Table 11—Maximum Allowable Vent Pipe Length (Ft) (Continued)
ALTITUDE (FT)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT VENT
(1-PIPE) ONLY
NUMBER OF 90° ELBOWS
TERMINATION
TYPE
PIPE DIA
(IN.)*
PIPE DIA
(IN.)*
1
2
3
4
5
6
4001 to 5000‡
40,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
60
55
50
45
44
39
2
2
70
70
70
70
70
70
60,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
15
10
5
NA
NA
NA
2
2
64
59
58
53
52
52
80,000
2 Pipe or 2-in
Concentric
2
2
44
39
26
21
20
11
2-1/2
2-1/2
70
70
70
70
70
70
100,000
2 Pipe or 3-in
Concentric
2-1/2
2-1/2
31
22
13
12
NA
NA
3
3
70
70
67
62
57
52
120,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
53
46
40
33
26
20
NA
3†
56
55
54
53
52
52
4† no disk
4† no disk
70
70
70
70
70
70
140,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
21
17
13
9
5
NA
4† no disk
NA
69
64
59
54
49
44
ALTITUDE (FT)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT VENT
(1-PIPE) ONLY
NUMBER OF 90° ELBOWS
TERMINATION
TYPE
PIPE DIA
(IN.)*
PIPE DIA
(IN.)*
1
2
3
4
5
6
5001 to 6000‡
40,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
57
52
47
42
40
35
2
2
70
70
70
70
70
70
60,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
14
9
NA
NA
NA
NA
2
2
60
55
54
49
48
47
80,000
2 Pipe or 2-in
Concentric
2
2
41
36
23
18
17
8
2-1/2
2-1/2
70
70
70
70
70
70
100,000
2 Pipe or 3-in
Concentric
2-1/2
2-1/2
29
21
12
11
NA
NA
3
3
70
67
62
57
52
47
120,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
42
35
29
22
15
9
NA
3†
53
52
50
49
48
47
4† no disk
4† no disk
70
70
70
70
70
70
140,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
12
8
NA
NA
NA
NA
4† no disk
NA
42
37
32
27
22
17
ALTITUDE (FT)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT VENT
(1-PIPE) ONLY
NUMBER OF 90° ELBOWS
TERMINATION
TYPE
PIPE DIA
(IN)*
PIPE DIA
(IN)*
1
2
3
4
5
6
6001 to 7000‡
40,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
53
48
43
38
37
32
2
2
70
70
68
67
66
64
60,000
2 Pipe or 2-in
Concentric
1-1/2
1-1/2
13
8
NA
NA
NA
NA
2
2
57
52
50
45
44
43
80,000
2 Pipe or 2-in
Concentric
2
2
38
33
21
16
15
6
2-1/2
2-1/2
70
70
68
67
66
64
100,000
2 Pipe or 3-in
Concentric
2-1/2
2-1/2
27
19
10
9
NA
NA
3
3
68
63
58
53
48
43
120,000
2 Pipe or 3-in.
Concentric
3† no disk
NA
31
24
18
11
NA
NA
NA
3†
49
48
47
45
44
43
4† no disk
4† no disk
70
70
70
70
67
62
140,000
2 Pipe or 3-in.
Concentric
4† no disk
NA
17
12
7
NA
NA
NA
See notes at end of table
—41—
→