3.2 Water Piping Materials, Joints, Valves, Supports & Disinfection

Why this section matters

Materials and joints are a large part of General Knowledge and System Installation. In the open-book exam, you must know which table to open and recognize the joining rules that inspectors enforce.

Approved materials (605.3 and 605.4)

Copper tube is identified by printed color markings: Type K green, Type L blue, Type M red. DWV copper (yellow) is a drainage tube and is not listed in either water table.

Ratings, lead and certification

• 605.3: Water service pipe installed underground outside the building must be rated at least 160 psi at 73.4°F. Where the available pressure is higher, use a rating at least that high. Service material not certified for distribution must end at or before the full-open valve at the building entrance.
• 605.4: Hot water distribution pipe must be rated at least 100 psi at 180°F. All water pipe must conform to NSF 61.
• 605.2: Water supply pipe and fittings may contain no more than 8% lead. Under 605.2.1, anything supplying water for drinking or cooking must comply with NSF 372, the low-lead standard that limits wetted surfaces to a 0.25% weighted-average lead content.
• 605.13.6: Solder and flux for water supply must be lead-free (0.2% lead or less) and conform to NSF 61.
• 605.1: Do not install water pipe in soil contaminated with solvents or fuels. If contamination is suspected, a soil and groundwater analysis is required.

Joining methods (605.9–605.24)

Prohibited joints (605.9): cement or concrete joints, fittings not approved for the installation, solvent-cement joints between different types of plastic, and saddle-type fittings.

Joints between different materials (605.23):

• Copper to galvanized steel requires a copper-alloy fitting, a dielectric fitting or an ASSE 1079 dielectric union (605.23.1).
• Plastic to other materials uses approved adapters or transition fittings (605.23.2).
• Stainless steel to other materials uses mechanical compression couplings or ASSE 1079 dielectric fittings (605.23.3).
• Hangers must not promote galvanic action (308.3).

Valves (606)

Full-open valves (606.1) are required:

• on the water service near the curb;
• at the building entrance;
• for each tenant in multi-tenant buildings;
• on the discharge side of every meter;
• at the base of each riser, except in one- and two-family dwellings and multifamily buildings two stories or less;
• at the top of each down-feed pipe, except in one- and two-family dwellings;
• at the entrance to each dwelling unit;
• to each tank;
• to every water heater.

Shutoff valves (606.2) are required:

• on the supply to each fixture, except bathtubs and showers in one- and two-family dwellings and in hotel sleeping units that have a unit valve;
• on the supply to each sillcock;
• on the supply to each appliance.

All valves must be accessible (606.3). Service and hose bibb valves must be identified, as must valves not next to the fixture they serve (606.4).

Valve materials must meet Table 605.7. Full-port ball and gate valves suit isolation. Globe valves throttle and have high pressure loss.

Supports (308)

* For sizes 2 inches and smaller, add a mid-story guide between vertical supports.

Hangers must carry the pipe and its contents and must be compatible with the pipe material (308.3). Expansion tanks are supported per the manufacturer, not by the piping (308.10). Bundled manifold piping follows Table 308.5, and bundled hot lines must be insulated (308.9).

Water hammer, manifolds and disinfection

• 604.9: Install ASSE 1010 water-hammer arrestors where quick-closing valves are used, following the manufacturer's sizing and placement. Field-built air chambers lose their air over time.

• 604.10: Manifolds for parallel (home-run) systems are sized by Table 604.10.1. A 1-inch manifold carries 10 gpm at 4 ft/s or 20 gpm at 8 ft/s. Valves at the manifold must be labeled for the fixture they serve (604.10.2), and the manifold must be accessible. Where the line is 50 feet or less and the meter shows at least 35 psi, each home run may be one size smaller than Table 604.5.

• 610.1 disinfection:

  1. Flush until clean water appears.
  2. Fill with chlorine solution of at least 50 ppm for 24 hours, or 200 ppm for 3 hours.
  3. Flush until the chlorine is gone.
  4. Repeat if bacteriological tests still show contamination.

  A method set by the health authority or water supplier, or AWWA C651/C652, may be used instead.

Exam traps

• Type M copper is listed in both Table 605.3 and Table 605.4. The IPC does not ban it underground.
• PVC is water service only.
• CPVC cement is orange or yellow. Purple primer is the PVC rule.
• PEX is supported every 32 inches in sizes up to 1 inch.