16
MAXIMUM ALLOWABLE PIPE LENGTH -- FT. (M)
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
0 to 2000
(0 to 610)
40,000
2Pipeor2-in.
(51 mm)
Concentric
1 (25) 1 (25) 5
(1.5) NA NA NA NA NA
1-1/2 (38) 1-1/2 (38) 70
(21.3)
70
(21.3)
65
(19.8)
60
(18.3)
60
(18.3)
55
(16.8)
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) 20
(6.1)
15
(4.6)
10
(3.0)
5
(1.5) NA NA
2 (51) 2 (51) 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
80,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 10
(3.0) NA NA NA NA NA
2 (51) 2 (51) 55
(16.8)
50
(15.2)
35
(10.7)
30
(9.1)
30
(9.1)
20
(6.1)
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 (51) 2 (51) 5
(1.5) NA NA NA NA NA
2-1/2 (64) 2-1/2 (64) 40
(12.2)
30
(9.1)
20
(6.1)
20
(6.1)
10
(3.0) NA
3 (76) 3 (76) 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
120,000
2Pipeor3-in.
(76 mm)
Concentric
2-1/2 (64)
one disk 2-1/2 (64) 10
(3.0) NA NA NA NA NA
3 (76)† NA 45
(13.7)
40
(12.2)
35
(10.7)
30
(9.1)
25
(7.6)
20
(6.1)
3 (76) † no disk 3 (76)† 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
2-1/2 (64)
one disk NA 5
(1.5) NA NA NA NA NA
3 (76)† NA 40
(12.1)
35
(10.6)
30
(9.1)
25
(7.6)
20
(6.1)
15
(4.6)
3 (76) † no disk NA 60
(18.3)
56
(17.0)
52
(15.8)
48
(14.6)
44
(13.4)
40
(12.2)
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
2001 to 3000
(610 to 914)
Canada
40,000
2Pipeor2-in.
(51 mm)
Concentric
1-1/2 (38) 1-1/2 (38) 67
(20.4)
62
(18.9)
57
(17.4)
52
(15.8)
52
(15.8)
47
(14.3)
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) 17
(5.2)
12
(3.7)
7
(2.1) NA NA NA
2 (51) 2 (51) 70
(21.3)
67
(20.4)
66
(20.1)
61
(18.6)
61
(18.6)
61
(18.6)
80,000
2Pipeor2-in.
(51 mm)
Concentric
2 (51) 2 (51) 49
(14.9)
44
(13.4)
30
(9.1)
25
(7.6)
25
(7.6)
15
(4.6)
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) 35
(10.7)
26
(7.9)
16
(4.9)
16
(4.9)
6
(1.8) NA
3 (76) 3 (76) 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
66
(20.1)
61
(18.6)
120,000
2Pipeor3-in.
(76 mm)
Concentric
3 (76) NA 14
(4.3)
9
(2.7) NA NA NA NA
NA 3 (76)† 63
(19.2)
62
(18.9)
62
(18.9)
61
(18.6)
61
(18.6)
61
(18.6)
3 (76)† no disk NA 70
(21.3)
70
(21.3)
63
(19.2)
56
(17.1)
50
(15.2)
43
(13.1)
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 20
(6.1)
15
(4.6)
10
(3.0)
5
(1.5) NA NA
3 (76)† no disk NA 39
(11.8)
35
(10.6)
31
(11.9)
27
(8.2)
23
(7.0)
19
(5.8)
4 (102)† no
disk NA 70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
70
(21.3)
See notes at end of table.
58MXB
