United States Stove Company VF30IN - Manual (Page 10)

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B. Vent room directly to the outdoors. See Ventilation Air from Outdoors, page 11.
C. Install a lower BTU/Hr firebox, if lower BTU/Hr size makes room unconfined.
If the actual BTU/Hr used is less than the maximum BTU/Hr the space can support, the space
is an unconfined space. You will need no additional fresh air ventilation.
WARNING
If the area in which the firebox and gas log 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.
VENTILATION AIR
Ventilation Air From Inside Building
This fresh air would come from an adjoining unconfined space. When ventilating to an ad-
joining unconfined space, you must provide two permanent openings: one within 12" of the
ceiling and one within 12" of the floor into adjoining room ( see options in Figure 1).
Follow the National Fuel Gas Code NFPA 54/ ANSI Z223.1, Section 5.3, Air for Combustion
and Ventilation for required size of ventilation grills or ducts.
WARNING
Rework worksheet, adding the space of the adjoining unconfined space. The
combined spaces must have enough fresh air to supply all appliances in both
spaces.
AIR FOR COMBUSTION AND VENTILATION
FIGURE 1. Ventilation Air from Inside Building