10
MAXIMUM ALLOWABLE EXPOSED VENT LENGTHS INSULATION TABLE -- FT. (M)
Maximum Length of Uninsulated and Insulated Vent Pipe-Ft (M)
Single Stage
Furnace
Input
Winter Design
Temp ° F (° C)
Pipe
Length in
Ft. & M
No Insulation 3/8-in. (9.5 mm) Insulation 1/2-in. (12.7 mm) Insulation
Pipe Diameter-inches (mm) Pipe Diameter-inches (mm) Pipe Diameter-inches (mm)
11/2 2 21/2 3 4 11/2 2 21/2 3 4 11/2 2 21/2 3 4
(38) (51) (64) (76) (102) (38) (51) (64) (76) (102) (38) (51) (64) (76) (102)
40000
20 (-10)
Ft. 48 42 42 N/A N/A 50 122 111 N/A N/ A 50 144 130 N/ A N/A
M 14.6 12.8 12.8 N/A N/A 15.2 37.2 33.8 N/A N/A 15.2 43.9 39.6 N/A N/ A
0 (-20)
Ft. 25 19 17 N/A N/A 50 75 66 N/A N/A 50 90 79 N/A N/A
M 7.6 5.8 5.2 N/A N/A 15.2 22.9 20.1 N/A N/A 15.2 27.4 24.1 N/A N/A
-20 (-30)
Ft. 14 7 5 N/A N/A 50 52 45 N/A N/A 50 64 55 N/A N/A
M 4.3 2.1 1.5 N/A N/A 15.2 15.8 13.7 N/A N/A 15.2 19.5 16.8 N/A N/A
-40 (-40)
Ft. 7 0 0 N/A N/A 50 38 31 N/A N/A 50 48 40 N/A N/A
M 2.1 0.0 0.0 N/A N/A 15.2 11.6 9.4 N/A N/A 15.2 14.6 12.2 N/A N/A
60000
20 (-10)
Ft. 30 61 61 54 N/A 30 135 163 142 N/A 30 135 191 166 N/A
M 9.1 18.6 18.6 16.5 N/A 9.1 41.1 49.7 43.3 N/A 9.1 41.1 58.2 50.6 N/A
0 (-20)
Ft. 30 31 30 23 N/A 30 113 100 85 N/A 30 135 120 101 N/A
M 9.1 9.4 9.1 7.0 N/A 9.1 34.4 30.5 25.9 N/A 9.1 41.1 36.6 30.8 N/A
-20 (-30)
Ft. 24 17 15 7 N/A 30 81 70 57 N/A 30 98 85 70 N/A
M 7.3 5.2 4.6 2.1 N/A 9.1 24.7 21.3 17.4 N/A 9.1 29.9 25.9 21.3 N/A
-40 (-40)
Ft. 15 8 5 0 N/A 30 61 52 40 N/A 30 75 64 51 N/A
M 4.6 2.4 1.5 0.0 N/A 9.1 18.6 15.8 12.2 N/A 9.1 22.9 19.5 15.5 N/A
80000
20 (-10)
Ft. 20 70 78 70 60 20 70 175 183 154 20 70 175 215 181
M 6.1 21.3 23.8 21.3 18.3 6.1 21.3 53.3 55.8 46.9 6.1 21.3 53.3 65.5 55.2
0 (-20)
Ft. 20 42 41 33 21 20 70 132 111 89 20 70 157 133 107
M 6.1 12.8 12.5 10.1 6.4 6.1 21.3 40.2 33.8 27.1 6.1 21.3 47.9 40.5 32.6
-20 (-30)
Ft. 20 25 23 14 1 20 70 94 77 57 20 70 113 94 71
M 6.1 7.6 7.0 4.3 0.3 6.1 21.3 28.7 23.5 17.4 6.1 21.3 34.4 28.7 21.6
-40 (-40)
Ft. 20 14 12 3 0 20 70 71 56 38 20 70 86 70 50
M 6.1 4.3 3.7 0.9 0.0 6.1 21.3 21.6 17.1 11.6 6.1 21.3 26.2 21.3 15.2
100000
20 (-10)
Ft. N/ A 25 99 89 78 N/A 25 110 233 265 N/A 25 110 235 229
M N/A 7.6 30.2 27.1 23.8 N/A 7.6 33.5 71.0 80.8 N/A 7.6 33.5 71.6 69.8
0 (-20)
Ft. N/ A 25 55 46 33 N/A 25 110 145 117 N/A 25 110 173 140
M N/A 7.6 16.8 14.0 10.1 N/A 7.6 33.5 44.2 35.7 N/A 7.6 33.5 52.7 42.7
-20 (-30)
Ft. N/ A 25 34 24 11 N/A 25 110 103 79 N/A 25 110 124 97
M N/A 7.6 10.4 7.3 3.4 N/ A 7.6 33.5 31.4 24.1 N/A 7.6 33.5 37.8 29.6
-40 (-40)
Ft. N/ A 23 20 11 0 N/A 25 95 77 55 N/A 25 110 94 70
M N/A 7.0 6.1 3.4 0.0 N/A 7.6 29.0 23.5 16.8 N/A 7.6 33.5 28.7 21.3
120000
20 (-10)
Ft. N/ A N/A 15 99 86 N/A N/A 15 100 219 N/A N/A 15 100 250
M N/A N/A 4.6 30.2 26.2 N/A N/A 4.6 30.5 66.8 N/A N/A 4.6 30.5 76.2
0 (-20)
Ft. N/ A N/A 15 51 38 N/A N/A 15 100 130 N/A N/A 15 100 156
M N/A N/A 4.6 15.5 11.6 N/A N/A 4.6 30.5 39.6 N/A N/A 4.6 30.5 47.5
-20 (-30)
Ft. N/ A N/A 15 28 14 N/A N/A 15 100 88 N/A N/A 15 100 108
M N/A N/A 4.6 8.5 4.3 N/A N/A 4.6 30.5 26.8 N/ A N/A 4.6 30.5 32.9
-40 (-40)
Ft. N/ A N/A 15 14 0 N/A N/A 15 85 62 N/A N/A 15 100 79
M N/A N/A 4.6 4.3 0.0 N/A N/A 4.6 25.9 18.9 N/ A N/A 4.6 30.5 24.1
140000
20 (-10)
Ft. N/ A N/A 10 90 99 N/A N/A 10 90 210 N/A N/A 10 90 210
M N/A N/A 3.0 27.4 30.2 N/A N/A 3.0 27.4 64.0 N/A N/A 3.0 27.4 64.0
0 (-20)
Ft. N/ A N/A 10 61 47 N/A N/A 10 90 153 N/A N/A 10 90 183
M N/A N/A 3.0 18.6 14.3 N/A N/A 3.0 27.4 46.6 N/A N/A 3.0 27.4 55.8
-20 (-30)
Ft. N/ A N/A 10 35 21 N/A N/A 10 90 104 N/A N/A 10 90 128
M N/A N/A 3.0 10.7 6.4 N/A N/A 3.0 27.4 31.7 N/A N/A 3.0 27.4 39.0
-40 (-40)
Ft. N/ A N/A 10 20 NA N/A N/A 10 90 75 N/A N/A 10 90 94
M N/A N/A 3.0 6.1 NA N/A N/A 3.0 27.4 22.9 N/A N/A 3.0 27.4 28.7
*Not all families have these models.
915SA