Page 27
TABLE 14
Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated
Attic or Crawl Space For Intake Air in Feet
NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent
length calculation.
Standard Termination at Elevation 0 - 4500 ft
No Of
90°
Elbows
1-1/2” Pipe
2” Pipe
2-1/2” Pipe
3” Pipe
Model
Model
Model
Model
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
71
56
34
14
100
100
78
43
118
117
98
98
2
15
10
n/a
66
51
29
9
95
95
73
38
113
112
93
93
3
10
n/a
61
46
24
4
90
90
68
33
108
107
88
88
4
n/a
56
41
19
n/a
85
85
63
28
103
102
83
83
5
51
36
14
80
80
58
23
98
97
78
78
6
46
31
9
75
75
53
18
93
92
73
73
7
41
26
4
70
70
48
13
88
87
68
68
8
36
21
n/a
65
65
43
8
83
82
63
63
9
31
16
60
60
38
3
78
77
58
58
10
26
11
55
55
33
n/a
73
72
53
53
Standard Termination Elevation 4500 - 10,000 f
t
No Of
90°
Elbows
1-1/2”
2” Pipe
2-1/2” Pipe
3” Pipe
Model
Model
Model
Model
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
71
56
34
n/a
100
100
78
43
118
117
98
98
2
15
10
n/a
66
51
29
95
95
73
38
113
112
93
93
3
10
n/a
61
46
24
90
90
68
33
108
107
88
88
4
n/a
56
41
19
85
85
63
28
103
102
83
83
5
51
36
14
80
80
58
23
98
97
78
78
6
46
31
9
75
75
53
18
93
92
73
73
7
41
26
4
70
70
48
13
88
87
68
68
8
36
21
n/a
65
65
43
8
83
82
63
63
9
31
16
60
60
38
3
78
77
58
58
10
26
11
55
55
33
n/a
73
72
53
53