Free study tools · 248 CMR 10.11
Pipe Hanger Spacing Calculator
How far apart can the hangers be, and how many do you need? Pick the pipe, the size and which way it runs. The calculator looks up the support interval in 248 CMR 10.11(4) and counts the supports for your run, one at each end included.
1. Describe the run
2. Result
248 CMR 10.11(4): support intervals
| Material | Horizontal (10.11(4)(b)) | Vertical (10.11(4)(a)) |
|---|---|---|
| Cast iron soil pipe | 5 ft; 10 ft where ten-foot lengths are used | At base and at each story height |
| Threaded pipe (SPS) | 12 ft | Every other story height |
| Copper tubing | 1-1/4 in. or less: 6 ft · 1-1/2 in. or over: 10 ft | Each story height, not more than 10 ft |
| Plastic pipe | 1-1/2 in. or less: 3 ft · 2 in. or over: 4 ft | Each story height, not more than 10 ft, and elsewhere as needed for alignment |
| Stainless steel tubing | 1-1/4 in. or less: 6 ft · 1-1/2 in. or over: 10 ft | Each story height, not more than 10 ft |
| Aluminum DWV | 10 ft | Each story height, or not more than 10 ft |
| CPVC pipe | 1 in. or less: 3 ft · larger sizes: see note below | Not listed separately |
| PEX tubing | Follow the manufacturer's installation instructions | |
Larger CPVC: 248 CMR 10.11(4)(b)11 gives a separate interval for larger CPVC, but the size cutoff is unreadable in the published text we checked, so we don't supply a number for CPVC over 1 inch. Look it up in your code book and enter it in "Your own spacing".
Other support rules in 248 CMR 10.11
- Bearing width: horizontal pipe clamps, brackets or strapping must have a bearing width of 3/4 inch or more.
- No piggybacking: piping shall not be supported by other piping connected to the plumbing system.
- Material: hangers, anchors and supports must be metal or another material strong enough for the pipe and its contents, and must follow the pipe and hanger manufacturers' installation instructions.
- Attachment: hangers and anchors must be securely attached to the building at intervals close enough to carry the pipe and its contents.
- Stack bases: cast iron stack bases sit on concrete, brick laid in cement mortar, metal brackets attached to the building, or another accepted method. Other materials must be supported so the base of the stack takes no extra stress or strain.
- Near fittings: 248 CMR 10.11 does not set a "within so many inches of each fitting or change of direction" rule. Follow the manufacturer's instructions.
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Study aid — confirm with the current 248 CMR and your inspector. Intervals are from 248 CMR 10.11 as published by Cornell LII (amended effective 12/8/2023) and were checked in September 2026. Manufacturer instructions can require closer spacing. PressureTest is independent and not affiliated with the Commonwealth of Massachusetts, the Board of State Examiners of Plumbers & Gas Fitters or PSI.