Payne PG95 Installation, Start-Up, Operating And Service And Maintenance Instructions page 46

Table 15 – Maximum Allowable Exposed Vent Lengths in Unconditioned Space − Ft.
Unit Size
0" Insulation
Pipe Dia. 1½
In.
20 20 20
Winter
0 5
Design
Temp -20
°F
-40
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
26,000* BTUH
3/8" Insulation 1/2" Insulation
2 1½ 2 1½
50 45 60
5 25 20 30
15 10 20
10 5 15
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
2
50
25
15
10
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
46
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
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