16
3.7
elbow vent length values
FEET
1°
0.03
EN
15°
0.45
30°
0.9
45°
1.35
90°*
2.7
* The fi rst 90° offset has a zero value and is shown in the formula as - 90°
3.8
top exit vertical termination
Simple venting confi guration (only one 90° elbow)
For vent confi gurations requiring more than one 90° elbow, the following formulas apply:
Formula 1: H
Formula 2: H
Example:
V
= 3 FT (0.9m)
1
V
= 8 FT (2.4m)
2
V
= V
+ V
T
1
H
= 2.5 FT (0.8m)
1
H
= 2 FT (0.6m)
2
H
= H
+ H
R
1
H
= .03 (three 90° elbows - 90°) = .03 (270° - 90°) = 5.4 FT (1.7m)
O
H
= H
+ H
T
R
H
+ V
= 9.9 FT (3m) + 11 FT (3.4m) = 20.9 FT (6.4m)
T
T
Formula 1:
Formula 2:
Since both formulas are met, this vent confi guration is acceptable.
W415-1541 / C / 11.23.17
INCHES
MILLIMETERS
0.5
12.7
6.0
152.4
11.0
279.4
16.0
406.4
32.0
812.8
REQUIRED
REQUIRED
VERTICAL
VERTICAL
RISE IN FEET
RISE IN FEET
(METERS)V
(METERS)V
REQUIRED
VERTICAL
RISE IN FEET
(METERS)V
< V
T
T
+ V
< 40 feet (12.2m)
T
T
= 3 FT (0.9m ) + 8 FT (2.4m) = 11 FT (3.4m)
2
= 2.5 FT (0.8m) + 2 FT (0.6m) = 4.5 FT (1.4m)
2
= 4.5 FT (1.4m) + 5.4 FT (1.6m) = 9.9 FT (3m)
O
H
< V
T
T
9.9 FT (3m) < 11 FT (3.4m)
H
+ V
< 40 FT (12.2m)
T
T
20.9 FT (6.4m) < 40 FT (12.2m)
(H
) < (V
)
T
T
See graph to determine the required vertical
rise V
for the required horizontal run H
T
40 (12.2)
40 (12.2)
39 (11.9)
39 (11.9)
30 (9.1)
30 (9.1)
20 (6.1)
20 (6.1)
40 (12.2)
T
39 (11.9)
T
10 (3.1)
10 (3.1)
30 (9.1)
0
2.5
5
0
2.5
5
(0.8)
(1.5)
20 (6.1)
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
(0.8)
(1.5)
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
T
10 (3.1)
The shaded area within the lines represents
acceptable values for H
0
2.5
5
7.5
(0.8)
(1.5)
(2.3)
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
(METERS) H
15.1A
7.5
10
12.5
15
17.5
7.5
10
12.5
15
17.5
(2.3)
(3.1)
(3.8)
(4.6)
(5.3)
(2.3)
(3.1)
(3.8)
(4.6)
(5.3)
(METERS) H
(METERS) H
T
T
and V
10
12.5
15
17.5
T
(3.1)
(3.8)
(4.6)
(5.3)
90°
90°
T
V
V
2
2
90°
90°
90°
V
H
90°
H
2
1
90°
1
V
V
1
90°
1
H
90°
1
V
1
16.1B
.
T
20
20
(6.1)
(6.1)
20
T
(6.1)
H
H
2
2
H
2