17
3.9TOP EXIT VERTICAL TERMINATION
(HT) < (VT)
Simple venting configurations. | See graph to determine the required vertical rise VT for the |
| required horizontal run HT. |
REQUIRED VERTICAL RISE IN FEET VT
40 |
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30 |
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20 |
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10 |
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3 |
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0 | 5 | 10 | 15 | 20 |
HORIZONTAL VENT RUN PLUS OFFSET IN FEET HT The shaded area within the lines represents acceptable
values for HT and VT
For vent configurations requiring one or more 90° elbows the following formulas apply:
Formula 1: HT < VT
Formula 2: HT + VT < 40 feet
Example 6:
V1 = 5 FT
V2 = 6 FT
V3 = 10 FT
VT = V1 + V2 + V3 = 5 + 6 + 10 = 21 FT
H1 = 8 FT
H2 = 2.5 FT
HR = H1 + H2 = 8 + 2.5 = 10.5 FT HO = .03 (four 90° elbows - 90°)
= .03 (360° - 90°) = 8.1 FT
HT = HR + HO = 10.5 + 8.1 = 18.6 FT HT + VT = 18.6 + 21 = 39.6 FT
Formula 1: | HT | < VT |
| 18.6 < 21 | |
Formula 2: | HT | + VT < 40 FT |
| 39.6 < 40 | |
Since both formulas are met, this vent configuration is acceptable.
90°
H1
V1
90°
V3
H2
V2
90°
90°
18.1
