17
MAXIMUM ALLOWABLE EXPOSED VENT PIPE LENGTH (FT)
WITH INSULATION IN WINTER DESIGN TEMPERATURE AMBIENT*
*
Pipe length (ft) specified for maximum vent pipe lengths located in unconditioned spaces. Vent pipes located in unconditioned space cannot
exceed the total allowable pipe length as specified in the Maximum Allowable Pipe Length table.
† Insulation thickness based on R value of 3.5 per in.
UNIT SIZE
WINTER DESIGN
TEMP °F
MAX PIPE DIA
(IN.)
INSULATION THICKNESS (IN.)†
0
3/8
1/2
3/4
1
040-14
20
2
21
37
42
50
57
0
2
10
22
25
30
35
- 20
2
5
14
17
21
25
060-14
20
2
30
55
61
70
70
0
2
16
33
38
46
53
- 20
2
9
23
26
33
38
080-14
080-20
20
2
37
65
70
70
70
0
2
20
39
45
55
63
- 20
2
11
27
31
39
45
100-20
20
2-1/2
41
70
70
70
70
0
2-1/2
21
42
48
59
68
- 20
2-1/2
11
28
33
41
49
120-20
20
3
49
70
70
70
70
0
3
26
51
58
70
70
- 20
3
15
35
40
50
59