W415-1283 / F / 04.30.18
EN
18
venting requirements
Simple venting configuration (only one
45° and 90° elbow)
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
(H
T
) > (V
T
)
For vent configurations requiring more than two 90° elbows, the following formulas apply:
Formula 1: H
T
< 4.2V
T
Formula 2: H
T
+ V
T
< 24.75 feet (7.5m)
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 (one 45° elbow + four 90° elbows - 135°)
= .03 (405 - 135°) = 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
< 4.2FT (1.3m) VT
4.2FT (1.3m) VT
=
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)
19.1 FT (5.8m) < 24.75 FT (7.5m)
Since both formulas are met, this vent configuration is acceptable.
13.3_2
0
5
(1.5)
15
(4.6)
20
(6.1)
8.3 (2.5)
4.2 (1.3)
12.5
(3.8)
4.8 (1.5)
12.3 (3.8)
10
(3.1)
90°
90°
45°
V
1
H
1
H
4
90° 90°
H
3
H
2
V
2
