1 Before installing boiler (continued)
Provide combustion and ventilation air openings:
Do not install an exhaust fan in boiler room. Adequate combustion and ventilation air must be provided to assure proper combustion and prevent possibility of flue gas leakage and carbon monoxide emissions, causing severe personal injury or death.
Opening sizes must comply with state, provincial or local codes. In their absence, use the following when boiler is in a confined room:
•Provide two permanent openings in boiler room — one within 12 inches of ceiling, one within 12 inches of floor. Minimum dimension of each opening is 3 inches.
1.When all air is taken from within building, each opening should be at least one square inch/1,000 Btuh boiler input and freely connect with areas having adequate infiltration from outside.
2.When all air is taken from outdoors, each opening should connect directly or by ducts from outdoors or crawl or attic spaces that freely connect with outdoors and sized as listed below:
a.through outside wall or vertical ducts - at least one square inch/4,000 Btuh boiler input.
b.through horizontal ducts - at least one square inch/2,000 Btuh boiler input.
c.where ducts are used, they should be same cross- sectional area as free area of openings they are connected to.
d.compensate for louver, grille or screen blockage when calculating free air openings. Refer to their manufacturer's instructions for size. If unknown, use:
•wood louvers -
•metal louvers or grilles -
•screens - not less than ¼ inch mesh.
Lock louvers in open position, or interlock with equipment to prove open before boiler operation.
When combustion and ventilation air enters through sidewall openings, ensure openings comply with Figures 2 and 3.
Figure 2 Combustion and ventilation air openings — Boiler room below grade
Figure 3 Combustion and ventilation air openings — Boiler room partially or completely above grade
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