EN
W415-1345 / D / 05.01.17
15
venting
(H
T
) > (V
T
)
Simple venting configuration (only one 90° elbow)
See graph to determine the required vertical rise V
T
for
the required horizontal run H
T
.
Horizontal vent run plus offset in feet (meters) H
T
For vent configurations requiring more than one 90° elbow, the following formulas apply:
Formula 1: H
T
< 4.2 V
T
Formula 2: H
T
+ V
T
< 24.75 feet (7.5m)
Example:
V
1
= V
T
= 6 ft (1.8m)
H
1
= 3 ft (0.9m)
H
2
= 5 ft (1.5m)
H
R
= H
1
+ H
2
= 3 ft (0.9m) + 5 ft (1.5m) = 8 ft (2.4m)
H
O
= .03 (two 90° elbows - 90°) = .03 (180° - 90°) = 2.7 ft (0.8m)
H
T
= H
R
+ H
O
= 8 ft (2.4m) + 2.7 ft (0.8m) = 10.7 ft (3.3m)
H
T
+ V
T
= 10.7 ft (3.3m) + 6 ft (1.8m) = 16.7 ft (5.1m)
Formula 1: H
T
< 4.2 V
T
4.2 V
T
= 4.2 ft (1.3m) x 6 ft (1.8m) = 25.2 ft (7.7m)
10.7 ft (3.3m) < 25.2 ft (7.7m)
Formula 2: H
T
+ V
T
< 24.75 ft (7.5m)
16.7 ft (5.1m) < 24.75 ft (7.5m)
Since both formulas are met, this vent configuration is acceptable.
0
5
(1.5)
15
(4.6)
20 (6.1)
8.3 (2.5)
4.2 (1.3)
12.5
(3.8)
1.6 (5)
4.8 (1.5)
12.3 (3.8)
2
(0.6)
The shaded area within the lines represents acceptable
values for H
T
and V
T
90°
V
1
H
1
H
2
90°
Example:
V
1
= 4 ft (1.2m)
V
2
= 1.5 ft (0.5m)
V
T
= V
1
+ V
2
= 4 ft (1.2m) + 1.5 ft (0.5m) = 5.5 ft (1.7m)
H
1
= 2 ft (0.6m)
H
2
= 1 ft (0.3m)
H
3
= 1 ft (0.3m)
H
4
= 1.5 ft (0.5m)
H
R
= H
1
+ H
2
+ H
3
+ H
4
= 2 ft (0.6m) + 1 ft (0.3m) + 1 ft (0.3m) + 1.5 ft (0.5m) = 5.5 ft (1.7m)
H
O
= .03 (four 90° elbows - 90°) = .03 (360° - 90°) = 8.1 ft (2.5m)
H
T
= H
R
+ H
O
= 5.5 ft (1.7m) + 8.1 ft (2.5m) = 13.6 ft (4.2m)
H
T
+ V
T
= 13.6 ft (4.2m) + 5.5 ft (1.7m) = 19.1 ft (5.8m)
Formula 1:
H
T
< 4.2 V
T
4.2 V
T
= 4.2 ft (1.3m) x 5.5 ft (1.7m) = 23.1 ft (7m)
13.6 ft (4.2m) < 23.1 ft (7m)
Formula 2:
H
T
+ V
T
< 24.75 ft (7.5m)
19.1 ft (5.8m) < 24.75 ft (7.5m)
Since both formulas are met, this vent configuration is acceptable.
90°
90°
90°
90°
H
1
H
2
V
1
V
2
H
3
H
4
10
(3.1)
19.5
(5.9)
Required vertical
rise in feet
(meters) V
T
SINGLE-SIDED
