenhouse gases. The Kigali Amendment and other regulatory measures aim to reduce HFC emissions and transition to lower-GWP alternatives such as hydrofluoroolefins (HFOs), hydrocarbons, or CO2-based systems.

Physical properties and safety: HFAs are typically gases or low-boiling liquids at room temperature, with generally low acute toxicity but varying flammability depending on structure; handling and leakage contribute to atmospheric lifetimes. They are being replaced by lower-GWP options in new equipment where feasible.