The provisions of this chapter shall govern the construction, installation, alteration and repair of hydronic piping systems. This chapter shall apply to hydronic piping systems that are part of heating, ventilation and air-conditioning systems. Such piping systems shall include steam, hot water, chilled water, steam condensate and ground source heat pump loop systems. Potable cold and hot water distribution systems shall be installed in accordance with the International Plumbing Code.
Piping material shall conform to the standards cited in this section.
Reused pipe, fittings, valves or other materials shall be clean and free of foreign materials and shall be approved by the code official for reuse.
Materials shall be rated for the operating temperature and pressure of the hydronic system. Materials shall be suitable for the type of fluid in the hydronic system.
Hydronic pipe shall conform to the standards listed in Table 1202.4. The exterior of the pipe shall be protected from corrosion and degradation.
| MATERIAL | STANDARD (see Chapter 15) |
| Acrylonitrile butadiene styrene (ABS) plastic pipe |
ASTM D 1527; ASTM F 2806 |
| Chlorinated polyvinyl chloride (CPVC) plastic pipe |
ASTM D 2846; ASTM F 441; ASTM F 442 |
| Copper or copper-alloy pipe | ASTM B 42; ASTM B 43; ASTM B 302 |
| Copper or copper-alloy tube (Type K, L or M) |
ASTM B 75; ASTM B 88; ASTM B 135; ASTM B 251 |
| Cross-linked polyethylene/ aluminum/cross-linked polyethylene (PEX-AL-PEX) pressure pipe |
ASTM F 1281; CSA CAN/CSA-B-137.10 |
| Cross-linked polyethylene (PEX) tubing |
ASTM F 876; ASTM F 877 |
| Ductile iron pipe | AWWA C115/A21.15; AWWA C151/A21.51 |
| Lead pipe | FS WW-P-325B |
| Polyethylene/aluminum/polyethylene (PE-AL-PE) pressure pipe |
ASTM F 1282; CSA B137.9 |
| Polypropylene (PP) plastic pipe | ASTM F 2389 |
| Polyvinyl chloride (PVC) plastic pipe |
ASTM D 1785; ASTM D 2241 |
| Raised temperature polyethylene (PE-RT) |
ASTM F 2623; ASTM F 2769 |
| Steel pipe | ASTM A 53; ASTM A 106 |
| Steel tubing | ASTM A 254 |
Hydronic pipe fittings shall be approved for installation with the piping materials to be installed, and shall conform to the respective pipe standards or to the standards listed in Table 1202.5.
| MATERIAL | STANDARD (see Chapter 15) |
| Copper and copper alloys | ASME B16.15; ASME B16.18; ASME B16.22; ASME B16.26; ASTM F 1974; ASTM B16.24; ASME B16.51 |
| Ductile iron and gray iron | ANSI/AWWA C110/A21.10; AWWA C153/A21.53; ASTM A 395; ASTM A 536; ASTM F 1476; ASTM F 1548 |
| Ductile iron | ANSI/AWWA C153/A21.53 |
| Gray iron | ASTM A 126 |
| Malleable iron | ASME B16.3 |
| PE-RT fittings | ASTM F 1807; ASTM F 2098; ASTM F 2159; ASTM F 2735; ASTM F 2769 |
| PEX fittings | ASTM F 877; ASTM F 1807; ASTM F 2159 |
| Plastic | ASTM D 2466; ASTM D 2467; ASTM F 438; ASTM F 439; ASTM F 877; ASTM F 2389; ASTM F 2735 |
| Steel | ASME B16.5; ASME B16.9; ASME B16.11; ASME B16.28; ASTM A 53; ASTM A 106; ASTM A 234; ASTM A 420; ASTM A 536; ASTM A 395; ASTM F 1476; ASTM F1548 |
Valves shall be constructed of materials that are compatible with the type of piping material and fluids in the system. Valves shall be rated for the temperatures and pressures of the systems in which the valves are installed.
Joints and connections shall be of an approved type. Joints and connections shall be tight for the pressure of the hydronic system.
Where required by Sections 1203.4 through 1203.14, the preparation and installation of brazed, mechanical, soldered, solventcemented, threaded and welded joints shall comply with Sections 1203.3.1 through 1203.3.8.
Joint surfaces shall be cleaned. An approved flux shall be applied where required. The joint shall be brazed with a filler metal conforming to AWS A5.8.
Mechanical joints shall be installed in accordance with the manufacturer's instructions.
Joint surfaces shall be cleaned. A flux conforming to ASTM B 813 shall be applied. The joint shall be soldered with a solder conforming to ASTM B 32.
Joint surfaces shall be clean and free of moisture. An approved primer shall be applied to CPVC and PVC pipe-joint surfaces. Joints shall be made while the cement is wet. Solvent cement conforming to the following standards shall be applied to all joint surfaces:
- ASTM D 2235 for ABS joints.
- ASTM F 493 for CPVC joints.
- ASTM D 2564 for PVC joints.
Exception: For CPVC pipe joint connections, a primer is not required where all of the following conditions apply:
- The solvent cement used is third-party certified as conforming to ASTM F 493.
- The solvent cement is yellow in color.
- The solvent cement is used only for joining 1/2-inch (12.7 mm) through 2-inch (51 mm) diameter CPVC pipe and fittings.
- The CPVC pipe and fittings are manufactured in accordance with ASTM D 2846.
Grooved and shouldered mechanical joints shall conform to the requirements of ASTM F 1476 and shall be installed in accordance with the manufacturer's instructions.
Mechanically extracted outlets shall have a height not less than three times the thickness of the branch tube wall.
Branch tubes shall not restrict the flow in the run tube. A dimple/depth stop shall be formed in the branch tube to ensure that penetration into the outlet is of the correct depth. For inspection purposes, a second dimple shall be placed 1/4 inch (6.4 mm) above the first dimple. Dimples shall be aligned with the tube run.
Mechanically formed tee fittings shall be brazed in accordance with Section 1203.3.1.
Joints between ABS plastic pipe or fittings shall be solvent-cemented or threaded joints conforming to Section 1203.3.
Joints between brass pipe or fittings shall be brazed, mechanical, threaded or welded joints conforming to Section 1203.3.
Joints between brass tubing or fittings shall be brazed, mechanical or soldered joints conforming to Section 1203.3.
Joints between copper or copper-alloy pipe or fittings shall be brazed, mechanical, soldered, threaded or welded joints conforming to Section 1203.3.
Joints between copper or copper-alloy tubing or fittings shall be brazed, mechanical or soldered joints conforming to Section 1203.3, flared joints conforming to Section 1203.8.1, push-fit joints conforming to Section 1203.8.2 or press-type joints conforming to Section 1203.8.3.
Flared joints shall be made by a tool designed for that operation.
Push-fit joints shall be installed in accordance with the manufacturer's instructions.
Press joints shall be installed in accordance with the manufacturer's instructions.
Joints between CPVC plastic pipe or fittings shall be solvent-cemented or threaded joints conforming to Section 1203.3.
Joints between polybutylene plastic pipe and tubing or fittings shall be mechanical joints conforming to Section 1203.3 or heatfusion joints conforming to Section 1203.10.1.
Joints shall be of the socket-fusion or butt-fusion type. Joint surfaces shall be clean and free of moisture. Joint surfaces shall be heated to melt temperatures and joined. The joint shall be undisturbed until cool. Joints shall be made in accordance with ASTM D 3309.
Joints between cross-linked polyethylene plastic tubing and fittings shall conform to Sections 1203.11.1 and 1203.11.2. Mechanical joints shall conform to Section 1203.3.
Where compression-type fittings include inserts and ferrules or O-rings, the fittings shall be installed without omitting the inserts and ferrules or O-rings.
Soldering on the metal portion of the system shall be performed not less than 18 inches (457 mm) from a plastic-to-metal adapter in the same water line.
Joints between PVC plastic pipe and fittings shall be solvent-cemented or threaded joints conforming to Section 1203.3.
Joints between steel pipe or fittings shall be mechanical joints that are made with an approved elastomeric seal, or shall be threaded or welded joints conforming to Section 1203.3.
Joints between steel tubing or fittings shall be mechanical or welded joints conforming to Section 1203.3.
Heat-fusion joints for polypropylene (PP) pipe and tubing joints shall be installed with socket-type heat-fused polypropylene fittings, electro-fusion polypropylene fittings or by butt fusion. Joint surfaces shall be clean and free from moisture. The joint shall be undisturbed until cool. Joints shall be made in accordance with ASTM F 2389.
Mechanical and compression sleeve joints shall be installed in accordance with the manufacturer's instructions.
Joints between raised temperature polyethylene tubing and fittings shall conform to Sections 1203.16.1 and 1203.16.2. Mechanical joints shall conform to Section 1203.3.
Where compression-type fittings include inserts and ferrules or O-rings, the fittings shall be installed without omitting the inserts and ferrules or O-rings.
Joints between polyethylene/aluminum/ polyethylene pressure pipe and fittings shall conform to Sections 1203.17.1 and 1203.17.2. Mechanical joints shall comply with Section 1203.3.
Where compression-type fittings include inserts and ferrules or O-rings, the fittings shall be installed without omitting the inserts and ferrules or O-rings.
Joints between cross-linked polyethylene/aluminum/cross-linked polyethylene pressure pipe and fittings shall conform to Sections 1203.18.1 and 1203.18.2. Mechanical joints shall comply with Section 1203.3.
Where compression-type fittings include inserts and ferrules or O-rings, the fittings shall be installed without omitting the inserts and ferrules or O-rings.
Pipe insulation installed in buildings shall conform to the requirements of the International Energy Conservation Code; shall be tested in accordance with ASTM E 84 or UL 723, using the specimen preparation and mounting procedures of ASTM E 2231; and shall have a maximum flame spread index of 25 and a smoke-developed index not exceeding 450. Insulation installed in an air plenum shall comply with Section 602.2.1.
Exception: The maximum flame spread index and smoke-developed index shall not apply to one- and two-family dwellings.
Hydronic piping shall be insulated to the thickness required by the International Energy Conservation Code.
Shutoff valves shall be installed on the supply and return side of a heat exchanger.
Exception: Shutoff valves shall not be required where heat exchangers are integral with a boiler; or are a component of a manufacturer's boiler and heat exchanger packaged unit and are capable of being isolated from the hydronic system by the supply and return valves required by Section 1005.1.
Shutoff valves shall be installed on the building supply and return of a central utility system.
Shutoff valves shall be installed on the connection to any pressure vessel.
Shutoff valves shall be installed on both sides of a pressure-reducing valve.
Shutoff valves shall be installed on connections to mechanical equipment and appliances. This requirement does not apply to components of a hydronic system such as pumps, air separators, metering devices and similar equipment.
Shutoff valves shall be installed at connections to nondiaphragm-type expansion tanks.
A pressure relief valve shall be installed on the low-pressure side of a hydronic piping system that has been reduced in pressure. The relief valve shall be set at the maximum pressure of the system design. The valve shall be installed in accordance with Section 1006.
Piping, valves, fittings and connections shall be installed in accordance with the conditions of approval.
Hydronic piping systems shall be designed and installed to permit the system to be drained. Where the system drains to the plumbing drainage system, the installation shall conform to the requirements of the International Plumbing Code.
Exception: The buried portions of systems embedded underground or under floors.
The potable water system shall be protected from backflow in accordance with the International Plumbing Code.
Openings for pipe penetrations in walls, floors or ceilings shall be larger than the penetrating pipe. Openings through concrete or masonry building elements shall be sleeved. The annular space surrounding pipe penetrations shall be protected in accordance with the International Building Code.
A pipe in a hydronic piping system in which the exterior temperature exceeds 250°F (121°C) shall have a minimum clearance of 1 inch (25 mm) to combustible materials.
The flow velocity of the hydronic piping system shall be controlled to reduce the possibility of water hammer. Where a quick-closing valve creates water hammer, an approved water-hammer arrestor shall be installed. The arrestor shall be located within a range as specified by the manufacturer of the quick-closing valve.
Piping shall be installed so as to prevent detrimental strains and stresses in the pipe. Provisions shall be made to protect piping from damage resulting from expansion, contraction and structural settlement. Piping shall be installed so as to avoid structural stresses or strains within building components.
Piping located in a flood hazard area shall be capable of resisting hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during the occurrence of flooding to the design flood elevation.
Upcodes Diagrams
Pipe shall be supported in accordance with Section 305.
Provisions shall be made to prevent the formation of condensation on the exterior of piping.
The flash point of transfer fluid in a hydronic piping system shall be not less than 50°F (28°C) above the maximum system operating temperature.
The transfer fluid shall be compatible with the makeup water supplied to the system.
Hydronic piping systems shall be tested hydrostatically at one and one-half times the maximum system design pressure, but not less than 100 psi (689 kPa). The duration of each test shall be not less than 15 minutes.
Steel pipe shall be welded by electrical arc or oxygen/acetylene method.
Polybutylene pipe and tubing shall be installed in continuous lengths or shall be joined by heat fusion in accordance with Section 1203.10.1.
PE-RT tubing shall be installed in continuous lengths or shall be joined by hydronic fittings listed in Table 1202.5.
Radiant floor heating systems shall be provided with a thermal barrier in accordance with Sections 1209.5.1 through 1209.5.4.
Exception: Insulation shall not be required in engineered systems where it can be demonstrated that the insulation will decrease the efficiency or have a negative effect on the installation.
In suspended floor applications, insulation shall be installed in the joist bay cavity serving the heating space above and shall consist of materials having a minimum R-value of 11.
A thermal break shall be provided consisting of asphalt expansion joint materials or similar insulating materials at a point where a heated slab meets a foundation wall or other conductive slab.
Insulating materials utilized in thermal barriers shall be installed such that the manufacturer's R-value mark is readily observable upon inspection.
Pipe and tubing shall be rated for the operating temperature and pressure of the ground-source heat pump loop system. Fittings shall be suitable for the pressure applications and recommended by the manufacturer for installation with the pipe and tubing material installed. Where used underground, materials shall be suitable for burial.
Ground-source heat pump ground-loop pipe and tubing shall conform to the standards listed in Table 1210.4.
| MATERIAL | STANDARD (see Chapter 15) |
| Chlorinated polyvinyl chloride (CPVC) | ASTM D 2846; ASTM F 441; ASTM F 442 |
| Cross-linked polyethylene (PEX) | ASTM F 876; ASTM F 877; CSA B137.5 |
| Polyethylene/aluminum/polyethylene (PE-AL-PE) pressure pipe | ASTM F 1282; CSA B137.9 |
| High-density polyethylene (HDPE) | ASTM D 2737; ASTM D 3035; ASTM F 714; AWWA C901; CSA B137.1; CSA C448; NSF 358-1 |
| Polypropylene (PP-R) | ASTM F 2389; CSA B137.11 |
| Polyvinyl chloride (PVC) | ASTM D 1785; ASTM D 2241 |
| Raised temperature polyethylene (PE-RT) | ASTM F 2623 |
Ground-source heat pump pipe fittings shall be approved for installation with the piping materials to be installed, shall conform to the standards listed in Table 1210.5 and, if installed underground, shall be suitable for burial.
| PIPE MATERIAL | STANDARD (see Chapter 15) |
| Chlorinated polyvinyl chloride (CPVC) | ASTM D 2846; ASTM F 437; ASTM F 438; ASTM F 439; CSA B137.6 |
| Cross-linked polyethylene (PEX) | ASTM F 877; ASTM F 1807; ASTM F 1960; ASTM F 2080; ASTM F 2159; ASTM F 2434; CSA B137.5 |
| Polyethylene/aluminum/polyethylene (PE-AL-PE) | ASTM F 1282; ASTM F 2434; CSA B137.9 |
| High Density Polyethylene (HDPE) | ASTM D 2683; ASTM D 3261; ASTM F 1055; CSA B137.1; CSA C448; NSF 358-1 |
| Polypropylene (PP-R) | ASTM F 2389; CSA B137.11 |
| Polyvinyl chloride (PVC) | ASTM D 2464; ASTM D 2466; ASTM D 2467; CSA B137.2; CSA B137.3 |
| Raised temperature polyethylene (PE-RT) | ASTM D 3261; ASTM F 1807; ASTM F 2159; CSA B137.1 |
Where required by Sections 1210.6.4 through 1210.6.6, the preparation and installation of mechanical and thermoplastic-welded joints shall comply with Sections 1210.6.3.1 and 1210.6.3.2.
Mechanical joints shall be installed in accordance with the manufacturer's instructions.
Joint surfaces for thermoplastic-welded joints shall be cleaned by an approved procedure. Joints shall be welded in accordance with the manufacturer's instructions.
Joints between CPVC plastic pipe or fittings shall be solvent-cemented or threaded joints complying with Section 1203.3.
Joints between cross-linked polyethylene plastic tubing and fittings shall comply with Sections 1210.6.5.1 and 1210.6.5.2. Mechanical joints shall comply with Section 1210.6.3.
Where compression-type fittings include inserts and ferrules or Orings, the fittings shall be installed without omitting the inserts and ferrules or O-rings.
Soldering on the metal portion of the system shall be performed not less than 18 inches (457 mm) from a plastic-to-metal adapter in the same water line.
Joints between polyethylene plastic pipe and tubing or fittings for groundsource heat pump loop systems shall be heat fusion joints complying with Section 1210.6.6.1, electrofusion joints complying with Section 1210.6.6.2, or stab-type insertion joints complying with Section 1210.6.6.3.
Joints shall be of the socket-fusion, saddle-fusion or butt-fusion type, joined in accordance with ASTM D 2657. Joint surfaces shall be clean and free from moisture. Joint surfaces shall be heated to melt temperatures and joined. The joint shall be undisturbed until cool. Fittings shall be manufactured in accordance with ASTM D 2683 or ASTM D 3261.
Joints shall be of the electrofusion type. Joint surfaces shall be clean and free from moisture, and scoured to expose virgin resin. Joint surfaces shall be heated to melt temperatures for the period of time specified by the manufacturer. The joint shall be undisturbed until cool. Fittings shall be manufactured in accordance with ASTM F 1055.
Joint surfaces shall be clean and free from moisture. Pipe ends shall be chamfered and inserted into the fittings to full depth. Fittings shall be manufactured in accordance with ASTM F 1924.
Heat-fusion joints for polypropylene (PP) pipe and tubing joints shall be installed with socket-type heat-fused polypropylene fittings, electrofusion polypropylene fittings or by butt fusion. Joint surfaces shall be clean and free from moisture. The joint shall be undisturbed until cool. Joints shall be made in accordance with ASTM F 2389.
Mechanical and compression sleeve joints shall be installed in accordance with the manufacturer's instructions.
Joints between raised temperature polyethylene tubing and fittings shall comply with Sections 1210.6.8.1 and 1210.6.8.2. Mechanical joints shall comply with Section 1210.6.3.
Where compression-type fittings include inserts and ferrules or Orings, the fittings shall be installed without omitting the inserts and ferrules or O-rings.
Joints between PVC plastic pipe and fittings shall be solvent-cemented or threaded joints comply with Section 1203.3.
Shutoff valves shall be installed on the supply and return side of a heat exchanger.
Exception: Shutoff valves shall not be required where heat exchangers are integral with a boiler or are a component of a manufacturer's boiler and heat exchanger packaged unit and are capable of being isolated from the hydronic system by the supply and return valves required by Section 1005.1.
Shutoff valves shall be installed on the building supply and return of a central utility system.
Shutoff valves shall be installed on the connection to any pressure vessel.
Shutoff valves shall be installed on both sides of a pressure-reducing valve.
Shutoff valves shall be installed on connections to mechanical equipment and appliances. This requirement does not apply to components of a ground-source loop system such as pumps, air separators, metering devices, and similar equipment.
Shutoff valves shall be installed at connections to nondiaphragm-type expansion tanks.
A pressure relief valve shall be installed on the low-pressure side of a hydronic piping system that has been reduced in pressure. The relief valve shall be set at the maximum pressure of the system design. The valve shall be installed in accordance with Section 1006.
Piping, valves, fittings, and connections shall be installed in accordance with the conditions of approval.
Where groundsource heat pump ground-loop systems have a connection to a potable water supply, the potable water system shall be protected from backflow in accordance with the International Plumbing Code.
Openings for pipe penetrations in walls, floors and ceilings shall be larger than the penetrating pipe. Openings through concrete or masonry building elements shall be sleeved. The annular space surrounding pipe penetrations shall be protected in accordance with the International Building Code.
A pipe in a ground-source heat pump piping system having an exterior surface temperature exceeding 250°F (121°C) shall have a minimum clearance of 1 inch (25 mm) from combustible materials.
Piping shall be installed so as to prevent detrimental strains and stresses in the pipe. Provisions shall be made to protect piping from damage resulting from expansion, contraction and structural settlement. Piping shall be installed so as to avoid structural stresses or strains within building components.
Piping located in a flood hazard area shall be capable of resisting hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during the occurrence of flooding to the design flood elevation.
Upcodes Diagrams
Pipe shall be supported in accordance with Section 305.
Antifreeze and other materials used in the system shall be chemically compatible with the pipe, tubing, fittings, and mechanical systems.
The transfer fluid shall be compatible with the makeup water supplied to the system.
Before connection header trenches are backfilled, the assembled loop system shall be pressure tested with water at 100 psi (689 kPa) for 15 minutes, in which time there shall not be observed leaks. Flow and pressure loss testing shall be performed and the actual flow rates and pressure drops shall be compared to the calculated design values. If actual flow rate or pressure drop values differ from calculated design values by more than 10 percent, the cause shall be identified and corrective action taken.