Rinnai c199e, Installation And Operation Manual

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8 C199 Manual
Unconfined Space:
An unconfined space is defined in National Fuel Gas
Code, ANSI Z223.1/NFPA 54 as “a space whose vol-
ume is not less than 50 cubic feet per 1000 Btu/hr
(4.8 m3 per kW per hour) of the aggregate input
rating of all appliances installed in that space. Rooms
communicating directly with the space in which the
appliances are installed, through openings not fur-
nished with doors, are considered a part of the un-
confined space.” If the “unconfined space” containing
the appliance(s) is in a building with tight construc-
tion, additional outside air may be required for proper
operation. Outside air openings should be sized the
same as for a confined space.
Confined Space:
(
Small Room, Closet, Alcove, Utility Room, Etc.)
A confined space is defined in the National Fuel Gas
Code, ANSI Z223.1/NFPA 54 as "a space whose vol-
ume is less than 50 cubic feet per 1000 Btu/hr (4.8 m3
per kW per hour) of the aggregate input rating of all
appliances installed in that space." A confined space
must have two combustion air openings. Size the
combustion air openings based on the BTU input for
all gas utilization equipment in the space and the
method by which combustion air is supplied:
Louvers and Grills
When sizing the permanent opening consideration
must be taken for the design of the louvers or grills to
maintain the required free area required for all gas
utilizing 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”.
Example:
Wood: 10 in x 12 in x 0.25 = 30 in
2
Metal: 10 in x 12 in x 0.75 = 90 in
2
Combustion Air Requirements ( Common Vent Applications Only )
Location
To maintain proper circulation of combustion air two
permanent openings (one upper, one lower) must be
positioned in confined spaces. The upper shall be
within 12 inches of the top of the confined space and
the lower opening shall be within 12 inches of the
bottom of the confined space. Openings must be
positioned as to never be obstructed.
Using Outdoor Air For Combustion
Outdoor air can be provided to a confined space
through two permanent openings, one commencing
within 12 in. (300mm) of the top and one commenc-
ing within 12” (300mm) of the bottom, of the con-
fined space. The openings shall communicate to the
outside by one of two ways:
Exhaust
Vent termination per ANSI Z223.1/NFPA 54.
For clearances not specified in ANSI Z223.1/
NFPA 54, clearances are in accordance with
local installation codes and the require-
ments of the gas supplier.
(Be sure to also maintain 12” above grade or
anticipated snow level)