Simple venting configurations.
For vent configurations requiring more than one 90° elbow, the following formulas apply:
Formula 1: H
< 3 V
T
T
Formula 2: H
+ V
< 40 FT (12.2m)
T
T
Example:
V
= 1.5 FT (0.5m)
1
V
= 5 FT (1.5m)
2
V
= V
+ V
= 1.5FT (0.5m) + 5FT (1.5m) = 6.5 FT (2m)
T
1
2
H
= 1 FT (0.3m)
1
H
= 1 FT (0.3m)
2
H
= 10.75 FT (3.3m)
3
H
= H
+ H
+ H
= 1FT (0.3m) + 1FT (0.3m) + 10.75FT (3.3m) = 12.75 FT (3.9m)
R
1
2
3
H
= .03 (three 90° elbows + one 45° elbow - 90°)
O
= .03 (270° + 45° - 90°) = 6.75 FT (2.1m)
H
= H
+ H
= 12.75FT (3.9m) + 6.75FT (2.1m) = 19.5 FT (5.9m)
T
R
O
H
+ V
= 19.5FT (5.9m) + 6.5FT (2m) = 26 FT (7.9m)
T
T
Formula 1:
H
< 3 V
T
T
3 V
= 3FT (0.9m) x 6.5FT (2m) = 19.5FT (5.9m)
T
19.5FT (5.9m) = 19.5FT (5.9m)
Formula 2:
H
+ V
< 40 FT (12.2m)
T
T
26 FT (7.9m) < 40 FT (12.2m)
Since both formulas are met, this vent configuration is acceptable.
(H
) > (V
)
T
T
See graph to determine the required vertical rise V
required horizontal run H
20 (6.1)
19 (5.8)
REQUIRED
VERTICAL
10 (3.1)
RISE IN
FEET
3 (0.9)
(METERS)V
T
0
(1.5)
HORIZONTAL VENT RUN PLUS OFFSET IN
The shaded area within the lines represents acceptable
90°
H
V
1
H
1
90°
.
T
5
10
15
20
(3.1)
(4.6)
(6.1)
FEET (METERS) H
T
values for H
and v
T
T
2
45°
H
3
18.7A
W415-1337 / 06.23.14
17
for the
T
EN
25
30
(7.6)
(9.1)
V
2
90°