Thread: Combustion Air?

Chapter 17 IRC requires an inlet and an outlet duct (one near ceiling/one near floor) for purpose of providing combustion air. Yet, I continually see one duct only in in ceilings of garages and laundry rooms. Could all of these be incorrect? Any info will be appreciated.

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Tom,

Do they meet this?

From the IRC.

G2407.6.2 (304.6.2) One-permanent-opening method.

One permanent opening, commencing within 12 inches (305 mm) of the top of the enclosure, shall be provided. The appliance shall have clearances of at least 1 inch (25 mm) from the sides and back and 6 inches (152 mm) from the front of the appliance. The opening shall directly communicate with the outdoors or through a vertical or horizontal duct to the outdoors, or spaces that freely communicate with the outdoors (see Figure G2407.6.2) and shall have a minimum free area of 1 square inch per 3,000 Btu/h (734
mm2/kW) of the total input rating of all appliances located in the enclosure and not less than the sum of the areas of all vent connectors in the space.

Combustion Air Sources

Now for the next question; do they really work?

Originally Posted by Michael Thomas

Combustion Air Sources

Note that this table Michael cites uses the incorrect units of BTU instead of BTU/h. Using BTU instead of BTU/h seems to be getting more common.

- BOB

Thanks Guys for the info. Don't know how I ever got along without you.

"Note that this table Michael cites uses the incorrect units of BTU instead of BTU/h. Using BTU instead of BTU/h seems to be getting more common."

Bob,

Head right on over to Ft. Collins, and bust their chops:

http://fcgov.com/nbs/pdf/basement.pdf