20
Table 6: Vent System and Combustion Air System Components Equivalent Length
vs. Component Nominal Diameter
Vent or Combustion Air System
Component Description
Equivalent Length (Ft.) for Vent or Combustion Air System Component
vs. Component Nominal Diameter (In.)
Component Nominal Diameter, In. 4” 6”
90° Elbow (Sch. 80 or Sch.40) 13 22
45° Elbow (Sch. 80 or Sch. 40) 4.5 7.5
Sch. 40 CPVC Pipe x 30 In. Long 2.5
Sch. 40 PVC Pipe x 1 Ft. Long 1
Sch. 40 PVC Pipe x 2 Ft. Long 2
Sch. 40 PVC Pipe x 3 Ft. Long 3
Sch. 40 PVC Pipe x 4 Ft. Long 4
Sch. 40 PVC Pipe x 5 Ft. Long 5
IV. Venting B. CPVC/PVC Venting (continued)
Figure 5: Expansion Loop and Offset
2 L
5
6"
MIN
6"
MIN
5
4
4
2
LONG RUN OF PIPE
CHANGE OF DIRECTION
(VERTICAL OR HORIZONTAL)
LOOP
(HORIZONTAL ONLY)
(TOP VIEW)
OFFSET
L
L
L
(L)
LOOP LENGTH
L
L
L
RESTRAINT (RESTRICTS MOVEMENT)
HANGER (ALLOWS MOVEMENT)
KEY
Nominal
Pipe
Dia. (In.)
Length of
Straight Run
(Ft.)
Loop Length
“L” (In.)
4
20 60
30 74
40 85
50 95
60 104
6
20 73
30 90
40 103
50 116
60 127
WARNING
Apply supplied dielectric grease to gasket inside vent section of two-pipe vent connector. Failure to apply the
grease could result in gasket rupture during vent pipe installation and gasket deterioration due to condensate
exposure.
Table 7: Expansion Loop Lengths