11
W415-0680 / 04.10.08
90°
90°
90°
H
1
V
2
H
2
V
1
when
(H
T
) < (V
T
)
Simple venting confi guration (only one 90° elbow)
See graph to determine the required vertical rise
V
T
for the required horizontal run
H
T
.
VERTICAL
R I S E I N
FEET
V
T
For vent confi gurations requiring more than one 90° elbow, the following formulas apply:
Formula 1: H
T
< V
T
Formula 2: H
T
+ V
T
< 40 feet
Example 1:
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
Since both formulas are met, this vent confi guration is acceptable.
HORIZONTAL VENT RUN PLUS OFFSET IN FEET
H
T
The shaded area within the lines represents acceptable values for H
T
and V
T
.
for the following symbols used in the venting calculations and examples are:
>
- greater
than
>
- equal to or greater than
<
- less
than
<
- equal to or less than
H
T
- total of both horizontal vent lengths (
H
R
) and offsets (
H
O
) in feet
H
R
- combined horizontal vent lengths in feet
H
O
- offset factor: .03 (total degrees of offset - 90°
*
) in feet
V
T
- combined vertical vent lengths in feet
feet
inches
1°
0.03
0.5
15°
0.45
6.0
30°
0.9
11.0
45°*
1.35
16.0
90°*
2.7
32.0
*
BCDV36CF the fi rst 90° offset has a zero value and is shown in the formula as
- 90°
*
BCDV42CF the fi rst 45° and 90° offset has a zero value and is shown in the formula as -45° and -
90° respectively or
-135°
combined.
DEFINITIONS
ELBOW VENT LENGTH VALUES
BCDV36CF(G) TOP EXIT / HORIZONTAL TERMINATION
FIGURE 20
FIGURE 21
Formula 2:
H
T
+ V
T
< 40 feet
20.9
<
40
Summary of Contents for BCDV2CFN
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Page 7: ...7 W415 0680 04 10 08 FIGURE 8...
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Page 51: ...51 W415 0680 04 10 08 NOTES...
Page 52: ...52 W415 0680 04 10 08 NOTES...