Napoleon BGD36CFNTR Installation And Operating Instructions Manual page 21

bGD42CF VERTICAL TERMINATION
when (H ) > (V )
T T
Simple venting configurations
FIGURE 40
See graph to determine the required vertical rise V
required horizontal run H
.
T
maximum vertical
rise in feet
V
T
horizontal vent run Plus offset in feet
The shaded area within the lines represents acceptable
values for H and V .
T T
For vent configurations requiring more than one 45º and
one 90° elbow the following formulas apply:
Formula 1: HT < 3VT
Formula 2: HT + VT < 40 feet
Example 4:
FIGURE 41
45°
for the
T
H
V
90°
2
H
H
1
2
V
1
90°
90°
V
=  ft
1
V
= .5 ft
2
V = V + V
=  + .5 = .5 ft
T 1 2
H
= 6 ft
1
H
=  ft
2
H = H + H
= 6 +  = 8 ft
R 1 2
H
= .0 (one 45° elbow + three 90° elbows - 5°)
O
= .0 (45 + 90 + 90 +90 - 5) = 5.4 ft
H = H + H
T R O
H + V
= .4 + .5 = 5.9 ft
T T
H < V
Formula :
T
3V
.4 < 7.5
Since this formula is not met, this vent configuration is
unacceptable.
H + V
Formula :
T
5.9 < 40
Since only formula 2 is met, this vent configuration
is unacceptable and a new fireplace location or vent
configuration will need to be established to satisfy both
formulas.
Example 5:
FIGURE 42
90°
45°
V
H
1
T
V
= .5 ft
1
V
= 8 ft
2
V = V + V
= .5 + 8 = 9.5 ft
T 1 2
H
=  ft
1
H
=  ft
2
H = H + H + H
R 1 2
H
= .0 (three 45° elbow + three 90° elbows - 5°)
O
= .0 (45 + 90 + 90 +90 - 5) = 6.75 ft
H = H + H
T R O
H + V
= .4 + 4.5 = 9 ft
T T
H < V
Formula :
T
3V
.4 < 7.5
H + V
Formula :
T
9 < 40
Since both formulas are met, this vent configuration is
acceptable.
= 8 + 5.4 = .4 ft
T
=  x .5 = 7.5 ft
T
< 40 feet
T
H
H
2
3
1
90°
=  +  + 0.75 = .75 ft
3
= .75 + 6.75 = 9.5 ft
T
=  x .5 = 7.5 ft
T
< 40 feet
T
W45-0566 / A / 07..06

V
2
90°