11
W415-0381 / H / 12.07.07
V1
HORIZONTAL TERMINATION
See graph to determine the re-
quired vertical rise VT for the
required horizontal run HT.
For vent confi gurations 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 8
REQUIRED
VERTICAL
RISE IN
INCHES (VT)
HORIZONTAL VENT RUN PLUS OFFSETS IN FEET
when (HT) > (VT)
Simple venting confi guration (only one 45º and 90° elbow)

Example 2:

V1 = 4 ft
V2 = 1.5 ft
VT = V1 +
V2
= 4 ft + 1.5 ft = 5.5 ft
H1 = 2 ft
H2 = 1 ft
H3 = 1 ft
H4 = 1.5 ft
HR = H1 + H2 + H3 + H4 = 2 + 1 + 1 + 1. 5 = 5.5 ft
HO = .03(one 45º elbow + four 90º elbows -135º)
=.03(405-135)=8.1ft
HT = HR + HO = 5.5 + 8.1 = 13.6ft
HT + VT = 13.6 + 5.5 = 19.1ft

Formula 1: H

T < 4.2 VT
4.2 VT = 4.2 x 5.5 = 23.1 ft
13.6 < 23.1

Formula 2: H

T + VT < 24.75 feet
19.1 < 24.75
Since both formulas are met, this vent confi guration is
acceptable.
H4
90°
H3
H1
90°
H2
90°
FIGURE 9
45°
The shaded area within the lines represents acceptable
values for HT and VT .
V2
90°