ICP 8MPT Installation Insrtuctions page 11

Free Area
iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii
Minimum Free AreaRequired f or Each Opening o r Duct toOutdoors
BTUH (kW) Two Vertical D ucts or Round Duct
Input Two Horizontal Ducts Single Opening Openings BTUH (kW)
Rating BTUH (kW) BTUH (kW) BTUH (kW) sq.
sq.
in./2,000(1 cm2/.09) sq. in./3,000 (1 cm2/.135) sq. in./4,000(1 cm2/.18)
in./4,000(6.5cm2/.18)
50,000 (14.65)
25sq.in.
(161 cm2)
16.7sq.in.
(108 cm2)
12.5sq.in.
(81 cm 2) 4" (101.6mm)
75,000 (21.98)
37.5sq.in.
(242 cm2)
25sq.in.
(161 cm2)
18.75 sq.in.
(121 cm2) 5" (127mm)
100,000 (29.31)
50sq.in.
(322 cm2)
33.3sq.in.
(215 cm2)
25sq.in.
(161 cm2) 6" (152.4mm)
125,000 (36.63)
62.50 sq.in.
(403
cm 2) 41.7sq.in.
(269 cm2)
31.25 sq.in.
(202 cm2) 7" (177.8mm)
150,000 75sq.in. 50sq.in. 37.5sq.in. 7" (177.8mm)
EXAMPLE: Determining Free Area
Furnace Water Heater Total Input
100,000 + 30,000 = (130,000 + 4,000) = 32.5 Scj. In. Vertical
29.31 8.8 (38.11 + .18) = 210 cmL Vertical
Furnace Water Heater Total Input
100,000 + 30,000 = (130,000 + 2,000) = 65 Sq. In. Horizontal
29.31 8.8 (38.11 + .09) = 423 cm2 Horizontal
Indoor CombustionAir
Standard and Known-Air-Infiltration Rate Methods
© NFPA & AGA
Indoor air is permitted for combustion and ventilation, if the Stan-
dard or Known-Air-Infiltration Rate Method is used.
CARBON MONOXIDE POISONING HAZARD
Failure to supply adequate combustion air 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,ODDBTUH (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 tess vol-
ume 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 in-
filtration 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 vol-
ume for the space.
,::' MINIMUM SPACE VOLUME FOR 100% COMBUSTION AND VENTILATION AIR FROM INDOORS
Other T hanFan- A ssisted Total Fan-assisted Total
30,000 BTU 40,000 BTU 50,000 BTU 50,000 BTU 75,000 100,000 B TU 125,000 B TU 150,000 B TU
ACH (8,790 kW) (11,720 kW) (14,650 k W) (14,650 kW) (21,975 kW) (29,300 kW) (36,625 kW) (43,950 kW)
ft3(m3)
0.60 1,050 (29.7) 1,400 (39.2) 1,750 (49) 1,250 (35) 1,875 (52.5) 2,500 (70) 3,125 (87.5) 3,750 (105)
0.50 1,260 (35.3) 1,680 (47.04) 2,100 (58.8) 1,500 (42) 2,250 (63) 3,000 (84) 3,750 (105) 4,500 (126)
0.40 1,575 (44.1) 2,100 (58.8) 2,625 (73.5) 1,875 (52.5) 2,813 (78.8) 3,750 (105) 4,688 (131.3) 5,625 (158)
0.30 2,100 (58.8) 2,800 (78.4) 3,500 (98) 2,500 (70) 3,750 (105) 5,000 (140) 6,250 (175) 7,500 (210.6)
0.20 3,150 (88.2) 4,200 (117.6) 5,250 (147) 3,750 (105) 5,625 (157.5) 7,500 (210) 9,375 (262.5) 11,250 (316)
0.10 6,300 (176.4) 8,400 (235.2) 10,500 (294) 7,500 (210) 11,250 (315) 15,000 (420) 18,750 (525) 22,500 (632)
0.00 NP NP NP NP NP NP NP NP
NP = Not Permitted
Table 2 Minimum Space Volumes were determined by using the
following equations from the National Fuel Gas Code NFPA
54/ANSI Z223.1-2006, 9.3.2.2:
1. For other than fan-assisted appliances such as a draft
hood-equipped water heater,
-- ACH 1000 BTUH
°sou eOVoumOo,.e > '0''( '°t"er )
-- ACH .293 kW
2. For fan-assisted appliances (such as this furnace), calcu-
late using the following equation:
11
Specifications are subject to change without notice
441 01 202301