Page 25
31-5000728 Rev. 0
Use the following steps to correctly size vent pipe diameter.
1
2
3
4
5
6
7
Figure 22. Vent Pipe Diameter Sizing
Furnace capacity?
Which termination?
Which needs most
elbows?
How many?
Desired pipe size?
What is the altitude?
Use Table 12A through
Table 13 to find max pipe
length or exhaust pipe
length. Includes all vent
pipe and elbows inside
and outside the house.
2” or 3”
Intake or
Exhaust?
Standard or
Concentric?
See Table 11
040, 060,
080, 100 btuh