Installation Manual

42 Rinnai I-Series Condensing Boiler Solo Manual
Unconned Space
An unconned space is dened in Naonal Fuel Gas Code, ANSI Z223.1/NFPA 54 as “a space whose
volume is not less than 50 cubic feet per 1000 Btu/hr (4.8 m3 per kW per hour) of the aggregate
input rang of all appliances installed in that space. Rooms communicang directly with the space
in which the appliances are installed, through openings not furnished with doors, are considered a
part of the unconned space.” If the “unconned space” containing the appliance(s) is in a building
with ght construcon, addional outside air may be required for proper operaon. Outside air
openings should be sized the same as for a conned space.
Conned Space
A conned space is dened in the Naonal Fuel Gas Code, ANSI Z223.1/NFPA 54 as "a space whose
volume is less than 50 cubic feet per 1000 Btu/hr (4.8 m3 per kW per hour) of the aggregate input
rang of all appliances installed in that space." Examples include a small room, closet, alcove,
ulity room, etc. A conned space must have two combuson air openings. Size the combuson air
openings based on the Btu input for all gas ulizaon equipment in the space and the method by
which combuson air is supplied.
Using Indoor Air For Combuson
When using air from other room(s) in the building, the total volume of the room(s) must be of
adequate volume (greater than 50 cubic feet per 1000 Btu/hr). Combuson air openings between
joining rooms must have at least 1 square inch of free area for each 1000 Btu/hr, but not less than
100 square inches each.
Using Outdoor Air For Combuson
Outdoor air can be provided to a conned space through two permanent openings, one
commencing within 12 in. (0.30 m) of the top and one commencing within 12 in. (0.30 m) of the
boom, of the conned space. The openings shall communicate to the outside by one of two ways.
When communicang directly with the outdoors through horizontal ducts, each opening shall have
a minimum free area of 1 in
2
/2000 Btu/hr (1100 mm
2
/kW) of total input rang of all appliances in
the conned space.
Note: If ducts are used, the cross seconal area of the duct must be greater than or equal to the
required free area of the openings to which they are connected.
Louvers and Grills
When sizing the permanent opening consideraon must be taken for the design of the louvers or
grills to maintain the required free area required for all gas ulizing equipment in the space. If the
free area of the louver or grill design is not available, assume wood louvers will have 25% free area
and metal louvers or grills will have 75% free area. Under no circumstance should the louver, grill
or screen have openings smaller than 1/4 in.
Examples: Wood: 10 in. x 12 in. x 0.25 = 30 in.
2
Metal: 10 in. x 12 in. x 0.75 = 90 in.
2