Water heater in closet

[Marc M]

M2005.2 Prohibited locations. Fuel-fired water heaters shall not be installed in a room used as a storage closet.Water heaters located in a bedroom or bathroom shall be installed in a sealed enclosure so that combustion air will not be taken from the living space.

Just trying to get a handle on this code,
is the point of this code, written in this manner to reduce the risk of carbon monoxide entering the room (thus the sealed closet etc...), or is it to ensure the WH has sufficient combustion air so there is no chance of incomplete combustion and then a risk of carbon monoxide? Or am I way off?
And, why limited to a bedroom or bathroom?

[Jerry Peck - Codeman]

Hi Marc,

"is the point of this code, written in this manner to reduce the risk of carbon monoxide entering the room (thus the sealed closet etc...), or is it to ensure the WH has sufficient combustion air so there is no chance of incomplete combustion and then a risk of carbon monoxide?"

Yes. Both.

"why limited to a bedroom or bathroom?"

Not in a bathroom a bathroom is (typically) a small area and combustion air could become a problem, even with dilution make-up air with the door closed and someone in there. Just not a wise idea to install a gas water heater in a bathroom where people will be in such a confined area.

Not in a bedroom as people will be sleeping in a bedroom and if a problem were to develop the occupants would never know, they would just continue to sleep forever.

Not in a storage closet as storage closets are small areas with storage, and there is the potential for combustion problems and fire from the stored items, which would likely include easily ignitable items and liquids and/or flammable items and liquids - neither of which you would want in a small area with an open flame source.

If the water heater is installed in a sealed enclosure (note that the sealed enclosure is not referred to as a "closet") such that no combustion air will be taken from the bedroom or bathroom living space.