11
HORIZONTAL TERMINATION
when (HT) > (VT)
Simple venting confi guration (only one 45º and 90° elbow)
See graph to determine the re-
FIGURE 8
quired vertical rise VT for the required horizontal run HT.
Example 2:
FIGURE 9 | 90° 90° |
90° | H4 |
H1 | H3 V |
2 | |
| H2 |
V1
45°
90°
REQUIRED
VERTICAL
RISE IN
INCHES (VT)
HORIZONTAL VENT RUN PLUS OFFSETS IN FEET
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 + four 90º elbows |
| |
HT | = HR + HO = 5.5 + 8.1 = 13.6ft |
HT + VT = 13.6 + 5.5 = 19.1ft
Formula 1: HT < 4.2 VT
4.2VT = 4.2 x 5.5 = 23.1 ft
13.6< 23.1
Formula 2: HT + VT < 24.75 feet
19.1 < 24.75
The shaded area within the lines represents acceptable values for HT and VT .
For vent confi gurations 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.