16
W415-0661 / 12.07.07
BGD42CF HORIZONTAL TERMINATION
when (H
T
) < (V
T
)
Simple venting confi guration (only
one 45º and 90° elbow)
45°
90°
For vent confi gurations requiring more than one 45º and 90°
elbow, the following formulas apply:
Formula 1: HT < VT
Formula 2: HT + VT < 40 feet
Example 1:
45°
90°
H
1
H
2
V
1
REQUIRED
VERTICAL
RISE IN FEET
(V
T
)
CALCULATED HORIZONTAL VENT RUN
PLUS OFFSETS IN FEET (H
T
)
The shaded area within the lines represents acceptable values for
H
T
and V
T
.
V
1
= 8 ft
V
T
V
1
= 8 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 (one 45° elbows + two 90° elbows - 135°)
= .03(225 - 135°) = 2.7 ft
H
T
= H
R
+ H
O
= 4.5 + 2.7 = 7.2 ft
H
T
+ V
T
= 7.2 + 8 = 15.2 ft
Formula 1: H
T
< V
T
7.2 < 8
Formula 2: H
T
+ V
T
< 40 feet
15.2 < 40
Since both formulas are met, this vent confi guration is acceptable.
FIGURE 34
FIGURE 35
when (H
T
) > (V
T
)
Simple venting con-
fi guration (only one
45º and 90° elbow)
See graph to deter-
mine the required
vertical rise V
T
for the
required horizontal
run H
T
.
REQUIRED VER-
TICAL RISE IN
INCHES
V
T
HORIZONTAL VENT
RUN PLUS OFFSETS
IN FEET (H
T
)
The shaded area within the lines
represents acceptable values for H
T
For vent confi gurations requiring more than one 45º and one 90°
elbow the following formulas apply:
Formula 1: HT < 4.2 VT
Formula 2: HT + VT < 24.75 feet
Example 2:
V
1
= 4 ft
V
2
= 1.5 ft
V
T
=
V
1
+
V
2
=
4 + 1.5 = 5.5 ft
H
1
= 2 ft
H
2
= 1 ft
H
3
= 1 ft
H
4
= 1.5 ft
H
R
= H
1
+ H
2
+ H
3
+ H
4
= 2 + 1 + 1 + 1.5 = 5.5 ft
H
O
= .03 (one 45° elbow + four 90° elbows - 135°)
= .03(405 - 135) = 8.1 ft
H
T
= H
R
+ H
O
= 5.5 + 8.1 = 13.6 ft
H
T
+ V
T
= 13.6 + 5.5 = 19.1 ft
Formula 1: H
T
< 4.2V
T
4.2V
T
= 4
.2 x
5.5 = 23.1 ft
13.6 < 16.8
Formula 2: H
T
+ V
T
< 24.75 feet
19.1 < 24.75
Since both formulas are met, this vent confi guration is accept-
able.
FIGURE 36
FIGURE 37
H
1
H
2
H
3
H
4
V
1
V
2
90°
45°
90°
90°
90°
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