Most all closets will be a confined space.

For the room to NOT be considered a confined space, you take the total INPUT BTU'S and divide by 20 (Example; 50,000 btu/ 20 = 2500 cubic feet of space). I used 50,000 btus as an example only-- most 50 gallon w/h's are approx. 40,000 input btu.

2500 would equal the (bottom) number in cubic feet of space in the room required to NOT BE a "confined space", any smaller than that and the "confined space" requirements are in effect.

Since most w/h closets are approximately 3 x 3 x 8, that would only equal 72 cubic feet. That's a far cry (72) from the 2000 Cu Ft. needed to not be a confined space for a 40,000 but w/h.

Since the confined space requirements are in effect, that means that indoor air openings shall have two openings minimum, each must meet the following:

• one square inch per 1,000 Btu opening size
• 100 square inches (minimum) in size
• not less than 3 inches in its smallest dimension
• one opening within 12 inches of the ceiling
• one opening within 12 of the floor

Now, if there are multiple gas applinaces in a closet (such as a water heater and a gas heater unit) you do the same thing as above, but combine the total btu's and divide by 20 to get the minimum cubic footage requirements for that to be considered a 'confined space'.


Richard