10.1 Hangers, Anchors & Pipe Protection
Key Takeaways
- 248 CMR 10.11 (12/8/2023) supports cast-iron soil vertically at the base and at each story, and horizontally at 5-foot intervals, or at 10-foot intervals when 10-foot lengths are used.
- Horizontal threaded pipe is supported at 12-foot intervals; copper 1¼ inches or less at 6 feet and 1½ inches or over at 10 feet; plastic 1½ inches or less at 3 feet and 2 inches or over at 4 feet.
- Piping shall not be supported by other plumbing piping; horizontal clamps need a bearing width of ¾ inch or more; hangers follow manufacturer instructions.
- 248 CMR 10.05 protects pipe from corrosion, freezing, vehicle damage, 18-gauge concealment plates, 1-inch PVC/ABS sleeves through concrete, and 18-gauge fire sleeves extending 20 inches on each side of a rated wall.
10.1 Hangers, Anchors & Pipe Protection
Quick Answer: Under 248 CMR 10.11 (effective 12/8/2023), hang cast-iron soil vertically at the base and each story, and horizontally every 5 feet — or every 10 feet when you actually used 10-foot lengths. Threaded pipe: 12 feet horizontal, every other story vertical. Copper horizontal: 6 feet at 1¼ inches or less, 10 feet at 1½ inches or over; vertical copper is each story, not more than 10 feet. Plastic horizontal: 3 feet at 1½ inches or less, 4 feet at 2 inches or over; vertical plastic is each story, not more than 10 feet, plus extra points so the stack stays plumb. Do not hang pipe from other plumbing pipe. Pair 10.11 with 248 CMR 10.05 sleeves, strike plates, and firestopping. PSI budgets two written hanger items. The Board still expects the whole interval table.
The PSI Candidate Information Bulletin dated October 3, 2025 lists Hangers and Supports as a two-item written cluster. That is not a reason to skip 10.11. Closed-book Massachusetts plumbing is built from 248 CMR 10.00, not from the International Plumbing Code hanger table you may have used on an out-of-state job. Independent OpenExamPrep teaching for the Massachusetts journeyman plumber exam uses the 12/8/2023 Uniform State Plumbing Code. It is not a Board publication and it does not claim official approval.
Cornell LII title trap. Cornell’s HTML heading for 248 CMR 10.11 sometimes reads Plumbing Fixtures. Fixtures live in 10.10. Open the 10.11 body anyway: the first sentence is hangers. If you study from the mis-title and skip the section, you lose the two easiest PSI points in this chapter.
What 10.11 actually requires before you pull a tape
248 CMR 10.11(1) says piping shall be installed with provisions, when necessary, for expansion, contraction, and/or structural settlement. Piping shall not be supported by other piping which is connected to the plumbing system. A copper water line is not a hanger for a 3-inch no-hub stack. A PVC vent is not a hanger for a water heater pan drain.
248 CMR 10.11(2) requires hangers, anchors, and supports of metal or other material strong enough for the pipe and its contents. Piers may be concrete, brick, or other acceptable material. Follow piping and hanger manufacturer installation instructions — those instructions can be tighter than 10.11; they cannot waive a closer 10.11 interval.
248 CMR 10.11(3) requires hangers and anchors securely attached to the building at intervals close enough to carry the load. 248 CMR 10.11(4)(b) adds that conventional horizontal clamps, brackets, or strapping shall have a bearing width of ¾ inch or more. A ½-inch plumbers’ tape wrap that cuts into PVC is not that bearing width.
248 CMR 10.03 defines Supports — Hangers — Anchors as devices for supporting and securing pipe, fixtures, and equipment to walls, ceilings, floors, or structural members. The exam question is almost always an interval, not the dictionary.
Vertical intervals (10.11(4)(a))
Support vertical pipe at not more than these distances:
| Material | Vertical support interval (12/8/2023) |
|---|---|
| Cast-iron soil pipe | At the base and at each story height |
| Threaded pipe (SPS) | Every other story height |
| Copper tubing | Each story height, but not more than 10-foot intervals |
| Plastic pipe | Each story height, but not more than 10-foot intervals, and elsewhere as 10.11 requires so the pipe remains plumb |
| Stainless-steel tubing | Each story height, but not more than 10-foot intervals |
| Aluminum DWV | Each story height, or intervals not exceeding 10 feet |
| PEX tubing | Follow the individual manufacturer’s installation instructions |
Scenario. A four-story Worcester no-hub soil stack needs a base support plus a riser clamp (or equivalent) at each floor, not “every other floor because it is heavy.” Threaded galvanized (SPS) on that same building may skip a floor vertically. Copper and plastic do not inherit the SPS every-other-story rule.
248 CMR 10.11(5) is the stack-base companion. Bases of cast-iron stacks shall be supported on concrete, brick laid in cement mortar, metal brackets attached to the building, or other generally accepted methods. Other piping materials shall be supported so they do not dump extra stress into the base of the stack. A plastic stack sitting on a closet bend with no base support is a 10.11(5)(b) failure even if the story clamps look even.
Horizontal intervals (10.11(4)(b))
These are the numbers PSI can ask without opening a book:
| Material | Maximum horizontal interval |
|---|---|
| Cast-iron soil pipe | 5 feet, except 10 feet when 10-foot lengths of cast-iron soil pipe are used |
| Threaded pipe | 12 feet |
| Copper tubing 1¼ in. or less | 6 feet |
| Copper tubing 1½ in. or over | 10 feet |
| Plastic pipe 1½ in. or less | 3 feet |
| Plastic pipe 2 in. or over | 4 feet |
| PEX tubing | Manufacturer’s instructions |
| Stainless-steel tubing 1¼ in. or less | 6 feet |
| Stainless-steel tubing 1½ in. or over | 10 feet |
| Aluminum DWV pipe | 10 feet |
| CPVC 1 in. or less | 3 feet |
| CPVC larger than 1 in. | 4 feet |
The 10-foot CI exception is not a gift for 5-foot hub pieces spaced at 10 feet. You only get 10-foot hanger spacing when the pipe lengths are 10 feet. A 5-foot no-hub barrel still wants a hanger about every 5 feet. Horizontal 1½-inch PVC at 4-foot centers is an IPC hangover; Massachusetts is 3 feet at 1½ inches and 4 feet starting at 2 inches.
Scenario. A 2-inch PVC building drain in a crawl space at ¼ inch per foot still needs hangers at 4 feet. A 1½-inch PVC fixture branch needs hangers at 3 feet. A ¾-inch copper water tube needs hangers at 6 feet, not the 10-foot copper rule that starts at 1½ inches. Threaded 1-inch SPS may run 12 feet between supports.
Protection, sleeves, and firestopping (10.05 with 10.11)
Hangers hold the pipe. 248 CMR 10.05(7) keeps the pipe from being destroyed after you hang it.
Corrosion. Pipe in contact with, through, or under masonry, concrete, or similar corrosive material gets a protective sleeve, coating, wrapping, or other means that prevents external corrosion (10.05(7)(a)).
Freezing. Water-supply or drainage piping outside, under a building, exposed, in an unheated area, in an exterior wall, or in unconditioned space shall be protected from freezing. The installing plumber is responsible for that covering (10.05(7)(b)).
Physical damage. Exposed drainage, vent, or water piping in parking garages, residential garages, warehouses, or similar buildings shall be protected from automobiles, carts, pallet jacks, or forklifts (10.05(7)(d)1.). Concealed water, waste, and vent piping other than cast/ductile iron, or any steel, located within 1 inch of exposed framing, shall be protected by steel shielding plates not less than 18 gauge. Plates extend a minimum of 2 inches beyond the piping (10.05(7)(d)2.).
Sleeves (10.05(10)). The annular space between a sleeve and pipe through an exterior wall shall be watertight or weathertight. PVC or ABS that penetrates concrete floors, slabs, or walls gets a sleeve with a 1-inch annular space. PVC or ABS through slabs on grade gets the same 1-inch sleeve space.
Thermal expansion (10.05(7)(e)). Protect piping when temperature swing or physical conditions warrant it. PVC gets expansion joints or loops when temperature variation, developed length between directional changes, and the material’s coefficient of linear expansion require it. 248 CMR 10.06(2)(g) sends PVC DWV expansion back to this same 10.05(7)(e) paragraph.
Non-metallic pipe through fire-rated construction (10.05(7)(f)). When piping passes through a rated fire-separation wall or enclosure to another dwelling unit or space, encase or shield it with a metal sleeve of 18 gauge (0.040 in.) or heavier extending 20 inches on each side of the wall, floor, or ceiling. Seal the annular space with non-combustible fire-retardant material. 780 CMR (Massachusetts building code) still governs building-side firestopping licenses. Exception: pipe penetrations in one- and two-family passenger-car garages under dwelling units need not be encased; seal them to stop smoke. The Mass.gov PVC for Mixed Use Installation Scenarios interpretation (enacted 05-29-2013) repeats that 780 CMR firestopping is enforced by the Building Inspector, not the plumbing Inspector defined in 248 CMR 3.01.
Do not size hangers from an IPC table. 248 CMR 10.11 is the interval list. 248 CMR 10.05 is the damage, sleeve, and fire list. Together they are the two-item PSI cluster.
Official resources
- 248 CMR 10.11 (Cornell LII) — 12/8/2023 hangers; ignore a “Plumbing Fixtures” HTML title
- 248 CMR 10.05 General Regulations (Cornell) — sleeves, 18-gauge plates, fire sleeves, expansion
- 248 CMR 10.00 Uniform State Plumbing Code (Mass.gov, effective 12/8/2023) — official PDF of 10.11
- 248 CMR 10.03 Definitions (Cornell) — Supports, Hangers, Anchors
A Massachusetts journeyman is hanging horizontal service-weight cast-iron soil pipe. Which 248 CMR 10.11 interval is correct?
What maximum horizontal hanger spacing does 248 CMR 10.11 set for 1½-inch PVC DWV and for 2-inch PVC DWV?
How must vertical cast-iron soil pipe be supported under 248 CMR 10.11?
A 1-inch Type L copper water tube and a 2-inch Type L copper DWV line run horizontally in the same joist bay. Which hanger spacing matches 248 CMR 10.11?