51
Table 14 – Maximum Allowable Exposed Vent Lengths Insulation Table -- Ft. / M
Two Stag e
Furnace High
Heat Input
Winter Design
Te mp ° 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 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 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 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 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 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 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 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 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
* Not all families have these models.
* Pipe len gth (ft) specified for maximum pipe lengths located in u nconditioned spaces. Pipes located in u nconditioned space cann ot exceed total allowable pipe
length calculated from Table 15 or 17.
† Insulation thickness based on R value of 3.5 per in.
59TP6A