Monessen Hearth Vent-Free Fireplace Systems DBX24C* - Manual (Page 10)

10 33D4047
GENERAL INSTALLATION INFORMATION
Figure 3 - Sample Room for Determining the Maximum Heater Rating
W
ARNING
If the area in which the heater may be operated is smaller than that defi ned as an
unconfi ned 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
BTU
/
Hr
50
Consider two connecting rooms with an open area between, with the following dimensions:
L
1
= 15 1 /
2
Ft., L
2
= 12 Ft., W = 12 Ft., H = 8 Ft.
BTU
/
Hr =
(15 1 /
2
+ 12) x (12) x (8)
x 1000 = 52800
BTU
/
Hr
50
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 = 29760
BTU
/
Hr
50