venting requirements
EN
Simple venting configuration
(only one 90° elbow)
For vent configurations requiring more than one 90° elbow, the following formulas apply:
Formula 1: H
< 4.2 V
T
Formula 2: H
+ V
< 24.75 feet (7.5m)
T
T
Example:
V
= V
= 6 FT (1.8m)
1
T
H
= 3 FT (0.9m)
1
H
= 5 FT (1.5m)
2
H
= H
+ H
= 3FT (0.9m) + 5FT (1.5m) = 8FT (2.4m)
R
1
2
H
= .03 (two 90° elbows - 90°) = .03 (180° - 90°) = 2.7FT (0.8m)
O
H
= H
+ H
= 8FT (2.4m) + 2.7FT (0.8m) = 10.7FT (3.3m)
T
R
O
H
+ V
= 10.7FT (3.3m) + 6FT (1.8m) = 16.7FT (5.1m)
T
T
Formula 1:
H
T
Formula 2:
H
T
16.7 FT (5.1m) < 24.75 FT (7.5m)
Since both formulas are met, this vent configuration is acceptable.
Example:
V
= 4 FT (1.2m)
1
V
= 1.5 FT (0.5m)
2
V
= V
+ V
= 4 FT (1.2m) + 1.5 FT (0.5m) = 5.5 FT (1.7m)
T
1
2
H
= 2 FT (0.6m)
1
H
= 1 FT (0.3m)
2
H
= 1 FT (0.3m)
3
H
= 1.5 FT (0.5m)
4
H
= H
+ H
+ H
+ H
R
1
2
3
H
= .03 (four 90° elbows - 90°) = .03 (360° - 90°) = 8.1 FT (2.5m)
O
H
= H
+ H
= 5.5 FT (1.7m) + 8.1 FT (2.5m) = 13.6 FT (4.2m)
T
R
O
H
+ V
= 13.6 FT (4.2m) + 5.5 FT (1.7m) = 19.1 FT (5.8m)
T
T
Formula 1:
H
T
13.6 FT (4.2m) < 23.1 FT (7m)
Formula 2:
H
T
19.1 FT (5.8m) < 24.75 FT (7.5m)
Since both formulas are met, this vent configuration is acceptable.
20
W415-2944 / B / 05.22.24
See graph to determine the required vertical rise V
REQUIRED
VERTICAL
RISE IN INCHES
(CENTIMETERS) V
HORIZONTAL VENT RUN PLUS OFFSET IN FEET (METERS) H
The shaded area within the lines represents acceptable values for H
T
< 4.2 V
T
4.2 V
= 4.2FT (1.3m) x 6FT (1.8m) = 25.2FT (7.7m)
T
+ V
< 24.75 FT (7.5m)
T
= 2FT (0.6m) + 1FT (0.3m) + 1FT (0.3m) + 1.5FT (0.5m) = 5.5 FT (1.7m)
4
< 4.2 V
T
4.2 V
= 4.2 FT (1.3m) x 5.5 FT (1.7m) = 23.1 FT (7m)
T
+ V
< 24.75 FT (7.5m)
T
(H
) > (V
)
T
T
150 (381)
147 (373)
100 (254)
T
57 (145)
50 (127)
8 (20.3)
0
5
10
(1.5)
(3.1)
2
(0.6)
90°
V
1
90°
V
1
for the required horizontal run H
T
15
20 (6.1)
(4.6)
12.5
19.5
(3.8)
(5.9)
and V
T
H
H
1
90°
90°
90°
H
1
V
2
H
H
2
3
90°
16.16
.
T
T
T
2
H
4