TOPIC: Cobustion Air

Hey guys I've been seeing a trend around here on combustion air pipes for closets.

I have been noticing a lot of new homes having only one large combustion air pipe for closets instead of the two high low configuration I was taught.  I have asked a plumber friend of mine about this and he said he doesn't know of any code changes. 

Anyone here know more about this?  Are they just trying to cut corners here?

Hey John;

Make up or combustion air supply ventilation is required at upper and lower 12" of the gas fired appliance enclosure, closet and or room.  If you don't see a second vent pipe extension, look for another wall mounted rectangular vent behind the appliance.  Keep in mind, depending on age of the structure and type of appliance ventilation requirements may vary, for example; a single gas fired water heater could be supplied by a louvered door to the interior of the structure, an older furnace on a raised foundation may have a make up air vent to the sub area, etc....

I find a lot of exterior closet mounted water heaters in condo complexes.  Seems the enclosure doors deteriorate and get replaced, but the HOA forgets to install vented doors and have thus compromised the make up air for every water heater in the complex.

See I thought they were suppose to have two, one high and one low.  I still need to take the time to look this up in my book.  Been a little busy.

www2.iccsafe.org/states/oregon/08_Reside...Combustion%20Air.pdf

M1702.2

What Marcel and Will said.  Great link Will!

In that first picture, it seems like insulation is coming through that large gap at the ceiling.  Does that go straight to the attic?    If it does, I would want that gap sealed for efficiency reasons.  If it does not, around here they would require more fire block.

Yeah they always go right to the attic.  That was actually a clean job from what I've seen!!!  lol