International comfort products C9MVX Installation Instructions Manual page 13

Indoor Combustion Air (Unconfined Space)
Standard and Known-Air-Infiltration Rate Methods
W NFPA & AGA
Indoor air is permitted for combustion and ventilation, if the
Standard or Known−Air−Infiltration Rate Method is used.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to this warning could result in personal
injury or death.
Most homes will require additional air from
outdoors for combustion and ventilation. A space
with at least 50 cubic feet per 1,000 BTUH (4.8 cubic
meters per kW) input rating or homes with tight
construction may need outdoor air, supplied
through ducts, to supplement air infiltration for
proper combustion and ventilation of flue gases.
The Standard Method may be used, if the space has no less
volume than 50 cubic feet per 1,000 BTUH (4.8 cubic meters per
kW) of the maximum input ratings for all gas appliances installed in
the space. The standard method permits indoor air to be used for
combustion and ventilation air.
The Known Air Infiltration Rate Method shall be used if the
infiltration rate is known to be less than 0.40 air changes per hour
MINIMUM SPACE VOLUME FOR 100% COMBUSTION AND VENTILATION AIR FROM INDOORS
Table 2
30,000 BTU
(8,790 kW)
ACH
0.60 1,050 (29.7)
0.50 1,260 (35.3)
0.40 1,575 (44.1)
0.30 2,100 (58.8)
0.20 3,150 (88.2)
0.10 6,300 (176.4)
0.00 NP
ACH = Air Changes per Hour
NP = Not Permitted
Table 2 Minimum Space Volumes were determined by using the
following equations from the National Fuel Gas Code ANSI
Z223.1/NFPA 54−2009, 9.3.2.2:
1. For appliances other than fan−assisted appliances (such
as a draft hood−equipped water heater), calculate using the
following equation:
Required Volume
other
Required Volume
other
440 01 2024 04
Other Than Fan-Assisted Total
40,000 BTU 50,000 BTU
(11,720 kW) (14,650 kW)
1,400 (39.2)
1,680 (47.04) 2,100 (58.8)
2,100 (58.8) 2,625 (73.5)
2,800 (78.4)
4,200 (117.6) 5,250 (147)
8,400 (235.2) 10,500 (294)
NP
(
I
3 other
21 ft

1000 BTUH
ACH
(
I
3 other
59 m

.293 kW
ACH
Specifications are subject to change without notice.
(ACH) and equal to or greater than 0.10 ACH. Infiltration rates
greater than 0.60 ACH shall not be used. The minimum required
volume of the space varies with the number of ACH and shall be
determined per Table 2 or Equations 1 and 2. Determine the
minimum required volume for each appliance in the space, and
add the volumes together to get the total minimum required
volume for the space.
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in
personal injury or death.
An unconfined space or homes with tight
construction may not have adequate air infiltration
for proper combustion and ventilation of flue gases.
Most homes will require additional air.
The Known Air Infiltration Rate Method shall be used if the
infiltration rate is known to be less than 0.40 air changes per hour
(ACH) and equal to or greater than 0.10 ACH. Infiltration rates
greater than 0.60 ACH shall not be used. The minimum required
volume of the space varies with the number of ACH and shall be
determined per Table 2 or Equations 1 and 2. Determine the
minimum required volume for each appliance in the space, and
add the volumes together to get the total minimum required
volume for the space.
50,000 BTU
(14,650 kW)
3 3
ft ( )
m
1,750 (49) 1,250 (35)
1,500 (42)
1,875 (52.5)
3,500 (98) 2,500 (70)
3,750 (105)
7,500 (210)
NP NP
2. For fan−assisted appliances (such as this furnace),
calculate using the following equation:
Required Volume
)
Required Volume
where:
)
I = all appliances other than fan−assisted input in BTUH
other
I = fan−assisted appliance input in BTUH
fan
ACH = air change per hour (percent of volume of space
exchanged per hour, expressed as a decimal)
WARNING
Fan-assisted Total
75,000 100,000 BTU
(21,975 kW) (29,300 kW)
1,875 (52.5) 2,500 (70)
2,250 (63) 3,000 (84)
2,813 (78.8) 3,750 (105)
3,750 (105) 5,000 (140)
5,625 (157.5) 7,500 (210)
11,250 (315) 15,000 (420)
NP NP
(
3
15 ft

fan
ACH
(
3
.42 m

fan
ACH
125,000 BTU
(36,625 kW)
3,125 (87.5)
3,750 (105)
4,688 (131.3)
6,250 (175)
9,375 (262.5)
18,750 (525)
NP
)
I
fan
1000 BTUH
)
I
fan
.293 kW
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