Terminology

• Water service: pipe from the public main or well to the building
• Distribution: piping inside the building to fixtures
• Copper Type K, L, M: wall thicknesses, heaviest to lightest
• PEX: cross-linked polyethylene tubing, crimp or expansion fittings
• CPVC / PP / PE-RT: other plastic water piping
• Press fittings: mechanical joints for copper and stainless steel
• PRV: pressure-reducing valve
• Booster pump: raises pressure for upper floors
• Water hammer arrester: absorbs pressure surges

Standards

Ratings

• Static pressure above 80 psi reduced to 80 psi or less with a pressure-reducing valve
• Water service pipe at least 3/4 in.; underground service pipe rated at least 160 psi
• Hot water distribution pipe rated at least 100 psi at 180°F
• Drinking water components meet NSF 372, a weighted average of 0.25 percent lead or less; solder and flux 0.2 percent lead or less
• Hanger spacing: copper pipe 12 ft horizontal; PEX 1 in. and smaller 32 in.; PVC 4 ft
• Water piping tested at working pressure, or at least 50 psi air for non-plastic pipe, for 15 minutes

Test standards

• ASTM B88: copper water tube
• ASTM F876: PEX tubing
• ASTM D2846: CPVC hot and cold water systems
• ASTM F2389: polypropylene pressure piping
• NSF 61 / NSF 372: drinking water system components

Components

• Pipe and fittings: copper, PEX, CPVC, PP, or stainless steel
• Valves: shutoff, balancing, and check valves
• Meter and backflow preventer at the service
• PRVs and booster pumps
• Insulation: on hot water and recirculation lines, and on cold lines against condensation

Detailing

• Stack plumbing walls and shafts for short, vertical risers
• Zone tall buildings by pressure with PRVs or booster systems
• Firestop penetrations of rated assemblies with listed systems for the pipe material
• Protect pipes from freezing; keep exterior water pipes below frost depth
• Provide shield plates where pipes are within 1-1/4 in. of framing faces

Uses

Specific uses

• All occupied buildings with fixtures
• High-rise residential and hotels with pressure zones
• Healthcare with high hot water demand
• Renovations using PEX to reduce labor

Pros and cons

Pros

• PEX installs quickly with few joints
• Copper is durable and heat tolerant
• Press fittings avoid open-flame soldering

Cons

• Copper cost and theft risk
• Plastic pipes are limited in plenums and by temperature
• Water hammer and pressure issues need design attention

Manufacturing and cost

Construction

• Copper drawn and cut to length; PEX extruded and cross-linked; pipe installed during rough-in, pressure tested, then insulated and concealed

Main manufacturers and suppliers

• Mueller Industries
• Uponor
• Viega
• NIBCO
• Charlotte Pipe

Trade associations: ASPE and PHCC.

Sources

• UpCodes: 2024 IPC Chapter 6 water supply and distribution (GSA adoption without amendments), https://up.codes/viewer/general-services-administration/ipc-2024/chapter/6/water-supply-and-distribution
• UpCodes: 2024 IPC Chapter 3 general regulations (supports and tests), https://up.codes/viewer/general-services-administration/ipc-2024/chapter/3/general-regulations
• Chicago Department of Transportation: 22 11 19 domestic water piping specialties (related 22 11 16), https://chicago.gov/content/dam/city/depts/dps/ContractAdministration/Specs/2021/Book 3. Part 2_1186934.pdf
• Wikimedia Commons: Modern plumbing illustrated - a comprehensive and thoroughly practical work on the modern and most approved methods of plumbing construction (1907) (14597275068).jpg, by Starbuck, R. M. (Internet Archive Book Images) (No restrictions), https://commons.wikimedia.org/wiki/File:Modern_plumbing_illustrated_-_a_comprehensive_and_thoroughly_practical_work_on_the_modern_and_most_approved_methods_of_plumbing_construction_(1907)_(14597275068).jpg