W415-1426 / D / 05.22.19
EN
12
venting
2.4 vent
fl ow charts
2.5 defi nitions
2.6
elbow vent lengths
Top Exit
Horizontal Termination
Vertical rise is equal
to or greater than the
horizontal run
Vertical rise is equal
to or greater than the
horizontal run
Vertical rise is less
than horizontal run
Vertical rise is less
than horizontal run
Horizontal run +
vertical rise to
maximum of
24.75 feet (7.5m)
Horizontal run +
vertical rise to
maximum of
19 (5.8m)
4.2 times the vertical
rise equal to or
greater than the
horizontal run
3 times the vertical
rise equal to or
greater than the
horizontal run
Horizontal run +
vertical rise to
maximum of
40 feet (12.2m)
Horizontal run +
vertical rise to
maximum of
40 feet (12.2m)
Vertical Termination
For the following symbols used in the venting calculations and
examples are:
> - greater than
> - equal to or greater than
< - less than
< - equal to or less than
H
T
- total of both horizontal vent lengths (Hr) and offsets (Ho) in feet
H
R
- combined horizontal vent lengths in feet
H
O
- offset factor: .03 (total degrees of offset - 90°*) in feet
H
O
- offset factor: .03 (total degrees of offset - 135°*) in feet
V
T
- combined vertical vent lengths in feet
Feet
Inches
Millimeters
1°
0.03
0.5
12.7
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).
