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915SB: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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Table 4 – Minimum Space Volumes for 100% Combustion, Ventilation and Dilution Air from Outdoors
NP = Not Permitted
L12F012
Fig. 6 – Air for Combustion, Ventilation, and Dilution for Outdoors
Outdoor Combustion Air Method
1. Provide the space with sufficient air for proper combustion,
ventilation, and dilution of flue gases using permanent horizontal or
vertical duct(s) or opening(s) directly communicating with the
outdoors or spaces that freely communicate with the outdoors.
2.
illustrates how to provide TWO OUTDOOR OPENINGS,
one inlet and one outlet combustion and ventilation air opening, to
the outdoors.
a. One opening MUST commence within 12 in. (300 mm) of the
ceiling and the second opening MUST commence within 12 in.
(300 mm) of the floor.
b. Size openings and ducts per
c. TWO HORIZONTAL DUCTS require 1 sq. in. (645 sq. mm) of
free area per 2,000 BTUh (1,100 mm2/kW) of combined input
for all gas appliances in the space per
and Table 3.
d. TWO OPENINGS OR VERTICAL DUCTS require 1 sq. in.
(645 sq. mm) of free area per 4,000 BTUh (550 mm2/kW) for
combined input of all gas appliances in the space per
and
Table 3.
L12F013
Fig. 7 – Air for Combustion, Ventilation, and Dilution from Indoors
3. ONE OUTDOOR OPENING requires:
a. 1 sq. in. (645 sq. mm) of free area per 3,000 BTUh (734
mm2/kW) for combined input of all gas appliances in the space
.
b. Not less than the sum of the areas of all vent connectors in the
space.
The opening shall commence within 12 in. (300 mm) of the ceiling.
Appliances in the space shall have clearances of at least 1 in. (25 mm)
from the sides and back and 6 in. (150 mm) from the front. The opening
shall directly communicate with the outdoors or shall communicate
through a vertical or horizontal duct to the outdoors or spaces (crawl or
attic) that freely communicate with the outdoors.
Indoor Combustion Air© NFPA & AGA
Standard and Known-Air-Infiltration Rate Methods
Indoor air is permitted for combustion, ventilation, and dilution, if the
Standard or Known-Air-Infiltration Method is used.
AIR
CHANGES
PER HOUR
(ACH)
OTHER THAN FAN-ASSISTED TOTAL
(1,000’S BTUH GAS INPUT RATE)
FAN-ASSISTED TOTAL
(1,000’S BTUH GAS INPUT RATE)
30
40
50
26
40
60
80
100
120
140
Space Volume Ft
3
(M
3
)
0.60
1,050 (29.7) 1,400 (39.6)
1,750
(49.5)
910 (25.8) 1,400 (39.6) 1,500 (42.5) 2,000 (56.6) 2,500 (70.8) 3,000 (84.9) 3,500 (99.1)
0.50
1,260 (35.6) 1,680 (47.5)
2,100
(59.4)
1092 (30.9) 1,680 (47.5) 1,800 (51.0) 2,400 (67.9) 3,000 (84.9)
3,600
(101.9)
4,200
(118.9)
0.40
1,575 (44.5) 2,100 (59.4)
2,625
(74.3)
1365
(38.7)
2,100 (59.4) 2,250 (63.7) 3,000 (84.9)
3,750
(106.1)
4,500
(127.3)
5,250
(148.6)
0.30
2,100 (59.4) 2,800 (79.2)
3,500
(99.1)
1820
(51.5)
2,800 (79.2) 3,000 (84.9)
4,000
(113.2)
5,000
(141.5)
6,000
(169.8)
7,000
(198.1)
0.20
3,150 (89.1)
4,200
(118.9)
5,250
(148.6)
2730
(77.3)
4,200
(118.9)
4,500
(127.3)
6,000
(169.8)
7,500
(212.2)
9,000
(254.6)
10,500
(297.1)
0.10
6,300
(178.0)
8,400
(237.8)
10,500
(297.3)
5460
(154.6)
8,400
(237.8)
9,000
(254.6)
12,000
(339.5)
15,000
(424.4)
18,000
(509.2)
21,000
(594.1)
0.00
NP
NP
NP
NP
NP
NP
NP
NP
NP
NP
*Minimum dimensions of 3‐in. (76mm)
NOTE
: Use any of the following combinations of openings:
A & B, C & D, D & E, F & G
* Minimum opening size is 100 sq in. (64516 sq. mm) with
minimum dimensions of 3‐in. (76mm)
{
Minimum of 3‐in. (76mm) when type‐B1 vent is used.