Modulex EXT Vent and Combustion Air Application Guide
Page 26 of
28
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
TAG-0054-0F
09/25/2017
Phone: 800-526-0288
GF-136-V
3.5.
COMMON VENT PIPING SIZE
Refer to Figures 6, 7 and 8 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 Modulex total BTU/hr. Input are shown in Table 6, below.
TABLE 6: Common Venting Pipe Run Lengths
TOTAL
BTU/HR
INPUT
(UP TO
AND
INCLUDIN
G)
Common Vent
Diameter
EQUIVALENT COMMON VENT LENGTHS
EXAMPLES
MAX.
LENGTH
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
Vent Cap
Equiv. Ft (m)
606,000
4”
(102 mm)
10 ft.
(3.05 m)
5 ft.
(1.5 m)
5 ft.
(1.5 m)
5 ft.
(1.5 m)
100 ft.
(30.5 m)
1,284,000
6”
(152 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
100 ft.
(30.5 m)
2,407,500
8”
(203 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
100 ft.
(30.5 m)
3,825,000
10”
(254 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
100 ft.
(30.5 m)
5,355,000
12”
(305 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
100 ft.
(30.5 m)
6,885,000
14”
(358 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
100 ft.
(30.5 m)
9,180,000
16”
(407 mm)
10 ft.
(3.05 m)
N/A
5 ft.
(1.5 m)
5 ft.
(1.5 m)
100 ft.
(30.5 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 boiler 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 100 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.