15
Combustion-air and vent piping
MAXIMUM ALLOWABLE PIPE LENGTH (FT)
See notes on pg. 16.
ALTITUDE
ABOVE SEA
LEVEL (FT)
UNIT SIZE TERMINATION TYPE
PIPE DIA
(IN.)*
NUMBER OF 90° ELBOWS
1 2 3 4 5 6
0 to 2000
040-14 2 Pipe or 2-In. Concentric
1-1/2 50 45 40 35 30 25
2707070707070
060-14 2 Pipe or 2-In. Concentric
1-1/2 50 45 40 35 30 25
2707070707070
080-14
080-20
2 Pipe or 2-In. Concentric
1-1/2 30 25 20 15 10 5
2707070707070
100-20 2 Pipe or 2-In. Concentric
2454035302520
2-1/2 70 70 70 70 70 70
120-20 2 Pipe or 3-In. Concentric
2-1/2 10 NA NA NA NA NA
3353015NANANA
3† 70 70 70 70 70 70
2001 to 3000
040-14 2 Pipe or 2-In. Concentric
1-1/2 45 40 35 30 25 20
2707070707070
060-14 2 Pipe or 2-In. Concentric
1-1/2 45 40 35 30 25 20
2707070707070
080-14
080-20
2 Pipe or 2-In. Concentric
1-1/2 26 21 16 11 6 NA
2707070707070
100-20 2 Pipe or 2-In. Concentric
2403530252015
2-1/2 70 70 70 70 70 70
120-20 2 Pipe or 3-In Concentric
3312612NANANA
3† 63 62 62 61 61 61
3001 to 4000
040-14 2 Pipe or 2-In. Concentric
1-1/2 42 37 32 27 22 17
2707070707070
060-14 2 Pipe or 2-In. Concentric
1-1/2 42 37 32 27 22 17
2707070707070
080-14
080-20
2 Pipe or 2-In. Concentric
1-1/2 25 20 15 10 5 NA
2707070707070
100-20 2 Pipe or 2-In. Concentric
2383328231813
2-1/2 70 70 70 70 70 70
120-20 2 Pipe or 3-In. Concentric
3292410NANANA
3† 59 59 58 57 57 56
4001 to 5000‡
040-14 2 Pipe or 2-In. Concentric
1-1/2 40 35 30 25 20 15
2707070707070
060-14 2 Pipe or 2-In. Concentric
1-1/2 40 35 30 25 20 15
2707070707070
080-14
080-20
2 Pipe or 2-In. Concentric
1-1/2 23 18 13 8 NA NA
2707070707068
100-20 2 Pipe or 2-In. Concentric
2363126211611
2-1/2 70 70 70 70 70 70
120-20 2 Pipe or 3-In. Concentric 3† 56 55 54 53 52 52
5001 to 6000‡
040-14 2 Pipe or 2-In. Concentric
1-1/2 37 32 27 22 17 12
2707070707070
060-14 2 Pipe or 2-In. Concentric
1-1/2 37 32 27 22 17 12
2707070707070
080-14
080-20
2 Pipe or 2-In. Concentric
1-1/2 22 17 12 7 NA NA
2707070706863
100-20 2 Pipe or 2-In. Concentric
23328231813 8
2-1/2 70 70 70 70 70 70
120-20 2 Pipe or 3-In. Concentric 3† 53 52 50 49 48 47