508134-01
Issue 2045
Page 28 of 56
Maximum Allowable Exhaust Vent Length with Furnace Installed in a Closet or Basement Using Ventilated Attic or Crawl
Space for Intake in Feet
Standard Termination at Elevation 0 - 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
15
10
n/a
51
36
14
85
100
28
107
107
88
2
10
n/a
46
31
9
80
95
23
102
102
83
3
n/a
41
26
4
75
90
18
97
97
78
4
36
21
n/a
70
85
13
92
92
73
5
31
16
65
80
8
87
87
68
6
26
11
60
75
n/a
82
82
63
7
21
6
55
70
77
77
58
8
16
n/a
50
65
72
72
53
9
11
45
60
67
67
48
10
6
40
55
62
62
43
NOTE
: Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length
calculation.
Table 11B.