508115-01
Issue 2043
Page 29 of 57
Maximum Allowable Exhaust Vent Lengths with Furnace Installed in a Closet or Basement Using Ventilated Attic or Crawl
Space for Intake Air in Feet
Standard Termination at Elevation 0 − 10,000 ft.
Number
of 90
°
Elbows
Used
1-1/2” Pipe
2” Pipe
2-1/2” Pipe
3” Pipe
Capacity
Capacity
Capacity
Capacity
045
070
090
110
045
070
090
110
045
070
090
110
045
070
090
110
1
15
10
n/a
n/a
61
46
24
n/a
100
80
43
n/a
127
127
108
108
2
10
n/a
56
41
19
95
75
38
122
122
103
103
3
n/a
51
36
14
90
70
33
117
117
98
98
4
46
31
n/a
85
65
28
112
112
93
93
5
41
26
80
60
23
107
107
88
88
6
36
21
75
55
18
102
102
83
83
7
31
16
70
50
13
97
97
78
78
8
26
11
65
45
n/a
92
92
73
73
9
21
n/a
60
40
87
87
68
68
10
16
55
35
82
82
63
63
NOTE
: Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length
calculation.
Table 12.
