Get the maximum hanger spacing, rod size and number of supports for steel, copper, CPVC and plastic pipe — per MSS SP-58 (HVAC), NFPA 13 (sprinkler) and IPC 308.5 (plumbing).
Maximum spans for straight horizontal runs. Add supports at changes of direction, next to valves, strainers and other concentrated loads, and where the manufacturer or project specification requires closer spacing. Insulated, vertical and seismic supports have their own rules.
| Size | Max span | Rod |
|---|
A pipe between two hangers behaves like a loaded beam. Larger pipe is stiffer and can span further; copper and plastics are less stiff than steel and need closer supports; and a pipe full of water weighs far more than one carrying steam or gas, so vapor service allows longer spans than water service in MSS SP-58. The tables limit both the sag (which traps water or air) and the bending stress.
| NPS | Steel — water | Steel — vapor | Copper — water | Copper — vapor | Rod |
|---|---|---|---|---|---|
| 1/2″ | 7 ft (2.1 m) | 8 ft (2.4 m) | 5 ft (1.5 m) | 6 ft (1.8 m) | 3/8″ |
| 3/4″ | 7 ft (2.1 m) | 9 ft (2.7 m) | 5 ft (1.5 m) | 7 ft (2.1 m) | 3/8″ |
| 1″ | 7 ft (2.1 m) | 9 ft (2.7 m) | 6 ft (1.8 m) | 8 ft (2.4 m) | 3/8″ |
| 1-1/4″ | 7 ft (2.1 m) | 9 ft (2.7 m) | 7 ft (2.1 m) | 9 ft (2.7 m) | 3/8″ |
| 1-1/2″ | 9 ft (2.7 m) | 12 ft (3.7 m) | 8 ft (2.4 m) | 10 ft (3.0 m) | 3/8″ |
| 2″ | 10 ft (3.0 m) | 13 ft (4.0 m) | 8 ft (2.4 m) | 11 ft (3.4 m) | 3/8″ |
| 2-1/2″ | 11 ft (3.4 m) | 14 ft (4.3 m) | 9 ft (2.7 m) | 13 ft (4.0 m) | 1/2″ |
| 3″ | 12 ft (3.7 m) | 15 ft (4.6 m) | 10 ft (3.0 m) | 14 ft (4.3 m) | 1/2″ |
| 3-1/2″ | 13 ft (4.0 m) | 16 ft (4.9 m) | 11 ft (3.4 m) | 15 ft (4.6 m) | 1/2″ |
| 4″ | 14 ft (4.3 m) | 17 ft (5.2 m) | 12 ft (3.7 m) | 16 ft (4.9 m) | 5/8″ |
| 5″ | 16 ft (4.9 m) | 19 ft (5.8 m) | 13 ft (4.0 m) | 18 ft (5.5 m) | 5/8″ |
| 6″ | 17 ft (5.2 m) | 21 ft (6.4 m) | 14 ft (4.3 m) | 20 ft (6.1 m) | 3/4″ |
| 8″ | 19 ft (5.8 m) | 24 ft (7.3 m) | 16 ft (4.9 m) | 23 ft (7.0 m) | 7/8″ |
| 10″ | 22 ft (6.7 m) | 26 ft (7.9 m) | 18 ft (5.5 m) | 25 ft (7.6 m) | 7/8″ |
| 12″ | 23 ft (7.0 m) | 30 ft (9.1 m) | 19 ft (5.8 m) | 28 ft (8.5 m) | 7/8″ |
| 14″ | 25 ft (7.6 m) | 32 ft (9.8 m) | — | — | 1″ |
| 16″ | 27 ft (8.2 m) | 35 ft (10.7 m) | — | — | 1″ |
| 18″ | 28 ft (8.5 m) | 37 ft (11.3 m) | — | — | 1″ |
| 20″ | 30 ft (9.1 m) | 39 ft (11.9 m) | — | — | 1-1/4″ |
| 24″ | 32 ft (9.8 m) | 42 ft (12.8 m) | — | — | 1-1/4″ |
Standard-weight steel pipe and copper tube, straight horizontal runs. Values follow the long-established MSS table (formerly SP-69); check the edition your project specifies.
Sprinkler piping uses its own table. Steel pipe (other than threaded lightwall) may be hung up to 12 ft (3.7 m) apart for 1¼″ and smaller and 15 ft (4.6 m) for 1½″ and larger. Copper, CPVC and threaded lightwall steel need closer spacing, and hanger rods are 3/8″ up to 4″ pipe, 1/2″ for 5″–8″ and 5/8″ for 10″–12″.
The plumbing code sets one span per material rather than a size table: PVC and ABS 4 ft, cast iron 5 ft (10 ft with 10 ft lengths), copper 6 ft up to 1¼″ and 10 ft for 1½″ and larger, CPVC 3 ft up to 1″ and 4 ft above, PEX 32 in, and steel 12 ft.
4″ steel chilled water line, 30 m straight run, MSS SP-58.
Under MSS SP-58, 10 ft (3.0 m) for water service and 13 ft (4.0 m) for vapor service. For sprinkler piping NFPA 13 allows 15 ft (4.6 m).
MSS SP-58 gives 5 ft for ½″ copper tube in water service, rising to 8 ft at 2″ and 12 ft at 4″. The plumbing code (IPC) uses 6 ft up to 1¼″ and 10 ft for 1½″ and larger.
For HVAC piping under MSS SP-58: 3/8″ rod up to 2″ pipe, 1/2″ for 2½–3½″, 5/8″ for 4–5″, 3/4″ for 6″, 7/8″ for 8–12″ and 1″ for 14–18″. Sprinkler pipe under NFPA 13 uses 3/8″ up to 4″.
Divide the run length by the maximum span, round up, and add one so both ends are supported. Add extra supports at bends, valves and other concentrated loads.
Steam and gas weigh almost nothing compared with water, so the same pipe carries much less load per metre and can span further before it sags or overstresses. MSS SP-58 therefore lists longer spans for vapor service.
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