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Table 14 – Maximum Allowable Exposed Vent Lengths Insulation Table - - Ft. / M
Two Stage
Winter Design
Furnace High
Temp ° F (° C)
Heat Input
20 (-10)
0 (-20)
40000*
-20 (-30)
-40 (-40)
20 (-10)
0 (-20)
60000
-20 (-30)
-40 (-40)
20 (-10)
0 (-20)
80000
-20 (-30)
-40 (-40)
20 (-10)
0 (-20)
100000
-20 (-30)
-40 (-40)
20 (-10)
0 (-20)
120000
-20 (-30)
-40 (-40)
* Not all families have these models.
* 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 15 or 17.
† Insulation thickness based on R value of 3.5 per in.
No Insulation
Pipe
Pipe Diameter-inches (mm)
Length in
1.5
2.0
2.5
3.0
Ft. & M
(38)
(51)
(64)
(76)
Ft.
40.0
35.0
35.0
N/A
M
12.2
10.7
10.7
N/A
Ft.
19.0
14.0
12.0
N/A
M
5.8
4.3
3.7
N/A
Ft.
9.0
3.0
1.0
N/A
M
2.7
0.9
0.3
N/A
Ft.
3.0
0.0
0.0
N/A
M
0.9
0.0
0.0
N/A
Ft.
30.0
51.0
51.0
45.0
M
9.1
15.5
15.5
13.7
Ft.
30.0
24.0
23.0
16.0
M
9.1
7.3
7.0
4.9
Ft.
18.0
11.0
9.0
1.0
M
5.5
3.4
2.7
0.3
Ft.
10.0
3.0
0.0
0.0
M
3.0
0.9
0.0
0.0
Ft.
20.0
64.0
64.0
56.0
M
6.1
19.5
19.5
17.1
Ft.
20.0
32.0
30.0
22.0
M
6.1
9.8
9.1
6.7
Ft.
20.0
17.0
14.0
6.0
M
6.1
5.2
4.3
1.8
Ft.
15.0
7.0
5.0
0.0
M
4.6
2.1
1.5
0.0
Ft.
N/A
25.0
79.0
70.0
M
N/A
7.6
24.1
21.3
Ft.
N/A
25.0
40.0
31.0
M
N/A
7.6
12.2
9.4
Ft.
N/A
23.0
21.0
13.0
M
N/A
7.0
6.4
4.0
Ft.
N/A
13.0
10.0
1.0
M
N/A
4.0
3.0
0.3
Ft.
N/A
N/A
15.0
85.0
M
N/A
N/A
4.6
25.9
Ft.
N/A
N/A
15.0
41.0
M
N/A
N/A
4.6
12.5
Ft.
N/A
N/A
15.0
20.0
M
N/A
N/A
4.6
6.1
Ft.
N/A
N/A
15.0
7.0
M
N/A
N/A
4.6
2.1
3/8-in. (9.5 mm)
Pipe Diameter-inches (mm)
4.0
1.5
2.0
2.5
3.0
(102)
(38)
(51)
(64)
(76)
N/A
50.0
104.0
94.0
N/A
N/A
15.2
31.7
28.7
N/A
N/A
50.0
61.0
54.0
N/A
N/A
15.2
18.6
16.5
N/A
N/A
50.0
41.0
35.0
N/A
N/A
15.2
12.5
10.7
N/A
N/A
39.0
29.0
23.0
N/A
N/A
11.9
8.8
7.0
N/A
N/A
30.0
135.0 138.0 120.0
N/A
9.1
41.1
42.1
36.6
N/A
30.0
93.0
82.0
69.0
N/A
9.1
28.3
25.0
21.0
N/A
30.0
65.0
56.0
44.0
N/A
9.1
19.8
17.1
13.4
N/A
30.0
48.0
40.0
29.0
N/A
9.1
14.6
12.2
8.8
47.0
20.0
70.0
173.0 150.0 125.0 20.0
14.3
6.1
21.3
52.7
45.7
11.0
20.0
70.0
104.0
87.0
3.4
6.1
21.3
31.7
26.5
0.0
20.0
70.0
71.0
57.0
0.0
6.1
21.3
21.6
17.4
0.0
20.0
61.0
52.0
40.0
0.0
6.1
18.6
15.8
12.2
59.0
N/A
25.0
110.0 186.0 155.0
18.0
N/A
7.6
33.5
56.7
19.0
N/A
25.0
110.0 109.0
5.8
N/A
7.6
33.5
33.2
0.0
N/A
25.0
91.0
74.0
0.0
N/A
7.6
27.7
22.6
0.0
N/A
25.0
68.0
53.0
0.0
N/A
7.6
20.7
16.2
73.0
N/A
N/A
15.0
100.0 190.0
22.3
N/A
N/A
4.6
30.5
29.0
N/A
N/A
15.0
100.0 109.0
8.8
N/A
N/A
4.6
30.5
7.0
N/A
N/A
15.0
94.0
2.1
N/A
N/A
4.6
28.7
0.0
N/A
N/A
15.0
69.0
0.0
N/A
N/A
4.6
21.0
51
1/2-in. (12.7 mm)
Pipe Diameter-inches (mm)
4.0
1.5
2.0
2.5
3.0
(102)
(38)
(51)
(64)
(76)
N/A
50.0
122.0 110.0
N/A
N/A
15.2
37.2
33.5
N/A
N/A
50.0
74.0
65.0
N/A
N/A
15.2
22.6
19.8
N/A
N/A
50.0
51.0
43.0
N/A
N/A
15.2
15.5
13.1
N/A
N/A
48.0
37.0
30.0
N/A
N/A
14.6
11.3
9.1
N/A
N/A
30.0
135.0 162.0 141.0
N/A
9.1
41.1
49.4
43.0
N/A
30.0
111.0
98.0
83.0
N/A
9.1
33.8
29.9
25.3
N/A
30.0
79.0
68.0
55.0
N/A
9.1
24.1
20.7
16.8
N/A
30.0
59.0
50.0
38.0
N/A
9.1
18.0
15.2
11.6
70.0
175.0 177.0 147.0
38.1
6.1
21.3
53.3
53.9
67.0
20.0
70.0
124.0 104.0
20.4
6.1
21.3
37.8
31.7
40.0
20.0
70.0
86.0
71.0
12.2
6.1
21.3
26.2
21.6
24.0
20.0
70.0
64.0
50.0
7.3
6.1
21.3
19.5
15.2
25.0
110.0 219.0 182.0
47.2
7.6
33.5
66.8
86.0
25.0
110.0 131.0 104.0
26.2
7.6
33.5
39.9
54.0
25.0
110.0
90.0
16.5
7.6
33.5
27.4
35.0
25.0
83.0
66.0
10.7
7.6
25.3
20.1
N/A
N/A
15.0
100.0 224.0
57.9
N/A
N/A
4.6
30.5
N/A
N/A
15.0
100.0 131.0
33.2
N/A
N/A
4.6
30.5
71.0
N/A
N/A
15.0
114.0
21.6
N/A
N/A
4.6
34.7
48.0
N/A
N/A
15.0
85.0
14.6
N/A
N/A
4.6
25.9
4.0
(102)
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
44.8
82.0
25.0
52.0
15.8
33.0
10.1
55.5
31.7
68.0
20.7
46.0
14.0
68.3
39.9
88.0
26.8
62.0
18.9
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