507266-04B
Page 21 of 56
Issue 1904
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 - 4500 ft
Number of 90° Elbows
Used
2" Pipe
2" Pipe
2" Pipe
Capacity
Capacity
Capacity
70
90
110
70
90
110
70
90
110
1
51
29
9
95
73
38
112
93
93
2
46
24
4
90
68
33
107
88
88
3
41
19
n/a
85
63
28
102
83
83
4
36
14
80
58
23
97
78
78
5
31
9
75
53
18
92
73
73
6
26
4
70
48
13
87
68
68
7
21
n/a
65
43
8
82
63
63
8
16
60
38
3
77
58
58
9
11
55
33
n/a
72
53
53
10
6
50
28
67
48
48
Standard Termination Elevation 4,501 - 10,000 ft
Number of 90° Elbows
Used
2" Pipe
2" Pipe
2" Pipe
Capacity
Capacity
Capacity
70
90
110
70
90
110
70
90
110
1
51
29
n/a
95
73
38
112
93
93
2
46
24
90
68
33
107
88
88
3
41
19
85
63
28
102
83
83
4
36
14
80
58
23
97
78
78
5
31
9
75
53
18
92
73
73
6
26
4
70
48
13
87
68
68
7
21
n/a
65
43
8
82
63
63
8
16
60
38
3
77
58
58
9
11
55
33
n/a
72
53
53
10
6
50
28
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.
