Combustion Air?

[Tom McDonnell]

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.

[Jerry Peck]

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.

[Michael Thomas]

Combustion Air Sources

[DavidR]

Now for the next question; do they really work? ;)

[Bob Mayer]

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

[Tom McDonnell]

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

[Michael Thomas]

"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: :D

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