Hearth clearances at gas inserts

[Konrad]

I'm a little unclear about the hearth requirements for gas inserts.

IRC appears to defualt to the manufacturer's listed installation requirements. The Code Check flip book (HVAC) calls out 16" for gas inserts.

Is there an industry standard, or have I misread the IRC?

[crusty]

It would depend on whether you are referring to a gas insert or a gas appliance installed in the fireplace. For a gas insert, manufacturer's specs would rule for a listed insert. Non listed would default to code requirements. If it is simply a gas appliance installed in the fireplace I believe standard fireplace hearth extension requirements would need to be upheld.