Garage Furnaces

Yes, I did take the IRC 2003 codes classes and yes I do have the code book.

When putting a furnace in a garage it must be 18" above the floor. The material used to build this can be wood, right ???
My question does there need to be something that has a fire rating to be between the furnace and the platform? Like drywall, sheet metal, etc. not plywood. My answer would have been yes, but I can’t find that in the codes book, section 24.

If someone could help me out with this, please give me the section in the code book.

Tom P’ski

M1402.2 Clearances. Clearances shall be provided in accordance with the listing and the manufacturer’s installation instructions.

With most furnaces, there is no heat produced at the platform/plenum. This is generally where the blower assembly is.

The fire rating of the plenum must conform to that of the required rating of the garage separation. Also, any ducts in the garage must be 20ga sheet metal (or equipped with fire dampers - CBC)

The furnace does not have to be 18 inches off of the floor the ruling is 18 inches to point of ignition which is the burners and the burners will measure 18 inches from the floor