Combustible air vent?

Old 07-17-02, 11:51 AM
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Combustible air vent?

I went to get a permit (which i still think may have ben a mistake) but the guy that reviewed my plans said I need to provide a vent (from the outside) into my mechanical room since I am closing it off from the rest of the basement, which is going to be used as a "recreation room". The size of the "mechanical room" is about 350 sq ft. and houses the water heater and furnace. Has anyone ever done this or heard of it? I don't really want to have to penetrate the wall to the out side....any suggestions? Is there a minimum amout of sq.ft that the mechanical room must be so i don't have to do this?
Old 07-17-02, 12:14 PM
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I had the same comment from my inspector. The alternative which was acceptable was a louvered door between the mechanical room and the finished portion of the basement. Now that it's in, I kind of like the look of that particular door.
Old 07-17-02, 12:21 PM
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Now that sounds like a good idea. I'll run it by him when he see's thati didn't chop a hole in the wall....thanks!!!
Old 07-17-02, 01:05 PM
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At least in our area, the vent is required for combustion air for the gas or oil fired furnace and water heater. If you have a source of combustion air piped directly from the otdoors to these items, the code is satisfied.
Old 07-17-02, 05:40 PM
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You think this permit might have been a mistake? On the contrary, this permit may have saved your life. Without adequate ventilation, the furnace will become starved for combustion air. When this happens, the furnace will begin sucking exhaust gases down from the flue. That resulting carbon monoxide can kill you and your whole family in their sleep. This is the primary reason why the permit system exists (and of course, the city can always use the extra revenue).

In most cases, you want that inspector to find all the code violations he can. The safety of your family depends on it.

Normally you need two fresh-air vents, one that comes in near the ceiling and one that comes in near the floor. The required size depends on the BTUs of your furnace and whether the ducts come in horizontally or vertically. But speak to your inspector about the louvered door idea -- it may be allowed in some circumstances.

It will not be practical to make the mechanical room large enough so that it does not require venting. The required size would be huge.

If your furnace installer left you the manual for the furnace, read it. It will tell you about the fresh air requirements. It will also tell you the required clearances of the walls in front, side, and back of your furnace.
Old 08-21-02, 10:29 AM
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well I found out that a louvered door will not satisfy the building code and inspector. Can anyone tell me how to complete this task? How big does the vent need to be? Does it just need to be an airway between the mechanical room and the outside? On my approved plans he wrote "provide combustion air into mechanical room per '94 UMC Chapter 7" Is this something I can do myself?

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