CHAPTER 21
HYDRONIC PIPING


  • SECTION M2101
    HYDRONIC PIPING SYSTEMS INSTALLATION

    M2101.1 General.
    Hydronic piping shall conform to Table M2101.1. Approved piping, valves, fittings and connections shall be installed in accordance with the manufacturer's installation instructions. Pipe and fittings shall be rated for use at the operating temperature and pressure of the hydronic system. Used pipe, fittings, valves or other materials shall be free of foreign materials.

    TABLE M2101.1
    HYDRONIC PIPING MATERIALS

    MATERIALUSE CODEaSTANDARDbJOINTSNOTES
    Brass pipe1ASTM B 43Brazed, welded, threaded, mechanical and flanged fittings
    Brass tubing1ASTM B 135Brazed, soldered and mechanical fittings
    Chlorinated poly (vinyl chloride)
    (CPVC) pipe and tubing
    1, 2, 3ASTM D 2846Solvent cement joints, compression joints and threaded adapters
    Copper pipe1ASTM B 42,
    B 302
    Brazed, soldered and mechanical fittings threaded, welded and flanged
    Copper tubing (type K, L or M)1, 2ASTM B 75,
    B 88, B 251,
    B 306
    Brazed, soldered and flared mechanical
    fittings
    Joints embedded in concrete
    Cross-linked polyethylene (PEX)1, 2, 3ASTM F 876, F 877(See PEX fittings)Install in accordance with manufacturer's instructions
    Cross-linked polyethylene/
    aluminum/cross-linked
    polyethylene-(PEX-AL-PEX)pressure pipe
    1, 2ASTM F 1281 or
    CAN/ CSA
    B137.10
    Mechanical, crimp/insertInstall in accordance with manufacturer's instructions
    PEX fittings ASTM F 877
    ASTM F 1807
    ASTM F 1960
    ASTM F 2098
    ASTM F 2159
    ASTM F 2735
    Copper-crimp/insert fittings, cold expansion fittings, stainless steel clamp, insert fittingsInstall in accordance with manufacturer's instructions
    Deleted
    Polybutylene (PB) pipe and tubing1, 2, 3ASTM D 3309Heat-fusion, crimp/insert and compressionJoints in concrete shall be
    heat-fused
    Polyethylene (PE) pipe, tubing and fittings (for ground source heat
    pump loop systems)
    1, 2, 4ASTM D 2513
    ASTM D 3350
    ASTM D 2513
    ASTM D 3035
    ASTM D 2447
    ASTM D 2683
    ASTM F 1055
    ASTM D 2837
    ASTM D 3350
    ASTM D 1693
    Heat-fusion
    Polyethylene/aluminum/polyethylene
    (PE-AL-PE) pressure pipe
    1, 2, 3ASTM F 1282
    CSA B 137.9
    Mechanical, crimp/insert
    Polypropylene (PP)1, 2, 3ISO 15874
    ASTM F 2389
    Heat-fusion joints, mechanical fittings, threaded adapters, compression joints
    Raised temperature polyethylene(PE-RT)1, 2, 3ASTM F 2623
    ASTM F 2769
    Copper crimp/insert fitting stainless steel clamp, insert fittings
    Soldering fluxes1ASTM B 813Copper tube joints
    Steel pipe1, 2ASTM A 53,
    A 106
    Brazed, welded, threaded, flanged and mechanical fittingsJoints in concrete shall be welded. Galvanized pipe shall not be welded or brazed.
    Steel tubing1ASTM A 254Mechanical fittings, welded
    For SI: °C = [(°F)-32]/1.8.
    a. Use code:
    1. Above ground.
    2. Embedded in radiant systems.
    3. Temperatures below 180°F only.
    4. Low temperature (below 130°F) applications only.
    b. Standards as listed in Chapter 44.

    M2101.2 System drain down.
    Hydronic piping systems shall be installed to permit draining of the system. Where the system drains to the plumbing drainage system, the installation shall conform to the requirements of Chapters 25 through 32 of this code.

    Exception: The buried portions of systems embedded underground or under floors.

    M2101.3 Protection of potable water.
    The potable water system shall be protected from backflow in accordance with the provisions listed in Section P2902.

    M2101.4 Pipe penetrations.
    Openings through concrete or masonry building elements shall be sleeved.

    M2101.5 Contact with building material.
    A hydronic piping system shall not be in direct contact with any building material that causes the piping material to degrade or corrode.

    M2101.6 Drilling and notching.
    Wood-framed structural members shall be drilled, notched or altered in accordance with the provisions of Sections R502.8, R602.6, R602.6.1 and R802.7. Holes in load bearing members of cold-formed steel light-frame construction shall be permitted only in accordance with Sections R505.2.5, R603.2.5 and R804.2.5. In accordance with the provisions of Sections R505.3.5, R603.3.4 and R804.3.4, cutting and notching of flanges and lips of load-bearing members of cold-formed steel light-frame construction shall not be permitted. Structural insulated panels (SIPs) shall be drilled and notched or altered in accordance with the provisions of Section R613.

    M2101.7 Prohibited tee applications.
    Fluid in the supply side of a hydronic system shall not enter a tee fitting through the branch opening.

    M2101.8 Expansion, contraction and settlement.
    Piping shall be installed so that piping, connections and equipment shall not be subjected to excessive strains or stresses. Provisions shall be made to compensate for expansion, contraction, shrinkage and structural settlement.

    M2101.9 Piping support.
    Hangers and supports shall be of material of sufficient strength to support the piping, and shall be fabricated from materials compatible with the piping material. Piping shall be supported at intervals not exceeding the spacing specified in Table M2101.9.

    TABLE M2101.9
    HANGER SPACING INTERVALS

    PIPING MATERIALMAXIMUM
    HORIZONTAL
    SPACING
    (feet)
    MAXIMUM
    VERTICAL
    SPACING
    (feet)
    ABS 410
    CPVC ≤ 1-inch pipe or tubing 35
    CPVC ≥ 11/4 inches410
    Copper or copper alloy pipe 1210
    Copper or copper alloy tubing 610
    PB pipe or tubing 2.674
    PE pipe or tubing 2.674
    PEX tubing 2.674
    PP < 1-inch pipe or tubing 2.674
    PP > 11/4 inches410
    PVC 410
    Steel pipe 1215
    Steel tubing 810
    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

    M2101.10 Tests.
    Hydronic piping shall be tested hydrostatically at a pressure of not less than 100 pounds per square inch (690 kPa) for a duration of not less than 15 minutes.

    SECTION M2102
    BASEBOARD CONVECTORS

    M2102.1 General.
    Baseboard convectors shall be installed in accordance with the manufacturer's installation instructions. Convectors shall be supported independently of the hydronic piping.

    SECTION M2103
    FLOOR HEATING SYSTEMS

    M2103.1 Piping materials.
    Piping for embedment in concrete or gypsum materials shall be standard-weight steel pipe, copper tubing, cross-linked polyethylene/aluminum/cross-linked polyethylene (PEX-AL-PEX) pressure pipe, chlorinated polyvinyl chloride (CPVC), polybutylene, cross-linked polyethylene (PEX) tubing or polypropylene (PP) with a minimum rating of 100 psi at 180°F (690 kPa at 82°C).

    M2103.2 Thermal barrier required.
    Radiant floor heating systems shall have a thermal barrier in accordance with Sections M2103.2.1 through M2103.2.4.

    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.

    M2103.2.1 Slab-on-grade installation.
    Radiant piping used in slab-on-grade applications shall have insulating materials having a minimum R-value of 5 installed beneath the piping.

    M2103.2.2 Suspended floor 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.

    M2103.2.3 Thermal break required.
    A thermal break consisting of asphalt expansion joint materials or similar insulating materials shall be provided at a point where a heated slab meets a foundation wall or other conductive slab.

    M2103.2.4 Thermal barrier material marking.
    Insulating materials used in thermal barriers shall be installed so that the manufacturer's R-value mark is readily observable upon inspection.

    M2103.3 Piping joints.
    Piping joints that are embedded shall be installed in accordance with the following requirements:

    1. Steel pipe joints shall be welded.

    2. Copper tubing shall be joined with brazing material having a melting point exceeding 1,000°F (538°C).

    3. Polybutylene pipe and tubing joints shall be installed with socket-type heat-fused polybutylene fittings.

    4. CPVC tubing shall be joined using solvent cement joints.

    5. Polypropylene pipe and tubing joints shall be installed with socket-type heat-fused polypropylene fittings.

    6. Cross-linked polyethylene (PEX) tubing shall be joined using cold expansion, insert or compression fittings.

    M2103.4 Testing.
    Piping or tubing to be embedded shall be tested by applying a hydrostatic pressure of not less than 100 psi (690 kPa). The pressure shall be maintained for 30 minutes, during which all joints shall be visually inspected for leaks.

    SECTION M2104
    LOW TEMPERATURE PIPING

    M2104.1 Piping materials.
    Low temperature piping for embedment in concrete or gypsum materials shall be as indicated in Table M2101.1.

    M2104.2 Piping joints.
    Piping joints, other than those in Section M2103.3, that are embedded shall comply with the following requirements:

    1. Cross-linked polyethylene (PEX) tubing shall be installed in accordance with the manufacturer's instructions.

    2. Polyethylene tubing shall be installed with heat fusion joints.

    3. Polypropylene (PP) tubing shall be installed in accordance with the manufacturer's instructions.

    M2104.2.1 Polyethylene plastic pipe and tubing for ground source heat pump loop systems.
    Joints between polyethylene plastic pipe and tubing or fittings for ground source heat pump loop systems shall be heat fusion joints conforming to Section M2104.2.1.1, electrofusion joints conforming to Section M2104.2.1.2 or stab-type insertion joints conforming to Section M2104.2.1.3.

    M2104.2.1.1 Heat-fusion joints.
    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.

    M2104.2.1.2 Electrofusion joints.
    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.

    M2104.2.1.3 Stab-type insert fittings.
    Joint surfaces shall be clean and free of moisture. Pipe ends shall be chamfered and inserted into the fitting to full depth. Fittings shall be manufactured in accordance with ASTM D 2513.

    M2104.3 Raised temperature polyethylene (PE-RT) plastic tubing.
    Joints between raised temperature polyethylene tubing and fittings shall conform to Sections M2104.3.1 and M2104.3.2. Mechanical joints shall be installed in accordance with the manufacturer's instructions.

    M2104.3.1 Compression-type fittings.
    Where compression-type fittings include inserts and ferrules or O-rings, the fittings shall be installed without omitting such inserts and ferrules or O-rings.

    M2104.3.2 PE-RT-to-metal connections.
    Solder joints in a metal pipe shall not occur within 18 inches (457 mm) of a transition from such metal pipe to PE-RT pipe.

    M2104.4 Polyethylene/Aluminum/Polyethylene (PE-AL-PE) pressure pipe.
    Joints between polyethylene/aluminum/polyethylene pressure pipe and fittings shall conform to Sections M2104.4.1 and M2104.4.2. Mechanical joints shall be installed in accordance with the manufacturer's instructions.

    M2104.4.1 Compression-type fittings.
    Where compression-type fittings include inserts and ferrules or O-rings, the fittings shall be installed without omitting such inserts and ferrules or O-rings.

    M2104.4.2 PE-AL-PE to metal connections.
    Solder joints in a metal pipe shall not occur within 18 inches (457 mm) of a transition from such metal pipe to PE-AL-PE pipe.

    SECTION M2105
    GROUND SOURCE HEAT PUMP SYSTEM LOOP
    PIPING

    M2105.1 Testing.
    The assembled loop system shall be pressure tested with water at 100 psi (690 kPa) for 30 minutes with no observed leaks before connection (header) trenches are backfilled. Flow rates and pressure drops shall be compared to calculated values. If actual flow rate or pressure drop figures differ from calculated values by more than 10 percent, the problem shall be identified and corrected.