Lennox 95G2UHV Installation Instructions Manual page 21

Maximum Allowable Exhaust Vent Lengths with Furnace Installed in a Closet or Basement Using Ventilated Attic or Crawl
1-1/2" Pipe
Number
of 90°
Capacity
Elbows
Used
45 70 90
1 20 15
2 15 10
3 10
4
5
n/a
6
n/a
7
n/a
8
9
10
1-1/2" Pipe
Number
of 90°
Capacity
Elbows
Used
45 70 90
1 20 15
2 15 10
3 10
4
5
n/a
6
n/a
7 n/a
8
9
10
* 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.
* Additional vent pipe and elbows used to terminate the vent pipe outside the structure must be included in the total vent length
calculation.
507266-05
Space for Intake Air in Feet
Standard Termination at Elevation 0 - 4,500 ft
2" Pipe
Capacity
110 135 45 70 90
66 51 29
61 46 24
56 41 19
51 36 14
46 31 9
n/a n/a
41 26 4
36 21
31 16
n/a
26 11
21 6
Standard Termination at Elevation 4,501 - 10,000 ft
2" Pipe
Capacity
110 135 45 70 90
66 51 29
61 46 24
56 41 19
51 36 14
46 31 9
n/a n/a
41 26 4
36 21
31 16
n/a
26 11
21 6
2-1/2" Pipe
Capacity
110 135 45 70 90
9 95 95 73
4 90 90 68
85 85 63
80 80 58
75 75 53
n/a
70 70 48
n/a
65 65 43
60 60 38
55 55 33
50 50 28
2-1/2" Pipe
Capacity
110 135 45 70 90
95 95 73
90 90 68
85 85 63
80 80 58
75 75 53
n/a n/a
70 70 48
65 65 43
60 60 38
55 55 33
50 50 28
Table 5C.
Issue 1933
3" Pipe
Capacity
110 135 45 70 90
38 113 112 93
33 108 107 88
28 103 102 83
23 98 97 78
18 93 92 73
n/a
13 88 87 68
8 83 82 63
3 78 77 58
73 72 53
n/a
68 67 48
3" Pipe
Capacity
110 135 45 70 90
38 113 112 93
33 108 107 88
28 103 102 83
23 98 97 78
18 93 92 73
n/a
13 88 87 68
8 83 82 63
3 78 77 58
73 72 53
n/a
68 67 48
110 135
93 89
88 84
83 79
78 74
73 69
68 64
63 59
58 54
53 49
48 44
110 135
93 89
88 84
83 79
78 74
73 69
68 64
63 59
58 54
53 49
48 44
Page 21 of 58