17
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
3001 to 4000
(914 to 1219)
40,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 64
(19.5)
59
(18.0)
54
(16.5)
49
(14.9)
48
(14.6)
43
(13.1)
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) 16
(4.9)
11
(3.4)
6
(1.8) NA NA NA
2 (51) 2 (51) 68
(20.7)
63
(19.2)
62
(18.9)
57
(17.4)
57
(17.4)
56
(17.1)
80,000
2Pipeor2-in.
(51 mm)
Concentric
2 (51) 2 (51) 46
(14.0)
41
(12.5)
28
(8.5)
23
(7.0)
22
(6.7)
13
(4.0)
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) 33
(10.1)
24
(7.3)
15
(4.6)
14
(4.3)
5
(1.5) NA
3 (76) 3 (76) 70
(21.3)
70
(21.3)
70
(21.3)
66
(20.1)
61
(18.6)
56
(17.1)
120,000
2Pipeor3-in.
(76 mm)
Concentric
3 (76)† no disk NA 65
(19.8)
58
(17.7)
51
(15.5)
44
(13.4)
38
(11.6)
31
(9.4)
NA 3 (76)† 59
(18.0)
59
(18.0)
58
(17.7)
57
(17.4)
57
(17.4)
56
(17.1)
4† no disk 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) one
disk† NA 11
(3.4)
6
(1.8) NA NA NA NA
3 (76)† no disk NA 30
(9.1)
26
(7.9)
22
(6.7)
18
(5.5)
14
(4.3)
10
(3.0)
4 (102)† no
disk NA 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
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
4001 to 5000‡
(1219 to 1524)
40,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 60
(18.3)
55
(16.8)
50
(15.2)
45
(13.7)
44
(13.4)
39
(11.9)
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) 15
(4.6)
10
(3.0)
5
(1.5) NA NA NA
2 (51) 2 (51) 64
(19.5)
59
(18.0)
58
(17.7)
53
(16.2)
52
(15.8)
52
(15.8)
80,000
2Pipeor2-in.
(51 mm)
Concentric
2 (51) 2 (51) 44
(13.4)
39
(11.9)
26
(7.9)
21
(6.4)
20
(6.1)
11
(3.4)
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) 31
(9.4)
22
(6.7)
13
(4.0)
12
(3.7) NA NA
3 (76) 3 (76) 70
(21.3)
70
(21.3)
67
(20.4)
62
(18.9)
57
(17.4)
52
(15.8)
120,000
2Pipeor3-in.
(76 mm)
Concentric
3 (76)†
no disk NA 53
(16.2)
46
(14.0)
40
(12.2)
33
(10.1)
26
(7.9)
20
(6.1)
NA 3 (76)† 56
(17.1)
55
(16.8)
54
(16.5)
53
(16.2)
52
(15.8)
52
(15.8)
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 21
(6.4)
17
(5.1)
13
(3.9)
9
(2.7)
5
(1.5) NA
4 (102)† no
disk NA 69
(21.0)
64
(19.5)
59
(17.9)
54
(16.4)
49
(15.0)
44
(13.4)
See notes at end of table.
58MXB
