507768-05
Page 21 of 56
Issue 2128
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 - 4,500 ft
Number
of 90°
Elbows
Used
1-1/2” Pipe
2” Pipe
2-1/2" Pipe
3" Pipe
Capacity
Capacity
Capacity
Capacity
030
045
070
090
110
030
045
070
090
110
030
045
070
090
110
030
045
070
090
110
1
20
15
10
n/a
n/a
66
51
29
9
95
95
73
38
113
112
93
93
2
15
10
n/a
61
46
24
4
90
90
68
33
108
107
88
88
3
10
n/a
56
41
19
n/a
85
85
63
28
103
102
83
83
4
n/a
51
36
14
80
80
58
23
98
97
78
78
5
46
31
9
85
75
53
18
93
92
73
73
6
41
26
4
70
70
48
13
88
87
68
68
7
36
21
n/a
65
65
43
8
83
82
63
63
8
31
16
60
60
38
3
78
77
58
58
9
26
11
55
55
33
n/a
73
72
53
53
10
21
6
50
50
28
68
67
48
48
Standard Termination Elevation 4,501 - 10,000 ft.
Number
of 90°
Elbows
Used
1-1/2” Pipe
2” Pipe
2-1/2" Pipe
3" Pipe
Capacity
Capacity
Capacity
Capacity
030
045
070
090
110
030
045
070
090
110
030
045
070
090
110
030
045
070
090
110
1
20
15
10
n/a
n/a
66
51
29
n/a
95
95
73
38
113
112
93
93
2
15
10
n/a
61
46
24
90
90
68
33
108
107
88
88
3
10
n/a
56
41
19
85
85
63
28
103
102
83
83
4
n/a
51
36
14
80
80
58
23
98
97
78
78
5
46
31
9
85
85
53
18
93
92
73
73
6
41
26
4
70
70
48
13
88
87
68
68
7
36
21
n/a
65
65
43
8
83
82
63
63
8
31
16
60
60
38
3
78
77
58
58
9
26
11
55
55
33
n/a
73
72
53
53
10
21
6
50
50
28
68
67
48
48
* 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.
* Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length
calculation.
Table 5C.