W415-1345 / D / 05.01.17
EN
14
venting
3.6
elbow vent length values
15°
0.45
6.0
152.4
30°
0.9
11.0
279.4
45°
1.35
16.0
406.4
90°*
2.7
32.0
812.8
* The fi rst 90° offset has a zero value and is shown in the formula as - 90°
* The fi rst 45° and° offset have a zero value and is shown in the formula as -45° and -90°
respectively or -135° when combined (for 45° exit only).
(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 feet
(meters) V
T
Horizontal vent run plus offset in feet (meters) H
T
For vent configurations requiring more than one 90° elbow, the following formulas apply:
Formula 1: H
T
< V
T
Formula 2: H
T
+ V
T
< 40 feet (12.2m)
Example:
V
1
= 3 ft (0.9m)
V
2
= 8 ft (2.4m)
V
T
= V
1
+ V
2
= 3 ft (0.9m) + 8 ft (2.4m) = 11 ft (3.4m)
H
1
= 2.5 ft (0.8m)
H
2
= 2 ft (0.6m)
H
R
= H
1
+ H
2
= 2.5ft (0.8m) + 2 ft (0.6m) = 4.5 ft (1.4m)
H
O
= .03 (two 90° elbows - 90°) = .03 (180° - 90°) = 5.4 ft (1.7m)
H
T
= H
R
+ H
O
= 4.5 ft (1.4m) + 5.4 ft (1.6m) = 9.9 ft (3m)
H
T
+ V
T
= 9.9 ft (3m) + 11 ft (3.4m) = 20.9 ft (6.4m)
Formula 1: H
T
< V
T
9.9 ft (3m) < 11 ft (3.4m)
Formula 2: H
T
+ V
T
< 40 ft (12.2m)
20.9 ft (6.4m) < 40 ft (12.2m)
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
0
2.5
(0.8)
5
(1.5)
7.5
(2.3)
10
(3.1)
12.5
(3.8)
15
(4.6)
40 (12.2)
10 (3.1)
20 (6.1)
30 (9.1)
17.5
(5.3)
20
(6.1)
39 (11.9)
90°
90°
90°
V
1
V
2
H
1
H
2
3.7
top exit horizontal termination
