Vermont Castings Jefferson Vent Free Gas Heater
4.Compare the maximum BTU/hour rating the space can support with the total BTU/hour used by the appli- ances.
Example: 76,800 BTU/hour the space can support 80,000 BTU/hour used by appliances
In this example, the maximum BTU/hour that the space can support is less than the total used by the appli- ances. The space is considered to be Confined Space.
Additional air must be provided to meet the require- ments of the
A confined space may be ventilated in two ways:
A. Open or provide at least two ventilating grilles to an adjoining unconfined space. (Fig. 2)
Each of the two grilles must provide an opening of at least 50 square inches, with all opening dimensions being at least 3”. One grille must be within 12” of the ceiling; the other within 12” of the floor. (If the total exceeds 100,000 BTU/hour, additional grilles will be needed.)
B. Vent the room directly to the outdoors. (Provide one square inch of opening for each 4,000 BTU/hour)
For further information on ventilation guidelines and sizing specifications, follow the National Fuel Gas Code/NFPA 54/ANSI Z223.1, Section 5.3.
If the total BTU/hour used by the appliances is less than the maximum BTU/hr the space can support, the room meets the Unconfined Space criteria and no further ventilation is needed.
W A R N I N G
This heater shall not be installed in a confined space unless provisions are made for adequate combustion and ventilation air.
W A R N I N G
If the area in which the heater may be operated is smaller than that defined as an unconfined space, 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.
Option 1 -
Vents to
Adjoining
RoomsOption 3 -
Vents to
Adjoining
Room
Option 2 -
Remove Door to
Adjoining Room
Fig. 5 Supplementing ventilation air.
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