18
MAXIMUM ALLOWABLE PIPE LENGTH -- FT. (M) (CONTINUED)
ALTITUDE
FT. (M)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT
VENT (1-PIPE)
ONLY NUMBER OF 90°ELBOWS
TERMINATION
TYPE
PIPE DIA
IN. (mm)*
PIPE DIA
IN. (mm)* 1 2 3 4 5 6
5001 to 6000‡
(1524 to 1829)
40,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 57
(17.4)
52
(15.8)
47
(14.3)
42
(12.8)
40
(12.2)
35
(10.7)
2 (51) 2 (51) 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
60,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 14
(4.3)
9
(2.7) NA NA NA NA
2 (51) 2 (51) 60
(18.3)
55
(16.8)
54
(16.5)
49
(14.9)
48
(14.6)
47
(14.3)
80,000
2Pipeor2-in.
(51 mm)
Concentric
2 (51) 2 (51) 41
(12.5)
36
(11.0)
23
(7.0)
18
(5.5)
17
(5.2)
8
(2.4)
2-1/2 (64) 2-1/2 (64) 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
100,000
2Pipeor3-in.
(76 mm)
Concentric
2-1/2 (64) 2-1/2 (64) 29
(8.8)
21
(6.4)
12
(3.7)
11
(3.4) NA NA
3 (76) 3 (76) 70
(21.3)
67
(20.4)
62
(18.9)
57
(17.4)
52
(15.8)
47
(14.3)
120,000
2Pipeor3-in.
(76 mm)
Concentric
3 (76)†
no disk NA 42
(12.8)
35
(10.7)
29
(8.8)
22
(6.7)
15
(4.6)
9
(2.7)
NA 3 (76)† 53
(16.2)
52
(15.8)
50
(15.2)
49
(14.9)
48
(14.6)
47
(14.3)
4 (102)† no
disk 4 (102)† no disk 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
140,000
2Pipeor3-in.
(76 mm)
Concentric
3 (76)† no disk NA 12
(3.6)
8
(2.4) NA NA NA NA
4 (102)† no
disk NA 42
(12.8)
37
(11.2)
32
(9.7)
27
(8.2)
22
(6.7)
17
(5.1)
ALTITUDE
FT. (M)
UNIT SIZE
(BTUH)
DIRECT VENT (2-PIPE) ONLY
NON-DIRECT
VENT (1-PIPE)
ONLY
NUMBER OF 90°ELBOWS
TERMINATION
TYPE
PIPE DIA
IN. (mm)*
PIPE DIA
IN. (mm)* 1 2 3 4 5 6
6001 to 7000‡
(1829 to 2134)
40,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 53
(16.2)
48
(14.6)
43
(13.1
38
(11.6)
37
(11.3)
32
(9.8)
2 (51) 2 (51) 70
(21.3)
70
(21.3)
68
(20.7)
67
(20.4)
66
(20.1)
64
(19.5)
60,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 13
(4.0)
8
(2.4) NA NA NA NA
2 (51) 2 (51) 57
(17.4)
52
(15.8)
50
(15.2)
45
(13.7)
44
(13.4)
43
(13.1)
80,000
2Pipeor2-in.
(51 mm)
Concentric
2 (51) 2 (51) 38
(11.6)
33
(10.1)
21
(6.4)
16
(4.9)
15
(4.6)
6
(1.8)
2-1/2 (64) 2-1/2 (64) 70
(21.3)
70
(21.3)
68
(20.7)
67
(20.4)
66
(20.1)
64
(19.5)
100,000
2Pipeor3-in.
(76 mm)
Concentric
2-1/2 (64) 2-1/2 (64) 27
(8.2)
19
(5.8)
10
(3.0)
9
(2.7) NA NA
3 (76) 3 (76) 68
(20.7)
63
(19.2)
58
(17.7)
53
(16.2)
48
(14.6)
43
(13.1)
120,000
2Pipeor3-in.
(76 mm)
Concentric
3 (76)†
no disk NA 31
(9.4)
24
(7.3)
18
(5.5)
11
(3.4) NA NA
NA 3 (76)† 49
(14.9)
48
(14.6)
47
(14.3)
45
(13.7)
44
(13.4)
43
(13.1)
140,000
2Pipeor3-in.
(76 mm)
Concentric
4 (102)† no
disk NA 17
(5.1)
12
(3.6)
7
(2.1) NA NA NA
See notes at end of table.
58MXB
