MINIMUM AREA IN SQUARE FEET FOR UNCONFINED SPACE INSTALLATIONS
FURNACE | WITH 8 FT. CEILING |
MAXIMUM BTUH | MINIMUM AREA IN SQUARE FEET |
INPUT RATING | OF UNCONFINED SPACE |
|
|
60,000 | 375 |
80,000 | 500 |
100,000 | 625 |
120,000 | 875 |
|
|
7
CONFINED
SPACE
1.All air from inside the building as in Figure 8: The confined space shall be provided with two perma- nent openings communicating directly with an addi- tional room(s) of sufficient volume so that the com- bined volume of all spaces meets the criteria for an unconfined space. The total input of all gas utiliza- tion equipment installed in the combined space shall be considered in making this determination. Refer to Table 2 for minimum open areas require- ments.
2.All air from outdoors as in Figure 9: The confined space shall be provided with two permanent open- ings, one commencing within 12 inches of the top and one commencing within 12 inches of the bot- tom of the enclosure. The openings shall communi- cate directly, or by ducts, with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors. Refer to Table 2, for minimum open areas requirements.
TABLE 2
MINIMUM FREE AREA IN SQUARE INCHES
EACH OPENING (FURNACE ONLY)
Furnace | Air | Air From Outside | ||
Maximum | ||||
From |
|
| ||
BTUH/INPUT |
|
| ||
Inside | Vertical | Horizontal | ||
Rating | ||||
| Duct | Duct | ||
|
| |||
60,000 | 100 | 15 | 30 | |
80,000 | 100 | 20 | 40 | |
100,000 | 100 | 25 | 50 | |
120,000 | 120 | 30 | 60 | |
|
|
|
| |
Installer’s Guide
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