13
W415-0496 / B / 08.10.05
VERTICAL TERMINATION

Example 3:

V
1
=5 ft
V
2
=10 ft
VT=
V
1
+
V
2
=
5 + 10 = 15 ft
H
1
=3 ft
H
2
=2.5 ft
HR=H1 + H2 = 3 + 2.5 = 5.5 ft
HO=.03(one 45º elbow + three 90º elbows - 135º)
=.03(45+90+90+90-135)=5.4
H
T
=H
R
+ H
O
= 5.5 + 5.4 = 10.9 ft
H
T
+ V
T
= 10.9 + 15 = 25.9 ft
Formula 1: H
T
< V
T
10.9 < 15
Formula 2: H
T
+ V
T
< 40 feet
25.9 < 40
Since both formulas are met, this vent configuration is ac-
ceptable.
when (HT) < (VT)
FIGURE 9
REQUIRED VERTICAL RISE IN
FEET (VT)
HORIZONTAL VENT RUN
PLUS OFFSETS IN FEET (HT)
FIGURE10
For vent configurations requiring more than one 45º and
one 90° elbow , the following formulas apply:
Formula 1: H
T

< V

T
Formula 2: H
T
+ V
T

< 40 feet

See graph to determine the required vertical rise VT for
the required horizontal run HT.
90°
90°
V1
H1
H2
V2
45°
45°
90°
The shaded area within the lines represents acceptable
values for HT and VT.