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 - 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
No Of
90°
Elbows
1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model Model
030 045 070 090 110
030
045
070 090 110
030
045
070 090 110
030
045
070 090 110
1 201510
n/a n/a
71 56 34 14 100 100 78 43 118 117 98 98
21510
n/a
66 51 29 9 95 95 73 38 113 112 93 93
310
n/a
61 46 24 4 90 90 68 33 108 107 88 88
4
n/a
56 41 19
n/a
85 85 63 28 103 102 83 83
5 513614 8080582398977878
6 46 31 9 75 75 53 18 93 92 73 73
7 41 26 4 70 70 48 13 88 87 68 68
83621
n/a
65 65 43 8 83 82 63 63
9 3116 606038 3 78775858
10 26 11 55 55 33 n/a 73 72 53 53
Standard Termination Elevation 4500 - 10,000 ft
No Of
90°
Elbows
1-1/2” 2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model Model
030 045 070 090 110
030
045
070 090 110
030
045
070 090 110
030
045
070 090 110
1 201510
n/a n/a
71 56 34
n/a
100 100 78 43 118 117 98 98
21510
n/a
66 51 29 95 95 73 38 113 112 93 93
310
n/a
61 46 24 90 90 68 33 108 107 88 88
4
n/a
56 41 19 85 85 63 28 103 102 83 83
5 513614 8080582398977878
6 46 31 9 75 75 53 18 93 92 73 73
7 41 26 4 70 70 48 13 88 87 68 68
83621
n/a
65 65 43 8 83 82 63 63
9 3116 606038 3 78775858
10 26 11 55 55 33 n/a 73 72 53 53