FRESH AIR FOR COMBUSTION AND VENTILATION
Continued
Example 2: Locating Heater in Confined (Closed) Area
NOTICE
A confined area has an air volume of less than 50 cubic feet for each 1000 BTU/Hr input rating of all appliances in the area (cubic feet equals length x width x height of area). Include adjoining rooms only if there are no doors between the rooms.
If you install this heater in a confined area, you must provide additional fresh air.
Ventilating Confined Area
This fresh air would come from an adjoining open area or outdoors.
WARNING
The adjoining open area must have enough fresh, outside air ventilation to supply any appliance in that area plus the confined area. Follow instructions under Example 1: Locating Heater in Unconfined (Open) Area, page 17 to make sure fresh air ventilation is adequate.
When ventilating to an adjoining open area, you must provide two permanent openings: one within 12" of the ceiling and one within 12" of the floor on the wall connecting the two areas. Follow the National Fuel Gas Code NFPA 54/ANSI Z223.1. It lists
Ventilation
Grills into
Closet for
Hot Water
Heater
12"
Ventilation Grills
Connecting Two Rooms to Meet Unconfined Space
12"
Recommended
Fresh Air Duct into Crawl Space in Furnace Area or in
Closet with Water Heater
Figure 15 - Ventilation Air from Inside Building
After providing ventilation between rooms, check for draft hood spillage (see Draft Hood Spillage Test, page 17). If draft hood spillage still occurs, provide more ventilation between rooms or provide permanent ventilation from outdoors. See Providing Permanent
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