Maximum Allowable Exposed Vent Lengths Insulation; Maximum Equivalent Vent Length - Bryant 986TB Installation, Start-Up, Operating And Service And Maintenance Instructions

Maximum Allowable Exposed Vent Length in Unconditioned Space − Ft.
Unit Size
Uninsulated
Pipe Dia. 1 ½ 2
in.
20 20 20
Winter
0 10 5
Design
­20 5
Temp
°F ­40
Unit Size
Pipe Dia. 1 ½ 2
in.
20 15 40
Winter
0 15 20
Design
­20 15 10
Temp
°F ­40 10 5
Unit Size
Pipe Dia. 2
in.
20 20
Winter
0 20
Design
­20 15
Temp
°F ­40 10
Unit Size
Uninsulated
Pipe Dia. 2 ½ 3
in.
20 10 50
Winter
0 10 20
Design
-20 10 10
Temp
°F -40 10 5
Maximum Allowable Exposed Vent Length in Unconditioned Space − Meters
Unit Size
Uninsulated
Pipe Dia. 38 51
mm
-7 6.1 6.1
Winter
-18 3.0 1.5
Design
-29 1.5
Temp
-40
°C
Unit Size
Pipe Dia. 38 51
mm
-7 4.6 12.2
Winter
-18 4.6 6.1
Design
-29 4.6 3.0
Temp
°C -40 3.0 1.5
Unit Size
Pipe Dia. 51
mm
-7 6.1
Winter
-18 6.1
Design
-29 4.6
Temp
°C -40 3.0
Table 15 – Maximum Allowable Exposed Vent Lengths Insulation Table
40,000* BTUH
3/8­in. Insulation 1/2­in. Insulation
2 ½ 1 ½ 2 2 ½ 1 ½ 2
20 20 50 45 20 60
5 20 25 20 20 30
20 15 10 20 20
15 10 5 15 15
Uninsulated
2 ½ 3 4
40 35 30
15 10 5
5
Uninsulated
2 ½ 3 4 2
50 40 35 20
20 15 10 20
10 5 20
5 20
120,000 BTUH
3/8­in. Insulation 1/2­in. Insulation
4 2 ½ 3 4 2 ½
40 10 75 95 10
15 10 55 45 10
10 35 25 10
10 25 15 10
40,000* BTUH
3/8­in. Insulation 1/2­in. Insulation
64 38 51 64 38 51
6.1 6.1 15.2 13.7 6.1 18.3 15.2
1.5 6.1 7.6 6.1 6.1 9.1
6.1 4.6 3.0 6.1 6.1
4.6 3.0 1.5 4.6 4.6
Uninsulated
64 76 102
12.2 10.7 9.1
4.6 3.0 1.5
1.5
Uninsulated
64 76 102 51
15.2 12.2 10.7 6.1
6.1 4.6 3.0 6.1
3.0 1.5 6.1
1.5 6.1
Uninsulated
2 ½ 1 ½ 2 2 ½ 3
50 20 30 30 25
25 15 15 10 10
15 10 5
10 5
80,000 BTUH
3/8­in. Insulation
1 ½ 2 2 ½ 3
15 50 90 75
15 50 45 35
15 35 30 20
15 25 20 15
100,000 BTUH
3/8­in. Insulation
2 ½ 3 4
80 95 80
55 45 35
35 30 20
25 20 10
Uninsulated
3 4 2 ½ 3
75 105 5 55
65 50 5 25
45 30 5 10
30 20 5 5
Uninsulated
64 38 51 64 76
6.1 9.1 9.1 7.6
7.6 4.6 4.6 3.0 3.0
4.6 3.0 1.5
3.0 1.5
80,000 BTUH
3/8­in. Insulation
38 51 64 76
4.6 15.2 27.4 22.9
4.6 15.2 13.7 10.7
4.6 10.7 9.1 6.1
4.6 7.6 6.1 4.6
100,000 BTUH
3/8­in. Insulation
64 76 102
24.4 28.9 24.4
16.8 13.7 10.7
10.7 9.1 6.1
7.6 6.1 3.0
52
60,000 BTUH
3/8­in. Insulation 1/2­in. Insulation
1 ½ 2 2 ½ 3 1 ½ 2
20 75 65 60 20 85
20 40 30 25 20 45
20 25 20 15 20 30
20 15 15 10 20 20
1/2­in. Insulation
4 1 ½ 2 2 ½
65 15 50 70
30 15 50 50
15 15 40 30
5 15 30 25
1/2­in. Insulation
2 2 ½ 3
20 80 105
20 65 55
20 45 35
20 30 25
140,000 BTUH
3/8­in. Insulation 1/2­in. Insulation
4 2 ½ 3 4 2 ½
50 5 65 105 5
15 5 65 50 5
5 5 45 30 5
5 30 20 5
60,000 BTUH
3/8­in. Insulation 1/2­in. Insulation
38 51 64 76 38 51
6.1 22.9 19.8 18.3 6.1 25.9 22.9 19.8
6.1 12.2 9.1 7.6 6.1 13.7 12.2
6.1 7.6 6.1 4.6 6.1 9.1
6.1 4.6 4.6 3.0 6.1 6.1
1/2­in. Insulation
102 38 51 64
19.8 4.6 15.2 21.3
9.1 4.6 15.2 15.2
4.6 4.6 12.2 9.1
1.5 4.6 9.1 7.6
1/2­in. Insulation
51 64 76
6.1 24.4 32.0
6.1 19.8 16.7
6.1 13.7 10.7
6.1 9.1 7.6
2 ½ 3
75 65
40 30
25 20
15 10
3 4
70 70
40 35
25 15
20 10
4
90
45
25
15
3 4
65 125
65 60
50 40
35 25
64 76
9.1
7.6 6.1
4.6 3.0
76 102
21.3 21.3
12.2 10.7
7.6 4.6
6.1 3.0
102
27.4
13.7
7.6
4.6