507769-05G / 31-5000656
Page 19 of 55
Issue 2223
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
045
070
090
045
070
090
045
070
090
045
070
090
1
10
10
n/a
51
36
14
85
65
28
107
107
88
2
n/a
n/a
46
31
9
80
60
23
102
102
83
3
41
26
n/a
75
55
18
97
97
78
4
36
21
70
50
13
92
92
73
5
31
16
65
45
8
87
87
68
6
26
11
60
40
n/a
82
82
63
7
21
n/a
55
35
77
77
58
8
16
50
30
72
72
53
9
11
45
25
67
67
48
10
n/a
40
20
62
62
43
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 8A.
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
1-1/2” Pipe
2” Pipe
2-1/2" Pipe
3" Pipe
Capacity
Capacity
Capacity
Capacity
045
070
090
045
070
090
045
070
090
045
070
090
1
n/a
n/a
n/a
30
20
10
80
53
28
107
107
88
2
25
15
n/a
75
48
23
102
102
83
3
20
10
70
43
18
97
97
78
4
15
n/a
65
38
13
92
92
73
5
10
60
33
n/a
87
87
68
6
n/a
55
28
82
82
63
7
50
23
77
77
58
8
45
18
72
72
53
9
40
13
67
67
48
10
35
n/a
62
62
43
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 8B.