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10
33D0237
W
ARNING
If the area in which the heater may be operated is smaller than that defined as an
unconfined space or if the building is of unusually tight construction, provide
adequate combustion and ventilation air by one of the methods described in the
National Fuel Gas Code, ANSI Z223.1, 1992, Section 5.3 or applicable local codes.
The following formula can be used to determine the maximum heater rating per the definition of unconfined space:
BTU/HR = (L1 + L2) Ft x (W) Ft x (H) Ft x 1000
50
Consider two connecting rooms with an open area between, with the following dimensions:
L1 = 15 1/2 Ft., L2 = 12 Ft., W = 12 Ft., H = 8 Ft.
BTU/HR = (15 1/2 + 12) x (12) x (8) x 1000
50
= 52800 BTU/HR
If there were a door between the two rooms the calculation would be based only on the room with the heater.
BTU/HR = (15 1/2) x (12) x (8) x 1000
50
= 29760 BTU/HR
GENERAL INSTALLATION INFORMATION
Figure 3 - Sample Room for Determining the Maximum Heater Rating