ICP F9MXE0801716A1 - Air for Combustion, V Entilation; Combination of Indoor and Outdoor Air

Air for Combustion,Ventilation, 3.
Figure 7 and Dilution from Indoors
I
I
I
INTERIOR
HEATED
SPACE
CIRCULATING AIR VENT THROUGH ROOF
DUCTS
I I I I
I I I I
I I I I
_(305mm)
E_ ----_SQIN.
_" _ = PER 1000
_: _ BTUH* IN DOOR
_ ORWALL
i C_ UNCONFINED
rr T 6" MIN (152ram)
u_ o0 (FRONT)0
z_
zZ PER 1000
g O___&_ALL
o
HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH
4.
a.
b.
C.
In spaces that use the Indoor Combustion Air Method,
infiltration should be adequate to provide air for
combustion, permanent ventilation and dilution of flue
gases. However, in buildings with unusually tight
construction, additional air MUST be provided using
the methods described in the Outdoor Combustion Air
Method section.
Unusually tight construction is defined as Construction
with:
Walls and ceilings exposed to the outdoors have a
continuous, sealed vapor barrier. Openings are
gasketed or sealed and
Doors and openable windows are weatherstripped
and
Other openings are caulked or sealed. These include
joints around window and door frames, between sole
plates and floors, between walt-ceiling joints, between
wall panels, at penetrations for plumbing, electrical
and gas lines, etc.
Combination of Indoor and Outdoor Air
I i i - 12" MAX (305mm)
I I
CIRCULATING AIR DUCTS
* Minimum opening size is 100 sq in. with
minimum dimensions of 3-in.
1- Minimum of 3-in. when type-B1 vent is used.
A03175
1.
2.
3.
a.
b.
C.
Indoor openings shall comply with the Indoor
Combustion Air Method below and,
Outdoor openings shall be located as required in the
Outdoor Combustion Air Method mentioned previously
and,
Outdoor openings shall be sized as follows:
Calculate the Ratio of all Indoor Space volume
divided by required volume for Indoor Combustion
Air Method.
Outdoor opening size reduction Factor is one minus
the Ratio in a. above.
Minimum size of Outdoor openings shall be the size
required in Outdoor Combustion Air Method above
multiplied by reduction Factor in b. above. The
minimum dimension of air openings shall be not less
than 3-in. (80 mm).
Table 3 Minimum Free Area Required for Each Combustion Air Opening or Duct to Outdoors
TWO HORIZONTAL DUCTS SINGLE DUCT OR OPENING TWO OPENINGS OR
VERTICAL DUCTS
(1 SQ. IN./2,000 BTUH) (1 SQ. IN./3,000 BTUH)
FURNACE (1,100 SQ. MM/KW) (734 SQ. MM/KW) (1 SQ. IN./4,000 BTUH)
(550 SQ. MM/KW)
INPUT
Round Round
(BTUH) Free Area of Duct Free Area of Open- Duct Free Area of Open- Round Duct
Opening and Duct In. (mm) ing and Duct In. (mm) ing and Duct In. (mm)
Sq. In (Sq. mm) Dia Sq. In (Sq. mm) Dia Sq. In (mm) Dia.
40,000* 20 (12904) 5 (127) 14 (8696) 5 (127) 10 (6452) 4 (102)
60,000 30 (19355) 6 (152) 20 (13043) 5 (127) 15 (9678) 5 (127)
80,000 40 (25807) 7 (178) 27 (17391) 6 (152) 20 (12904) 5 (127)
100,000 50 (32258) 8 (203) 34 (21739) 7 (178) 25 (16130) 6 (152)
120,000 60 (38709) 9 (229) 40 (26087) 7 (178) 30 (19355) 6 (152)
140,000" 70 (45161) 10 (254) 47 (30435) 8 (203) 35 (22581) 7 (178)
• Not all families have these models,
EXAMPLE: Determining Free Area
FURNACE WATER HEATER TOTAL INPUT
100,000 + 30,000 = (130,000 divided by 4,000)
60,000 + 40,000 = (100,000 divided by 3,000)
80,000 + 30,000 = (110,000 divided by 2,000)
= 32.5 Sq. In. for each two Vertical Ducts or Openings
= 33.3 Sq. In. for each Single Duct or Opening
= 55.0 Sq. In. for each two Horizontal Ducts
440 01 4001 02 Specificati ..... bject to change without notice. 11