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TAG-0043_0C
Venting and Combustion Air Guide
Page
170
of
200
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
•
Ph.: 800-526-0288
07/21/11
3.5 COMMON VENT PIPE SIZING
Refer to Figures 6 and 7 in Section 2 for typical common vent installations. The maximum length is the
sum of the equivalent straight length of horizontal runs, vertical runs, and fittings of the individual vent
connector and the common vent pipe. The maximum length is the combined length of straight
horizontal and vertical runs, and the equivalent straight length of fittings. The required diameters for a
given Innovation total BTU/hr Input are as follows:
Total BTU/hr Input
(up to and including)
1,212,000 2,120,000 3,180,000 4,240,000
Common Vent Diameter
6”
(152 mm)
8”
(203 mm)
10”
(254 mm)
12”
(305 mm)
Maximum Vent
à
Individual Connector plus
Common Vent
Equivalent Feet (Meters)
140
(42.7 m)
140
(42.7 m)
140
(42.7 m)
140
(42.7 m)
Total
BTU/hr
Input
(up to and
including)
Common
Vent
Diameter
Equivalent Common Vent Lengths Examples
Maximum Length
à
Individual Connector
plus Common Vent
Equivalent Ft (m)
Sharp 90°
Elbow
Equiv. Ft (m)
Sweep 90°
Elbow
Equiv. Ft (m)
45° Elbow
Equiv. Ft (m)
WYE or
Termination
Tee or
Rain Cap
Equiv. Ft (m)
1,212,000
6”
(152 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
140 ft.
(42.7 m)
2,120,000
8”
(203 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
140 ft.
(42.7 m)
3,180,000
10”
(254 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
140 ft.
(42.7 m)
4,240,000
12”
(305 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
140 ft.
(42.7 m)
NOTES:
•
The chart above shows equivalent pipe lengths of the fittings for the common vent pipe. See
section 3.4 for equivalent lengths for fittings for the individual heater connector.
•
The maximum equivalent length shown is the sum of the equivalent length of the longest
individual connector plus the equivalent length of the common vent pipe.
If the maximum
equivalent length exceeds 140 equivalent ft, contact your AERCO sales representative or
AERCO International for design assistance and approval.
•
It is important to use a WYE as a means to connect the individual vent into the common vent
pipe. This will ensure the least amount of pressure drop. DO NOT use a TEE, 90°, or 45° elbow.
Pg 18 of 22
