ADOPTS WITH AMENDMENTS:

International Residential Code 2015 (IRC 2015)

Part I — Administrative

Part II — Definitions

Part III — Building Planning and Construction

Part IV — Energy Conservation

Part V — Mechanical

Part VI — Fuel Gas

Part VII — Plumbing

Part VIII — Electrical

Part IX — Referenced Standards

Heads up: There are no amended sections in this chapter.

Chapter 21 Hydronic Piping

AMENDMENT
This section has been amended at the state or city level.
The text of this chapter is extracted from the 2018 edition of the North Carolina Mechanical Code and has been modified where necessary to conform to the scope of application of the North Carolina Residential Code for One- and Two-Family Dwellings. The section numbers appearing in parentheses after each section number are the section numbers of the corresponding text in the North Carolina Mechanical Code.

M2101.1 General

AMENDMENT
This section has been amended at the state or city level.
Hydronic piping shall conform to Table M2101.1. Approved piping, valves, fittings and connections shall be installed in accordance with the manufacturer's 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 (1202.4) HYDRONIC PIPING MATERIALS

MATERIAL USE
CODEa
STANDARDb JOINTS NOTES
Acrylonitrile butadiene styrene
(ABS) plastic pipe
1, 5 ASTM D 1527;
ASTM F 2806;
ASTM F 2969
Solvent cement joints
Brass pipe 1 ASTM B 43 Brazed, welded, threaded, mechanical and
flanged fittings
Brass tubing 1 ASTM B 135 Brazed, soldered and mechanical fittings
Chlorinated poly (vinyl chloride)
(CPVC) pipe and tubing
1, 2, 3 ASTM D 2846 Solvent cement joints, compression joints
and threaded adapters
Copper pipe 1 ASTM B 42,
B 302
Brazed, soldered and mechanical fittings
threaded, welded and flanged
Copper tubing (type K, L or M) 1, 2 ASTM B 75,
B 88, B 251,
B 306
Brazed, soldered and flared mechanical
fittings
Joints embedded in
concrete
Cross-linked polyethylene (PEX) 1, 2, 3 ASTM 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, 2 ASTM F 1281 or
CAN/ CSA B137.10
Mechanical, crimp/insert Install 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
fittings
Install in accordance with
manufacturer's instructions
Polybutylene (PB) pipe and tubing 1, 2, 3 ASTM D 3309 Heat-fusion, crimp/insert and compression Joints in concrete shall be
heat-fused
Polyethylene/aluminum/polyethylene
(PE-AL-PE) pressure pipe
1, 2, 3 ASTM F 1282
CSA B 137.9
Mechanical, crimp/insert
Polypropylene (PP) 1, 2, 3 ISO 15874
ASTM F 2389
Heat-fusion joints, mechanical fittings,
threaded adapters, compression joints
Raised temperature polyethylene
(PE-RT)
1, 2, 3 ASTM F 2623
ASTM F 2769
Copper crimp/insert fitting stainless steel
clamp, insert fittings
Raised temperature polyethylene
(PE-RT) fittings
1, 2,3 ASTM F 1807
ASTM F 2159
ASTM F 2735
ASTM F 2769
ASTM F 2098
Copper crimp/insert fitting stainless steel
clamp, insert fittings
Steel pipe 1, 2 ASTM A 53,
A 106
Brazed, welded, threaded, flanged and
mechanical fittings
Joints in concrete shall be
welded. Galvanized pipe
shall not be welded or
brazed.
Steel tubing 1 ASTM A 254 Mechanical 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.
5. Temperatures below 160°F only.
b. Standards as listed in Chapter 44.

M2101.2 (1206.2) System Drain Down

AMENDMENT
This section has been amended at the state or city level.
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 (1206.3) Protection of Potable Water

AMENDMENT
This section has been amended at the state or city level.
The potable water system shall be protected from backflow in accordance with the provisions listed in Section P2902.

M2101.4 (1206.4) Pipe Penetrations

AMENDMENT
This section has been amended at the state or city level.
Openings through concrete or masonry building elements shall be sleeved.

M2101.5 (1206.6) Contact With Building Material

AMENDMENT
This section has been amended at the state or city level.
A hydronic piping system shall not be in direct contact with any building material that causes the piping material to degrade or corrode.
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 R505.2.6, R603.2.6 and R804.2.6. In accordance with the provisions of Sections R505.3.5, R603.3.4 and R804.3.3, 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 R610.7.
Fluid in the supply side of a hydronic system shall not enter a tee fitting through the branch opening.
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 (305.4) Piping Support

AMENDMENT
This section has been amended at the state or city level.
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 MATERIAL MAXIMUM
HORIZONTAL
SPACING
(feet)
MAXIMUM
VERTICAL
SPACING
(feet)
ABS 4 10a
CPVC ≤ 1-inch pipe or tubing 3 5a
CPVC ≥ 11/4 inches 4 10a
Copper or copper alloy pipe 12 10
Copper or copper alloy tubing 6 10
PB pipe or tubing 2.67 4
PE pipe or tubing 2.67 4
PE-RT ≤ 1 inch 2.67 10a
PE-RT ≥ 11/4 inches 4 10a
PEX tubing 2.67 4
PP < 1-inch pipe or tubing 2.67 4
PP > 11/4 inches 4 10a
PVC 4 10a
Steel pipe 12 15
Steel tubing 8 10

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
a. For sizes 2 inches and smaller, a guide shall be installed midway between required vertical supports. Such guides shall prevent pipe movement in a direction perpendicular to the axis of the pipe.
Hydronic piping systems shall be tested hydrostatically at a pressure of one and one-half times the maximum system design pressure, but not less than 100 pounds per square inch (689 kPa). The duration of each test shall be not less than 15 minutes and not more than 20 minutes.

M2101.10.1 (1201.4) Test Gauges

AMENDMENT
This section has been amended at the state or city level.
Gauges used for testing shall be as follows:
  1. Tests requiring a pressure of 10 pounds per square inch (psi) (69 kPa) or less shall utilize a testing gauge having increments of 0.10 psi (0.69 kPa) or less.
  2. Tests requiring a pressure of greater than 10 psi (69 kPa) but less than or equal to 100 psi (689 kPa) shall utilize a testing gauge having increments of 1 psi (6.9 kPa) or less.
  3. Tests requiring a pressure of greater than 100 psi (689 kPa) shall utilize a testing gauge having increments of 2 psi (14 kPa) or less.

M2101.10.2 (1209.2) Pressurizing During Installation

AMENDMENT
This section has been amended at the state or city level.
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.

M2101.11 (1206.11) Condensation

AMENDMENT
This section has been amended at the state or city level.
Provisions shall be made to prevent the formation of condensation on the exterior of hydronic piping.

M2101.12 (1206.4) Pipe Penetrations

AMENDMENT
This section has been amended at the state or city level.
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.

M2101.13 (1206.5) Clearance to Combustibles

AMENDMENT
This section has been amended at the state or city level.
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.

M2101.14 (1206.6) Contact With Building Material

AMENDMENT
This section has been amended at the state or city level.
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.

M2101.15 (1206.7) Water Hammer

AMENDMENT
This section has been amended at the state or city level.
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.

M2101.16 (1206.8) Steam Piping Pitch

AMENDMENT
This section has been amended at the state or city level.
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.

M2101.17 (1206.9) Strains and Stresses

AMENDMENT
This section has been amended at the state or city level.
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 to avoid structural stresses or strains within building components.

M2101.17.1 (1206.9.1) Flood Hazard

AMENDMENT
This section has been amended at the state or city level.
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.

Section M2102 Baseboard Convectors Joints and Connections

AMENDMENT
This section has been amended at the state or city level.

M2102.1 General

AMENDMENT
This section has been amended at the state or city level.

M2102.1 (1203.3) Joint Preparation and Installation

AMENDMENT
This section has been amended at the state or city level.
oints 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. 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.

     Where required by Sections M2102.2 through M2102.12, the preparation and installation of brazed, mechanical, soldered, solvent cemented, threaded and welded joints shall comply with Sections M2102.1.1 through M2102.1.8.

M2102.1.1 (1203.3.1) Brazed Joints

AMENDMENT
This section has been amended at the state or city level.
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.

M2102.1.2 (1203.3.2) Mechanical Joints

AMENDMENT
This section has been amended at the state or city level.
Mechanical joints shall be installed in accordance with the manufacturer's instructions.

M2102.1.3 (1203.3.3) Soldered Joints

AMENDMENT
This section has been amended at the state or city level.
Joint surfaces shall be cleaned. A flux conforming to ASTM B813 shall be applied. The joint shall be soldered with a solder conforming to ASTM B32.

M2102.1.4 (1203.3.4) Solvent-Cemented Joints

AMENDMENT
This section has been amended at the state or city level.
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 D2235 for ABS joints.
  2. ASTM F493 for CPVC joints.
  3. ASTM D2564 for PVC joints.
CPVC joints shall be made in accordance with ASTM D2846.
Exception: For CPVC pipe joint connections, a primer is not required where all of the following conditions apply:
  1. The solvent cement used is third-party certified as conforming to ASTM F493.
  2. The solvent cement is yellow in color.
  3. The solvent cement is used only for joining 1/2-inch (12.7 mm) through 2-inch (51 mm) diameter CPVC pipe and fittings.
  4. The CPVC pipe and fittings are manufactured in accordance with ASTM D2846.

M2102.1.5 (1203.3.5) Threaded Joints

AMENDMENT
This section has been amended at the state or city level.
Threads shall conform to ASME B1.20.1. 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.

M2102.1.6 (1203.3.6) Welded Joints

AMENDMENT
This section has been amended at the state or city level.
Joint surfaces shall be cleaned by an approved procedure. Joints shall be welded with an approved filler metal.

M2102.1.7 (1203.3.7) Grooved and Shouldered Mechanical Joints

AMENDMENT
This section has been amended at the state or city level.
Grooved and shouldered mechanical joints shall conform to the requirements of ASTM F1476 and shall be installed in accordance with the manufacturer's instructions.

M2102.1.8 (1203.3.8) Mechanically Formed Tee Fittings

AMENDMENT
This section has been amended at the state or city level.
Mechanically extracted outlets shall have a height not less than three times the thickness of the branch tube wall.

M2102.1.8.1 (1203.3.8.1) Full Flow Assurance

AMENDMENT
This section has been amended at the state or city level.
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.

M2102.1.8.2 (1203.3.8.2) Brazed Joints

AMENDMENT
This section has been amended at the state or city level.
Mechanically formed tee fittings shall be brazed in accordance with Section M2102.1.1.

M2102.2 (1203.4) ABS Plastic Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between ABS plastic pipe or fittings shall be solvent-cemented or threaded joints conforming to Section M2102.1.

M2102.3 (1203.5) Brass Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between brass pipe or fittings shall be brazed, mechanical, threaded or welded joints conforming to Section M2102.1.

M2102.4 (1203.6) Brass Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between brass tubing or fittings shall be brazed, mechanical or soldered joints conforming to Section M2102.1.

M2102.5 (1203.7) Copper or Copper-Alloy Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between copper or copper-alloy pipe or fittings shall be brazed, mechanical, soldered, threaded or welded joints conforming to Section M2102.1.

M2102.6 (1203.8) Copper or Copper-Alloy Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between copper or copper-alloy tubing or fittings shall be brazed, mechanical or soldered joints conforming to Section M2102.1, flared joints conforming to Section M2102.6.1, push-fit joints conforming to Section M2102.6.2 or presstype joints conforming to Section M2102.6.3.

M2102.6.1 (1203.8.1) Flared Joints

AMENDMENT
This section has been amended at the state or city level.
Flared joints shall be made by a tool designed for that operation.

M2102.6.2 (1203.8.2) Push-Fit Joints

AMENDMENT
This section has been amended at the state or city level.
Push-fit joints shall be installed in accordance with the manufacturer's instructions.

M2102.6.3 (1203.8.3) Press Joints

AMENDMENT
This section has been amended at the state or city level.
Press joints shall be installed in accordance with the manufacturer's instructions.

M2102.7 (1203.9) CPVC Plastic Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between CPVC plastic pipe or fittings shall be solvent-cemented or threaded joints conforming to Section M2102.1.

M2102.8 (1203.10) Polybutylene Plastic Pipe and Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between polybutylene plastic pipe and tubing or fittings shall be mechanical joints conforming to Section M2102.1 or heat-fusion joints conforming to Section M2102.8.1.

M2102.8.1 (1203.10.1) Heat-Fusion Joints

AMENDMENT
This section has been amended at the state or city level.
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 D3309.

M2102.9 (1203.11) Cross-Linked Polyethylene (PEX) Plastic Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between cross-linked polyethylene plastic tubing and fittings shall conform to Sections M2102.9.1 and M2102.9.2 Mechanical joints shall conform to Section M2102.1.

M2102.9.1 (1203.11.1) Compression-Type Fittings

AMENDMENT
This section has been amended at the state or city level.
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.

M2102.9.2 (1203.11.2) Plastic-To-Metal Connections

AMENDMENT
This section has been amended at the state or city level.
Soldering on the metal portion of the system shall be performed not less than 18 inches (457 mm) from a plastic-tometal adapter in the same water line.

M2102.10 (1203.12) PVC Plastic Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between PVC plastic pipe and fittings shall be solvent-cemented or threaded joints conforming to Section M2102.1.

M2102.11 (1203.13) Steel Pipe

AMENDMENT
This section has been amended at the state or city level.
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 M2102.1.

M2102.12 (1203.14) Steel Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between steel tubing or fittings shall be mechanical or welded joints conforming to Section M2102.1.

M2102.13 (1203.15) Polypropylene (PP) Plastic

AMENDMENT
This section has been amended at the state or city level.
Joints between PP plastic pipe and fittings shall comply with Sections M2102.13.1 and M2102.13.2.

M2102.13.1 (1203.15.1) Heat-Fusion Joints

AMENDMENT
This section has been amended at the state or city level.
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 F2389.

M2102.13.2 (1203.15.2) Mechanical and Compression Sleeve Joints

AMENDMENT
This section has been amended at the state or city level.
Mechanical and compression sleeve joints shall be installed in accordance with the manufacturer's instructions.

M2102.14 (1203.16) Raised Temperature Polyethylene (PE-RT) Plastic Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between raised temperature polyethylene tubing and fittings shall conform to Sections M2102.14.1 and M2102.14.2. Mechanical joints shall conform to Section M2102.1.

M2102.14.1 (1203.16.1) Compression-Type Fittings

AMENDMENT
This section has been amended at the state or city level.
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.

M2102.14.2 (1203.16.2) PE-RT-To-Metal Connections

AMENDMENT
This section has been amended at the state or city level.
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.

M2102.15 (1203.17) Polyethylene/Aluminum/Polyethylene (PE-ALPE) Pressure Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between polyethylene/aluminum/ polyethylene pressure pipe and fittings shall conform to Sections M2102.15.1 and M2102.15.2. Mechanical joints shall comply with Section M2102.1.

M2102.15.1 (1203.17.1) Compression-Type Fittings

AMENDMENT
This section has been amended at the state or city level.
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.

M2102.15.2 (1203.17.2) PE-AL-PE-To-Metal Connections

AMENDMENT
This section has been amended at the state or city level.
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.
Joints between cross-linked polyethylene/aluminum/crosslinked polyethylene pressure pipe and fittings shall conform to Sections M2102.16.1 and M2102.16.2. Mechanical joints shall comply with Section M2102.1.

M2102.16.1 (1203.18.1) Compression-Type Fittings

AMENDMENT
This section has been amended at the state or city level.
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.

M2102.16.2 (1203.18.2) PEX-AL-PEX-To-Metal Connections

AMENDMENT
This section has been amended at the state or city level.
Solder joints in a metal pipe shall not occur within 18 inches (457 mm) of a transition from such metal pipe to PEX-AL-PEX pipe.
Piping for embedment in concrete or gypsum materials shall be standard-weight steel pipe, copper and copper alloy pipe and tubing, cross-linked polyethylene/aluminum/cross-linked polyethylene (PEX-AL-PEX) pressure pipe, chlorinated polyvinyl chloride (CPVC), polybutylene, cross-linked polyethylene (PEX) tubing, polyethylene of raised temperature (PE-RT) or polypropylene (PP) with a minimum rating of 100 psi at 180°F (690 kPa at 82°C).
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.
Radiant piping used in slab-on-grade applications shall have insulating materials having a minimum R-value of 5 installed beneath the piping.
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 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.
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

AMENDMENT
This section has been amended at the state or city level.

M2103.4 Testing

AMENDMENT
This section has been amended at the state or city level.
Low temperature piping for embedment in concrete or gypsum materials shall be as indicated in Table M2101.1.
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.
  4. Raised temperature polyethylene (PE-RT) shall be installed in accordance with the manufacturer's instructions.
Joints between raised temperature polyethylene tubing and fittings shall conform to Sections M2104.3.1, M2104.3.2 and M2104.3.3. Mechanical joints shall be installed in accordance with the manufacturer's instructions.
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.
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.
PE-RT insert fittings shall be installed in accordance with the manufacturer's instructions.
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.
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.
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.

M2105.1 (1210.1) Plastic Ground-Source Heat-Pump Loop Piping

AMENDMENT
This section has been amended at the state or city level.
Plastic piping and tubing material used in water-based ground-source heat-pump ground-loop systems shall conform to the standards specified in this section.

M2105.2 (1210.2) Used Materials

AMENDMENT
This section has been amended at the state or city level.
Reused pipe, fittings, valves, and other materials shall not be used in ground-source heat-pump loop systems.

M2105.3 (1210.3) Material Rating

AMENDMENT
This section has been amended at the state or city level.
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.

M2105.4 (1210.4) Piping and Tubing Materials Standards

AMENDMENT
This section has been amended at the state or city level.
Ground-source heat-pump ground-loop pipe and tubing shall conform to the standards listed in Table M2105.4.

TABLE M2105.4 GROUND-SOURCE LOOP PIPE

MATERIAL STANDARD
Chlorinated polyvinyl chloride
(CPVC)
ASTM D 2846; ASTM F 437; ASTM F 438; ASTM F 439;
ASTM F 441; ASTM F 442; CSA B137.6
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; AWWA C 903
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; CSA 137.3
Raised temperature polyethylene
(PE-RT)
ASTM F 2623; ASTM F 2769

M2105.5 (1210.5) Fittings

AMENDMENT
This section has been amended at the state or city level.
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 M2105.5 and, where installed underground, shall be suitable for burial.

TABLE M2105.5 GROUND-SOURCE LOOP PIPE FITTINGS

PIPE MATERIAL STANDARD
Chlorinated polyvinyl chloride (CPVC) ASTM D 2846; ASTM F 437; ASTM F 438; ASTM F 439;
ASTM F 1970; 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 2434; ASTM F 1282; 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; NSF 358-2
Polyvinyl chloride (PVC) ASTM D 2464; ASTM D 2466; ASTM D 2467; ASTM F 1970,
CSA B137.2; CSA B137.3
Raised temperature polyethylene
(PE-RT)
ASTM D 3261; ASTM F 1807; ASTM F 2159; F 2769; B137.1

M2105.6 (1210.6) Joints and Connections

AMENDMENT
This section has been amended at the state or city level.
Joints and connections shall be of an approved type. Joints and connections shall be tight for the pressure of the ground-source loop system. Joints used underground shall be approved for such applications.

M2105.6.1 (1210.6.1) Joints Between Different Piping Materials

AMENDMENT
This section has been amended at the state or city level.
Joints between different piping materials shall be made with approved transition fittings.

M2105.7 (1210.6.2) Preparation of Pipe Ends

AMENDMENT
This section has been amended at the state or city level.
Pipe shall be cut square, reamed, and shall be free of burrs and obstructions. CPVC, PE and PVC pipe shall be chamfered. Pipe ends shall have full-bore openings and shall not be undercut.

M2105.8 (1210.6.3) Joint Preparation and Installation

AMENDMENT
This section has been amended at the state or city level.
Where required by Sections M2105.9 through M2105.11, the preparation and installation of mechanical and thermoplastic-welded joints shall comply with Sections M2105.8.1 and M2015.8.2.

M2105.8.1 (1210.6.3.1) Mechanical Joints

AMENDMENT
This section has been amended at the state or city level.
Mechanical joints shall be installed in accordance with the manufacturer's instructions.

M2105.8.2 (1210.6.3.2) Thermoplastic-Welded Joints

AMENDMENT
This section has been amended at the state or city level.
Joint surfaces for thermoplastic-welded joints shall be cleaned by an approved procedure. Joints shall be welded in accordance with the manufacturer's instructions.

M2105.9 (1210.6.4) CPVC Plastic Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between CPVC plastic pipe or fittings shall be solvent-cemented in accordance with Section P2906.9.1.2. Threaded joints between fittings and CPVC plastic pipe shall be in accordance with Section M2105.9.1.
Threads shall conform to ASME B1.20.1. The pipe shall be Schedule 80 or heavier plastic pipe and 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.

M2105.10 (1210.6.5) Cross-Linked Polyethylene (PEX) Plastic Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between cross-linked polyethylene plastic tubing and fittings shall comply with Sections M2105.10.1 and M2105.10.2. Mechanical joints shall comply with Section M2105.8.1.

M2105.10.1 (1210.6.5.1) Compression-Type Fittings

AMENDMENT
This section has been amended at the state or city level.
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.

M2105.10.2 (1210.6.5.2) Plastic-To-Metal Connections

AMENDMENT
This section has been amended at the state or city level.
Solder joints in a metal pipe shall not occur within 18 inches (457 mm) of a transition from such metal pipe to plastic pipe or tubing.

M2105.11 (1210.6.6) Polyethylene Plastic Pipe and Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between polyethylene plastic pipe and tubing or fittings for ground-source heat-pump loop systems shall be heat-fusion joints complying with Section M2105.11.1, electrofusion joints complying with Section M2105.11.2, or stab-type insertion joints complying with Section M2105.11.3.

M2105.11.1 (1210.6.6.1) Heat-Fusion Joints

AMENDMENT
This section has been amended at the state or city level.
Joints shall be of the socket-fusion, saddle-fusion or butt-fusion type, and joined in accordance with ASTM D 2657. 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 or ASTM D 3261.

M2105.11.2 (1210.6.6.1) Electrofusion Joints

AMENDMENT
This section has been amended at the state or city level.
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.

M2105.11.3 (1210.6.6.3) Stab-Type Insert Fittings

AMENDMENT
This section has been amended at the state or city level.
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 F 1924.

M2105.12 (1210.6.7) Polypropylene (PP) Plastic

AMENDMENT
This section has been amended at the state or city level.
Joints between PP plastic pipe and fittings shall comply with Sections M2105.12.1 and M2105.12.2.

M2105.12.1 (1210.6.7.1) Heat-Fusion Joints

AMENDMENT
This section has been amended at the state or city level.
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.

M2105.12.2 (1210.6.7.2) Mechanical and Compression Sleeve Joints

AMENDMENT
This section has been amended at the state or city level.
Mechanical and compression sleeve joints shall be installed in accordance with the manufacturer's instructions.

M2105.13 (1210.6.8) Raised Temperature Polyethylene (PE-RT) Plastic Tubing

AMENDMENT
This section has been amended at the state or city level.
Joints between raised temperature polyethylene tubing and fittings shall comply with Sections M2105.13.1 and M2105.13.2. Mechanical joints shall comply with Section M2105.8.1.

M2105.13.1 (1210.6.8.1) Compression-Type Fittings

AMENDMENT
This section has been amended at the state or city level.
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.

M2105.13.2 (1210.6.8.2) PE-RT-To-Metal Connections

AMENDMENT
This section has been amended at the state or city level.
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 or tubing.

M2105.14 (1210.6.9) PVC Plastic Pipe

AMENDMENT
This section has been amended at the state or city level.
Joints between PVC plastic pipe or fittings shall be solvent-cemented in accordance with Section P2906.9.1.4. Threaded joints between fittings and PVC plastic pipe shall be in accordance with Section M2105.9.1.

M2105.15 (1210.7) Shutoff Valves

AMENDMENT
This section has been amended at the state or city level.
Shutoff valves shall be installed in ground-source loop piping systems in the locations indicated in Sections M2105.15.1 through M2105.15.6.
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 M2001.3.
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 ground-source loop systems such as pumps, air separators, metering devices, and similar equipment.
Shutoff valves shall be installed at connections to nondiaphragm-type expansion tanks.

M2105.16 (1210.7.7) Reduced Pressure

AMENDMENT
This section has been amended at the state or city level.
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 M2002.

M2105.17 (1210.8) Installation

AMENDMENT
This section has been amended at the state or city level.
Piping, valves, fittings, and connections shall be installed in accordance with the manufacturer's instructions.

M2105.18 (1210.8.1) Protection of Potable Water

AMENDMENT
This section has been amended at the state or city level.
Where ground-source 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 Section P2902.

M2105.19 (1210.8.2) Pipe Penetrations

AMENDMENT
This section has been amended at the state or city level.
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 Section P2606.1.

M2105.20 (1210.8.3) Clearance From Combustibles

AMENDMENT
This section has been amended at the state or city level.
A pipe in a ground-source heat pump piping system having an exterior surface temperature exceeding 250°F (121°C) shall have a clearance of not less than 1 inch (25 mm) from combustible materials.

M2105.21 (1210.8.4) Contact With Building Material

AMENDMENT
This section has been amended at the state or city level.
A ground-source heat-pump ground-loop piping system shall not be in direct contact with building materials that cause the piping or fitting material to degrade or corrode, or that interfere with the operation of the system.

M2105.22 (1210.8.5) Strains and Stresses

AMENDMENT
This section has been amended at the state or city level.
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.

M2105.23 (1210.8.7) Pipe Support

AMENDMENT
This section has been amended at the state or city level.
Pipe shall be supported in accordance with Section M2101.9.

M2105.24 (1210.8.8) Velocities

AMENDMENT
This section has been amended at the state or city level.
Ground-source heat-pump ground-loop systems shall be designed so that the flow velocities do not exceed the maximum flow velocity recommended by the pipe and fittings manufacturer. Flow velocities shall be controlled to reduce the possibility of water hammer.

M2105.25 (1210.8.9) Labeling and Marking

AMENDMENT
This section has been amended at the state or city level.
Ground-source heat-pump ground-loop system piping shall be marked with tape, metal tags or other methods where it enters a building. The marking shall state the following words: "GROUND-SOURCE HEAT-PUMP LOOP SYSTEM." The marking shall indicate if antifreeze is used in the system and shall indicate the chemicals by name and concentration.

M2105.26 (1210.8.10) Chemical Compatibility

AMENDMENT
This section has been amended at the state or city level.
Antifreeze and other materials used in the system shall be chemically compatible with the pipe, tubing, fittings and mechanical systems.

M2105.27 (1210.9) Makeup Water

AMENDMENT
This section has been amended at the state or city level.
The transfer fluid shall be compatible with the makeup water supplied to the system.

M2105.28 (1210.10) Testing

AMENDMENT
This section has been amended at the state or city level.
Before connection header trenches are backfilled, the assembled loop system shall be pressure tested with water at 100 psi (689 kPa) for 15 minutes without 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.

M2105.29 (1210.11) Embedded Piping

AMENDMENT
This section has been amended at the state or city level.
Ground-source heat-pump ground-loop 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.

Section M2106 Baseboard Convectors

AMENDMENT
This section has been amended at the state or city level.

M2106.1 General

AMENDMENT
This section has been amended at the state or city level.
Baseboard convectors shall be installed in accordance with the manufacturer's instructions. Convectors shall be supported independently of the hydronic piping.
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