16
BGD42CF HORIZONTAL TERMINATION
when (HT) < (VT) | 90° | ||
Simple venting confi guration (only | |||
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one 45º and 90° elbow) |
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FIGURE 34
45°
REQUIRED
VERTICAL RISE IN FEET (VT)
CALCULATED HORIZONTAL VENT RUN
PLUS OFFSETS IN FEET (HT)
The shaded area within the lines represents acceptable values for HT and VT .
when (HT) > (VT) Simple venting con-
figuration (only one 45º and 90° elbow)
FIGURE 36
See graph to deter- mine the required vertical rise VT for the required horizontal run HT.
REQUIRED VER-
TICAL RISE IN
INCHES VT
The shaded area within the lines represents acceptable values for HT and VT .
HORIZONTAL VENT RUN PLUS OFFSETS IN FEET (HT)
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:
90° | H2 |
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V1 |
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FIGURE 35 |
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45° |
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H1 |
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V1 = 8 ft |
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VT V1= 8 ft |
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H1 = 2.5 ft |
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H2 = 2 ft |
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HR = H1 + H2 = 2.5 + 2 = 4.5 ft |
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HO = .03 (one 45° elbows + two 90° elbows - 135°) |
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= .03(225 - 135°) = 2.7 ft |
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HT = HR + HO = 4.5 + 2.7 = 7.2 ft |
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HT + VT = 7.2 + 8 = 15.2 ft |
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Formula 1: HT < VT |
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7.2< 8
Formula 2: HT + VT < 40 feet 15.2 < 40
Since both formulas are met, this vent confi guration is acceptable.
For vent confi gurations requiring more than one 45º and one 90° elbow the following formulas apply:
Formula 1: HT < 4.2 VT |
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Formula 2: HT + VT < 24.75 feet | 90° |
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Example 2: | H1 | H4 | ||
90° | 90° H3 | V2 | ||
V1 90° H2
45°
FIGURE 37
V1 = 4 ft
V2 = 1.5 ft
VT = V1 + V2 = 4 + 1.5 = 5.5 ft
H1 = 2 ft
H2 = 1 ft
H3 = 1 ft
H4 = 1.5 ft
HR = H1 + H2 + H3 + H4 = 2 + 1 + 1 + 1.5 = 5.5 ft
HO = .03 (one 45° elbow + four 90° elbows - 135°)
= .03(405 - 135) = 8.1 ft |
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HT = HR + HO = 5.5 | + 8.1 | = 13.6 ft | |
HT + VT | = 13.6 + | 5.5 = | 19.1 ft |
Formula 1: | HT < 4.2VT | ||
4.2VT = 4.2 x 5.5 = 23.1 ft 13.6 < 16.8
Formula 2: HT + VT < 24.75 feet
19.1 < 24.75
Since both formulas are met, this vent confi guration is accept- able.
