12
W415-0496 / B / 08.10.05
V1
HORIZONTAL TERMINATION
See graph to determine the re-
quired vertical rise VT for the re-
quired horizontal run HT.
For vent configurations requiring more than one 45º and
90° elbow the following formulas apply:

Formula 1: HT < 4.2 VT

Formula 2: HT + VT < 24.75 feet

FIGURE 7
REQUIRED
VERTICAL
RISE IN
INCHES (VT)
HORIZONTAL VENT RUN PLUS OFFSETS IN FEET (HT)
when (HT) > (VT)
Simple venting configuration (only one 45º and 90° elbow)

Example 2:

V
1
=4 ft
V
2
= 1.5 ft
VT=V1 +
V
2
= 4 ft + 1.5 ft = 5.5 ft
H
1
=2 ft
H
2
=1 ft
H
3
=1 ft
H
4
= 1.5 ft
HR=H1 + H2 + H3 + H4 = 2 + 1 + 1 + 1. 5 = 5.5 ft
H
O
= .03(one 45º elbow + three 90º elbow -135º)
=.03(315-135)=5.4ft
H
T
=H
R
+ H
O
= 5.5 +5.4 = 10.9 ft
H
T
+ V
T
= 10.9 + 5.5 = 16.4 ft

Formula 1:H

T

< 4.2 V

T
4.2 VT = 4.2 x 5.5 = 23.1 ft
10.9 < 16.8

Formula 2:H

T
+ V
T

< 24.75 feet

16.4 < 24.75
Since both formulas are met, this vent configuration is ac-
ceptable.
H4
90°
H3
H1
90°
H2
90°
FIGURE 8
45°
The shaded area within the lines represents acceptable
values for HT and VT .
V2