11
W415-0341 / F / 11.21.05
when
(H
T
) < (V
T
)
Simple venting configuration (only one 90° elbow)
VERTICAL
RISE IN
FEET
V
T
FIGURE 10
See graph to determine the required vertical rise
V
T
for the
required horizontal run
H
T
.
For vent configurations requiring more than one 90° el-
bow, the following formulas apply:
Formula 1: H
T
< V
T
Formula 2: H
T
+ V
T
< 40 feet
90°
90°
Example 3:
V
1
= 3 ft
V
2
= 8 ft
V
T
=
V
1
+
V
2
= 3 + 8 = 11 ft
H
1
= 2.5 ft
H
2
= 2 ft
H
R
=
H
1
+
H
2
= 2.5 + 2 = 4.5 ft
H
O
= .03(three 90° elbows - 90°) = .03(270° - 90°) = 5.4 ft
H
T
=
H
R
+
H
O
= 4.5 + 5.4 = 9.9 ft
H
T
+ V
T
= 9.9 + 11 = 20.9 ft
Formula 1:
H
T
< V
T
9.9 < 11
Formula 2:
H
T
+ V
T
< 40 feet
20.9 < 40
Since both formulas are met, this vent configuration is ac-
ceptable.
FIGURE 11
90°
H
1
V
2
H
2
V
1
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
H
T
The shaded area within the lines represents acceptable
values for H
T
and V
T
.
BGD34 & GD34 HORIZONTAL TERMINATION
