EN
W415-2354 / B / 12.09.20
21
venting requirements
2.9 top and rear exit vertical termination
Simple venting configurations.
See graph to determine the required vertical rise
V
T
for the
required horizontal run
H
T
.
REQUIRED
VERTICAL RISE
IN FEET
(METERS)
V
T
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
(METERS)
H
T
The shaded area within the lines represents acceptable
values for
H
T
and
H
T
0
5
(1.5)
10
(3.1)
15
(4.6)
20
(6.1)
40 (12.2)
10 (3.1)
20 (6.1)
30 (9.1)
3 (0.9)
(H
T
) < (V
T
)
18.2A
For vent configurations requiring one or more 90° elbows (top exit) or one or more 90° elbows
(rear exit), the following formulas apply:
Formula 1: H
T
< V
T
Formula 2: H
T
+ V
T
< 40 feet (12.2m)
Example:
V
1
= 5 FT (1.5m)
V
2
= 6 FT (1.8m)
V
3
= 10 FT (3.1m)
V
T
=
V
1
+ V
2
+ V
3
= 5FT (1.5m) + 6FT (1.8m) + 10FT (3.1m) = 21 FT (6.4m)
H
1
= 8 FT (2.4m)
H
2
= 2.5 FT (0.8m)
H
R
=
H
1
+ H
2
= 8FT (2.4m) + 2.5FT (0.8m) = 10.5FT (3.2m)
H
O
= .03 (four 90° elbows - 90°)
= .03 (360° - 90°) = 8.1 FT (2.5m)
H
T
=
H
R
+ H
O
= 10.5FT (3.2m) + 8.1FT (2.5m) = 18.6FT (5.7m)
H
T
+ V
T
= 18.6FT (5.7m) + 21FT (6.4m) = 39.6FT (12.1m)
Formula 1:
H
T
< 3.5V
T
18.6 FT (5.7m) < 21 FT (6.4m)
Formula 2:
H
T
+ V
T
< 40 FT (12.2m)
39.6FT (12.1m) < 40 FT (12.2m)
Since both formulas are met, this vent configuration is acceptable.
