13
TOP OR REAR EXIT VERTICAL TERMINATION
(HT) < (VT)
Simple venting configurations
Example 6:
FIGURE 16
FIGURE 17 | V3 |
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| 90° |
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| 90° | V2 |
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| H2 |
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| V1 | H1 | 90° |
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| 90° |
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| See graph to determine the required vertical rise VT for the |
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| required horizontal run HT. |
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| V1 | =5 ft |
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| V | =6 ft |
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| 40 |
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| V32 | =10 ft |
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REQUIRED |
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| VT | = V1 + V2 + V3 = 5 + 6 + 10 = 21 ft |
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VERTICAL RISE |
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IN FEET |
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| H1 | =8 ft |
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VT |
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| H | =2.5 ft |
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30 |
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| HR2 | = H1 | + H2 = 8 + 2.5 = 10.5 ft |
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| HO | = .03 (four 90° elbows - 90°) |
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| = .03 (90 + 90 + 90 + 90 - 90) = 8.1 ft |
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| HT | =HR + HO | = 10.5 + 8.1 = 18.6 ft |
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| 20 |
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| HT + VT | = 18.6 + 21 = 39.6 ft |
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| Formula 1: | HT < VT |
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| 18.6 < 21 |
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| Formula 2: | HT + VT < 40 feet |
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| 39.6 < 40 |
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| Since both formulas are met, this vent configuration is | ||||
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| acceptable. |
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| 0 | 5 | 10 | 15 | 20 |
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| HORIZONTAL VENT RUN PLUS OFFSET IN FEET | HT |
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The shaded area within the lines represents acceptable values for HT and VT .
For vent configurations requiring more than zero 90° elbow (top exit) or one 90° elbow (rear exit), the following formulas apply:
Formula 1: HT < VT
Formula 2: HT + VT < 40 feet
