12
BGD36CF(G) TOP EXIT / HORIZONTAL TERMINATION
when (HT) > (VT) | FIGURE 22 Example 3: |
Simple venting confi guration (only one 90° elbow)
See graph to determine the required vertical | FIGURE 24 |
rise VT for the required horizontal run HT. | V1 |
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H1 | 90° | H4 | |
H2 | |||
V2 | |||
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| H3 | |
90° |
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REQUIRED VERTICAL RISE
IN INCHES VT
HORIZONTAL VENT
RUN PLUS OFFSET IN
FEET HT
The shaded area within the lines represents acceptable values for HT and VT .
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 (four 90° elbows - 90°) = .03(360° - 90°) = 8.1 ft
HT = HR + HO = 5.5 + 8.1 = 13.6 ft HT + VT = 13.6 + 5.5 = 19.1 ft
Formula 1: HT < 4.2 VT
4.2VT = 4.2 x 5.5 = 23.1 ft
13.6< 23.1
Formula 2: HT + VT < 24.75 feet
19.1 < 24.75
For vent confi gurations requiring more than one 90° elbow the fol- lowing formulas apply:
Formula 1: HT < 4.2 VT
Formula 2: HT + VT < 24.75 feet
Example 2:
Since both formulas are met, this vent confi guration is ac- ceptable.
H1 | H2 | |
V1 | ||
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90° | FIGURE 23 | |
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V1=VT = 6 ft H1=3 ft H2=5 ft
HR=H1 + H2 = 3 + 5 = 8 ft
HO=.03 (two 90° elbows - 90°) = .03(180° - 90°) = 2.7 ft HT=HR + HO = 8 + 2.7 = 10.7 ft
HT + VT = 10.7 + 6 =16.7
Formula 1: HT < 4.2 VT
4.2VT = 4.2 x 6 = 25.2 ft
10.7 < 25.2
Formula 2: HT + VT < 24.75 feet
16.7 < 24.75
Since both formulas are met, this vent confi guration is acceptable.