11
HORIZONTAL TERMINATION
when (HT) > (VT) | Example 2: |
Simple venting configuration (only one 45º and 90° elbow) |
|
See graph to determine the re-
quired vertical rise VT for the re- FIGURE 7 quired horizontal run HT.
REQUIRED
VERTICAL
RISE IN
INCHES (VT)
HORIZONTAL VENT RUN PLUS OFFSETS IN FEET (HT)
FIGURE 8 | 90° | 90° | H4 | |
45° |
| H3 | ||
H1 | V2 | |||
H2 | ||||
|
| |||
|
|
|
V1 90°
V1 | = 4 ft |
V2 | = 1.5 ft |
VT | = V1 + V2 = 4 ft + 1.5 ft = 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(one 45º elbow + three 90º elbow |
| |
HT | = HR + HO = 5.5 +5.4 = 10.9 ft |
HT + VT = 10.9 + 5.5 = 16.4 ft
Formula 1: HT < 4.2 VT
4.2VT = 4.2 x 5.5 = 23.1 ft
10.9< 23.1
Formula 2: HT + VT < 24.75 feet
16.4 < 24.75
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 ac- ceptable.