2.4
vent application flow chart
Horizontal Termination
Vertical rise is equal
to or greater than
the horizontal run
Horizontal run +
vertical rise to
maximum of
35 feet (10.7m)
2.5
definitions
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
- total of both horizontal vent lengths (Hr) and offsets (Ho) in feet
T
H
- combined horizontal vent lengths in feet
R
H
- offset factor: .03 (total degrees of offset - 90°*) in feet
O
H
- offset factor: .03 (total degrees of offset - 135°*) in feet
O
V
- combined vertical vent lengths in feet
T
2.6
elbow vent lengths
Feet
Inches
1°
0.03
0.5
15°
0.45
6.0
30°
0.9
11.0
45°
1.35
16.0
90°*
2.7
32.0
* 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).
TOP EXIT
Vertical rise is less
than horizontal run
Horizontal run +
vertical rise to
maximum of 24.75
feet (7.5m)
4.2 times the
vertical rise equal to
or greater than the
horizontal run
Millimeters
12.7
152.4
279.4
406.4
812.8
venting requirements
Vertical Termination
Vertical rise is equal
to or greater than
the horizontal run
Horizontal run +
vertical rise to
maximum of
35 feet (10.7m)
10.3
11.1
12.1
Vertical rise is less
than horizontal run
Horizontal run +
vertical rise to
maximum of
35 feet (10.7m)
3 times the vertical
rise equal to or
greater than the
horizontal run
15
W415-2197 / C / 10.14.20
EN