This gas water heater is installed in a closet in the garage there is some ventilation as you can see in the picture. Would you consider adequate or not?
I have never fully examined a manufacturer’s recommendations for installation of the gas water heater in a closet because I’ve never had the need to yet. Would information such as air requirements be in there?
Forthcoming I assume?
Yes, the air requirements would be in the manufacturer’s installation manual.
Measure the openings but from here they look too small. Check out page 8 of the pdf
It looks fine. No biggie. A drywall saw and 5 minutes would make it even better.
Been working up till now, so why it should be a problem or a defect now?
Same can be said about a deck that is still standing but does not conform to the minimum standards, no? to be more precise, how do we know it’s working correctly? was a combustion test done with the door shut? was it done while the heater ran for 30 minutes instead of 5? etc, etc… we have no idea by the pictures alone other than it hadn’t burned the place down.
Sounds like the Agents line.
So how does the OP know it is a problem.?
The openings for combustion air in the closet do not meet the NFPA (and thus also the manufacturer’s) prescribed minimums. Again, it may actually be just fine if tested and found to be properly functioning under extreme conditions, but we, as inspectors, don’t normally perform such exhaustive tests, a plumber/HVAC tech would. But even then, one can claim that the tech did not follow the prescribed installation method. If there is a problem with the unit later, for example, the warranty could be void.
Therefore, clear to me that the OP needs more research to determine if the installation is adequate or not before he starts reporting it is wrong or recommends correction.
His doubting of whether or not it is adequate could be as simple as what you stated here above.
Sometime just a few minor footwork can answer you own question since none of us are there to see all the conditions that may affect what you report other than just looking at a picture with no information whatsoever.
Just trying to get a point across for the OP.
Of course, he is asking us what’s in the manual 
But this is the norm on here, as you are well aware
Almost everything we inspect was working until now. I have an old zinsco panel in the old house we just got and the panels been working, it is on the very high end of the list of things to replace, but just because it works doesn’t mean its right.
I saw something out of the ordinary and wasn’t sure if there was a standard that I was not aware of. It seemed very minimal and lacking in my mind so I asked a question. Now I know for the future and will know exactly were to turn to find the answer which was very helpful.
Thank you to all who were helpful in helping me find the answer.
A couple of installation items you will encounter for confined spaces are louvered air inlets. The IFGC specifically rates the wooden louvers at 25% air flow of louver area and the metal louvers at 75% of louver opening. The other consideration is that the minimum dimension of a combustion air opening is 3 inches (for the minimum 100 square inches that would be 3x33.33). The area under a door does not work even if 3 inches because it is not 12 inches from the floor.
304.5.3.1 Combining spaces on the same story.
Where combining spaces on the same story, each opening
shall have a minimum free area of 1 square inch per
1,000 Btu/h (2200 mm2/kW) of the total input rating of
all appliances in the space, but not less than 100 square
inches (0.06 m2). One permanent opening shall commence
within 12 inches (305 mm) of the top and one
permanent opening shall commence within 12 inches
(305 mm) of the bottom of the enclosure. The minimum
dimension of air openings shall be not less than 3
inches (76 mm).
304.10 Louvers and grilles. The required size of openings
for combustion, ventilation and dilution air shall be based on
the net free area of each opening. Where the free area through
a design of louver, grille or screen is known, it shall be used
in calculating the size opening required to provide the free
area specified. Where the design and free area of louvers and
grilles are not known, it shall be assumed that wood louvers
will have 25-percent free area and metal louvers and grilles
will have 75-percent free area. Screens shall have a mesh size
not smaller than 1/4 inch (6.4 mm).
There’s more but those are the basics.
Good info there, Bob.
