38
6.11 Multiple Boiler Venting - Venting Layout
Available pressure at flue outlet is 0.40" w.c. (100pa)
6 - COMBUSTION AIR AND VENT PIPING
Flue Outlet
Maximum Vertical Length
Heat input
BTUH
Heat input
(kW)
Number of
appliances
6 in (150 mm)
6 in / 8 in *
(150 / 200 mm)
8 in (200 mm)
443,578
130
2
98 ft
4 13/16 in
30.0 m
98 ft
4 13/16 in
30.0 m
98 ft
4 13/16 in
30.0 m
887,156
260
4
98 ft
4 13/16 in
30.0 m
98 ft
4 13/16 in
30.0 m
98 ft
4 13/16 in
30.0 m
1,330,735
390
6
-
-
98 ft
4 13/16 in
30.0 m
98 ft
4 13/16 in
30.0 m
*6 in. / 8 in. Vent System:
• Horizontal vent pipe size 6 in. (150 mm)
• Vertical vent pipe size 8 in. (200.00 mm).
• Length between vertical vent pipe and last horizontal
vent collector pipe = 3 ft 4 in (1.00 m).
• For calculating other lengths between last collector
and shaft, length of vertical height must be reduced
by this additional length and by the numbers of bends
according to the table.
Elbow Type
6 in.
8 in.
-
Equivalent Length
Equivalent Length
45°
5 ft 7 in
1.7m
12 ft
3.8 m
90°
13 ft 1 in
4.0m
19 ft
5.8 m
6 in. Cascade Vent System Example
Elbow Equivalent Length
45°
90°
Number of Elbows
-
3
Equivalent Length
-
13 ft 1 in
(4.0m)
Total Equivalent Length
39 ft 4-21/64 in (12.0m)
Total Equivalent Length
39 ft 4 - 21/64 in
(12.0m)
Horizontal Length
5 ft (1.5m)
Total Equivalent Horizontal Length
44 ft. (13.4m)
Maximum Vertical Length
98 ft. (29.9m)
Total Vertical Length
54 ft. (16.5m)
FIGURE 6-34
P/N 240011654, Rev. C [06/08/2017]
