NOTE − Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake and Exhaust must be same pipe
size.
NOTE − Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.
Number Of
90° Elbows
Used
045
070
1
81
66
2
76
61
3
71
56
4
66
51
5
61
46
6
56
41
7
51
36
8
46
31
9
41
26
10
36
21
Number Of
90° Elbows
Usedl
045
070
1
73
58
2
68
53
3
63
48
4
58
43
5
53
38
6
48
33
7
43
28
8
38
23
9
33
18
10
28
13
Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated
NOTE − Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.
Number Of
90° Elbows
Used
045
070
1
71
56
2
66
51
3
61
46
4
56
41
5
51
36
6
46
31
7
41
26
8
36
21
9
31
16
Maximum Allowable Intake or Exhaust Vent Length in Feet