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    CHAPTER12
    MECHANICAL ADMINISTRATION

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1201
    GENERAL

    M1201.1 Scope.

    The provisions of Chapters 12 through 24 shall regulate the design, installation, maintenance, alteration and inspection of mechanical systems that are permanently installed and used to control environmental conditions within buildings. These chapters shall also regulate those mechanical systems, system components, equipment and appliances specifically addressed in this code.

    M1201.2 Application.

    In addition to the general administration requirements of Chapter 1, the administrative provisions of this chapter shall also apply to the mechanical requirements of Chapters 13 through 24.

    SECTIONM1202
    EXISTING MECHANICAL SYSTEMS

    M1202.1 Additions, alterations or repairs.

    Additions, alterations, renovations or repairs to a mechanical system shall conform to the requirements for a new mechanical system without requiring the existing mechanical system to comply with all of the requirements of this code. Additions, alterations or repairs shall not cause an existing mechanical system to become unsafe, hazardous or overloaded. Minor additions, alterations or repairs to existing mechanical systems shall meet the provisions for new construction, unless such work is done in the same manner and arrangement as was in the existing system, is not hazardous, and is approved.

    M1202.2 Existing installations.

    Except as otherwise provided for in this code, a provision in this code shall not require the removal, alteration or abandonment of, nor prevent the continued use and maintenance of, an existing mechanical system lawfully in existence at the time of the adoption of this code.

    M1202.3 Maintenance.

    Mechanical systems, both existing and new, and parts thereof shall be maintained in proper operating condition in accordance with the original design and in a safe and sanitary condition. Devices or safeguards that are required by this code shall be maintained in compliance with the code edition under which installed. The owner or the owner’s designated agent shall be responsible for maintenance of the mechanical systems. To determine compliance with this provision, the building official shall have the authority to require a mechanical system to be reinspected.

    CHAPTER13
    GENERAL MECHANICAL SYSTEM REQUIREMENTS

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1301
    GENERAL

    M1301.1 Scope.

    The provisions of this chapter shall govern the installation of mechanical systems not specifically covered in other chapters applicable to mechanical systems. Installations of mechanical appliances, equipment and systems not addressed by this code shall comply with the applicable provisions of the International Mechanical Code and the International Fuel Gas Code.

    M1301.1.1 Flood-resistant installation.

    In flood hazard areas as established by Table R301.2(1), mechanical appliances, equipment and systems shall be located or installed in accordance with Section R322.1.6.

    M1301.2 Identification.

    Each length of pipe and tubing and each pipe fitting utilized in a mechanical system shall bear the identification of the manufacturer.

    M1301.3 Installation of materials.

    Materials shall be installed in strict accordance with the standards under which the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions shall be followed. Where the requirements of referenced standards or manufacturer’s instructions do not conform to minimum provisions of this code, the provisions of this code shall apply.

    M1301.4 Plastic pipe, fittings and components.

    Plastic pipe, fittings and components shall be third-party certified as conforming to NSF 14.

    M1301.5 Third-party testing and certification.

    Piping, tubing and fittings shall comply with the applicable referenced standards, specifications and performance criteria of this code and shall be identified in accordance with Section M1301.2. Piping, tubing and fittings shall either be tested by an approved third-party testing agency or certified by an approved third-party certification agency.

    SECTIONM1302
    APPROVAL

    M1302.1 Listed and labeled.

    Appliances regulated by this code shall be listed and labeled for the application in which they are installed and used, unless otherwise approved in accordance with Section R104.11.

    SECTIONM1303
    LABELING OF APPLIANCES

    M1303.1 Label information.

    A permanent factory-applied nameplate(s) shall be affixed to appliances on which shall appear, in legible lettering, the manufacturer’s name or trademark, the model number, a serial number and the seal or mark of the testing agency. A label also shall include the following:

    1. 1.Electrical appliances. Electrical rating in volts, amperes and motor phase; identification of individual electrical components in volts, amperes or watts and motor phase; and in Btu/h (W) output and required clearances.

    2. 2.Absorption units. Hourly rating in Btu/h (W), minimum hourly rating for units having step or automatic modulating controls, type of fuel, type of refrigerant, cooling capacity in Btu/h (W) and required clearances.

    3. 3.Fuel-burning units. Hourly rating in Btu/h (W), type of fuel approved for use with the appliance and required clearances.

    4. 4.Electric comfort-heating appliances. The electric rating in volts, amperes and phase; Btu/h (W) output rating; individual marking for each electrical component in amperes or watts, volts and phase; and required clearances from combustibles.

    5. 5.Maintenance instructions. Required regular maintenance actions and title or publication number for the operation and maintenance manual for that particular model and type of product.

    SECTIONM1304
    TYPE OF FUEL

    M1304.1 Fuel types.

    Fuel-fired appliances shall be designed for use with the type of fuel to which they will be connected and the altitude at which they are installed. Appliances that comprise parts of the building mechanical system shall not be converted for the use of a different fuel, except where approved and converted in accordance with the manufacturer’s instructions. The fuel input rate shall not be increased or decreased beyond the limit rating for the altitude at which the appliance is installed.

    SECTIONM1305
    APPLIANCE ACCESS

    M1305.1 Appliance access for inspection service, repair and replacement.

    Appliances shall be accessible for inspection, service, repair and replacement without removing permanent construction, other appliances, or any other piping or ducts not connected to the appliance being inspected, serviced, repaired or replaced. A level working space not less than 30 inches deep and 30 inches wide (762 mm by 762 mm) shall be provided in front of the control side to service an appliance.

    M1305.1.1 Furnaces and air handlers.

    Furnaces and air handlers within compartments or alcoves shall have a minimum working space clearance of 3 inches (76 mm) along the sides, back and top with a total width of the enclosing space being not less than 12 inches (305 mm) wider than the furnace or air handler. Furnaces having a firebox open to the atmosphere shall have not less than a 6-inch (152 mm) working space along the front combustion chamber side. Combustion air openings at the rear or side of the compartment shall comply with the requirements of Chapter 17.

    Exception: This section shall not apply to replacement appliances installed in existing compartments and alcoves where the working space clearances are in accordance with the equipment or appliance manufacturer’s installation instructions.

    M1305.1.2 Appliances in rooms.

    Appliances installed in a compartment, alcove, basement or similar space shall be accessed by an opening or door and an unobstructed passageway measuring not less than 24 inches (610 mm) wide and large enough to allow removal of the largest appliance in the space, provided there is a level service space of not less than 30 inches (762 mm) deep and the height of the appliance, but not less than 30 inches (762 mm), at the front or service side of the appliance with the door open.

    M1305.1.3 Appliances in attics.

    Attics containing appliances shall be provided with an opening and a clear and unobstructed passageway large enough to allow removal of the largest appliance, but not less than 30 inches (762 mm) high and 22 inches (559 mm) wide and not more than 20 feet (6096 mm) long measured along the centerline of the passageway from the opening to the appliance. The passageway shall have continuous solid flooring in accordance with Chapter 5 not less than 24 inches (610 mm) wide. A level service space not less than 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present along all sides of the appliance where access is required. The clear access opening dimensions shall be not less than of 20 inches by 30 inches (508 mm by 762 mm), and large enough to allow removal of the largest appliance.

    Exceptions:

    1. 1.The passageway and level service space are not required where the appliance can be serviced and removed through the required opening.

    2. 2.Where the passageway is unobstructed and not less than 6 feet (1829 mm) high and 22 inches (559 mm) wide for its entire length, the passageway shall be not more than 50 feet (15 250 mm) long.

    M1305.1.3.1 Electrical requirements.

    A luminaire controlled by a switch located at the required passageway opening and a receptacle outlet shall be installed at or near the appliance location in accordance with Chapter 39. Exposed lamps shall be protected from damage by location or lamp guards.

    M1305.1.4 Appliances under floors.

    Underfloor spaces containing appliances shall be provided with an unobstructed passageway large enough to remove the largest appliance, but not less than 30 inches (762 mm) high and 22 inches (559 mm) wide, nor more than 20 feet (6096 mm) long measured along the centerline of the passageway from the opening to the appliance. A level service space not less than 30 inches (762 mm) deep and 30 inches (762 mm) wide shall be present at the front or service side of the appliance. If the depth of the passageway or the service space exceeds 12 inches (305 mm) below the adjoining grade, the walls of the passageway shall be lined with concrete or masonry extending 4 inches (102 mm) above the adjoining grade in accordance with Chapter 4. The rough-framed access opening dimensions shall be not less than 22 inches by 30 inches (559 mm by 762 mm), and large enough to remove the largest appliance.

    Exceptions:

    1. 1.The passageway is not required where the level service space is present when the access is open, and the appliance can be serviced and removed through the required opening.

    2. 2.Where the passageway is unobstructed and not less than 6 feet high (1929 mm) and 22 inches (559 mm) wide for its entire length, the passageway shall not be limited in length.

    M1305.1.4.1 Ground clearance.

    Equipment and appliances supported from the ground shall be level and firmly supported on a concrete slab or other approved material extending not less than 3 inches (76 mm) above the adjoining ground. Such support shall be in accordance with the manufacturer’s installation instructions. Appliances suspended from the floor shall have a clearance of not less than 6 inches (152 mm) from the ground.

    M1305.1.4.2 Excavations.

    Excavations for appliance installations shall extend to a depth of 6 inches (152 mm) below the appliance and 12 inches (305 mm) on all sides, except that the control side shall have a clearance of 30 inches (762 mm).

    M1305.1.4.3 Electrical requirements.

    A luminaire controlled by a switch located at the required passageway opening and a receptacle outlet shall be installed at or near the appliance location in accordance with Chapter 39. Exposed lamps shall be protected from damage by location or lamp guards.

    SECTIONM1306
    CLEARANCES FROM COMBUSTIBLE CONSTRUCTION

    M1306.1 Appliance clearance.

    Appliances shall be installed with the clearances from unprotected combustible materials as indicated on the appliance label and in the manufacturer’s installation instructions.

    Note: “A” equals the required clearance with no protection. “B” equals the reduced clearance permitted in accordance with Table M1306.2. The protection applied to the construction using combustible material shall extend far enough in each direction to make “C” equal to “A.”

    FIGURE M1306.1

    REDUCED CLEARANCE DIAGRAM

    M1306.2 Clearance reduction.

    The reduction of required clearances to combustible assemblies or combustible materials shall be based on Section M1306.2.1 or Section M1306.2.2.

    TABLE M1306.2

    REDUCTION OF CLEARANCES WITH SPECIFIED FORMS OF PROTECTIONa, c, d, e, f, g, h, i, j, k, l

    TYPE OF PROTECTION APPLIED TO AND COVERING ALL SURFACES OF COMBUSTIBLE MATERIAL WITHIN THE DISTANCE SPECIFIED AS THE REQUIRED CLEARANCE WITH NO PROTECTION (See Figures M1306.1 and M1306.2)WHERE THE REQUIRED CLEARANCE WITHOUT PROTECTION FROM APPLIANCE, VENT CONNECTOR, OR SINGLE WALL METAL PIPE IS:
    36 inches18 inches12 inches9 inches6 inches
    Allowable clearances with specified protection (Inches)b
    Use column 1 for clearances above an appliance or horizontal connector. Use column 2 for clearances from an appliance, vertical connector and single-wall metal pipe.
    Above column 1Sides and rear column 2Above column 1Sides and rear column 2Above column 1Sides and rear column 2Above column 1Sides and rear column 2Above column 1Sides and rear column 2
    31/2-inch-thick masonry wall without ventilated air space2412965
    1/2-inch insulation board over 1-inch glass fiber or mineral wool batts2418129966543
    Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) over 1-inch glass fiber or mineral wool batts reinforced with wire or rear face with a ventilated air space181296645333
    31/2-inch-thick masonry wall with ventilated air space126666
    Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) with a ventilated air space 1-inch off the combustible assembly181296645332
    1/2-inch-thick insulation board with ventilated air space181296645333
    Galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) with ventilated air space over 24 gage sheet steel with a ventilated space181296645333
    1-inch glass fiber or mineral wool batts sandwiched between two sheets of galvanized sheet steel having a minimum thickness of 0.0236-inch (No. 24 gage) with a ventilated air space181296645333

    For SI: 1 inch = 25.4 mm, 1 pound per cubic foot = 16.019 kg/m3, °C = [(°F)-32/1.8], 1 Btu/(h × ft2 × °F/in.) = 0.001442299 (W/cm2 × °C/cm).

    1. a.Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance and relief, and accessibility of servicing.

    2. b.Clearances shall be measured from the surface of the heat producing appliance or equipment to the outer surface of the combustible material or combustible assembly.

    3. c.Spacers and ties shall be of noncombustible material. Spacers and ties shall not be used directly opposite appliance or connector.

    4. d.Where all clearance reduction systems use a ventilated air space, adequate provision for air circulation shall be provided as described. (See Figures M1306.1 and M1306.2.)

    5. e.There shall be not less than 1 inch between clearance reduction systems and combustible walls and ceilings for reduction systems using ventilated air space.

    6. f.If a wall protector is mounted on a single flat wall away from corners, adequate air circulation shall be permitted to be provided by leaving only the bottom and top edges or only the side and top edges open with not less than a 1-inch air gap.

    7. g.Mineral wool and glass fiber batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot and a minimum melting point of 1,500°F.

    8. h.Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu inch per square foot per hour °F or less. Insulation board shall be formed of noncombustible material.

    9. i.There shall be not less than 1 inch between the appliance and the protector. The clearance between the appliance and the combustible surface shall not be reduced below that allowed in this table.

    10. j.All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.

    11. k.Listed single-wall connectors shall be permitted to be installed in accordance with the terms of their listing and the manufacturer’s instructions.

    12. l.For limitations on clearance reduction for solid-fuel-burning appliances see Section M1306.2.3.

    For SI: 1 inch = 25.4 mm.

    FIGURE M1306.2

    WALL PROTECTOR CLEARANCE REDUCTION SYSTEM

    M1306.2.1 Labeled assemblies.

    The allowable clearance shall be based on an approved reduced clearance protective assembly that is listed and labeled in accordance with UL 1618.

    M1306.2.2 Reduction table.

    Reduction of clearances shall be in accordance with the appliance manufacturer’s instructions and Table M1306.2. Forms of protection with ventilated air space shall conform to the following requirements:

    1. 1.Not less than 1-inch (25 mm) air space shall be provided between the protection and combustible wall surface.

    2. 2.Air circulation shall be provided by having edges of the wall protection open not less than 1 inch (25 mm).

    3. 3.If the wall protection is mounted on a single flat wall away from corners, air circulation shall be provided by having the bottom and top edges, or the side and top edges not less than 1 inch (25 mm).

    4. 4.Wall protection covering two walls in a corner shall be open at the bottom and top edges not less than 1 inch (25 mm).

    M1306.2.3 Solid-fuel appliances.

    Table M1306.2 shall not be used to reduce the clearance required for solid-fuel appliances listed for installation with minimum clearances of 12 inches (305 mm) or less. For appliances listed for installation with minimum clearances greater than 12 inches (305 mm), Table M1306.2 shall not be used to reduce the clearance to less than 12 inches (305 mm).

    SECTIONM1307
    APPLIANCE INSTALLATION

    M1307.1 General.

    Installation of appliances shall conform to the conditions of their listing and label and the manufacturer’s instructions. The manufacturer’s operating and installation instructions shall remain attached to the appliance.

    M1307.2 Anchorage of appliances.

    Appliances designed to be fixed in position shall be fastened or anchored in an approved manner. In Seismic Design Categories D0, D1 and D2, and in townhouses in Seismic Design Category C, water heaters and thermal storage units shall be anchored or strapped to resist horizontal displacement caused by earthquake motion in accordance with one of the following:

    1. 1.Anchorage and strapping shall be designed to resist a horizontal force equal to one-third of the operating weight of the water heater storage tank, acting in any horizontal direction. Strapping shall be at points within the upper one-third and lover one-third of the appliance’s vertical dimensions. At the lower point, the strapping shall maintain a minimum distance of 4 inches (102 mm) above the controls.

    2. 2.The anchorage strapping shall be in accordance with the appliance manufacturer’s recommendations.

    M1307.3 Elevation of ignition source.

    Appliances having an ignition source shall be elevated such that the source of ignition is not less than 18 inches (457 mm) above the floor in garages. For the purpose of this section, rooms or spaces that are not part of the living space of a dwelling unit and that communicate with a private garage through openings shall be considered to be part of the garage.

    Exception: Elevation of the ignition source is not required for appliances that are listed as flammable-vapor-ignition resistant.

    M1307.3.1 Protection from impact.

    Appliances shall not be installed in a location subject to vehicle damage except where protected by approved barriers.

    M1307.4 Hydrogen generating and refueling operations.

    Ventilation shall be required in accordance with Section M1307.4.1, M1307.4.2 or M1307.4.3 in private garages that contain hydrogen-generating appliances or refueling systems. For the purpose of this section, rooms or spaces that are not part of the living space of a dwelling unit and that communicate directly with a private garage through openings shall be considered to be part of the private garage.

    M1307.4.1 Natural ventilation.

    Indoor locations intended for hydrogen-generating or refueling operations shall be limited to a maximum floor area of 850 square feet (79 m2) and shall communicate with the outdoors in accordance with Sections M1307.4.1.1 and M1307.4.1.2. The maximum rated output capacity of hydrogen-generating appliances shall not exceed 4 standard cubic feet per minute (1.9 L/s) of hydrogen for each 250 square feet (23 m2) of floor area in such spaces. The minimum cross-sectional dimension of air openings shall be 3 inches (76 mm). Where ducts are used, they shall be of the same cross-sectional area as the free area of the openings to which they connect. In those locations, equipment and appliances having an ignition source shall be located so that the source of ignition is not within 12 inches (305 mm) of the ceiling.

    M1307.4.1.1 Two openings.

    Two permanent openings shall be constructed within the garage. The upper opening shall be located entirely within 12 inches (305 mm) of the ceiling of the garage. The lower opening shall be located entirely within 12 inches (305 mm) of the floor of the garage. Both openings shall be constructed in the same exterior wall. The openings shall communicate directly with the outdoors and shall have a minimum free area of 1/2 square foot per 1,000 cubic feet (1.7 m2/1000 m3) of garage volume.

    M1307.4.1.2 Louvers and grilles.

    In calculating free area required by Section M1307.4.1, the required size of openings shall be based on the net free area of each opening. If the free area through a design of louver or grille is known, it shall be used in calculating the size opening required to provide the free area specified. If the design and free area are not known, it shall be assumed that wood louvers will have a 25-percent free area and metal louvers and grilles will have a 75-percent free area. Louvers and grilles shall be fixed in the open position.

    M1307.4.2 Mechanical ventilation.

    Indoor locations intended for hydrogen-generating or refueling operations shall be ventilated in accordance with Section 502.16 of the International Mechanical Code. In these locations, equipment and appliances having an ignition source shall be located so that the source of ignition is below the mechanical ventilation outlet(s).

    M1307.4.3 Specially engineered installations.

    As an alternative to the provisions of Sections M1307.4.1 and M1307.4.2, the necessary supply of air for ventilation and dilution of flammable gases shall be provided by an approved engineered system.

    M1307.5 Electrical appliances.

    Electrical appliances shall be installed in accordance with Chapters 14, 15, 19, 20 and 34 through 43 of this code.

    M1307.6 Plumbing connections.

    Potable water and drainage system connections to equipment and appliances regulated by this code shall be in accordance with Chapters 29 and 30.

    SECTIONM1308
    MECHANICAL SYSTEMS INSTALLATION

    M1308.1 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 R505.2.6, 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.

    M1308.2 Protection against physical damage.

    Where piping will be concealed within light-frame construction assemblies, the piping shall be protected against penetration by fasteners in accordance with Sections M1308.2.1 through M1308.2.3.

    Exception: Cast iron piping and galvanized steel piping shall not be required to be protected.

    M1308.2.1 Piping through bored holes or notches.

    Where piping is installed through holes or notches in framing members and is located less than 11/2 inches (38 mm) from the framing member face to which wall, ceiling or floor membranes will be attached, the pipe shall be protected by shield plates that cover the width of the pipe and the framing member and that extend 2 inches (51 mm) to each side of the framing member. Where the framing member that the piping passes through is a bottom plate, bottom track, top plate or top track, the shield plates shall cover the framing member and extend 2 inches (51 mm) above the bottom framing member and 2 inches (51 mm) below the top framing member.

    M1308.2.2 Piping in other locations.

    Where piping is located within a framing member and is less than 11/2 inches (38 mm) from the framing member face to which wall, ceiling or floor membranes will be attached, the piping shall be protected by shield plates that cover the width and length of the piping. Where piping is located outside of a framing member and is located less than 11/2 inches (38 mm) from the nearest edge of the face of the framing member to which the membrane will be attached, the piping shall be protected by shield plates that cover the width and length of the piping.

    M1308.2.3 Shield plates.

    Shield plates shall be of steel material having a thickness of not less than 0.0575 inch (1.463 mm) (No. 16 gage).

    CHAPTER14
    HEATING AND COOLING EQUIPMENT AND APPLIANCES

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1401
    GENERAL

    M1401.1 Installation.

    Heating and cooling equipment and appliances shall be installed in accordance with the manufacturer’s instructions and the requirements of this code.

    M1401.2 Access.

    Heating and cooling equipment and appliances shall be located with respect to building construction and other equipment and appliances to permit maintenance, servicing and replacement. Clearances shall be maintained to permit cleaning of heating and cooling surfaces; replacement of filters, blowers, motors, controls and vent connections; lubrication of moving parts; and adjustments.

    Exception: Access shall not be required for ducts, piping, or other components approved for concealment.

    M1401.3 Equipment and appliance sizing.

    Heating and cooling equipment and appliances shall be sized in accordance with ACCA Manual S or other approved sizing methodologies based on building loads calculated in accordance with ACCA Manual J or other approved heating and cooling calculation methodologies.

    Exception: Heating and cooling equipment and appliance sizing shall not be limited to the capacities determined in accordance with Manual S where either of the following conditions applies:

    1. 1.The specified equipment or appliance utilizes multistage technology or variable refrigerant flow technology and the loads calculated in accordance with the approved heating and cooling calculation methodology are within the range of the manufacturer’s published capacities for that equipment or appliance.

    2. 2.The specified equipment or appliance manufacturer’s published capacities cannot satisfy both the total and sensible heat gains calculated in accordance with the approved heating and cooling calculation methodology and the next larger standard size unit is specified.

    M1401.4 Exterior installations.

    Equipment and appliances installed outdoors shall be listed and labeled for outdoor installation. Supports and foundations shall prevent excessive vibration, settlement or movement of the equipment. Supports and foundations shall be in accordance with Section M1305.1.4.1.

    M1401.5 Flood hazard.

    In flood hazard areas as established by Table R301.2(1), heating and cooling equipment and appliances shall be located or installed in accordance with Section R322.1.6.

    SECTIONM1402
    CENTRAL FURNACES

    M1402.1 General.

    Oil-fired central furnaces shall conform to ANSI/UL 727. Electric furnaces shall conform to UL 1995.

    M1402.2 Clearances.

    Clearances shall be provided in accordance with the listing and the manufacturer’s installation instructions.

    M1402.3 Combustion air.

    Combustion air shall be supplied in accordance with Chapter 17. Combustion air openings shall be unobstructed for a distance of not less than 6 inches (152 mm) in front of the openings.

    SECTIONM1403
    HEAT PUMP EQUIPMENT

    M1403.1 Heat pumps.

    Electric heat pumps shall be listed and labeled in accordance with UL 1995 or UL/CSA/ANCE 60335-2-40.

    SECTIONM1404
    REFRIGERATION COOLING EQUIPMENT

    M1404.1 Compliance.

    Refrigeration cooling equipment shall comply with Section M1411.

    SECTIONM1405
    BASEBOARD CONVECTORS

    M1405.1 General.

    Electric baseboard convectors shall be installed in accordance with the manufacturer’s instructions and Chapters 34 through 43 of this code. Electric baseboard heaters shall be listed and labeled in accordance with UL 1042.

    SECTIONM1406
    RADIANT HEATING SYSTEMS

    M1406.1 General.

    Electric radiant heating systems shall be installed in accordance with the manufacturer’s instructions and Chapters 34 through 43 of this code and shall be listed for the application.

    M1406.2 Clearances.

    Clearances for radiant heating panels or elements to any wiring, outlet boxes and junction boxes used for installing electrical devices or mounting luminaires shall comply with Chapters 34 through 43 of this code.

    M1406.3 Installation of radiant panels.

    Radiant panels installed on wood framing shall conform to the following requirements:

    1. 1.Heating panels shall be installed parallel to framing members and secured to the surface of framing members or mounted between framing members.

    2. 2.Mechanical fasteners shall penetrate only the unheated portions provided for this purpose. Panels shall not be fastened at any point closer than 1/4 inch (6.4 mm) to an element. Other methods of attachment of the panels shall be in accordance with the panel manufacturer’s instructions.

    3. 3.Unless listed and labeled for field cutting, heating panels shall be installed as complete units.

    M1406.4 Installation in concrete or masonry.

    Radiant heating systems installed in concrete or masonry shall conform to the following requirements:

    1. 1.Radiant heating systems shall be identified as being suitable for the installation, and shall be secured in place as specified in the manufacturer’s installation instructions.

    2. 2.Radiant heating panels or radiant heating panel sets shall not be installed where they bridge expansion joints unless protected from expansion and contraction.

    M1406.5 Finish surfaces.

    Finish materials installed over radiant heating panels or systems shall be installed in accordance with the manufacturer’s instructions. Surfaces shall be secured so that nails or other fastenings do not pierce the radiant heating elements.

    SECTIONM1407
    DUCT HEATERS

    M1407.1 General.

    Electric duct heaters shall be installed in accordance with the manufacturer’s instructions and Chapters 34 through 43 of this code. Electric duct heaters shall comply with UL 1996.

    M1407.2 Installation.

    Electric duct heaters shall be installed so that they will not create a fire hazard. Class 1 ducts, duct coverings and linings shall be interrupted at each heater to provide the clearances specified in the manufacturer’s installation instructions. Such interruptions are not required for duct heaters listed and labeled for zero clearance to combustible materials. Insulation installed in the immediate area of each heater shall be classified for the maximum temperature produced on the duct surface.

    M1407.3 Installation with heat pumps and air conditioners.

    Duct heaters located within 4 feet (1219 mm) of a heat pump or air conditioner shall be listed and labeled for such installations. The heat pump or air conditioner shall additionally be listed and labeled for such duct heater installations.

    M1407.4 Access.

    Duct heaters shall be accessible for servicing, and clearance shall be maintained to permit adjustment, servicing and replacement of controls and heating elements.

    M1407.5 Fan interlock.

    The fan circuit shall be provided with an interlock to prevent heater operation when the fan is not operating.

    SECTIONM1408
    VENTED FLOOR FURNACES

    M1408.1 General.

    Oil-fired vented floor furnaces shall comply with UL 729 and shall be installed in accordance with their listing, the manufacturer’s instructions and the requirements of this code.

    M1408.2 Clearances.

    Vented floor furnaces shall be installed in accordance with their listing and the manufacturer’s instructions.

    M1408.3 Location.

    Location of floor furnaces shall conform to the following requirements:

    1. 1.Floor registers of floor furnaces shall be installed not less than 6 inches (152 mm) from a wall.

    2. 2.Wall registers of floor furnaces shall be installed not less than 6 inches (152 mm) from the adjoining wall at inside corners.

    3. 3.The furnace register shall be located not less than 12 inches (305 mm) from doors in any position, draperies or similar combustible objects.

    4. 4.The furnace register shall be located not less than 5 feet (1524 mm) below any projecting combustible materials.

    5. 5.The floor furnace burner assembly shall not project into an occupied under-floor area.

    6. 6.The floor furnace shall not be installed in concrete floor construction built on grade.

    7. 7.The floor furnace shall not be installed where a door can swing within 12 inches (305 mm) of the grille opening.

    M1408.4 Access.

    An opening in the foundation not less than 18 inches by 24 inches (457 mm by 610 mm), or a trap door not less than 22 inches by 30 inches (559 mm by 762 mm) shall be provided for access to a floor furnace. The opening and passageway shall be large enough to allow replacement of any part of the equipment.

    M1408.5 Installation.

    Floor furnace installations shall conform to the following requirements:

    1. 1.Thermostats controlling floor furnaces shall be located in the room in which the register of the floor furnace is located.

    2. 2.Floor furnaces shall be supported independently of the furnace floor register.

    3. 3.Floor furnaces shall be installed not closer than 6 inches (152 mm) to the ground. The minimum clearance shall be 2 inches (51 mm), where the lower 6 inches (152 mm) of the furnace is sealed to prevent water entry.

    4. 4.Where excavation is required for a floor furnace installation, the excavation shall extend 30 inches (762 mm) beyond the control side of the floor furnace and 12 inches (305 mm) beyond the remaining sides. Excavations shall slope outward from the perimeter of the base of the excavation to the surrounding grade at an angle not exceeding 45 degrees (0.79 rad) from horizontal.

    5. 5.Floor furnaces shall not be supported from the ground.

    SECTIONM1409
    VENTED WALL FURNACES

    M1409.1 General.

    Oil-fired vented wall furnaces shall comply with UL 730 and shall be installed in accordance with their listing, the manufacturer’s instructions and the requirements of this code.

    M1409.2 Location.

    The location of vented wall furnaces shall conform to the following requirements:

    1. 1.Vented wall furnaces shall be located where they will not cause a fire hazard to walls, floors, combustible furnishings or doors. Vented wall furnaces installed between bathrooms and adjoining rooms shall not circulate air from bathrooms to other parts of the building.

    2. 2.Vented wall furnaces shall not be located where a door can swing within 12 inches (305 mm) of the furnace air inlet or outlet measured at right angles to the opening. Doorstops or door closers shall not be installed to obtain this clearance.

    M1409.3 Installation.

    Vented wall furnace installations shall conform to the following requirements:

    1. 1.Required wall thicknesses shall be in accordance with the manufacturer’s installation instructions.

    2. 2.Ducts shall not be attached to a wall furnace. Casing extensions or boots shall be installed only where listed as part of a listed and labeled appliance.

    3. 3.A manual shut off valve shall be installed ahead of all controls.

    M1409.4 Access.

    Vented wall furnaces shall be provided with access for cleaning of heating surfaces; removal of burners; replacement of sections, motors, controls, filters and other working parts; and for adjustments and lubrication of parts requiring such attention. Panels, grilles and access doors that must be removed for normal servicing operations shall not be attached to the building construction.

    SECTIONM1410
    VENTED ROOM HEATERS

    M1410.1 General.

    Vented room heaters shall be tested in accordance with ASTM E 1509 for pellet-fuel burning, UL 896 for oil-fired or UL 1482 for solid fuel-fired and installed in accordance with their listing, the manufacturer’s installation instructions and the requirements of this code.

    M1410.2 Floor mounting.

    Room heaters shall be installed on noncombustible floors or approved assemblies constructed of noncombustible materials that extend not less than 18 inches (457 mm) beyond the appliance on all sides.

    Exceptions:

    1. 1.Listed room heaters shall be installed on noncombustible floors, assemblies constructed of noncombustible materials or floor protectors listed and labeled in accordance with UL 1618. The materials and dimensions shall be in accordance with the appliance manufacturer’s instructions.

    2. 2.Room heaters listed for installation on combustible floors without floor protection shall be installed in accordance with the appliance manufacturer’s instructions.

    SECTIONM1411
    HEATING AND COOLING EQUIPMENT

    M1411.1 Approved refrigerants.

    Refrigerants used in direct refrigerating systems shall conform to the applicable provisions of ANSI/ASHRAE 34.

    M1411.2 Refrigeration coils in warm-air furnaces.

    Where a cooling coil is located in the supply plenum of a warm-air furnace, the furnace blower shall be rated at not less than 0.5-inch water column (124 Pa) static pressure unless the furnace is listed and labeled for use with a cooling coil. Cooling coils shall not be located upstream from heat exchangers unless listed and labeled for such use. Conversion of existing furnaces for use with cooling coils shall be permitted provided the furnace will operate within the temperature rise specified for the furnace.

    M1411.3 Condensate disposal.

    Condensate from cooling coils and evaporators shall be conveyed from the drain pan outlet to an approved place of disposal. Such piping shall maintain a minimum horizontal slope in the direction of discharge of not less than 1/8 unit vertical in 12 units horizontal (1-percent slope). Condensate shall not discharge into a street, alley or other areas where it would cause a nuisance.

    M1411.3.1 Auxiliary and secondary drain systems.

    In addition to the requirements of Section M1411.3, a secondary drain or auxiliary drain pan shall be required for each cooling or evaporator coil where damage to any building components will occur as a result of overflow from the equipment drain pan or stoppage in the condensate drain piping. Such piping shall maintain a minimum horizontal slope in the direction of discharge of not less than 1/8 unit vertical in 12 units horizontal (1-percent slope). Drain piping shall be not less than 3/4-inch (19 mm) nominal pipe size. One of the following methods shall be used:

    1. 1.An auxiliary drain pan with a separate drain shall be installed under the coils on which condensation will occur. The auxiliary pan drain shall discharge to a conspicuous point of disposal to alert occupants in the event of a stoppage of the primary drain. The pan shall have a minimum depth of 1.5 inches (38 mm), shall be not less than 3 inches (76 mm) larger than the unit or the coil dimensions in width and length and shall be constructed of corrosion-resistant material. Galvanized sheet steel pans shall have a minimum thickness of not less than 0.0236-inch (0.6010 mm) (No. 24 Gage). Nonmetallic pans shall have a minimum thickness of not less than 0.0625 inch (1.6 mm).

    2. 2.A separate overflow drain line shall be connected to the drain pan installed with the equipment. This overflow drain shall discharge to a conspicuous point of disposal to alert occupants in the event of a stoppage of the primary drain. The overflow drain line shall connect to the drain pan at a higher level than the primary drain connection.

    3. 3.An auxiliary drain pan without a separate drain line shall be installed under the coils on which condensation will occur. This pan shall be equipped with a water level detection device conforming to UL 508 that will shut off the equipment served prior to overflow of the pan. The pan shall be equipped with a fitting to allow for drainage. The auxiliary drain pan shall be constructed in accordance with Item 1 of this section.

    4. 4.A water level detection device conforming to UL 508 shall be installed that will shut off the equipment served in the event that the primary drain is blocked. The device shall be installed in the primary drain line, the overflow drain line or the equipment-supplied drain pan, located at a point higher than the primary drain line connection and below the overflow rim of such pan.

    M1411.3.1.1 Water-level monitoring devices.

    On down-flow units and other coils that do not have secondary drain or provisions to install a secondary or auxiliary drain pan, a water-level monitoring device shall be installed inside the primary drain pan. This device shall shut off the equipment served in the event that the primary drain becomes restricted. Devices shall not be installed in the drain line.

    M1411.3.2 Drain pipe materials and sizes.

    Components of the condensate disposal system shall be ABS, cast iron, copper, cross-linked polyethylene, CPVC, galvanized steel, PE-RT, polyethylene, polypropylene or PVC pipe or tubing. Components shall be selected for the pressure and temperature rating of the installation. Joints and connections shall be made in accordance with the applicable provisions of Chapter 30. Condensate waste and drain line size shall be not less than 3/4-inch (19 mm) nominal diameter from the drain pan connection to the place of condensate disposal. Where the drain pipes from more than one unit are manifolded together for condensate drainage, the pipe or tubing shall be sized in accordance with an approved method.

    M1411.3.3 Drain line maintenance.

    Condensate drain lines shall be configured to permit the clearing of blockages and performance of maintenance without requiring the drain line to be cut.

    M1411.3.4 Appliances, equipment and insulation in pans.

    Where appliances, equipment or insulation are subject to water damage when auxiliary drain pans fill, those portions of the appliances,equipment and insulation shall be installed above the flood level rim of the pan. Supports located inside of the pan to support the appliance or equipment shall be water resistant and approved.

    M1411.4 Condensate pumps.

    Condensate pumps located in uninhabitable spaces, such as attics and crawl spaces, shall be connected to the appliance or equipment served such that when the pump fails, the appliance or equipment will be prevented from operating. Pumps shall be installed in accordance with the manufacturer’s instructions.

    M1411.5 Auxiliary drain pan.

    Category IV condensing appliances shall have an auxiliary drain pan where damage to any building component will occur as a result of stoppage in the condensate drainage system. These pans shall be installed in accordance with the applicable provisions of Section M1411.3.

    Exception: Fuel-fired appliances that automatically shut down operation in the event of a stoppage in the condensate drainage system.

    M1411.6 Insulation of refrigerant piping.

    Piping and fittings for refrigerant vapor (suction) lines shall be insulated with insulation having a thermal resistivity of not less than R-4 and having external surface permeance not exceeding 0.05 perm [2.87 ng/(s · m2 · Pa)] when tested in accordance with ASTM E 96.

    M1411.7 Location and protection of refrigerant piping.

    Refrigerant piping installed within 11/2 inches (38 mm) of the underside of roof decks shall be protected from damage caused by nails and other fasteners.

    M1411.8 Locking access port caps.

    Refrigerant circuit access ports located outdoors shall be fitted with locking-type tamper-resistant caps or shall be otherwise secured to prevent unauthorized access.

    SECTIONM1412
    ABSORPTION COOLING EQUIPMENT

    M1412.1 Approval of equipment.

    Absorption systems shall be installed in accordance with the manufacturer’s instructions. Absorption equipment shall comply with UL 1995 or UL/CSA/ANCE 60335-2-40.

    M1412.2 Condensate disposal.

    Condensate from the cooling coil shall be disposed of as provided in Section M1411.3.

    M1412.3 Insulation of piping.

    Refrigerant piping, brine piping and fittings within a building shall be insulated to prevent condensation from forming on piping.

    M1412.4 Pressure-relief protection.

    Absorption systems shall be protected by a pressure-relief device. Discharge from the pressure-relief device shall be located where it will not create a hazard to persons or property.

    SECTIONM1413
    EVAPORATIVE COOLING EQUIPMENT

    M1413.1 General.

    Evaporative cooling equipment and appliances shall comply with UL 1995 or UL/CSA/ANCE 60335-2-40 and shall be installed:

    1. 1.In accordance with the manufacturer’s instructions.

    2. 2.On level platforms in accordance with Section M1305.1.4.1.

    3. 3.So that openings in exterior walls are flashed in accordance with Section R703.4.

    4. 4.So as to protect the potable water supply in accordance with Section P2902.

    5. 5.So that air intake opening locations are in accordance with Section R303.5.1.

    SECTIONM1414
    FIREPLACE STOVES

    M1414.1 General.

    Fireplace stoves shall be listed, labeled and installed in accordance with the terms of the listing. Fireplace stoves shall be tested in accordance with UL 737.

    M1414.2 Hearth extensions.

    Hearth extensions for fireplace stoves shall be installed in accordance with the listing of the fireplace stove. The supporting structure for a hearth extension for a fireplace stove shall be at the same level as the supporting structure for the fireplace unit. The hearth extension shall be readily distinguishable from the surrounding floor area.

    SECTIONM1415
    MASONRY HEATERS

    M1415.1 General.

    Masonry heaters shall be constructed in accordance with Section R1002.

    CHAPTER15
    EXHAUST SYSTEMS

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1501
    GENERAL

    M1501.1 Outdoor discharge.

    The air removed by every mechanical exhaust system shall be discharged to the outdoors in accordance with Section M1506.3. Air shall not be exhausted into an attic, soffit, ridge vent or crawl space.

    Exception: Whole-house ventilation-type attic fans that discharge into the attic space of dwelling units having private attics shall be permitted.

    SECTIONM1502
    CLOTHES DRYER EXHAUST

    M1502.1 General.

    Clothes dryers shall be exhausted in accordance with the manufacturer’s instructions.

    M1502.2 Independent exhaust systems.

    Dryer exhaust systems shall be independent of all other systems and shall convey the moisture to the outdoors.

    Exception: This section shall not apply to listed and labeled condensing (ductless) clothes dryers.

    M1502.3 Duct termination.

    Exhaust ducts shall terminate on the outside of the building. Exhaust duct terminations shall be in accordance with the dryer manufacturer’s installation instructions. If the manufacturer’s instructions do not specify a termination location, the exhaust duct shall terminate not less than 3 feet (914 mm) in any direction from openings into buildings. Exhaust duct terminations shall be equipped with a backdraft damper. Screens shall not be installed at the duct termination.

    M1502.4 Dryer exhaust ducts.

    Dryer exhaust ducts shall conform to the requirements of Sections M1502.4.1 through M1502.4.7.

    M1502.4.1 Material and size.

    Exhaust ducts shall have a smooth interior finish and be constructed of metal having a minimum thickness of 0.0157 inches (0.3950 mm) (No. 28 gage). The duct shall be 4 inches (102 mm) nominal in diameter.

    M1502.4.2 Duct installation.

    Exhaust ducts shall be supported at intervals not to exceed 12 feet (3658 mm) and shall be secured in place. The insert end of the duct shall extend into the adjoining duct or fitting in the direction of airflow. Exhaust duct joints shall be sealed in accordance with Section M1601.4.1 and shall be mechanically fastened. Ducts shall not be joined with screws or similar fasteners that protrude more than 1/8 inch (3.2 mm) into the inside of the duct.

    M1502.4.3 Transition duct.

    Transition ducts used to connect the dryer to the exhaust duct system shall be a single length that is listed and labeled in accordance with UL 2158A. Transition ducts shall be not greater than 8 feet (2438 mm) in length. Transition ducts shall not be concealed within construction.

    M1502.4.4 Dryer exhaust duct power ventilators.

    Domestic dryer exhaust duct power ventilators shall conform to UL 705 for use in dryer exhaust duct systems. The dryer exhaust duct power ventilator shall be installed in accordance with the manufacturer’s instructions.

    M1502.4.5 Duct length.

    The maximum allowable exhaust duct length shall be determined by one of the methods specified in Sections M1502.4.5.1 through M1502.4.5.3.

    M1502.4.5.1 Specified length.

    The maximum length of the exhaust duct shall be 35 feet (10 668 mm) from the connection to the transition duct from the dryer to the outlet terminal. Where fittings are used, the maximum length of the exhaust duct shall be reduced in accordance with Table M1502.4.5.1. The maximum length of the exhaust duct does not include the transition duct.

    TABLE M1502.4.5.1

    DRYER EXHAUST DUCT FITTING EQUIVALENT LENGTH

    DRYER EXHAUST DUCT FITTING TYPEEQUIVALENT LENGTH
    4 inch radius mitered 45 degree elbow2 feet 6 inches
    4 inch radius mitered 90 degree elbow5 feet
    6 inch radius smooth 45 degree elbow1 foot
    6 inch radius smooth 90 degree elbow1 foot 9 inches
    8 inch radius smooth 45 degree elbow1 foot
    8 inch radius smooth 90 degree elbow1 foot 7 inches
    10 inch radius smooth 45 degree elbow9 inches
    10 inch radius smooth 90 degree elbow1 foot 6 inches

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 degree = 0.0175 rad.

    M1502.4.5.2 Manufacturer’s instructions.

    The size and maximum length of the exhaust duct shall be determined by the dryer manufacturer’s installation instructions. The code official shall be provided with a copy of the installation instructions for the make and model of the dryer at the concealment inspection. In the absence of fitting equivalent length calculations from the clothes dryer manufacturer, Table M1502.4.5.1 shall be used.

    M1502.4.5.3 Dryer exhaust duct power ventilator.

    The maximum length of the exhaust duct shall be determined in accordance with the manufacturer’s instructions for the dryer exhaust duct power ventilator.

    M1502.4.6 Length identification.

    Where the exhaust duct equivalent length exceeds 35 feet (10 668 mm), the equivalent length of the exhaust duct shall be identified on a permanent label or tag. The label or tag shall be located within 6 feet (1829 mm) of the exhaust duct connection.

    M1502.4.7 Exhaust duct required.

    Where space for a clothes dryer is provided, an exhaust duct system shall be installed. Where the clothes dryer is not installed at the time of occupancy the exhaust duct shall be capped or plugged in the space in which it originates and identified and marked “future use.”

    Exception: Where a listed condensing clothes dryer is installed prior to occupancy of the structure.

    M1502.5 Protection required.

    Protective shield plates shall be placed where nails or screws from finish or other work are likely to penetrate the clothes dryer exhaust duct. Shield plates shall be placed on the finished face of framing members where there is less than 11/4 inches (32 mm) between the duct and the finished face of the framing member. Protective shield plates shall be constructed of steel, shall have a minimum thickness of 0.062-inch (1.6 mm) and shall extend not less than 2 inches (51 mm) above sole plates and below top plates.

    SECTIONM1503
    RANGE HOODS

    M1503.1 General.

    Range hoods shall discharge to the outdoors through a duct. The duct serving the hood shall have a smooth interior surface, shall be air tight, shall be equipped with a back-draft damper and shall be independent of all other exhaust systems. Ducts serving range hoods shall not terminate in an attic or crawl space or areas inside the building.

    Exception: Where installed in accordance with the manufacturer’s instructions, and where mechanical or natural ventilation is otherwise provided, listed and labeled ductless range hoods shall not be required to discharge to the outdoors.

    M1503.2 Duct material.

    Ducts serving range hoods shall be constructed of galvanized steel, stainless steel or copper.

    Exception: Ducts for domestic kitchen cooking appliances equipped with down-draft exhaust systems shall be permitted to be constructed of schedule 40 PVC pipe and fittings provided that the installation complies with all of the following:

    1. 1.The duct is installed under a concrete slab poured on grade.

    2. 2.The underfloor trench in which the duct is installed is completely backfilled with sand or gravel.

    3. 3.The PVC duct extends not more than 1 inch (25 mm) above the indoor concrete floor surface.

    4. 4.The PVC duct extends not more than 1 inch (25 mm) above grade outside of the building.

    5. 5.The PVC ducts are solvent cemented.

    M1503.3 Kitchen exhaust rates.

    Where domestic kitchen cooking appliances are equipped with ducted range hoods or down-draft exhaust systems, the fans shall be sized in accordance with Section M1507.4.

    M1503.4 Makeup air required.

    Exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (0.19 m3/s) shall be mechanically or naturally provided with makeup air at a rate approximately equal to the exhaust air rate. Such makeup air systems shall be equipped with not less than one damper. Each damper shall be a gravity damper or an electrically operated damper that automatically opens when the exhaust system operates. Dampers shall be accessible for inspection, service, repair and replacement without removing permanent construction or any other ducts not connected to the damper being inspected, serviced, repaired or replaced.

    M1503.4.1 Location.

    Kitchen exhaust makeup air shall be discharged into the same room in which the exhaust system is located or into rooms or duct systems that communicate through one or more permanent openings with the room in which such exhaust system is located. Such permanent openings shall have a net cross-sectional area not less than the required area of the makeup air supply openings.

    SECTIONM1504
    INSTALLATION OF MICROWAVE OVENS

    M1504.1 Installation of a microwave oven over a cooking appliance.

    The installation of a listed and labeled cooking appliance or microwave oven over a listed and labeled cooking appliance shall conform to the terms of the upper appliance’s listing and label and the manufacturer’s installation instructions. The microwave oven shall conform to UL 923.

    SECTIONM1505
    OVERHEAD EXHAUST HOODS

    M1505.1 General.

    Domestic open-top broiler units shall have a metal exhaust hood, having a minimum thickness of 0.0157-inch (0.3950 mm) (No. 28 gage) with 1/4 inch (6.4 mm) clearance between the hood and the underside of combustible material or cabinets. A clearance of not less than 24 inches (610 mm) shall be maintained between the cooking surface and the combustible material or cabinet. The hood shall be not less than the width of the broiler unit, extend over the entire unit, discharge to the outdoors and be equipped with a backdraft damper or other means to control infiltration/exfiltration when not in operation. Broiler units incorporating an integral exhaust system, and listed and labeled for use without an exhaust hood, need not have an exhaust hood.

    SECTIONM1506
    EXHAUST DUCTS AND EXHAUST OPENINGS

    M1506.1 Duct construction.

    Where exhaust duct construction is not specified in this chapter, construction shall comply with Chapter 16.

    M1506.2 Duct length.

    The length of exhaust and supply ducts used with ventilating equipment shall not exceed the lengths determined in accordance with Table M1506.2.

    Exception: Duct length shall not be limited where the duct system complies with the manufacturer’s design criteria or where the flow rate of the installed ventilating equipment is verified by the installer or approved third party using a flow hood, flow grid or other airflow measuring device.

    TABLE M1506.2

    DUCT LENGTH

    DUCT TYPEFLEX DUCTSMOOTH-WALL DUCT
    Fan airflow rating (CFM @ 0.25 inch wca)50801001251502002503005080100125150200250300
    Diameterb (inches)Maximum lengthc, d, e (feet)
    3XXXXXXXX5XXXXXXX
    4564XXXXXX1143110XXXXX
    5NL8142162XXXNL1529151284XX
    6NLNL1589155181XNLNLNL16811253259
    7NLNLNLNL161784019NLNLNLNLNL1488854
    8 and aboveNLNLNLNLNL18911169NLNLNLNLNLNL198133

    For SI: 1 foot = 304.8 mm.

    1. a.Fan airflow rating shall be in acordance with ANSI/AMCA 210-ANSI/ASHRAE 51.

    2. b.For noncircular ducts, calculate the diameter as four times the cross-sectional area divided by the perimeter.

    3. c.This table assumes that elbows are not used. Fifteen feet of allowable duct length shall be deducted for each elbow installed in the duct run.

    4. d.NL = no limit on duct length of this size.

    5. e.X = not allowed. Any length of duct of this size with assumed turns and fittings will exceed the rated pressure drop.

    M1506.3 Exhaust openings.

    Air exhaust openings shall terminate not less than 3 feet (914 mm) from property lines; 3 feet (914 mm) from operable and nonoperable openings into the building and 10 feet (3048 mm) from mechanical air intakes except where the opening is located 3 feet (914 mm) above the air intake. Openings shall comply with Sections R303.5.2 and R303.6.

    SECTIONM1507
    MECHANICAL VENTILATION

    M1507.1 General.

    Where local exhaust or whole-house mechanical ventilation is provided, the equipment shall be designed in accordance with this section.

    M1507.2 Recirculation of air.

    Exhaust air from bathrooms and toilet rooms shall not be recirculated within a residence or to another dwelling unit and shall be exhausted directly to the outdoors. Exhaust air from bathrooms and toilet rooms shall not discharge into an attic, crawl space or other areas inside the building.

    M1507.3 Whole-house mechanical ventilation system.

    Whole-house mechanical ventilation systems shall be designed in accordance with Sections M1507.3.1 through M1507.3.3.

    M1507.3.1 System design.

    The whole-house ventilation system shall consist of one or more supply or exhaust fans, or a combination of such, and associated ducts and controls. Local exhaust or supply fans are permitted to serve as such a system. Outdoor air ducts connected to the return side of an air handler shall be considered as providing supply ventilation.

    M1507.3.2 System controls.

    The whole-house mechanical ventilation system shall be provided with controls that enable manual override.

    M1507.3.3 Mechanical ventilation rate.

    The whole-house mechanical ventilation system shall provide outdoor air at a continuous rate of not less than that determined in accordance with Table M1507.3.3(1).

    Exception: The whole-house mechanical ventilation system is permitted to operate intermittently where the system has controls that enable operation for not less than 25-percent of each 4-hour segment and the ventilation rate prescribed in Table M1507.3.3(1) is multiplied by the factor determined in accordance with Table M1507.3.3(2).

    TABLE M1507.3.3(1)

    CONTINUOUS WHOLE-HOUSE MECHANICAL VENTILATION SYSTEM AIRFLOW RATE REQUIREMENTS

    DWELLING UNIT FLOOR AREA (square feet)NUMBER OF BEDROOMS
    0 - 12 - 34 - 56 - 7> 7
    Airflow in CFM
    < 1,5003045607590
    1,501 - 3,00045607590105
    3,001 - 4,500607590105120
    4,501 - 6,0007590105120135
    6,001 - 7,50090105120135150
    > 7,500105120135150165

    For SI: 1 square foot = 0.0929 m2, 1 cubic foot per minute = 0.0004719 m3/s.

    TABLE M1507.3.3(2)

    INTERMITTENT WHOLE-HOUSE MECHANICAL VENTILATION RATE FACTORSa, b

    RUN-TIME PERCENTAGE IN EACH 4-HOUR SEGMENT25%33%50%66%75%100%
    Factora4321.51.31.0
    1. a.For ventilation system run time values between those given, the factors are permitted to be determined by interpolation.

    2. b.Extrapolation beyond the table is prohibited.

    M1507.4 Local exhaust rates.

    Local exhaust systems shall be designed to have the capacity to exhaust the minimum air flow rate determined in accordance with Table M1507.4.

    TABLE M1507.4

    MINIMUM REQUIRED LOCAL EXHAUST RATES FOR ONE- AND TWO-FAMILY DWELLINGS

    AREA TO BE EXHAUSTEDEXHAUST RATES
    Kitchens100 cfm intermittent or 25 cfm continuous
    Bathrooms-Toilet RoomsMechanical exhaust capacity of 50 cfm intermittent or 20 cfm continuous

    For SI: 1 cubic foot per minute = 0.0004719 m3/s.

    CHAPTER16
    DUCT SYSTEMS  

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1601
    DUCT CONSTRUCTION  

    M1601.1 Duct design.

    Duct systems serving heating, cooling and ventilation equipment shall be installed in accordance with the provisions of this section and ACCA Manual D, the appliance manufacturer’s installation instructions or other approved methods.

    M1601.1.1 Above-ground duct systems.

    Above-ground duct systems shall conform to the following:

    1. 1.Equipment connected to duct systems shall be designed to limit discharge air temperature to not greater than 250°F (121°C).

    2. 2.Factory-made ducts shall be listed and labeled in accordance with UL 181 and installed in accordance with the manufacturer’s instructions.

    3. 3.Fibrous glass duct construction shall conform to the SMACNA Fibrous Glass Duct Construction Standards or NAIMA Fibrous Glass Duct Construction Standards.

    4. 4.Field-fabricated and shop-fabricated metal and flexible duct constructions shall conform to the SMACNA HVAC Duct Construction Standards—Metal and Flexible except as allowed by Table M1601.1.1. Galvanized steel shall conform to ASTM A 653.

    5. 5.The use of gypsum products to construct return air ducts or plenums is permitted, provided that the air temperature does not exceed 125°F (52°C) and exposed surfaces are not subject to condensation.

    6. 6.Duct systems shall be constructed of materials having a flame spread index of not greater than 200.

    7. 7.Stud wall cavities and the spaces between solid floor joists to be used as air plenums shall comply with the following conditions:

      1. 7.1.These cavities or spaces shall not be used as a plenum for supply air.

      2. 7.2.These cavities or spaces shall not be part of a required fire-resistance-rated assembly.

      3. 7.3.Stud wall cavities shall not convey air from more than one floor level.

      4. 7.4.Stud wall cavities and joist-space plenums shall be isolated from adjacent concealed spaces by tight-fitting fireblocking in accordance with Section R602.8.

      5. 7.5.Stud wall cavities in the outside walls of building envelope assemblies shall not be utilized as air plenums.

    TABLE M1601.1.1

    DUCT CONSTRUCTION MINIMUM SHEET METAL THICKNESS FOR SINGLE DWELLING UNITSa

    ROUND DUCT DIAMETER (inches)STATIC PRESSURE
    1/2 inch water gage1 inch water gage
    Thickness (inches)Thickness (inches)
    GalvanizedAluminumGalvanizedAluminum
    ≤ 120.0130.0180.0130.018
    12 to 140.0130.0180.0160.023
    15 to 170.0160.0230.0190.027
    180.0160.0230.0240.034
    19 to 200.0190.0270.0240.034
    RECTANGULAR DUCT DIMENSION (inches)STATIC PRESSURE
    1/2 inch water gage1 inch water gage
    Thickness (inches)Thickness (inches)
    GalvanizedAluminumGalvanizedAluminum
    ≤ 80.0130.0180.0130.018
    9 to 100.0130.0180.0160.023
    11 to 120.0160.0230.0190.027
    13 to 160.0190.0270.0190.027
    17 to 180.0190.0270.0240.034
    19 to 200.0240.0340.0240.034

    For SI: 1 inch = 25.4 mm, 1 inch water gage = 249 Pa.

    1. a.Ductwork that exceeds 20 inches by dimension or exceeds a pressure of 1 inch water gage (250 Pa) shall be constructed in accordance with SMACNA HVAC Duct Construction Standards—Metal and Flexible.

    M1601.1.2 Underground duct systems.

    Underground duct systems shall be constructed of approved concrete, clay, metal or plastic. The maximum duct temperature for plastic ducts shall not be greater than 150°F (66°C). Metal ducts shall be protected from corrosion in an approved manner or shall be completely encased in concrete not less than 2 inches (51 mm) thick. Nonmetallic ducts shall be installed in accordance with the manufacturer’s instructions. Plastic pipe and fitting materials shall conform to cell classification 12454-B of ASTM D 1248 or ASTM D 1784 and external loading properties of ASTM D 2412. Ducts shall slope to an accessible point for drainage. Where encased in concrete, ducts shall be sealed and secured prior to any concrete being poured. Metallic ducts having an approved protective coating and nonmetallic ducts shall be installed in accordance with the manufacturer’s instructions.

    M1601.2 Vibration isolators.

    Vibration isolators installed between mechanical equipment and metal ducts shall be fabricated from approved materials and shall not exceed 10 inches (254 mm) in length.

    M1601.3 Duct insulation materials.

    Duct insulation materials shall conform to the following requirements:

    1. 1.Duct coverings and linings, including adhesives where used, shall have a flame spread index not higher than 25, and a smoke-developed index not over 50 when tested in accordance with ASTM E 84 or UL 723, using the specimen preparation and mounting procedures of ASTM E 2231.

      Exception: Spray application of polyurethane foam to the exterior of ducts in attics and crawl spaces shall be permitted subject to all of the following:

      1. 1.The flame spread index is not greater than 25 and the smoke-developed index is not greater than 450 at the specified installed thickness.

      2. 2.The foam plastic is protected in accordance with the ignition barrier requirements of Sections R316.5.3 and R316.5.4.

      3. 3.The foam plastic complies with the requirements of Section R316.

    2. 2.Duct coverings and linings shall not flame, glow, smolder or smoke when tested in accordance with ASTM C 411 at the temperature to which they are exposed in service. The test temperature shall not fall below 250°F (121°C). Coverings and linings shall be listed and labeled.

    3. 3.External reflective duct insulation shall be legibly printed or identified at intervals not greater than 36 inches (914 mm) with the name of the manufacturer, the product R-value at the specified installed thickness and the flame spread and smoke-developed indices. The installed thickness of the external duct insulation shall include the enclosed air space(s). The product R-value for external reflective duct insulation shall be determined in accordance with ASTM C1668.

    4. 4.External duct insulation and factory-insulated flexible ducts shall be legibly printed or identified at intervals not longer than 36 inches (914 mm) with the name of the manufacturer, the thermal resistance R-value at the specified installed thickness and the flame spread and smoke-developed indexes of the composite materials. Spray polyurethane foam manufacturers shall provide the same product information and properties, at the nominal installed thickness, to the customer in writing at the time of foam application. Nonreflective duct insulation product R-values shall be based on insulation only, excluding air films, vapor retarders or other duct components, and shall be based on tested C-values at 75°F (24°C) mean temperature at the installed thickness, in accordance with recognized industry procedures. The installed thickness of duct insulation used to determine its R-value shall be determined as follows:

      1. 4.1.For duct board, duct liner and factory-made rigid ducts not normally subjected to compression, the nominal insulation thickness shall be used.

      2. 4.2.For ductwrap, the installed thickness shall be assumed to be 75 percent (25-percent compression) of nominal thickness.

      3. 4.3.For factory-made flexible air ducts, The installed thickness shall be determined by dividing the difference between the actual outside diameter and nominal inside diameter by two.

      4. 4.4.For spray polyurethane foam, the aged R-value per inch measured in accordance with recognized industry standards shall be provided to the customer in writing at the time of foam application. In addition, the total R-value for the nominal application thickness shall be provided.

    M1601.4 Installation.

    Duct installation shall comply with Sections M1601.4.1 through M1601.4.10.

    M1601.4.1 Joints, seams and connections.

    Longitudinal and transverse joints, seams and connections in metallic and nonmetallic ducts shall be constructed as specified in SMACNA HVAC Duct Construction Standards—Metal and Flexible and NAIMA Fibrous Glass Duct Construction Standards. Joints, longitudinal and transverse seams, and connections in ductwork shall be securely fastened and sealed with welds, gaskets, mastics (adhesives), mastic-plus-embedded-fabric systems, liquid sealants or tapes. Tapes and mastics used to seal fibrous glass ductwork shall be listed and labeled in accordance with UL 181A and shall be marked “181A-P” for pressure-sensitive tape, “181 A-M” for mastic or “181 A-H” for heat-sensitive tape.

    Tapes and mastics used to seal metallic and flexible air ducts and flexible air connectors shall comply with UL 181B and shall be marked “181 B-FX” for pressure-sensitive tape or “181 BM” for mastic. Duct connections to flanges of air distribution system equipment shall be sealed and mechanically fastened. Mechanical fasteners for use with flexible nonmetallic air ducts shall comply with UL 181B and shall be marked 181B-C. Crimp joints for round metallic ducts shall have a contact lap of not less than 1 inch (25 mm) and shall be mechanically fastened by means of not less than three sheet-metal screws or rivets equally spaced around the joint.

    Closure systems used to seal all ductwork shall be installed in accordance with the manufacturers’ instructions.

    Exceptions:

    1. 1.Spray polyurethane foam shall be permitted to be applied without additional joint seals.

    2. 2.Where a duct connection is made that is partially inaccessible, three screws or rivets shall be equally spaced on the exposed portion of the joint so as to prevent a hinge effect.

    3. 3.For ducts having a static pressure classification of less than 2 inches of water column (500 Pa), additional closure systems shall not be required for continuously welded joints and seams and locking-type joints and seams of other than the snap-lock and button-lock types.

    M1601.4.2 Duct lap.

    Crimp joints for round and oval metal ducts shall be lapped not less than 1 inch (25 mm) and the male end of the duct shall extend into the adjoining duct in the direction of airflow.

    M1601.4.3 Plastic duct joints.

    Joints between plastic ducts and plastic fittings shall be made in accordance with the manufacturer’s installation instructions.

    M1601.4.4 Support.

    Factory-made ducts listed in accordance with UL 181 shall be supported in accordance with the manufacturer’s installation instructions. Field- and shop-fabricated fibrous glass ducts shall be supported in accordance with the SMACNA Fibrous Glass Duct Construction Standards or the NAIMA Fibrous Glass Duct Construction Standards. Field- and shop-fabricated metal and flexible ducts shall be supported in accordance with the SMACNA HVAC Duct Construction Standards—Metal and Flexible.

    M1601.4.5 Fireblocking.

    Duct installations shall be fireblocked in accordance with Section R602.8.

    M1601.4.6 Duct insulation.

    Duct insulation shall be installed in accordance with the following requirements:

    1. 1.A vapor retarder having a maximum permeance of 0.05 perm [2.87 ng/(s · m2 · Pa)] in accordance with ASTM E 96, or aluminum foil with a minimum thickness of 2 mils (0.05 mm), shall be installed on the exterior of insulation on cooling supply ducts that pass through unconditioned spaces conducive to condensation except where the insulation is spray polyurethane foam with a maximum water vapor permeance of 3 perm per inch [1722 ng/(s · m2 · Pa)] at the installed thickness.

    2. 2.Exterior duct systems shall be protected against the elements.

    3. 3.Duct coverings shall not penetrate a fireblocked wall or floor.

    M1601.4.7 Factory-made air ducts.

    Factory-made air ducts shall not be installed in or on the ground, in tile or metal pipe, or within masonry or concrete.

    M1601.4.8 Duct separation.

    Ducts shall be installed with not less than 4 inches (102 mm) separation from earth except where they meet the requirements of Section M1601.1.2.

    M1601.4.9 Ducts located in garages.

    Ducts in garages shall comply with the requirements of Section R302.5.2.

    M1601.4.10 Flood hazard areas.

    In flood hazard areas as established by Table R301.2(1), duct systems shall be located or installed in accordance with Section R322.1.6.

    M1601.5 Under-floor plenums.

    Under-floor plenums shall be prohibited in new structures. Modification or repairs to under-floor plenums in existing structures shall conform to the requirements of this section.

    M1601.5.1 General.

    The space shall be cleaned of loose combustible materials and scrap, and shall be tightly enclosed. The ground surface of the space shall be covered with a moisture barrier having a minimum thickness of 4 mils (0.1 mm). Plumbing waste cleanouts shall not be located within the space.

    Exception: Plumbing waste cleanouts shall be permitted to be located in unvented crawl spaces that receive conditioned air in accordance with Section R408.3.

    M1601.5.2 Materials.

    The under-floor space, including the sidewall insulation, shall be formed by materials having flame spread index values not greater than 200 when tested in accordance with ASTM E 84 or UL 723.

    M1601.5.3 Furnace connections.

    A duct shall extend from the furnace supply outlet to not less than 6 inches (152 mm) below the combustible framing. This duct shall comply with the provisions of Section M1601.1. A noncombustible receptacle shall be installed below any floor opening into the plenum in accordance with the following requirements:

    1. 1.The receptacle shall be securely suspended from the floor members and shall be not more than 18 inches (457 mm) below the floor opening.

    2. 2.The area of the receptacle shall extend 3 inches (76 mm) beyond the opening on all sides.

    3. 3.The perimeter of the receptacle shall have a vertical lip not less than 1 inch (25 mm) in height at the open sides.

    M1601.5.4 Access.

    Access to an under-floor plenum shall be provided through an opening in the floor with minimum dimensions of 18 inches by 24 inches (457 mm by 610 mm).

    M1601.5.5 Furnace controls.

    The furnace shall be equipped with an automatic control that will start the air-circulating fan when the air in the furnace bonnet reaches a temperature not higher than 150°F (66°C). The furnace shall additionally be equipped with an approved automatic control that limits the outlet air temperature to 200°F (93°C).

    M1601.6 Independent garage HVAC systems.

    Furnaces and air-handling systems that supply air to living spaces shall not supply air to or return air from a garage.

    SECTIONM1602
    RETURN AIR

    M1602.1 Outdoor air openings.

    Outdoor intake openings shall be located in accordance with Section R303.5.1. Opening protection shall be in accordance with Section R303.6

    M1602.2 Return air openings.

    Return air openings for heating, ventilation and air conditioning systems shall comply with all of the following:

    1. 1.Openings shall not be located less than 10 feet (3048 mm) measured in any direction from an open combustion chamber or draft hood of another appliance located in the same room or space.

    2. 2.The amount of return air taken from any room or space shall be not greater than the flow rate of supply air delivered to such room or space.

    3. 3.Return and transfer openings shall be sized in accordance with the appliance or equipment manufacturers’ installation instructions, Manual D or the design of the registered design professional.

    4. 4.Return air shall not be taken from a closet, bathroom, toilet room, kitchen, garage, mechanical room, boiler room, furnace room or unconditioned attic.

      Exceptions:

      1. 1.Taking return air from a kitchen is not prohibited where such return air openings serve the kitchen only, and are located not less than 10 feet (3048 mm) from the cooking appliances.

      2. 2.Dedicated forced-air systems serving only the garage shall not be prohibited from obtaining return air from the garage.

    5. 5.Taking return air from an unconditioned crawl space shall not be accomplished through a direct connection to the return side of a forced-air furnace. Transfer openings in the crawl space enclosure shall not be prohibited.

    6. 6.Return air from one dwelling unit shall not be discharged into another dwelling unit.

    CHAPTER17
    COMBUSTION AIR

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1701
    GENERAL

    M1701.1 Scope.

    Solid fuel-burning appliances shall be provided with combustion air in accordance with the appliance manufacturer’s installation instructions. Oil-fired appliances shall be provided with combustion air in accordance with NFPA 31. The methods of providing combustion air in this chapter do not apply to fireplaces, fireplace stoves and direct-vent appliances. The requirements for combustion and dilution air for gas-fired appliances shall be in accordance with Chapter 24.

    M1701.2 Opening location.

    In flood hazard areas as established in Table R301.2(1), combustion air openings shall be located at or above the elevation required in Section R322.2.1 or R322.3.2.

    CHAPTER18
    CHIMNEYS AND VENTS  

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1801
    GENERAL

    M1801.1 Venting required.

    Fuel-burning appliances shall be vented to the outdoors in accordance with their listing and label and manufacturer’s installation instructions except appliances listed and labeled for unvented use. Venting systems shall consist of approved chimneys or vents, or venting assemblies that are integral parts of labeled appliances. Gas-fired appliances shall be vented in accordance with Chapter 24.

    M1801.2 Draft requirements.

    A venting system shall satisfy the draft requirements of the appliance in accordance with the manufacturer’s installation instructions, and shall be constructed and installed to develop a positive flow to convey combustion products to the outside atmosphere.

    M1801.3 Existing chimneys and vents.

    Where an appliance is permanently disconnected from an existing chimney or vent, or where an appliance is connected to an existing chimney or vent during the process of a new installation, the chimney or vent shall comply with Sections M1801.3.1 through M1801.3.4.

    M1801.3.1 Size.

    The chimney or vent shall be resized as necessary to control flue gas condensation in the interior of the chimney or vent and to provide the appliance, or appliances served, with the required draft. For the venting of oil-fired appliances to masonry chimneys, the resizing shall be done in accordance with NFPA 31.

    M1801.3.2 Flue passageways.

    The flue gas passageway shall be free of obstructions and combustible deposits and shall be cleaned if previously used for venting a solid or liquid fuel-burning appliance or fireplace. The flue liner, chimney inner wall or vent inner wall shall be continuous and free of cracks, gaps, perforations, or other damage or deterioration that would allow the escape of combustion products, including gases, moisture and creosote.

    M1801.3.3 Cleanout.

    Masonry chimneys shall be provided with a cleanout opening complying with Section R1003.17.

    M1801.3.4 Clearances.

    Chimneys and vents shall have airspace clearance to combustibles in accordance with this code and the chimney or vent manufacturer’s installation instructions.

    Exception: Masonry chimneys equipped with a chimney lining system tested and listed for installation in chimneys in contact with combustibles in accordance with UL 1777, and installed in accordance with the manufacturer’s instructions, shall not be required to have a clearance between combustible materials and exterior surfaces of the masonry chimney. Noncombustible firestopping shall be provided in accordance with this code.

    M1801.4 Space around lining.

    The space surrounding a flue lining system or other vent installed within a masonry chimney shall not be used to vent any other appliance. This shall not prevent the installation of a separate flue lining in accordance with the manufacturer’s installation instructions and this code.

    M1801.5 Mechanical draft systems.

    A mechanical draft system shall be used only with appliances listed and labeled for such use. Provisions shall be made to prevent the flow of fuel to the equipment when the draft system is not operating. Forced draft systems and portions of induced draft systems under positive pressure during operation shall be designed and installed to prevent leakage of flue gases into a building.

    M1801.6 Direct-vent appliances.

    Direct-vent appliances shall be installed in accordance with the manufacturer’s instructions.

    M1801.7 Support.

    Venting systems shall be adequately supported for the weight of the material used.

    M1801.8 Duct penetrations.

    Chimneys, vents and vent connectors shall not extend into or through supply and return air ducts or plenums.

    M1801.9 Fireblocking.

    Vent and chimney installations shall be fireblocked in accordance with Section R602.8.

    M1801.10 Unused openings.

    Unused openings in any venting system shall be closed or capped.

    M1801.11 Multiple-appliance venting systems.

    Two or more listed and labeled appliances connected to a common natural draft venting system shall comply with the following requirements:

    1. 1.Appliances that are connected to common venting systems shall be located on the same floor of the dwelling.

      Exception: Engineered systems as provided for in Section G2427.

    2. 2.Inlets to common venting systems shall be offset such that no portion of an inlet is opposite another inlet.

    3. 3.Connectors serving appliances operating under a natural draft shall not be connected to any portion of a mechanical draft system operating under positive pressure.

    M1801.12 Multiple solid fuel prohibited.

    A solid fuel-burning appliance or fireplace shall not connect to a chimney passageway venting another appliance.

    SECTIONM1802
    VENT COMPONENTS  

    M1802.1 Draft hoods.

    Draft hoods shall be located in the same room or space as the combustion air openings for the appliances.

    M1802.2 Vent dampers.

    Vent dampers shall comply with Sections M1802.2.1 and M1802.2.2.

    M1802.2.1 Manually operated.

    Manually operated dampers shall not be installed except in connectors or chimneys serving solid fuel-burning appliances.

    M1802.2.2 Automatically operated.

    Automatically operated dampers shall conform to UL 17 and be installed in accordance with the terms of their listing and label. The installation shall prevent firing of the burner when the damper is not opened to a safe position.

    M1802.3Draft regulators.

    Draft regulators shall be provided for oil-fired appliances that must be connected to a chimney. Draft regulators provided for solid fuel-burning appliances to reduce draft intensity shall be installed and set in accordance with the manufacturer’s installation instructions.

    M1802.3.1 Location.

    Where required, draft regulators shall be installed in the same room or enclosure as the appliance so that a difference in pressure will not exist between the air at the regulator and the combustion air supply.

    SECTIONM1803
    CHIMNEY AND VENT CONNECTORS

    M1803.1 General.

    Connectors shall be used to connect fuel-burning appliances to a vertical chimney or vent except where the chimney or vent is attached directly to the appliance.

    M1803.2 Connectors for oil and solid fuel appliances.

    Connectors for oil and solid fuel-burning appliances shall be constructed of factory-built chimney material, Type L vent material or single-wall metal pipe having resistance to corrosion and heat and thickness not less than that of galvanized steel as specified in Table M1803.2.

    TABLE M1803.2

    THICKNESS FOR SINGLE-WALL METAL PIPE CONNECTORS

    DIAMETER OF CONNECTOR (inches)GALVANIZED SHEET METAL GAGE NUMBERMINIMUM THICKNESS (inch)
    Less than 6260.019
    6 to 10240.024
    Over 10 through 16220.029

    For SI: 1 inch = 25.4 mm.

    M1803.3 Installation.

    Vent and chimney connectors shall be installed in accordance with the manufacturer’s instructions and within the space where the appliance is located. Appliances shall be located as close as practical to the vent or chimney. Connectors shall be as short and straight as possible and installed with a slope of not less than 1/4 inch (6 mm) rise per foot of run. Connectors shall be securely supported and joints shall be fastened with sheet metal screws or rivets. Devices that obstruct the flow of flue gases shall not be installed in a connector unless listed and labeled or approved for such installations.

    M1803.3.1 Floor, ceiling and wall penetrations.

    A chimney connector or vent connector shall not pass through any floor or ceiling. A chimney connector or vent connector shall not pass through a wall or partition unless the connector is listed and labeled for wall pass-through, or is routed through a device listed and labeled for wall pass-through and is installed in accordance with the conditions of its listing and label. Connectors for oil-fired appliances listed and labeled for Type L vents, passing through walls or partitions shall be in accordance with the following:

    1. 1.Type L vent material for oil appliances shall be installed with not less than listed and labeled clearances to combustible material.

    2. 2.Single-wall metal pipe shall be guarded by a ventilated metal thimble not less than 4 inches (102 mm) larger in diameter than the vent connector. A minimum 6 inches (152 mm) of clearance shall be maintained between the thimble and combustibles.

    M1803.3.2 Length.

    The horizontal run of an uninsulated connector to a natural draft chimney shall not exceed 75 percent of the height of the vertical portion of the chimney above the connector. The horizontal run of a listed connector to a natural draft chimney shall not exceed 100 percent of the height of the vertical portion of the chimney above the connector.

    M1803.3.3 Size.

    A connector shall not be smaller than the flue collar of the appliance.

    Exception: Where installed in accordance with the appliance manufacturer’s instructions.

    M1803.3.4 Clearance.

    Connectors shall be installed with clearance to combustibles as set forth in Table M1803.3.4. Reduced clearances to combustible materials shall be in accordance with Table M1306.2 and Figure M1306.1.

    TABLE M1803.3.4

    CHIMNEY AND VENT CONNECTOR CLEARANCES TO COMBUSTIBLE MATERIALSa

    TYPE OF CONNECTORMINIMUM CLEARANCE (inches)
    Single-wall metal pipe connectors:
    Oil and solid-fuel appliances18
    Oil appliances listed for use with Type L vents9
    Type L vent piping connectors:
    Oil and solid-fuel appliances9
    Oil appliances listed for use with Type L vents3b

    For SI: 1 inch = 25.4 mm.

    1. a.These minimum clearances apply to unlisted single-wall chimney and vent connectors. Reduction of required clearances is permitted as in Table M1306.2.

    2. b.Where listed Type L vent piping is used, the clearance shall be in accordance with the vent listing.

    M1803.3.5 Access.

    The entire length of a connector shall be accessible for inspection, cleaning and replacement.

    M1803.4 Connection to fireplace flue.

    Connection of appliances to chimney flues serving fireplaces shall comply with Sections M1803.4.1 through M1803.4.4.

    M1803.4.1 Closure and accessibility.

    A noncombustible seal shall be provided below the point of connection to prevent entry of room air into the flue. Means shall be provided for access to the flue for inspection and cleaning.

    M1803.4.2 Connection to factory-built fireplace flue.

    A different appliance shall not be connected to a flue serving a factory-built fireplace unless the appliance is specifically listed for such an installation. The connection shall be made in conformance with the appliance manufacturer’s instructions.

    M1803.4.3 Connection to masonry fireplace flue.

    A connector shall extend from the appliance to the flue serving a masonry fireplace to convey the flue gases directly into the flue. The connector shall be accessible or removable for inspection and cleaning of both the connector and the flue. Listed direct-connection devices shall be installed in accordance with their listing.

    M1803.4.4 Size of flue.

    The size of the fireplace flue shall be in accordance with Section M1805.3.1.

    SECTIONM1804
    VENTS

    M1804.1 Type of vent required.

    Appliances shall be provided with a listed and labeled venting system as set forth in Table M1804.1.

    TABLE M1804.1

    VENT SELECTION CHART

    VENT TYPESAPPLIANCE TYPES
    Type L oil ventsOil-burning appliances listed and labeled for venting with Type L vents
    Pellet ventsPellet fuel-burning appliances listed and labeled for use with pellet vents

    M1804.2 Termination.

    Vent termination shall comply with Sections M1804.2.1 through M1804.2.6.

    M1804.2.1 Through the roof.

    Vents passing through a roof shall extend through flashing and terminate in accordance with the manufacturer’s installation requirements.

    M1804.2.2 Decorative shrouds.

    Decorative shrouds shall not be installed at the termination of vents except where the shrouds are listed and labeled for use with the specific venting system and are installed in accordance with the manufacturer’s instructions.

    M1804.2.3 Natural draft appliances.

    Vents for natural draft appliances shall terminate not less than 5 feet (1524 mm) above the highest connected appliance outlet, and natural draft gas vents serving wall furnaces shall terminate at an elevation not less than 12 feet (3658 mm) above the bottom of the furnace.

    M1804.2.4 Type L vent.

    Type L venting systems shall conform to UL 641 and shall terminate with a listed and labeled cap in accordance with the vent manufacturer’s installation instructions not less than 2 feet (610 mm) above the roof and not less than 2 feet (610 mm) above any portion of the building within 10 feet (3048 mm).

    M1804.2.5 Direct vent terminations.

    Vent terminals for direct-vent appliances shall be installed in accordance with the manufacturer’s instructions.

    M1804.2.6 Mechanical draft systems.

    Mechanical draft systems shall comply with UL 378 and shall be installed in accordance with their listing, the manufacturer’s instructions and, except for direct-vent appliances, the following requirements:

    1. 1.The vent terminal shall be located not less than 3 feet (914 mm) above a forced air inlet located within 10 feet (3048 mm).

    2. 2.The vent terminal shall be located not less than 4 feet (1219 mm) below, 4 feet (1219 mm) horizontally from, or 1 foot (305 mm) above any door, window or gravity air inlet into a dwelling.

    3. 3.The vent termination point shall be located not closer than 3 feet (914 mm) to an interior corner formed by two walls perpendicular to each other.

    4. 4.The bottom of the vent terminal shall be located not less than 12 inches (305 mm) above finished ground level.

    5. 5.The vent termination shall not be mounted directly above or within 3 feet (914 mm) horizontally of an oil tank vent or gas meter.

    6. 6.Power exhauster terminations shall be located not less than 10 feet (3048 mm) from lot lines and adjacent buildings.

    7. 7.The discharge shall be directed away from the building.

    M1804.3 Installation.

    Type L and pellet vents shall be installed in accordance with the terms of their listing and label and the manufacturer’s instructions.

    M1804.3.1 Size of single-appliance venting systems.

    An individual vent for a single appliance shall have a cross-sectional area equal to or greater than the area of the connector to the appliance, but not less than 7 square inches (4515 mm2) except where the vent is an integral part of a listed and labeled appliance.

    M1804.4 Door swing.

    Appliance and equipment vent terminals shall be located such that doors cannot swing within 12 inches (305 mm) horizontally of the vent terminals. Door stops or closers shall not be installed to obtain this clearance.

    SECTIONM1805
    MASONRY AND FACTORY-BUILT CHIMNEYS

    M1805.1 General.

    Masonry and factory-built chimneys shall be built and installed in accordance with Sections R1003 and R1005, respectively. Flue lining for masonry chimneys shall comply with Section R1003.11.

    M1805.2 Masonry chimney connection.

    A chimney connector shall enter a masonry chimney not less than 6 inches (152 mm) above the bottom of the chimney. Where it is not possible to locate the connector entry at least 6 inches (152 mm) above the bottom of the chimney flue, a cleanout shall be provided by installing a capped tee in the connector next to the chimney. A connector entering a masonry chimney shall extend through, but not beyond, the wall and shall be flush with the inner face of the liner. Connectors, or thimbles where used, shall be firmly cemented into the masonry.

    M1805.3 Size of chimney flues.

    The effective area of a natural draft chimney flue for one appliance shall be not less than the area of the connector to the appliance. The area of chimney flues connected to more than one appliance shall be not less than the area of the largest connector plus 50 percent of the areas of additional chimney connectors.

    Exception: Chimney flues serving oil-fired appliances sized in accordance with NFPA 31.

    M1805.3.1 Size of chimney flue for solid-fuel appliance.

    Except where otherwise specified in the manufacturer’s installation instructions, the cross-sectional area of a flue connected to a solid-fuel-burning appliance shall be not less than the area of the flue collar or connector, and not larger than three times the area of the flue collar.

    CHAPTER19
    SPECIAL APPLIANCES, EQUIPMENT AND SYSTEMS

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM1901
    RANGES AND OVENS

    M1901.1 Clearances.

    Freestanding or built-in ranges shall have a vertical clearance above the cooking top of not less than 30 inches (762 mm) to unprotected combustible material. Reduced clearances are permitted in accordance with the listing and labeling of the range hoods or appliances. The installation of a listed and labeled cooking appliance or microwave oven over a listed and labeled cooking appliance shall be in accordance with Section M1504.1. The clearances for a domestic open-top broiler unit shall be in accordance with Section M1505.1.

    M1901.2 Cooking appliances.

    Cooking appliances shall be listed and labeled for household use and shall be installed in accordance with the manufacturer’s instructions. The installation shall not interfere with combustion air or access for operation and servicing. Electric cooking appliances shall comply with UL 1026 or UL 858. Solid-fuel-fired fireplace stoves shall comply with UL 737.

    SECTIONM1902
    SAUNA HEATERS

    M1902.1 Locations and protection.

    Sauna heaters shall be protected from accidental contact by persons with a guard of material having a low thermal conductivity, such as wood. The guard shall not have a substantial effect on the transfer of heat from the heater to the room.

    M1902.2 Installation.

    Sauna heaters shall be installed in accordance with the manufacturer’s instructions. Sauna heaters shall comply with UL 875.

    M1902.3 Combustion air.

    Combustion air and venting for a nondirect vent-type heater shall be provided in accordance with Chapters 17 and 18, respectively.

    M1902.4 Controls.

    Sauna heaters shall be equipped with a thermostat that will limit room temperature to not greater than 194°F (90°C). Where the thermostat is not an integral part of the heater, the heat-sensing element shall be located within 6 inches (152 mm) of the ceiling.

    SECTIONM1903
    STATIONARY FUEL CELL POWER PLANTS

    M1903.1 General.

    Stationary fuel cell power plants having a power output not exceeding 1,000 kW, shall comply with ANSI/CSA America FC 1 and shall be installed in accordance with the manufacturer’s instructions and NFPA 853.

    SECTIONM1904
    GASEOUS HYDROGEN SYSTEMS

    M1904.1 Installation.

    Gaseous hydrogen systems shall be installed in accordance with the applicable requirements of Sections M1307.4 and M1903.1 and the International Fuel Gas Code, the International Fire Code and the International Building Code.

    CHAPTER20
    BOILERS AND WATER HEATERS

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM2001
    BOILERS

    M2001.1 Installation.

    In addition to the requirements of this code, the installation of boilers shall conform to the manufacturer’s instructions. The manufacturer’s rating data, the name-plate and operating instructions of a permanent type shall be attached to the boiler. Boilers shall have their controls set, adjusted and tested by the installer. A complete control diagram together with complete boiler operating instructions shall be furnished by the installer. Solid and liquid fuel-burning boilers shall be provided with combustion air as required by Chapter 17.

    M2001.1.1 Standards.

    Packaged oil-fired boilers shall be listed and labeled in accordance with UL 726. Packaged electric boilers shall be listed and labeled in accordance with UL 834. Solid fuel-fired boilers shall be listed and labeled in accordance with UL 2523. Boilers shall be designed, constructed and certified in accordance with the ASME Boiler and Pressure Vessel Code, Section I or IV. Controls and safety devices for boilers with fuel input ratings of 12,500,000 Btu/hr (3 663 388 watts) or less shall meet the requirements of ASME CSD-1. Gas-fired boilers shall conform to the requirements listed in Chapter 24.

    M2001.2 Clearance.

    Boilers shall be installed in accordance with their listing and label.

    M2001.3 Valves.

    Every boiler or modular boiler shall have a shutoff valve in the supply and return piping. For multiple boiler or multiple modular boiler installations, each boiler or modular boiler shall have individual shutoff valves in the supply and return piping.

    Exception: Shutoff valves are not required in a system having a single low-pressure steam boiler.

    M2001.4 Flood-resistant installation.

    In flood hazard areas established in Table R301.2(1), boilers, water heaters and their control systems shall be located or installed in accordance with Section R322.1.6.

    SECTIONM2002
    OPERATING AND SAFETY CONTROLS

    M2002.1 Safety controls.

    Electrical and mechanical operating and safety controls for boilers shall be listed and labeled.

    M2002.2 Hot water boiler gauges.

    Every hot water boiler shall have a pressure gauge and a temperature gauge, or combination pressure and temperature gauge. The gauges shall indicate the temperature and pressure within the normal range of the system’s operation.

    M2002.3 Steam boiler gauges.

    Every steam boiler shall have a water-gauge glass and a pressure gauge. The pressure gauge shall indicate the pressure within the normal range of the system’s operation. The gauge glass shall be installed so that the midpoint is at the normal water level.

    M2002.4 Pressure-relief valve.

    Boilers shall be equipped with pressure-relief valves with minimum rated capacities for the equipment served. Pressure-relief valves shall be set at the maximum rating of the boiler. Discharge shall be piped to drains by gravity to within 18 inches (457 mm) of the floor or to an open receptor.

    M2002.5 Boiler low-water cutoff.

    Steam and hot water boilers shall be protected with a low-water cutoff control.

    Exception: A low-water cutoff is not required for coil-type and water-tube type boilers that require forced circulation of water through the boiler and that are protected with a flow sensing control.

    M2002.6 Operation.

    Low-water cutoff controls and flow sensing controls required by Section M2002.5 shall automatically stop the combustion operation of the appliance when the water level drops below the lowest safe water level as established by the manufacturer or when the water circulation flow is less than that required for safe operation of the appliance, respectively.

    SECTIONM2003
    EXPANSION TANKS

    M2003.1 General.

    Hot water boilers shall be provided with expansion tanks. Nonpressurized expansion tanks shall be securely fastened to the structure or boiler and supported to carry twice the weight of the tank filled with water. Provisions shall be made for draining nonpressurized tanks without emptying the system.

    M2003.1.1 Pressurized expansion tanks.

    Pressurized expansion tanks shall be consistent with the volume and capacity of the system. Tanks shall be capable of withstanding a hydrostatic test pressure of two and one-half times the allowable working pressure of the system.

    M2003.2 Minimum capacity.

    The minimum capacity of expansion tanks shall be determined from Table M2003.2.

    TABLE M2003.2

    EXPANSION TANK MINIMUM CAPACITYa FOR FORCED HOT-WATER SYSTEMS

    SYSTEM VOLUMEb (gallons)PRESSURIZED DIAPHRAGM TYPENONPRESSURIZED TYPE
    101.01.5
    201.53.0
    302.54.5
    403.06.0
    504.07.5
    605.09.0
    706.010.5
    806.512.0
    907.513.5
    1008.015.0

    For SI: 1 gallon = 3.785 L, 1 pound per square inch gauge = 6.895 kPa, °C = [(°F)-32]/1.8.

    1. a.Based on average water temperature of 195°F (91°C), fill pressure of 12 psig and a maximum operating pressure of 30 psig.

    2. b.System volume includes volume of water in boiler, convectors and piping, not including the expansion tank.

    SECTIONM2004
    WATER HEATERS USED FOR SPACE HEATING

    M2004.1 General.

    Water heaters used to supply both potable hot water and hot water for space heating shall be installed in accordance with this chapter, Chapter 24, Chapter 28 and the manufacturer’s instructions.

    SECTIONM2005
    WATER HEATERS

    M2005.1 General.

    Water heaters shall be installed in accordance with Chapter 28, the manufacturer’s instructions and the requirements of this code. Water heaters installed in an attic shall comply with the requirements of Section M1305.1.3. Gas-fired water heaters shall comply with the requirements in Chapter 24. Domestic electric water heaters shall comply with UL 174. Oiled-fired water heaters shall comply with UL 732. Thermal solar water heaters shall comply with Chapter 23 and UL 174. Solid fuel-fired water heaters shall comply with UL 2523.

    M2005.2 Prohibited locations.

    Fuel-fired water heaters shall not be installed in a room used as a storage closet. Water heaters located in a bedroom or bathroom shall be installed in a sealed enclosure so that combustion air will not be taken from the living space. Installation of direct-vent water heaters within an enclosure is not required.

    M2005.2.1 Water heater access.

    Access to water heaters that are located in an attic or underfloor crawl space is permitted to be through a closet located in a sleeping room or bathroom where ventilation of those spaces is in accordance with this code.

    M2005.3 Electric water heaters.

    Electric water heaters shall also be installed in accordance with the applicable provisions of Chapters 34 through 43.

    M2005.4 Supplemental water-heating devices.

    Potable water heating devices that use refrigerant-to-water heat exchangers shall be approved and installed in accordance with the manufacturer’s instructions.

    SECTIONM2006
    POOL HEATERS

    M2006.1 General.

    Pool and spa heaters shall be installed in accordance with the manufacturer’s installation instructions. Oil-fired pool heaters shall comply with UL 726. Electric pool and spa heaters shall comply with UL 1261.

    M2006.2 Clearances.

    The clearances shall not interfere with combustion air, draft hood or flue terminal relief, or accessibility for servicing.

    M2006.3 Temperature-limiting devices.

    Pool heaters shall have temperature-relief valves.

    M2006.4 Bypass valves.

    Where an integral bypass system is not provided as a part of the pool heater, a bypass line and valve shall be installed between the inlet and outlet piping for use in adjusting the flow of water through the heater.

    CHAPTER21
    HYDRONIC PIPING  

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM2101
    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 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

    MATERIALUSECODEaSTANDARDbJOINTSNOTES
    Acrylonitrile butadiene styrene(ABS) plastic pipe1, 5ASTM D 1527;ASTM F 2806;ASTM F 2969Solvent cement joints
    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 tubing1, 2, 3ASTM D 2846Solvent cement joints, compression joints and threaded adapters
    Copper pipe1ASTM B 42,B 302Brazed, soldered and mechanical fittings threaded, welded and flanged
    Copper tubing (type K, L or M)1, 2ASTM B 75,B 88, B 251,B 306Brazed, soldered and flared mechanical fittingsJoints 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 pipe1, 2ASTM F 1281 orCAN/ CSA B137.10Mechanical, crimp/insertInstall in accordance with manufacturer’s instructions
    PEX fittingsASTM F 877ASTM F 1807ASTM F 1960ASTM F 2098ASTM F 2159ASTM F 2735Copper-crimp/insert fittings, cold expansion fittings, stainless steel clamp, insert fittingsInstall in accordance with manufacturer’s instructions
    Polybutylene (PB) pipe and tubing1, 2, 3ASTM D 3309Heat-fusion, crimp/insert and compressionJoints in concrete shall be heat-fused
    Polyethylene/aluminum/polyethylene (PE-AL-PE) pressure pipe1, 2, 3ASTM F 1282CSA B 137.9Mechanical, crimp/insert
    Polypropylene (PP)1, 2, 3ISO 15874ASTM F 2389Heat-fusion joints, mechanical fittings, threaded adapters, compression joints
    Raised temperature polyethylene (PE-RT)1, 2, 3ASTM F 2623ASTM F 2769Copper crimp/insert fitting stainless steel clamp, insert fittings
    Raised temperature polyethylene (PE-RT) fittings1, 2, 3ASTM F 1807ASTM F 2159ASTM F 2735ASTM F 2769ASTM F 2098Copper crimp/insert fitting stainless steel clamp, insert fittings
    Steel pipe1, 2ASTM A 53,A 106Brazed, 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.

    1. a.Use code:

      1. 1.Above ground.

      2. 2.Embedded in radiant systems.

      3. 3.Temperatures below 180°F only.

      4. 4.Low temperature (below 130°F) applications only.

      5. 5.Temperatures below 160°F only.

    2. 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 R505.2.6, 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.

    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 MATERIALMAXIMUMHORIZONTAL SPACING (feet)MAXIMUMVERTICAL SPACING (feet)
    ABS410a
    CPVC ≤ 1-inch pipe or tubing35a
    CPVC ≥ 11/4 inches410a
    Copper or copper alloy pipe1210
    Copper or copper alloy tubing610
    PB pipe or tubing2.674
    PE pipe or tubing2.674
    PE-RT ≤ 1 inch2.6710a
    PE-RT ≥ 11/4 inches410a
    PEX tubing2.674
    PP < 1-inch pipe or tubing2.674
    PP > 11/4 inches410a
    PVC410a
    Steel pipe1215
    Steel tubing810

    For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

    1. 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.

    M2101.10 Tests.

    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.

    SECTIONM2102
    BASEBOARD CONVECTORS

    M2102.1 General.

    Baseboard convectors shall be installed in accordance with the manufacturer’s instructions. Convectors shall be supported independently of the hydronic piping.

    SECTIONM2103
    FLOOR HEATING SYSTEMS

    M2103.1 Piping materials.

    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).

    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.

    Copper and copper alloy systems shall be soldered in accordance with ASTM B 828. Fluxes for soldering shall be in accordance with ASTM B 813. Brazing fluxes shall be in accordance with AWS A5.31. Piping joints that are embedded shall be installed in accordance with the following requirements:

    1. 1.Steel pipe joints shall be welded.

    2. 2.Copper tubing shall be joined by brazing complying with Section P3003.6.1.

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

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

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

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

    7. 7.Raised temperature polyethylene (PE-RT) tubing shall be joined using 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, the joints shall be visually inspected for leaks.

    SECTIONM2104
    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. 1.Cross-linked polyethylene (PEX) tubing shall be installed in accordance with the manufacturer’s instructions.

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

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

    4. 4.Raised temperature polyethylene (PE-RT) shall be installed in accordance with the manufacturer’s instructions.

    M2104.3 Raised temperature polyethylene (PE-RT) plastic tubing.

    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.

    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.

    M2104.3.3 PE-RT insert fittings.

    PE-RT insert fittings shall be installed in accordance with the manufacturer’s instructions.

    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.

    SECTIONM2105
    GROUND-SOURCE HEAT-PUMP
    SYSTEM LOOP PIPING
     

    M2105.1 Plastic ground-source heat-pump loop piping.

    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 Used materials.

    Reused pipe, fittings, valves, and other materials shall not be used in ground-source heat-pump loop systems.

    M2105.3 Material rating.

    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 Piping and tubing materials standards.

    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

    MATERIALSTANDARD
    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 pipeASTM 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 Fittings.

    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 MATERIALSTANDARD
    Chlorinated polyvinyl chloride (CPVC)ASTM D 2846; ASTM F 437; ASTM F 438; ASTM F 439;ASTM F 1970; CSA B 137.6
    Cross-linked polyethylene(PEX)ASTM F 877; ASTM F 1807; ASTM F 1960; ASTM F 2080;ASTM F 2159; ASTM F 2434; CSA B 137.5
    Polyethylene/aluminum/polyethylene(PE-AL-PE)ASTM F 2434; ASTM F 1282; CSA B 137.9
    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 B 137.2; CSA B 137.3
    Raised temperature polyethylene(PE-RT)ASTM D 3261; ASTM F 1807; ASTM F 2159; F 2769; B 137.1

    M2105.6 Joints and connections.

    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 Joints between different piping materials.

    Joints between different piping materials shall be made with approved transition fittings.

    M2105.7 Preparation of pipe ends.

    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 Joint preparation and installation.

    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 Mechanical joints.

    Mechanical joints shall be installed in accordance with the manufacturer’s instructions.

    M2105.8.2 Thermoplastic-welded joints.

    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 CPVC plastic pipe.

    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.

    M2105.9.1 Threaded joints.

    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 Cross-linked polyethylene (PEX) plastic tubing.

    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 Compression-type fittings.

    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 Plastic-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 plastic pipe or tubing.

    M2105.11 Polyethylene plastic pipe and tubing.

    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 Heat-fusion joints.

    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 Electrofusion joints.

    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 Stab-type insert fittings.

    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 Polypropylene (PP) plastic.

    Joints between PP plastic pipe and fittings shall comply with Sections M2105.12.1 and M2105.12.2.

    M2105.12.1 Heat-fusion joints.

    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 Mechanical and compression sleeve joints.

    Mechanical and compression sleeve joints shall be installed in accordance with the manufacturer’s instructions.

    M2105.13 Raised temperature polyethylene (PE-RT) plastic tubing.

    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 Compression-type fittings.

    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 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 or tubing.

    M2105.14 PVC plastic pipe.

    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 Shutoff valves.

    Shutoff valves shall be installed in ground-source loop piping systems in the locations indicated in Sections M2105.15.1 through M2105.15.6.

    M2105.15.1 Heat exchangers.

    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.

    M2105.15.2 Central systems.

    Shutoff valves shall be installed on the building supply and return of a central utility system.

    M2105.15.3 Pressure vessels.

    Shutoff valves shall be installed on the connection to any pressure vessel.

    M2105.15.4 Pressure-reducing valves.

    Shutoff valves shall be installed on both sides of a pressure-reducing valve.

    M2105.15.5 Equipment and appliances.

    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.

    M2105.15.6 Expansion tanks.

    Shutoff valves shall be installed at connections to nondiaphragm-type expansion tanks.

    M2105.16 Reduced pressure.

    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 Installation.

    Piping, valves, fittings, and connections shall be installed in accordance with the manufacturer’s instructions.

    M2105.18 Protection of potable water.

    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 Pipe penetrations.

    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 Clearance from combustibles.

    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 Contact with building material.

    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 Strains and stresses.

    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.

    M2105.22.1 Flood hazard.

    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 Pipe support.

    Pipe shall be supported in accordance with Section M2101.9.

    M2105.24 Velocities.

    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 Labeling and marking.

    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 Chemical compatibility.

    Antifreeze and other materials used in the system shall be chemically compatible with the pipe, tubing, fittings and mechanical systems.

    M2105.27 Makeup water.

    The transfer fluid shall be compatible with the makeup water supplied to the system.

    M2105.28 Testing.

    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 Embedded piping.

    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.

    CHAPTER22
    SPECIAL PIPING AND STORAGE SYSTEMS

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM2201
    OIL TANKS

    M2201.1 Materials.

    Supply tanks shall be listed and labeled and shall conform to UL 58 for underground tanks and UL 80 for indoor tanks.

    M2201.2 Above-ground tanks.

    The maximum amount of fuel oil stored above ground or inside of a building shall be 660 gallons (2498 L). The supply tank shall be supported on rigid noncombustible supports to prevent settling or shifting.

    Exception: The storage of fuel oil, used for space or water heating, above ground or inside buildings in quantities exceeding 660 gallons (2498 L) shall comply with NFPA 31.

    M2201.2.1 Tanks within buildings.

    Supply tanks for use inside of buildings shall be of such size and shape to permit installation and removal from dwellings as whole units. Supply tanks larger than 10 gallons (38 L) shall be placed not less than 5 feet (1524 mm) from any fire or flame either within or external to any fuel-burning appliance.

    M2201.2.2 Outside above-ground tanks.

    Tanks installed outside above ground shall be a minimum of 5 feet (1524 mm) from an adjoining property line. Such tanks shall be suitably protected from the weather and from physical damage.

    M2201.3 Underground tanks.

    Excavations for underground tanks shall not undermine the foundations of existing structures. The clearance from the tank to the nearest wall of a basement, pit or property line shall be not less than 1 foot (305 mm). Tanks shall be set on and surrounded with noncorrosive inert materials such as clean earth, sand or gravel well tamped in place. Tanks shall be covered with not less than 1 foot (305 mm) of earth. Corrosion protection shall be provided in accordance with Section M2203.7.

    M2201.4 Multiple tanks.

    Cross connection of two supply tanks shall be permitted in accordance with Section M2203.6.

    M2201.5 Oil gauges.

    Inside tanks shall be provided with a device to indicate when the oil in the tank has reached a predetermined safe level. Glass gauges or a gauge subject to breakage that could result in the escape of oil from the tank shall not be used. Liquid-level indicating gauges shall comply with UL 180.

    M2201.6 Flood-resistant installation.

    In flood hazard areas as established by Table R301.2(1), tanks shall be installed in accordance with Section R322.2.4 or R322.3.7.

    M2201.7 Tanks abandoned or removed.

    Exterior above-grade fill piping shall be removed when tanks are abandoned or removed. Tank abandonment and removal shall be in accordance with the International Fire Code.

    SECTIONM2202
    OIL PIPING, FITTING AND CONNECTIONS

    M2202.1 Materials.

    Piping shall consist of steel pipe, copper and copper alloy pipe and tubing or steel tubing conforming to ASTM A 539. Aluminum tubing shall not be used between the fuel-oil tank and the burner units.

    M2202.2 Joints and fittings.

    Piping shall be connected with standard fittings compatible with the piping material. Cast iron fittings shall not be used for oil piping. Unions requiring gaskets or packings, right or left couplings, and sweat fittings employing solder having a melting point less than 1,000°F (538°C) shall not be used for oil piping. Threaded joints and connections shall be made tight with a lubricant or pipe thread compound.

    M2202.3 Flexible connectors.

    Flexible metallic hoses shall be listed and labeled in accordance with UL 536 and shall be installed in accordance with their listing and labeling and the manufacturer’s installation instructions. Connectors made from combustible materials shall not be used inside of buildings or above ground outside of buildings.

    SECTIONM2203
    INSTALLATION

    M2203.1 General.

    Piping shall be installed in a manner to avoid placing stresses on the piping, and to accommodate expansion and contraction of the piping system.

    M2203.2 Supply piping.

    Supply piping used in the installation of oil burners and appliances shall be not smaller than 3/8-inch (9 mm) pipe or 3/8-inch (9 mm) outside diameter tubing. Copper tubing and fittings shall be a minimum of Type L.

    M2203.3 Fill piping.

    Fill piping shall terminate outside of buildings at a point not less than 2 feet (610 mm) from any building opening at the same or lower level. Fill openings shall be equipped with a tight metal cover.

    M2203.4 Vent piping.

    Vent piping shall be not smaller than 11/4-inch (32 mm) pipe. Vent piping shall be laid to drain toward the tank without sags or traps in which the liquid can collect. Vent pipes shall not be cross connected with fill pipes, lines from burners or overflow lines from auxiliary tanks. The lower end of a vent pipe shall enter the tank through the top and shall extend into the tank not more than 1 inch (25 mm).

    M2203.5 Vent termination.

    Vent piping shall terminate outside of buildings at a point not less than 2 feet (610 mm), measured vertically or horizontally, from any building opening. Outer ends of vent piping shall terminate in a weather-proof cap or fitting having an unobstructed area at least equal to the cross-sectional area of the vent pipe, and shall be located sufficiently above the ground to avoid being obstructed by snow and ice.

    M2203.6 Cross connection of tanks.

    Cross connection of two supply tanks, not exceeding 660 gallons (2498 L) aggregate capacity, with gravity flow from one tank to another, shall be acceptable providing that the two tanks are on the same horizontal plane.

    M2203.7 Corrosion protection.

    Underground tanks and buried piping shall be protected by corrosion-resistant coatings or special alloys or fiberglass-reinforced plastic.

    SECTIONM2204
    OIL PUMPS AND VALVES

    M2204.1 Pumps.

    Oil pumps shall be positive displacement types that automatically shut off the oil supply when stopped. Automatic pumps shall be listed and labeled in accordance with UL 343 and shall be installed in accordance with their listing.

    M2204.2 Shutoff valves.

    A readily accessible manual shutoff valve shall be installed between the oil supply tank and the burner. Where the shutoff valve is installed in the discharge line of an oil pump, a pressure-relief valve shall be incorporated to bypass or return surplus oil. Valves shall comply with UL 842.

    M2204.3 Maximum pressure.

    Pressure at the oil supply inlet to an appliance shall be not greater than 3 pounds per square inch (20.7 kPa).

    M2204.4 Relief valves.

    Fuel-oil lines incorporating heaters shall be provided with relief valves that will discharge to a return line when excess pressure exists.

    CHAPTER23
    SOLAR THERMAL ENERGY SYSTEMS

    User note: Code change proposals to this chapter will be considered by the IRC – Plumbing and Mechanical Code
    Development Committee during the 2015 (Group A) Code Development Cycle. See explanation on page iv.

    SECTIONM2301
    THERMAL SOLAR ENERGY SYSTEMS

    M2301.1 General.

    This section provides for the design, construction, installation, alteration and repair of equipment and systems using thermal solar energy to provide space heating or cooling, hot water heating and swimming pool heating.

    M2301.2 Design and installation.

    The design and installation of thermal solar energy systems shall comply with Sections M2301.2.1 through M2301.2.13.

    M2301.2.1 Access.

    Solar energy collectors, controls, dampers, fans, blowers and pumps shall be accessible for inspection, maintenance, repair and replacement.

    M2301.2.2 Collectors and panels.

    Solar collectors and panels shall comply with Sections M2301.2.2.1 and M2301.2.2.2.

    M2301.2.2.1 Roof-mounted collectors.

    The roof shall be constructed to support the loads imposed by roof-mounted solar collectors. Roof-mounted solar collectors that serve as a roof covering shall conform to the requirements for roof coverings in Chapter 9 of this code. Where mounted on or above the roof coverings, the collectors and supporting structure shall be constructed of noncombustible materials or fire-retardant-treated wood equivalent to that required for the roof construction.

    M2301.2.2.2 Collector sensors.

    Collector sensor installation, sensor location and the protection of exposed sensor wires from ultraviolet light shall be in accordance with SRCC 300.

    M2301.2.3 Pressure and temperature relief valves and system components.

    System components containing fluids shall be protected with temperature and pressure relief valves or pressure relief valves. Relief devices shall be installed in sections of the system so that a section cannot be valved off or isolated from a relief device. Direct systems and the potable water portion of indirect systems shall be equipped with a relief valve in accordance with Section P2804. For indirect systems, pressure relief valves in solar loops shall comply with SRCC 300. System components shall have a working pressure rating of not less than the setting of the pressure relief device.

    M2301.2.4 Vacuum relief.

    System components that might be subjected to pressure drops below atmospheric pressure during operation or shutdown shall be protected by a vacuum-relief valve.

    M2301.2.5 Piping insulation.

    Piping shall be insulated in accordance with the requirements of Chapter 11. Exterior insulation shall be protected from ultraviolet degradation. The entire solar loop shall be insulated. Where split-style insulation is used, the seam shall be sealed. Fittings shall be fully insulated.

    Exceptions:

    1. 1.Those portions of the piping that are used to help prevent the system from overheating shall not be required to be insulated.

    2. 2.Those portions of piping that are exposed to solar radiation, made of the same material as the solar collector absorber plate and are covered in the same manner as the solar collector absorber, or that are used to collect additional solar energy, shall not be required to be insulated.

    3. 3.Piping in thermal solar systems using unglazed solar collectors to heat a swimming pool shall not be required to be insulated.

    M2301.2.6 Protection from freezing.

    System components shall be protected from damage resulting from freezing of heat-transfer liquids at the winter design temperature provided in Table R301.2(1). Freeze protection shall be provided by heating, insulation, thermal mass and heat transfer fluids with freeze points lower than the winter design temperature, heat tape or other approved methods, or combinations thereof.

    Exception: Where the winter design temperature is greater than 32°F (0°C).

    M2301.2.7 Storage tank sensors.

    Storage tank sensors shall comply with SRCC 300.

    M2301.2.8 Expansion tanks.

    Expansion tanks in solar energy systems shall be installed in accordance with Section M2003 in solar collector loops that contain pressurized heat transfer fluid. Where expansion tanks are used, the system shall be designed in accordance with SRCC 300 to provide an expansion tank that is sized to withstand the maximum operating pressure of the system.

    Exception: Expansion tanks shall not be required in drain-back systems.

    M2301.2.9 Roof and wall penetrations.

    Roof and wall penetrations shall be flashed and sealed in accordance with Chapter 9 of this code to prevent entry of water, rodents and insects.

    M2301.2.10 Description and warning labels.

    Solar thermal systems shall comply with description label and warning label requirements of Section M2301.2.11.2 and SRCC 300.

    M2301.2.11 Solar loop.

    Solar loops shall be in accordance with Sections M2301.2.11.1 and M2301.2.11.2.

    M2301.2.11.1 Solar loop isolation.

    Valves shall be installed to allow the solar collectors to be isolated from the remainder of the system.

    M2301.2.11.2 Drain and fill valve labels and caps.

    Drain and fill valves shall be labeled with a description and warning that identifies the fluid in the solar loop and a warning that the fluid might be discharged at high temperature and pressure. Drain caps shall be installed at drain and fill valves.

    M2301.2.12 Maximum temperature limitation.

    Systems shall be equipped with means to limit the maximum water temperature of the system fluid entering or exchanging heat with any pressurized vessel inside the dwelling to 180°F (82°C). This protection is in addition to the required temperature- and pressure-relief valves required by Section M2301.2.3.

    M2301.2.13 Thermal storage unit seismic bracing.

    In Seismic Design Categories D0, D1 and D2 and in town-houses in Seismic Design Category C, thermal storage units shall be anchored in accordance with Section M1307.2.

    M2301.3 Labeling.

    Labeling shall comply with Sections M2301.3.1 and M2301.3.2.

    M2301.3.1 Collectors and panels.

    Solar thermal collectors and panels shall be listed and labeled in accordance with SRCC 100 or SRCC 600. Collectors and panels shall be listed and labeled to show the manufacturer’s name, model number, serial number, collector weight, collector maximum allowable temperatures and pressures, and the type of heat transfer fluids that are compatible with the collector or panel. The label shall clarify that these specifications apply only to the collector or panel.

    M2301.3.2 Thermal storage units.

    Pressurized thermal storage units shall be listed and labeled to show the manufacturer’s name, model number, serial number, storage unit maximum and minimum allowable operating temperatures and pressures, and the type of heat transfer fluids that are compatible with the storage unit. The label shall clarify that these specifications apply only to the thermal storage unit.

    M2301.4 Heat transfer gasses or liquids and heat exchangers.

    Essentially toxic transfer fluids, ethylene glycol, flammable gases and flammable liquids shall not be used as heat transfer fluids. Heat transfer gasses and liquids shall be rated to withstand the system’s maximum design temperature under operating conditions without degradation. Heat exchangers used in solar thermal systems shall comply with Section P2902.5.2 and SRCC 300.

    Heat transfer fluids shall be in accordance with SRCC 300. The flash point of the heat transfer fluids utilized in solar thermal systems shall be not less than 50°F (28°C) above the design maximum nonoperating or no-flow temperature attained by the fluid in the collector.

    M2301.5 Backflow protection.

    Connections from the potable water supply to solar systems shall comply with Section P2902.5.5.

    M2301.6 Filtering.

    Air provided to occupied spaces that passes through thermal mass storage systems by mechanical means shall be filtered for particulates at the outlet of the thermal mass storage system.

    M2301.7 Solar thermal systems for heating potable water.

    Where a solar thermal system heats potable water to supply a potable hot water distribution system, the solar thermal system shall be in accordance with Sections M2301.7.1, M2301.7.2 and P2902.5.5.

    M2301.7.1 Indirect systems.

    Heat exchangers that are components of indirect solar thermal heating systems shall comply with Section P2902.5.2.

    M2301.7.2 Direct systems.

    Where potable water is directly heated by a solar thermal system, the pipe, fittings, valves and other components that are in contact with the potable water in the solar heating system shall comply with the requirements of Chapter 29.