9
VERTICAL TERMINATION
when (HT) < (VT) | Example 4: |
FIGURE 10
FIGURE 11
| 90° | V3 |
90° |
|
|
V | H2 |
|
H1 | 2 | 90° |
| ||
V1 |
| |
| 90° |
|
See graph to determine the required vertical rise VT for the required horizontal run HT.
REQUIRED VERTICAL
RISE IN FEET
VT
HORIZONTAL VENT RUN PLUS OFFSET IN FEET HT
The shaded area within the lines represents acceptable values for HT and VT .
For vent confi gurations 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
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 (90 + 90 + 90 + 90 - 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 feet 39.6 < 40
Since both formulas are met, this vent configuration is acceptable.