13
W415-1371 / 09.15.14
EN
(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
.
REQUIRED
VERTICAL RISE
IN INCHES
(MILLIMETERS)
V
T
HORIZONTAL VENT RUN PLUS OFFSET IN FEET (METERES)
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
= 3FT (0.9m) + 5FT (1.5m) = 8 FT (2.4m)
H
O
= .03 (two 90° elbows - 90°) = .03 (180° - 90°) = 2.7FT (0.8m)
H
T
=
H
R
+ H
O
= 8FT (2.4m) + 2.7FT (0.8m) = 10.7FT (3.3m)
H
T
+ V
T
= 10.7FT (3.3m) + 6FT (1.8m) = 16.7FT (5.1m)
Formula 1: H
T
< 4.2 V
T
4.2 V
T
=
4.2FT (1.3m) x 6FT (1.8m) = 25.2FT (7.7m)
10.7FT (3.3m) < 25.2FT (7.7m)
Formula 2: H
T
+ V
T
< 24.75 FT (7.5m)
16.7FT (5.1m) < 24.75 (7.5m)
Since both formulas are met, this vent configuration is acceptable.
0
5
(1.5)
15
(4.6)
20 (6.1)
100 (2540)
50 (1270)
150 (3810)
12.5
(3.8)
19 1/2
(495.3)
57 (1447.8)
147
(3733.8)
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
= 4FT (1.2m) + 1.5FT (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
= 2FT (0.6m) + 1FT (0.3m) + 1FT (0.3m) + 1.5FT (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)
19.1FT (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)
16.1_2A
24 (7.3)
18
(5.5)
