12
W415-0381 / H / 12.07.07
90°
90°
V1
H1
H2
V2
45°
90°
45°
VERTICAL TERMINATION

Example 3:

V1 = 5 ft
V2 = 10 ft
VT =
V1
+
V2 =
5 + 10 = 15 ft
H1 = 3 ft
H2 = 2.5 ft
HR = H1 + H2 = 3 + 2.5 = 5.5 ft
HO = .03(one 45º elbow + three 90º elbows - 135º)
= .03(45+90+90+90-135)=5.4
HT = HR + HO = 5.5 + 5.4 = 10.9 ft
HT + VT = 10.9 + 15 = 25.9 ft
Formula 1: H
T < VT
10.9 < 15
Formula 2: H
T + VT < 40 feet
25.9 < 40
Since both formulas are met, this vent confi guration is
acceptable.
when (HT) < (VT)
Simple venting confi gurations
FIGURE 10
REQUIRED VERTICAL RISE
IN FEET (VT)
HORIZONTAL VENT RUN PLUS
OFFSETS IN FEET (HT)
FIGURE11
For vent confi gurations requiring more than one 45º and one
90° elbow , the following formulas apply:

Formula 1: HT < VT

Formula 2: HT + VT < 40 feet
See graph to determine the required vertical rise VT for the
required horizontal run HT.
The shaded area within the lines represents acceptable
values for HT and VT.