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, condenser water, cooling coil condensate drain, steam condensate and ground source heat pump loop systems. Potable cold and hot water distribution systems shall be installed in accordance with the New York City Plumbing Code.
Piping for hydronic systems shall be sized for the demand of the system.
Piping material shall conform to the standards cited in this section.
Exception: Embedded piping regulated by Section 1209.
Reused pipe, fittings, valves or other materials shall be clean and free of foreign materials.
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 D 2282 |
| Brass pipe | ASTM B 43 |
| Brass tubing | ASTM B 135 |
| Copper or copper-alloy pipe | ASTM B 42; ASTM B 302 |
| Copper or copper-alloy tube (Type K, L or M) |
ASTM B 75; ASTM B 88; ASTM B 251 |
| Chlorinated polyvinyl chloride (CPVC) plastic pipe |
ASTM D 2846; ASTM F 441; ASTM F 442 |
| 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 |
| Polyethylene (PE) pipe, tubing and fittings (for ground source heat pump loop systems) |
ASTM D,2513;,ASTM D 3035; ASTM D 2447;,ASTM D 2683; ASTM F 1055;,ASTM D 2837; ASTM D 3350; ASTM D 1693 |
| Polyvinyl chloride (PVC) plastic pipe |
ASTM D 1785; ASTM D 2241 |
| 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) |
| Bronze | ASME B 16.24 |
| Copper and copper alloys | ASME B 16.15; ASME B 16.18; ASME B 16.22; ASME B 16.23; ASME B 16.26; ASME B 16.29 |
| Gray iron | ASTM A 126 |
| Malleable iron | ASME B 16.3 |
| Plastic | ASTM D 2466; ASTM D 2467; ASTM D 2468; ASTM F 438; ASTM F 439; ASTM F 877 |
| Steel | ASME B 16.5; ASME B 16.9; ASME B16.11; ASME B16.28; ASTM A 420 |
| Brass | ASTM F 1974 |
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.
Flexible connectors, expansion and vibration control devices and fittings shall be of an approved type.
Joints and connections shall be of an approved type. Joints and connections shall be tight for the pressure of the hydronic system.
Joints between different piping materials shall be made with approved adapter fittings. Joints between different metallic piping materials shall be made with approved dielectric fittings or brass converter fittings.
Pipe shall be cut square, reamed and chamfered, and shall be free of burrs and obstructions. Pipe ends shall have full-bore openings and shall not be undercut.
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 A 5.8.
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.
CPVC joints shall be made in accordance with ASTM D 2846. 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:
1. ASTM D 2235 for ABS joints.
2. ASTM F 493 for CPVC joints.
3. ASTM D 2564 for PVC joints.
Threads shall conform to ASME B 1.20.1. Schedule 80 or heavier plastic pipe shall be threaded with dies specifically designed for plastic pipe. Thread lubricant, pipe-joint compound or tape shall be applied on the male threads only and shall be approved for application on the piping material.
Joint surfaces shall be cleaned by an approved procedure. Joints shall be welded with an approved filler metal.
Grooved and shouldered joints shall be approved and installed in accordance with the manufacturer's installation 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 0.25 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 or flared joints conforming to Section 1203.8.1.
Flared joints shall be made by a tool designed for that operation.
Joints between CPVC plastic pipe or fittings shall be solvent-cemented or threaded joints conforming to Section 1203.3.
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.
When 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 at least 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.
Joints between polyethylene plastic pipe and tubing or fittings for ground source heat pump loop systems shall be heat fusion joints conforming to Section 1203.15.1, electrofusion joints conforming to Section 1203.15.2, or stab-type insertion joints conforming to Section 1203.15.3.
Joints shall be of the socket-fusion, saddle-fusion or butt-fusion type, fabricated in accordance with the piping manufacturer's instructions. 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. Fittings shall be manufactured in accordance with ASTM D 2683.
Joints shall be of the electrofusion type. Joint surfaces shall be clean and free of 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 of moisture. Pipe ends shall be chamfered and inserted into the fittings to full depth. Fittings shall be manufactured in accordance with ASTM D 2513.
Pipe insulation installed in buildings shall conform to the requirements of the New York City Energy Conservation Code, shall be tested in accordance with ASTM E 84 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.
Hydronic piping shall be insulated to the thickness required by the New York City 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 when 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 central utility systems, and district heating and cooling systems.
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.
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.
Fluid in the supply side of a hydronic system shall not enter a tee fitting through the branch opening.
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 New York City Plumbing Code.
The potable water system shall be protected from backflow in accordance with the New York City 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 New York City 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.
A hydronic piping system shall not be in direct contact with building materials that cause the piping material to degrade or corrode, or that interfere with the operation of the system.
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.
Steam piping shall be installed to drain to the boiler or the steam trap. Steam systems shall not have drip pockets that reduce the capacity of the steam piping.
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 areas of special flood hazard shall comply with Appendix G of the New York City Building Code.
Pipe shall be supported in accordance with Section 305. Seismic supports shall be provided where required by the New York City Building Code.
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 a minimum of 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 other than ground-source heat pump loop systems shall be tested hydrostatically at one and one half times the system design operating pressure, but not less than 100 psi (689 kPa). The duration of each test shall be not less than 2 hours. Ground-source heat pump loop systems shall be tested in accordance with Section 1208.1.1.
Before connection (header) trenches are backfilled, the assembled loop system shall be pressure tested with water at 100 psi (689 kPa) for 30 minutes with no 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 problem shall be identified and corrected.
Piping for heating panels shall be standard-weight steel pipe, Type L copper tubing, or approved plastic pipe or tubing rated at 100 psi (689 kPa) at 180°F (82°C).
Piping to be embedded in concrete shall be pressure tested prior to pouring concrete. During pouring, the pipe shall be maintained at the proposed operating pressure.
Steel pipe shall be welded by electrical arc or oxygen/acetylene method.
Copper tubing shall be joined by brazing with filler metals having a melting point of not less than 1,000°F (538°C).
The provisions of this section shall apply to high-pressure steam piping system which is defined as a system operating at a steam pressure of more than 15 psi (103 kPa). For purposes of this section, loops, bends or offsets of the piping shall not be considered expansion joints.
For purposes of this section, the replacement of existing steam piping systems, the installation of a new system in existing buildings, as well as installations in buildings hereafter constructed, shall be considered to be new high-pressure steam piping systems. The following requirements are applicable:
The design of new steam piping systems shall be conducted as follows:
1. The system shall be designed by an engineer. An application and plans shall be filed and the approval of the department obtained. The plans and application shall contain, but not be limited to, the following information:
1.1. Size and location of all steam piping.
1.2 The operating pressures and temperatures.
1.3 The location, type, specifications and details of all expansion joints.
1.4 The design, size, material and location of all anchors, guides and auxiliary steel, and the stresses thereon.
2. Systems using utility street steam shall be designed for a pressure of 200 psig (1379 kPa) and 413°F (212°C) up to and including the steam pressure reducing valve or valves which reduce the pressure of 90 psig (621 kPa) or below. For steam pressures between 90 psig (621 kPa) and 16 psig (110 kPa), the system shall be designed for 125 psig (108 kPa).
The installation of new steam piping systems shall be conducted as follows:
1. Installations, including any welding, shall be by special inspection by the engineer responsible for the design, or by an engineer acceptable to him or her.
2. Welders shall be qualified for all required pipe sizes, wall thicknesses and positions in accordance with the ASME Boiler and Pressure Vessel Code, Section IX. Requalification is required every three years or sooner if the commissioner has a specific reason to doubt a welder's ability to make sound welds.
3. Welder qualification testing shall be performed by an agency listed with the department, and if the testing is by radiography, the inspection shall have a minimum radiography qualification of Level II in accordance with the ASNT, Document No. SNT-TC-1A.
4. Copies of the certified welder qualification reports shall be maintained by the responsible welding agency and the company performing the welding, and shall be made available upon request to the department.
5. No reports from any welding inspection agency shall be accepted unless such agency has first requested and obtained approval from the department in accordance with rules of the department.
6. Pipe welding shall conform to the following:
6.1 All piping over 2 inches (51 mm) shall be butt-welded. Piping 2 inches (76 mm) and under may be socket-welded or threaded.
6.2 Threaded piping may continue to be used for existing construction in sizes of 6 inches (152 mm) and under.
6.3 Where welding is not feasible, the commissioner may allow an acceptable alternative.
7. Radiographic examination, when required, shall be performed on butt-welds in accordance with ASME B31.1 based on the piping pressure and shall be as follows:
| Piping Pressure | Percentage |
| 90 psig (621 kPa) or below | Not Required |
| 91 psig (627 kPa) to 150 psig (1034 kPa) |
10 at Random |
| Over 150 psig (1034 kPa) | 100 |
However, if, in the opinion of the engineer responsible for special inspection, radiographic examination is not required for piping at pressure between 90 psig (621 kPa) and 150 psig (1034 kPa), the engineer shall so specify in writing, and the final report on the installation may omit the foregoing, and be predicated on all of the other requirements noted in this section, and a hydrostatic test.
Hydrostatic testing shall be conducted on the completed installation at 150 percent of the design pressure for all piping pressure. Where the changes in an existing steam system involve less than 30 percent of the piping in the system, the testing may be in accordance with ASME B31.1.
The commissioner, where deemed necessary, shall require the replacement or relocation of any joints, guides or anchors. The commissioner shall cause the joints in potentially hazardous locations, such as those that are located adjacent to tenant occupied spaces, to be relocated, unless means exist or are provided for eliminating the hazard.
Existing steam piping systems shall be in accordance with Sections 1210.3.1 through 1210.3.3. Upon the completion of a new high-pressure steam piping system and department approval of same, the rules relating to maintenance requirements and the keeping of records for existing high-pressure steam piping systems shall apply.
Expansion joints, anchorage and guides shall be inspected as follows:
1. Expansion joints shall be inspected weekly.
2. The anchorage and guides shall be inspected annually. Exposure of the structural attachments to the buildings of the anchorages or guides shall not be required..
3. A record of such inspections shall be kept by the person in charge of the mechanical equipment of the building or other qualified person designated by the owner and acceptable to the commissioner. The records shall be available at the premises and subject to inspection by the commissioner.
No joint, anchorage or guides shall be repaired, replaced or relocated without a work permit issued by the department. The application for the permit shall contain all pertinent information and shall be filed by an engineer knowledgeable as to high-pressure steam piping systems. The engineer shall be responsible for the special inspection of the proposed work in accordance with the approved application. This provision shall not apply to the repacking of a slip or ball joint; however, records of such repacking shall be kept in the inspection records as provided in Section 1210.3.1, Item 3. When, in the opinion of the engineer, the requirement for prior department approval would create an imminent health or safety hazard, the engineer may permit the work to proceed without prior approval. In such cases, the engineer shall, prior to the repair, replacement or relocation, notify by telephone the borough commissioner of the borough in which the building is located; and, if the emergency occurs at other than normal working hours, he or she shall notify the department in a manner prescribed by the commissioner. This shall be followed by the filing of the application for department approval as specified in Section 28-105.4.1 of the Administrative Code.