W415-3091 / C / 05.11.22
EN
22
venting requirements
(H
T
) > (V
T
)
Simple venting configurations.
See graph to determine the required vertical rise V
T
for the
required horizontal run H
T
.
For vent configurations requiring more than two 90° elbows the following formulas apply:
Formula 1: H
T
< 3V
T
Formula 2: H
T
+ V
T
< 40 feet (12.2m)
Example:
V
1
= 2 ft (0.6m)
V
2
= 1 ft (0.3m)
V
3
= 1.5 ft (0.5m)
V
T
= V
1
+V
2
+V
3
= 2 ft (0.6m) + 1 ft (0.3m) + 1.5 ft (0.5m) = 4.5 ft (1.4m)
H
1
= 6 ft (1.8m)
H
2
= 2 ft (0.6m)
H
R
= H
1
+ H
2
= 6 ft (1.8m) + 2 ft (0.6m) = 8 ft (2.4m)
H
O
= .03 (four 90° elbows - 90°)
= .03 (360° - 90°) = 8.1 ft (2.5m)
H
T
= H
R
+ H
O
= 8 ft (2.4m) + 8.1 ft (2.5m) = 16.1 ft (4.9m)
H
T
+ V
T
= 16.1ft (4.9m) + 4.5 ft (1.4m) = 20.6 ft (6.3m)
Formula 1:
H
T
< 3V
T
3V
T
= 3 ft (0.9m) x 4.5 ft (1.4m) = 13.5 ft (4.1m)
16.1 ft (4.9m) > 13.5 ft (4.1m)
Since this formula is not met, this vent configuration is unacceptable.
Formula 2:
H
T
+ V
T
< 40 ft (12.2m)
20.6 ft (6.3m) < 40 ft (12.2m)
Since only formula 2 is met, this vent configuration is unacceptable and a new appliance location or vent configuration will
need to be established to satisfy both formulas.
The shaded area within the lines represents acceptable
values for H
T
and V
T
0
5
(1.5)
10 (3.1)
15
(4.6)
20
(6.1)
10 (3.1)
20 (6.1)
3 (0.9)
25
(7.6)
30
(9.1)
19 (5.8)
90°
V
1
V
2
H
1
H
2
90°
90°
90°
V
3
14.1_2
Required vertical
rise in feet
(meters) V
T
Horizontal vent run plus offset in feet (meters) H
T
