12
HORIZONTAL TERMINATION
when (HT) > (VT)
Simple venting configuration (only one 45º and 90° elbow)
See graph to determine
the required vertical rise VTFIGURE 7 for the required horizontal
run HT.
Example 2: | 90° |
| 90° | |
FIGURE 8 | H3 | |||
H1 | H4 | |||
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45° |
| H2 | V2 | |
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| 90° |
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V1 |
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| 150 |
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| 140 |
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| V1 | = 4 ft |
REQUIRED |
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130 |
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| V2 | = 1.5 ft | |
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VERTICAL | 120 |
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| VT | = V1 + V2 = 4 ft + 1.5 ft = 5.5 ft |
RISE IN | 110 |
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| H1 | = 2 ft |
INCHES (VT) |
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100 |
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| H2 | = 1 ft | |
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| 90 |
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| H3 | = 1 ft |
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| H4 | = 1.5 ft | |
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| 80 |
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| HR | = H1 + H2 + H3 + H4 = 2 + 1 + 1 + 1. 5 = 5.5 ft |
| 70 |
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| HO | = .03(one 45º elbow + three 90º elbow |
| 60 |
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| HT | = HR + HO = 5.5 +5.4 = 10.9 ft | |
| 50 |
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| HT + VT | = 10.9 + 5.5 = 16.4 ft | |
| 40 |
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| Formula 1: HT < 4.2 VT | ||
| 30 |
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| 4.2 VT = 4.2 x 5.5 = 23.1 ft | |
| 20 |
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| 10.9 < 16.8 | |
| 10 |
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| Formula 2: HT + VT < 24.75 feet | ||
| 0 | 5 | 10 | 15 | ||
| 20 | 16.4 < 24.75 | ||||
HORIZONTAL VENT RUN PLUS OFFSETS IN FEET |
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The shaded area within the lines represents acceptable values for HT and VT .
For vent configurations requiring more than one 45º and 90° elbow the following formulas apply:
Formula 1: HT < 4.2 VT
Formula 2: HT + VT < 24.75 feet
Since both formulas are met, this vent configuration is acceptable.
