Filter
Top Products
Page 21
TABLE 6
Maximum Allowable Exhaust Vent Lengths With Furnace Installed in a Closet or Basement Using Ventilated
Attic or Crawl Space For Intake Air in Feet
NOTE - Size intake and exhaust pipe length separately. Values in table are for Intake OR Exhaust, not combined total. Both Intake and Exhaust must be same pipe
size.
NOTE - Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length calculation.
Standard Termination at Elevation 0 - 4500 ft
Number Of
90° Elbows
Used
2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model
045 070 090 110 135 045 070 090 110 135 045 070 090 110 135
1 71 56 34 14
n/a
100 100 78 43
n/a
118 117 98 98 94
2 66 51 29 9 95 95 73 38 113 112 93 93 89
3 61 46 24 4 90 90 68 33 108 107 88 88 84
4 56 41 19
n/a
85 85 63 28 103 102 83 83 79
5 51 36 14 80 80 58 23 98 97 78 78 74
6 46 31 9 85 75 63 18 93 92 73 73 69
7 41 26 4 70 70 48 13 88 87 68 68 64
8 36 21
n/a
65 65 43 8 83 82 63 63 59
9 31 16 60 60 38 3 78 77 58 58 54
10 26 11 55 55 33 n/a 73 72 53 53 49
Standard Termination Elevation 4500 - 10,000 ft
Number Of
90° Elbows
Used
2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model
045 070 090 110 135 045 070 090 110 135 045 070 090 110 135
1 71 56 34
n/a n/a
100 100 78 43
n/a
118 117 98 98 94
2 66 51 29 95 95 73 38 113 112 93 93 89
3 61 46 24 90 90 68 33 108 107 88 88 84
4 56 41 19 85 85 63 28 103 102 83 83 79
5 51 36 14 80 80 58 23 98 97 78 78 74
6 46 31 9 85 85 53 18 93 92 73 73 69
7 41 26 4 70 70 48 13 88 87 68 68 64
8 36 21
n/a
65 65 43 8 83 82 63 63 59
9 31 16 60 60 38 3 78 77 58 58 54
10 26 11 55 55 33 n/a 73 72 53 53 49