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TABLE 22
Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated
Attic or Crawl Space For Intake Air in Feet
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.
Standard Termination at Elevation 0 - 4500 ft
Number Of 90° El
bows Used
2” Pipe
2-1/2” Pipe
3” Pipe
Model
Model
Model
040
060
080
040
060
080
040
060
080
1
71
56
34
100
100
78
118
117
98
2
66
51
29
95
95
73
113
112
93
3
61
46
24
90
90
68
108
107
88
4
56
41
19
85
85
63
103
102
83
5
51
36
14
80
80
58
98
97
78
6
46
31
9
85
75
63
93
92
73
7
41
26
4
70
70
48
88
87
68
8
36
21
n/a
65
65
43
83
82
63
9
31
16
60
60
38
78
77
58
10
26
11
55
55
33
73
72
53
