Curious to know how the following confined space issue would be presented\worded in your inspection report:
I have a gas fired water heater and furnace, both vented VIA chimney, with an aggregate of 120k BTU/h.
50 cubic feet of combustion air needed per 1k BTU/h, which puts me at 6k cu ft combustible air needed.
The room this equipment is located is in a basement, is roughly 870 cubic ft, and incorporates a 16.25sq ft door opening, with no door attached.
The room adjacent to the equipment\door opening is 3,249 cu ft, which puts me at 4,125 cu ft. So I’m shy 1,875 cu ft of needed air.
It should be noted that the ‘adjacent room’ incorporates the stairwell to the main floor, with a door at the top of the stairwell. The stairwell space is roughly 110 cu ft - still well below what is required.
Also of note is this scenario applies to my house, which I’ve lived in for 20yrs. I’ve never had any issue with negative pressure impacting the water heater venting (smoke test), and don’t believe the lack of combustible air was flagged as ‘defect’ when my inspection took place (although it’s hard to recall after all this time). I do recall the inspector telling me verbally to never put a door on the utility room.
I know I’m going encounter this scenario once I start doing inspections, hence the question to those with first had experience.
It’s a judgement call and comes with experience. Is the indoor area where combustion air is taken from a tight construction? is it finished? if it’s a tight construction, I would call it out, if not I would make a comment about it explaining if the area is ever sealed to improve energy loss and or finished, additional combustion air may be required. A lot of times you can see daylight through the openings lack of combustion air won’t be a problem in such a building.
Thanks, Simon.
The secondary area the combustion air is pulled from is finished (half finished basement), but not the room housing the equipment itself - primary room. Being built in the mid 50’s the primary room is not tight.
My dilemma is how to classify something like this in a report. Defect, Safety, Repair, etc.?
Observation. You need to describe what you observed. You can always recommend additional combustion air for enhanced safety. As noted, if I felt there was enough draft in the unfinished part and the fact that it opens to larger room. Unless I saw inadequate draft issues, I would not recommend repair. There is nothing to repair at the moment, it’s working fine. However, should any changes take place such as equipment upgrade, remodeling, etc… the area would have to be re-evaluated for proper combustion air.
Remember, we’re not code inspectors, we do not enforce minimum code by the book. If this was new construction, it would probably fail code inspection without additional air ducts. But in existing, old construction, you have to inspect the entire structure as a whole. Remember, HVAC guys take this into account, so they put it in without additional combustion air, it works just fine for decades, then you come marching along and start giving out orders how everything is wrong. You cannot just write everything up or it becomes a code inspection. You have to learn to assess, is it really an issue the way it is built, what can happen, when, how, etc… based on that you state your observation and recommendation.
lack of combustion air won’t be a problem in such a building.