1,1,1,3,3-Pentafluoropropane (HFC-245fa) is a hydrofluorocarbon is a colorless gas used primarily for closed-cell spray foam insulation.

Unlike CFC and HCFC blowing agents formerly used for this purpose, it has no ozone depletion potential and is nearly non-toxic.

Although it is intended to remain trapped within the foam insulation, it is practically non-biodegradable with a lifetime of 7.2 years when it eventually does escape into the atmosphere.

[5][6] Honeywell refers to this as "acceptable" in their literature, but they don't include the actual number.

AlliedSignal, who adopted the Honeywell name after acquiring it, decided in 1999 to provide a non ozone depleting blowing agent as an alternative for dichlorofluoroethane (HCFC-141b) and trichlorofluoromethane (CFC-11).