Combustion Air And Ventilation - American Standard GRWF130A94A0A Installation Manual

3.5 Combustion Air and Ventilation

Important: All aspects of the installation of this boiler,
including materials, methods of providing combustion
air and methods of venting products of combustion to the
outdoors must comply with all local codes and the fol-
lowing national standards:
1) CSA B149.1 (most recent edition) - Natural Gas and
Propane Installation Code (Canada)
2) NFPA 54 (most recent edition) - National Fuel Gas Code
(US)
3) NFPA 58 (most recent edition) - Liquefi ed Petroleum
Gas Code (US)
Adequate fl ow of combustion and ventilating air must not
be obstructed from reaching the boiler. Air openings pro-
vided in the boiler casing must be kept free of obstructions
which restrict the fl ow of air. Airfl ow restrictions affect
the effi ciency and safe operation of the boiler. Keep this
in mind should you choose to remodel or change the area
which contains your boiler. Boilers must have a free fl ow
of air for proper performance.
Provisions for combustion and ventilation air shall be
made in accordance with "latest edition" of Section 5.3, Air
for Combustion and Ventilation, of the National Fuel Gas
Code, ANSI Z223.1, or Sections 7.2, 7.3 or 7.4 of CAN/CGA
B149 Installation Codes, and applicable provisions of the
local building codes. Special conditions created by me-
chanical exhausting of air and fi replaces must be consid-
ered to avoid unsatisfactory boiler operation.
Boiler locations may be in "confi ned space" or "unconfi ned
space". Unconfi ned space is defi ned in Table 4 and Figure
10.
Fig. 10
UNCONFINED
50 CU. FT. OR MORE
PER 1000 BTU/HR. INPUT
ALL EQUIP. INSTALLED
These spaces must have adequate air by infi ltration to
provide air for combustion, ventilation, and dilution of
fl ue gases. Buildings with tight construction (for example,
weather stripping, heavily insulated, caulked, vapor bar-
rier, etc.), may need additional air provided as described for
confi ned space.
Confi ned spaces are installations with less than 50 cu. ft. of
space per 1000 BTU/hr input from all equipment installed.
Air for combustion and ventilation requirements can be
supplied from inside the building as in Figure 12 or from
the outdoors, as in Figure 13.
CONFINED
Fig. 11
LESS THAN 50 CU. FT.
PER 1000 BTU/HR. INPUT
ALL EQUIP INSTALLED
1. All air from inside the building as in Figure 12: The
confi ned space shall be provided with two permanent
openings communicating directly with an additional
room(s) of suffi cient volume so that the combined vol-
18-CG02D1-4
18
ume of all spaces meets the criteria for an unconfi ned
space. The total input of all gas utilization equipment
installed in the combined space shall be considered
in making this determination. Refer to Table 4, for
minimum open areas required.
2. All air from outdoors as in Figure 13: The confi ned
space shall be provided with two permanent open-
ings, one commencing within 12 inches of the top and
one commencing within 12 inches of the bottom of the
enclosure. The openings shall communicate directly,
or by ducts, with the outdoors or spaces (crawl or attic)
that freely communicate with the outdoors. Refer to
Table 5, for minimum open areas required.
A variety of potential sources of carbon monoxide can be
found in a building or dwelling such as gas-fi red clothes
dryers, gas cooking stoves, water heaters, boilers and
fi replaces. The U.S. Consumer Product Safety Commission
recommends that users of gas-burning appliances install
carbon monoxide detectors as well as fi re and smoke
detectors per the manufacturer's installation instructions
to help alert dwelling occupants of the presence of fi re,
smoke or unsafe levels of carbon monoxide. These devices
should be listed by Underwriters Laboratories, Inc. Stan-
dards for Single and Multiple Station Carbon Monoxide
Alarms, UL 2034 or CSA International Standard, Residen-
tial Carbon Monoxide Alarming Devices, CSA 6.19.
TABLE 4
Minimum Area in Square Feet for Unconfi ned
Space Installations
Boiler Maximum
BTUH / Input Rating
90,000
130,000
173,000
215,000
TABLE 5
Minimum Free Area in Square Inches Each
Opening (Boiler Only)
Boiler Air From
Maximum Inside
BTUH /
Input Rating
90,000 100
130,000 130
173,000 175
215,000 215
With 8 Foot Ceiling
Minimum Area in Square
Feet of Unconfi ned
Space
560
810
1080
1340
Air From Outside
Vertical Horizon-
Duct tal Duct
25 50
35 70
45 90
55 110