Piping

Standards

• Domestic Water Piping

  Potable cold water, hot water, and hot water return piping inside a building — the pipe and tube, the fittings and joints, the valves and water hammer arrestors installed in the line, and the supports, expansion provisions, insulation, freeze protection, identification, pressure testing, flushing, and disinfection that go with them. The scope runs from the discharge of the building water service assembly to the stop, union, or rough-in connection at each fixture and each item of equipment, in commercial, institutional, industrial, and multifamily buildings served by a utility supply or by a private on-site source.

• Hydronic Piping

  Closed-loop hydronic distribution piping for heating hot water (HHW), chilled water (CHW), dual-temperature water (DTW), and condenser water (CW) in commercial, institutional, and industrial buildings, within the ASME B31.9 building-services envelope (up to 160 psig and 250°F). Covers pipe material and wall selection by service and size band, joining methods, fittings and flanges, dissimilar-metal isolation, delivery and storage, piping installation and routing discipline, the interfaces to supports, expansion compensation, valves, specialties, insulation, identification, and system cleaning, and the structural pressure test that proves the installed system.

• Mechanical Insulation

  Field-applied thermal insulation for mechanical piping, ductwork, and equipment in commercial, institutional, and light-industrial buildings. Covers insulation of heating hot water, steam, steam condensate, and other hot service piping; chilled water, dual-temperature, and other below-ambient service piping that requires a continuous vapor barrier; HVAC supply, return, outside-air, and exhaust ductwork (concealed and exposed, indoor and outdoor); and mechanical equipment such as tanks, breechings, pumps, and heat exchangers. Includes selection of insulation material by service (mineral or glass fiber, closed-cell elastomeric, rigid cellular phenolic, cellular glass, and calcium silicate for high temperature), insulation thickness by the adopted edition of ASHRAE 90.1, jacketing and vapor retarders (all-service jacket indoors, PVC fitting covers, metal jacket outdoors and in mechanical rooms), insulated pipe supports and protection shields, penetration coordination, and the condensation-control provisions that govern cold-service work.

• Natural Gas Piping

  Field-installed fuel-gas piping conveying natural gas or undiluted liquefied petroleum (LP) gas from the utility meter or LP-gas second-stage regulator to gas-fired appliances and equipment, including interior distribution piping, exterior aboveground piping, and buried exterior service piping within the property line. Covers system pressure tiers (low-pressure systems at or below ½ psig and elevated-pressure systems at 2 psig and 5 psig with line-pressure regulators), pipe and tubing materials by service and location (Schedule 40 steel, polyethylene for underground use, corrugated stainless steel tubing, and copper where the gas sulfur content permits), threaded and welded joints, gas valves, line-pressure regulators with overpressure protection, sediment traps and appliance connections, corrosion protection of buried steel, electrical bonding of metallic piping and CSST, and the complete pressure-test and purging sequence required by NFPA 54.

• Refrigerant Piping

  Field-installed refrigerant piping that interconnects the components of split-system air conditioners and heat pumps, variable refrigerant flow systems, direct-expansion coils, computer room units, and packaged equipment supplied with a field-piped condensing section. Covers tube material and temper, joining methods and brazing filler metal, braze purge, field-installed specialties, line routing, oil return, insulation and its vapor seal, supports and seismic restraint, penetrations and firestopping, refrigerant concentration limits and the detection and mitigation provisions that go with mildly flammable refrigerants, piping identification, and the pressure test, evacuation, decay test, and charging sequence that puts the system into service.

• Sanitary Waste and Vent Piping

  The sanitary drain, waste, and vent piping inside a building and the building drain out to five feet beyond the foundation wall, in commercial, institutional, industrial, and multifamily buildings: the pipe, fittings, joints, and couplings in cast iron, PVC, ABS, copper, galvanized steel, stainless steel, and polyethylene; the fixture traps, trap arms, and the venting that protects them; the slope and the changes of direction of horizontal drainage; the indirect waste receptors that take equipment discharge; the connections to fixtures, floor drains, cleanouts, grease interceptors, sumps, and ejectors; hangers, vertical support, seismic restraint, thermal movement, acoustic treatment, sleeves, and firestopping; below-slab bedding and backfill; and the rough-in and final tests that prove the system tight.

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