16
Maximum Allowable Pipe Length (Ft) Continued
ALTITUDE
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.)*
123 456
5001 to 6000‡
40,000
2 Pipe or 2-In.
Concentric
1-1/2 1-1/2 37 3227 22 17 12
2 2 70 70 70 70 70 70
60,000
2 Pipe or 2-In.
Concentric
1-1/2 1-1/2 37 3227 22 17 12
2 2 70 70 70 70 70 70
80,000
2Pipeor2-In.
Concentric
1-1/2 1-1/2 22 17 12 7 NA NA
2 2 70 70 70 70 68 63
100,000
2Pipeor2-In.
Concentric
2233 28 23 18 138
2-1/2 2-1/2 70 70 70 70 70 70
120,000
2 Pipe or 3-In.
Concentric
3† 3 53 52 50 49 48 47
ALTITUDE
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.)*
123 456
6001 to 7000‡
40,000
2 Pipe or 2-In.
Concentric
1-1/2 1-1/2 35 3025 20 15 10
2 2 70 70 68 67 66 64
60,000
2 Pipe or 2-In.
Concentric
1-1/2 1-1/2 35 3025 20 15 10
2 2 70 70 68 67 66 64
80,000
2 Pipe or 2-In.
Concentric
1-1/2 1-1/2 20 15 10 5 NA NA
2 2 70 70 68 67 62 57
100,000
2Pipeor2-In.
Concentric
2231262116 11 6
2-1/2 2-1/2 70 70 68 67 66 64
120,000
2Pipeor3-In.
Concentric
3† 3 49 48 47 45 44 43
ALTITUDE
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.)*
123 456
7001 to 8000‡
40,000
2Pipeor2-In.
Concentric
1-1/2 1-1/2 32272217 12 7
2 2 66 65 63 62 60 59
60,000
2 Pipe or 2-In.
Concentric
1-1/2 1-1/2 32272217 12 7
2 2 66 65 63 62 60 59
80,000
2 Pipe or 2-In.
Concentric
1-1/2 1-1/2 18 138NA NA NA
2 2 66 65 63 62 57 52
100,000
2 Pipe or 2-In.
Concentric
2 2 29 24 19 14 9 NA
2-1/2 2-1/2 66 65 63 62 60 59
120,000
2Pipeor3-In.
Concentric
3† 3 46 44 4
3 41 40 38
See notes on page 17.
Combustion-air and vent piping for Direct Vent/2-Pipe
(All Sizes) and Non-Direct Vent/1-Pipe (Sizes 040
through 120 Only) Applications