9
MAXIMUM ALLOWABLE EXPOSED VENT LENGTHS INSULATION TABLE -- FT. (M)
Maximum Length of Uninsulated and Insulated Vent Pipe-Ft (M)
Two
Stage
Furnace
High Heat
Input
Winter
Design
Temp
°
F
(
°
C)
Pipe
Length in
Ft. & M
No Insulation
3/8-in. (9.5 mm)
1/2-in. (12.7 mm)
Pipe Diameter-inches (mm)
Pipe Diameter-inches (mm)
Pipe Diameter-inches (mm)
1.5
2.0
2.5
3.0
4.0
1.5
2.0
2.5
3.0
4.0
1.5
2.0
2.5
3.0
4.0
(38)
(51) (64) (76) (102)
(38)
(51)
(64)
(76) (102)
(38)
(51)
(64)
(76)
(102)
40000**
20 (-10)
Ft.
40.0
35.0 35.0
N/A
N/A
50.0
104.0 94.0
N/A
N/A
50.0
122.0 110.0
N/A
N/A
M
12.2
10.7 10.7
N/A
N/A
15.2
31.7
28.7
N/A
N/A
15.2
37.2
33.5
N/A
N/A
0 (-20)
Ft.
19.0
14.0 12.0
N/A
N/A
50.0
61.0
54.0
N/A
N/A
50.0
74.0
65.0
N/A
N/A
M
5.8
4.3
3.7
N/A
N/A
15.2
18.6
16.5
N/A
N/A
15.2
22.6
19.8
N/A
N/A
-20 (-30)
Ft.
9.0
3.0
1.0
N/A
N/A
50.0
41.0
35.0
N/A
N/A
50.0
51.0
43.0
N/A
N/A
M
2.7
0.9
0.3
N/A
N/A
15.2
12.5
10.7
N/A
N/A
15.2
15.5
13.1
N/A
N/A
-40 (-40)
Ft.
3.0
0.0
0.0
N/A
N/A
39.0
29.0
23.0
N/A
N/A
48.0
37.0
30.0
N/A
N/A
M
0.9
0.0
0.0
N/A
N/A
11.9
8.8
7.0
N/A
N/A
14.6
11.3
9.1
N/A
N/A
60000
20 (-10)
Ft.
30.0
51.0 51.0 45.0
N/A
30.0
135.0 138.0 120.0
N/A
30.0
135.0 162.0 141.0
N/A
M
9.1
15.5 15.5 13.7
N/A
9.1
41.1
42.1
36.6
N/A
9.1
41.1
49.4
43.0
N/A
0 (-20)
Ft.
30.0
24.0 23.0 16.0
N/A
30.0
93.0
82.0
69.0
N/A
30.0
111.0 98.0
83.0
N/A
M
9.1
7.3
7.0
4.9
N/A
9.1
28.3
25.0
21.0
N/A
9.1
33.8
29.9
25.3
N/A
-20 (-30)
Ft.
18.0
11.0
9.0
1.0
N/A
30.0
65.0
56.0
44.0
N/A
30.0
79.0
68.0
55.0
N/A
M
5.5
3.4
2.7
0.3
N/A
9.1
19.8
17.1
13.4
N/A
9.1
24.1
20.7
16.8
N/A
-40 (-40)
Ft.
10.0
3.0
0.0
0.0
N/A
30.0
48.0
40.0
29.0
N/A
30.0
59.0
50.0
38.0
N/A
M
3.0
0.9
0.0
0.0
N/A
9.1
14.6
12.2
8.8
N/A
9.1
18.0
15.2
11.6
N/A
80000
20 (-10)
Ft.
20.0
64.0 64.0 56.0 47.0
20.0
70.0 173.0 150.0 125.0
20.0
70.0 175.0 177.0 147.0
M
6.1
19.5 19.5 17.1 14.3
6.1
21.3
52.7
45.7
38.1
6.1
21.3
53.3
53.9
44.8
0 (-20)
Ft.
20.0
32.0 30.0 22.0 11.0
20.0
70.0 104.0 87.0
67.0
20.0
70.0 124.0 104.0
82.0
M
6.1
9.8
9.1
6.7
3.4
6.1
21.3
31.7
26.5
20.4
6.1
21.3
37.8
31.7
25.0
-20 (-30)
Ft.
20.0
17.0 14.0
6.0
0.0
20.0
70.0
71.0
57.0
40.0
20.0
70.0
86.0
71.0
52.0
M
6.1
5.2
4.3
1.8
0.0
6.1
21.3
21.6
17.4
12.2
6.1
21.3
26.2
21.6
15.8
-40 (-40)
Ft.
15.0
7.0
5.0
0.0
0.0
20.0
61.0
52.0
40.0
24.0
20.0
70.0
64.0
50.0
33.0
M
4.6
2.1
1.5
0.0
0.0
6.1
18.6
15.8
12.2
7.3
6.1
21.3
19.5
15.2
10.1
100000
20 (-10)
Ft.
N/A
25.0 79.0 70.0 59.0
N/A
25.0 110.0 186.0 155.0
N/A
25.0 110.0 219.0 182.0
M
N/A
7.6
24.1 21.3 18.0
N/A
7.6
33.5
56.7
47.2
N/A
7.6
33.5
66.8
55.5
0 (-20)
Ft.
N/A
25.0 40.0 31.0 19.0
N/A
25.0 110.0 109.0 86.0
N/A
25.0 110.0 131.0 104.0
M
N/A
7.6
12.2
9.4
5.8
N/A
7.6
33.5
33.2
26.2
N/A
7.6
33.5
39.9
31.7
-20 (-30)
Ft.
N/A
23.0 21.0 13.0
0.0
N/A
25.0
91.0
74.0
54.0
N/A
25.0 110.0
90.0
68.0
M
N/A
7.0
6.4
4.0
0.0
N/A
7.6
27.7
22.6
16.5
N/A
7.6
33.5
27.4
20.7
-40 (-40)
Ft.
N/A
13.0 10.0
1.0
0.0
N/A
25.0
68.0
53.0
35.0
N/A
25.0
83.0
66.0
46.0
M
N/A
4.0
3.0
0.3
0.0
N/A
7.6
20.7
16.2
10.7
N/A
7.6
25.3
20.1
14.0
120000
20 (-10)
Ft.
N/A
N/A 15.0 85.0 73.0
N/A
N/A
15.0 100.0 190.0
N/A
N/A
15.0
100.0 224.0
M
N/A
N/A
4.6
25.9 22.3
N/A
N/A
4.6
30.5
57.9
N/A
N/A
4.6
30.5
68.3
0 (-20)
Ft.
N/A
N/A 15.0 41.0 29.0
N/A
N/A
15.0 100.0 109.0
N/A
N/A
15.0
100.0 131.0
M
N/A
N/A
4.6
12.5
8.8
N/A
N/A
4.6
30.5
33.2
N/A
N/A
4.6
30.5
39.9
-20 (-30)
Ft.
N/A
N/A 15.0 20.0
7.0
N/A
N/A
15.0
94.0
71.0
N/A
N/A
15.0
114.0
88.0
M
N/A
N/A
4.6
6.1
2.1
N/A
N/A
4.6
28.7
21.6
N/A
N/A
4.6
34.7
26.8
-40 (-40)
Ft.
N/A
N/A 15.0
7.0
0.0
N/A
N/A
15.0
69.0
48.0
N/A
N/A
15.0
85.0
62.0
M
N/A
N/A
4.6
2.1
0.0
N/A
N/A
4.6
21.0
14.6
N/A
N/A
4.6
25.9
18.9
* Pipe length (ft) specified for maximum pipe lengths located in unconditioned spaces. Pipes located in unconditioned space cannot exceed total allowable pipe
length calculated from
Table
1 or 3.
**Not all families have these models.
† Insulation thickness based on R value of 3.5 per in.
