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TABLE 12
Maximum Allowable Intake or Exhaust Vent Length
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
1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model Model
045 070 090 110 045 070 090 110 045 070 090 110 045 070 090 110
1 15 15
N/A N/A
81 66 44 14 115 115 93 48 138 137 118 108
2 10 10 76 61 39 9 110 110 88 43 133 132 113 103
3
N/A N/A
71 56 34
N/A
105 105 83 38 128 127 108 98
4 66 51 29 100 100 78 33 123 122 103 93
5 61 46 24 95 95 73 28 118 117 98 88
6 56 41 19 90 90 68 23 113 112 93 83
7 51 36 14 85 85 63 18 108 107 88 78
8 46 31 n/a 80 80 58 13 103 102 83 73
9 41 26 n/a 75 75 53
N/A
98 97 78 68
10 36 21 n/a 70 70 48 93 92 73 63
Standard Termination Elevation 4500 - 10,000 ft
Number Of
90° Elbows
Used
1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model Model
045 070 090 110 045 070 090 110 045 070 090 110 045 070 090 110
1 15 15
N/A N/A
81 66 44
N/A
115 115 93 48 138 137 118 108
2 10 10 76 61 39 110 110 88 43 133 132 113 103
3
N/A N/A
71 56 34 105 105 83 38 128 127 108 98
4 66 51 29 100 100 78 33 123 122 103 93
5 61 46 24 95 95 73 28 118 117 98 88
6 56 41 19 90 90 68 23 113 112 93 83
7 51 36 14 85 85 63 18 108 107 88 78
8 46 31 n/a 80 80 58 13 103 102 83 73
9 41 26 n/a 75 75 53
N/A
98 97 78 68
10 36 21 n/a 70 70 48 93 92 73 63
Concentric Termination at Elevation 0 - 4500 ft
Number Of 90°
Elbows Used
1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe
Models Model Model Model
045 070 090 110 045 070 090 110 045 070 090 110 045 070 090 110
1 10 10
N/A N/A
73 58 42 12 105 105 89 44 121 121 114 104
2
N/A N/A
68 53 37 7 100 100 84 39 116 116 109 99
3 63 48 32
N/A
95 95 79 34 111 111 104 94
4 58 43 27 90 90 74 29 106 106 99 89
5 53 38 22 85 85 69 24 101 101 94 84
6 48 33 17 80 80 64 19 96 96 89 79
7 43 28 12 75 75 59 14 91 91 84 74
8 38 23
n/a
70 70 54 9 86 86 79 69
9 33 18 65 65 49
N/A
81 81 74 64
10 28 13 60 60 44 76 76 69 59
Concentric Termination Elevation 4501 - 10,000 ft
Number Of 90°
Elbows Used
1-1/2” Pipe 2” Pipe 2-1/2” Pipe 3” Pipe
Model Model Model Model
045 070 090 110 045 070 090 110 045 070 090 110 045 070 090 110
1 10 10
N/A N/A
73 58 42
N/A
105 105 89 44 121 121 114 104
2
N/A N/A
68 53 37 100 100 84 39 116 116 109 99
3 63 48 32 95 95 79 34 111 111 104 94
4 58 43 27 90 90 74 29 106 106 99 89
5 53 38 22 85 85 69 24 101 101 94 84
6 48 33 17 80 80 64 19 96 96 89 79
7 43 28 12 75 75 59 14 91 91 84 74
8 38 23
n/a
70 70 54 9 86 86 79 69
9 33 18 65 65 49
N/A
81 81 74 64
10 28 13 60 60 44 76 76 69 59