Bryant 310A Installation, Start--Up, Operating, And Service And Maintenance page 10

DUCTS
TO
O UTDOORS
12 " MAX
(305mm)
1 SQ IN. VENT
PER 2000 B
THR OUGH
BTUH* R OOF
DUCT S
TO
OUTDOORS
1 SQ IN.
PER 2000
A
BTUH*
12 " MAX
(305mm)
CIRCULA TING AIR DUCT S
*Minimum dimensions of 3--- in. (76 mm).
NOTE: Use any of the following combinations of openings:
A & B C & D D & E F & G
Fig. 7 --- Air for Combustion, Ventilation, and Dilution for
Outdoors
The Standard Method:
1. The space has no less volume than 50 cu/ft. per 1,000
Btuh of the maximum input ratings for all gas appliances
installed in the space and
2. The air infiltration rate is not known to be less than 0.40
air changes per hour (ACH).
The Known Air Infiltration Rate Method shall be used, if the
infiltration rate is known to be:
1. Less than 0.40 ACH and
2. 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 3 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.
Table 3 - - Minimum Space Volumes were determined by using
the following equations from the National Fuel Gas Code ANSI
Z223.1- -2009/NFPA 54- -2009, 9.3.2.2:
1. For other than fan- -assisted appliances, such as a draft
hood- -equipped water heater:
= 21ft
Volume
ACH
Other
2. For fan- -assisted appliances such as this furnace:
= 15ft
Volume
ACH
Fan
If:
1 SQ IN.
PER 4000
BTUH*
12 "
D
(305mm)
MAX
F
1 SQ IN .
PER
4000
BTUH*
1 SQ IN .
PER
4000
BTUH*
E
G
12 "
(305mm)
MAX
C
12 " MAX
(305mm)
DUCT
1 SQ IN.
TO
PER 4000
OUTDOORS
BTUH*
A03174
I
3
other
1000 Btu/hr
A04002
I
3
fan
1000 Btu/hr
A04003
CIRCULATING AIR
DUCTS
INTERIOR
HEATED
SPACE
CIRCULATING AIR DUCTS
* Minimum opening size is 100 sq in. (64516 sq. mm)with minimum dimensions
of 3 in. (76 mm)
† Minimum of 3 in. (76 mm) when type-B1 vent is used.
Fig. 8 --- Air for Combustion, Ventilation, and Dilution from
Indoors
I
other = combined input of all other than fan- -assisted
appliances in Btuh/hr
I
fan = combined input of all fan- -assisted appliances in Btuh/hr
ACH = air changes per hour (ACH shall not exceed 0.60.) The
following requirements apply to the Standard Method and to the
Known Air Infiltration Rate Method.
1. Adjoining rooms can be considered part of a space if:
a. There are no closeable doors between rooms.
b. Combining spaces on same floor level. Each opening
shall have free area of at least 1 in.
2
mm /kW) of the total input rating of all gas appliances
in the space, but not less than 100 in.
opening shall commence within 12 in. (300 mm) of
the ceiling and the second opening shall commence
within 12 in. (300 mm) of the floor. The minimum
dimension of air openings shall be at least 3 in. (80
mm). (See Fig. 8.)
c. Combining space on different floor levels. The
volumes of spaces on different floor levels shall be
considered as communicating spaces if connected by
one or more permanent openings in doors or floors
having free area of at least 2 in.
2
mm /kW) of total input rating of all gas appliances.
2. An attic or crawlspace may be considered a space that
freely communicates with the outdoors provided there are
adequate permanent ventilation openings directly to out-
doors having free area of at least 1- -in.
input rating for all gas appliances in the space.
3. In spaces that use the Indoor Combustion Air Method, in-
filtration should be adequate to provide air for combus-
tion, permanent ventilation and dilution of flue gases.
However, in buildings with unusually tight construction,
additional air MUST be provided using the methods de-
scribed in the Outdoor Combustion Air Method section.
10
VENT THROUGH ROOF
12" MAX (305mm)
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
UNCONFINED
SPACE
6" MIN (152mm)
(FRONT)
Ü
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
12" MA X
(305mm)
A03175
2
/1,000 Btuh (2,000
2
(0.06 m2). One
2
/1,000 Btuh (4,400
2
/4,000 Btuh of total