508297-01
Page 21 of 57
Issue 2219
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 - 2,000 ft
Number
of 90°
Elbows
Used
1-1/2” Pipe
2” Pipe
2-1/2" Pipe
3" Pipe
Capacity
Capacity
Capacity
Capacity
030 045 070 090 110 135
030/
045 070 090 110 135
030/
045 070 090 110 135
030/
045 070 090 110 135
1
20
15
10
n/a n/a n/a
71
56
34
14
n/a
100 100 78
43
n/a
118 117 98
98
60
2
15
10
n/a
66
51
29
9
95
95
73
38
113 112 93
93
55
3
10
n/a
61
46
24
n/a
90
90
68
33
108 107 88
88
50
4
n/a
56
41
19
85
85
63
28
103 102 83
83
45
5
51
36
14
80
80
58
23
98
97
78
78
40
6
46
31
9
75
75
53
18
93
92
73
73
35
7
41
26
n/a
70
70
48
13
88
87
68
68
30
8
36
21
65
65
43
n/a
83
82
63
63
25
9
31
16
60
60
38
78
77
58
58
20
10
26
11
55
55
33
73
72
53
53
15
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.
NOTE - Contact your local FTC if more than 85ft of venting is needed.
Table 6A.
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 2,001 - 10,000 ft
Number of
90° Elbows
Used
2” Pipe
2-1/2" Pipe
3" Pipe
Capacity
Capacity
Capacity
030/
045
070
090
110
135
030/
045
070
090
110
135
030/
045
070
090
110
135
1
71
30
15
n/a
n/a
100
96
53
38
n/a
118
117
98
98
60
2
66
25
10
95
91
48
33
113
112
93
93
55
3
61
20
n/a
90
86
43
28
108
107
88
88
50
4
56
15
85
81
38
23
103
102
83
83
45
5
51
10
80
76
33
18
98
97
78
78
40
6
46
n/a
75
71
28
13
93
92
73
73
35
7
41
70
66
23
n/a
88
87
68
68
30
8
36
65
61
18
83
82
63
63
25
9
31
60
56
13
78
77
58
58
20
10
26
55
51
n/a
73
72
53
53
15
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.
NOTE - Contact your local FTC if more than 85ft of venting is needed.
Table 6B.