Page 28
TABLE 15
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
Number Of
90° Elbows
Used
2” Pipe
2-1/2” Pipe
3” Pipe
Model
Model
Model
045
070
090
110
135
045
070
090
110
135
045
070
090
110
135
1
71
56
34
14
n/a
100
100
78
43
n/a
128
117
98
98
94
2
66
51
29
9
95
95
73
38
113
112
93
93
89
3
61
46
24
4
90
90
68
33
108
107
88
88
84
4
56
41
19
n/a
85
85
63
28
103
102
83
83
79
5
51
36
14
80
80
58
23
108
97
78
78
74
6
46
31
9
75
75
53
18
93
92
73
73
89
7
41
26
4
70
70
48
13
88
87
68
68
64
8
36
21
n/a
65
65
43
8
83
82
63
63
59
9
31
16
60
60
38
3
78
77
58
58
54
10
26
11
55
55
33
n/a
73
72
53
53
49
Standard Termination Elevation 4500 - 10,000 ft
Number Of
90° Elbows
Used
2” Pipe
2-1/2” Pipe
3” Pipe
Model
Model
Model
045
070
090
110
135
045
070
090
110
135
045
070
090
110
135
1
71
56
34
n/a
n/a
100
100
78
43
n/a
118
117
98
98
94
2
66
51
29
95
95
73
38
113
112
93
93
89
3
61
46
24
90
90
68
33
108
107
88
88
84
4
56
41
19
85
85
63
28
103
102
83
83
79
5
51
36
14
80
80
58
23
98
97
78
78
74
6
46
31
9
75
75
53
18
93
92
73
73
69
7
41
26
4
70
70
48
13
88
87
68
68
64
8
36
21
n/a
65
65
43
8
83
82
63
63
59
9
31
16
60
60
38
3
78
77
58
58
54
10
26
11
55
55
33
n/a
73
72
53
53
49