16
W415-0672 / C / 08.13.12
Simple venting configuration
(only two 90° elbows)
See graph to determine the required vertical rise
V
T
for the
required horizontal run
H
T
.
REQUIRED
VERTICAL
RISE IN
INCHES
V
T
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
H
T
For vent configurations requiring more than two 90° elbows, the following formulas apply:
Formula 1: H
T
< 3.5V
T
Formula 2: H
T
+ V
T
< 24.75 feet
Example:
V
1
= 4 FT
V
2
= 1.5 FT
V
T
=
V
1
+ V
2
= 4 + 1.5 = 5.5 FT
H
1
= 2 FT
H
2
= 1 FT
H
3
= 1 FT
H
4
= 1.5 FT
H
R
=
H
1
+ H
2
+ H
3
+ H
4
= 2 + 1 + 1 + 1.5 = 5.5 FT
H
O
= .03 (four 90° one 45° elbow - 90°)
= .03 (90 + 90 + 90 + 90 + 45 - 90) = 9.45 FT
H
T
=
H
R
+ H
O
= 5.5 + 9.45 = 14.95 FT
H
T
+ V
T
= 14.95 + 5.5 = 20.45 FT
Formula 1:
H
T
< 3.5V
T
3.5V
T
= 3.5 x 5.5 = 19.25 FT
14.95
<
19.25
Formula 2:
H
T
+ V
T
< 24.75 FT
20.45 < 24.75
Since both formulas are met, this vent configuration is acceptable.
The shaded area within the lines represents acceptable
values for
H
T
and
V
T
90°
V
1
V
2
H
2
90°
90°
H
3
(H
T
) > (V
T
)
50
100
150
0
2.5
5
7.5
10
12.5
15
17.5
20
147
12
66
1
3.4
19.25
16.14
H
1
45°
90°
H
3
