S-13 - Piping and Cross-connection Control For Solar Thermal Systems.  


Latest version.
  • S-13.1   Cross Connection Control.

    No piping installation, or part thereof, shall be made in such a manner that it will be possible for used, unclean, polluted, or contaminated water, mixtures, or substances to enter a portion of the potable water system from a pipe, tank, receptor, or any other equipment by reason of backsiphonage, suction, or any other cause, either during normal use and operation thereof, or where such pipe, tank, receptor, or equipment is subject to pressure exceeding the operating pressure in the potable water system.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.2   Materials.

    S-13.2.1   Piping Materials.

    Piping, tubing and fittings materials shall comply with Table S-13.2. Joining methods shall be in accordance with Section 605.0. Materials in contact with the heat transfer medium shall be approved for such use. Galvanized steel shall not be used for solar thermal piping systems containing antifreeze. Black steel shall not be used in systems with entrained air. Unions between dissimilar metals shall comply with Sections 310.6 and 605.15. The material used shall be capable of withstanding the maximum temperature and pressure of the system.

    (Ord. 2016-0055 § 20, 2016: Ord. 2013-0050 § 22, 2013.)

    S-13.2.1.1   Adhesives.

    Adhesives used in a solar collector shall not vaporize at the design temperature.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.2.1.2   Potable Water.

    Materials in contact with potable water shall comply with NSF 61.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.2.1.3   Racks.

    Dissimilar metals used for racking shall be isolated to prevent galvanic corrosion. Paint shall not be used as a method of isolation.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.2.2   Screwed Fittings.

    Screwed fittings shall be ABS, cast-iron, copper, copper alloy, malleable iron, PVC, steel, stainless steel or other approved materials. Threads shall be tapped out of solid metal or molded in solid ABS or PVC.

    (Ord. 2013-0050 § 22, 2013.)

    S-13.2.3   Storage Tank Connectors.

    Flexible metallic storage tank connectors or reinforced flexible storage tank connectors connecting a storage tank to the piping system shall be in accordance with the applicable standards (ASME A112.18.6-2009/CSA B 125.6-2009 (R2014)). Copper or stainless steel flexible connectors shall not exceed 24 inches (610 mm). PEX, PE-AL-PE, or PE-RT tubing shall not be installed within the first 18 inches (457 mm) of piping connected to a storage tank.

    (Ord. 2016-0055 § 20, 2016: Ord. 2013-0050 § 22, 2013.)

    S-13.2.3.1   Flexible Connectors.

    Listed flexible connectors shall be installed in readily accessible locations, unless otherwise indicated in the listing.

    (Ord. 2013-0050 § 22, 2013.)

    TABLE S-13.2
    MATERIALS FOR SOLAR THERMAL SYSTEM, PIPING, TUBING, AND FITTINGS

    MATERIAL PIPING/TUBING FITTINGS
    Copper/Copper Alloy ASTM B42, ASTM B43, ASTM B75, ASTM B88, ASTM B135, ASTM B251 , ASTM B302, ASTM B447 ASME B16.15, ASME B16.18, ASME B16.22, ASME B16.23, ASME B16.24, ASME B16.26, ASME B16.29, ASME B16.51
    Ductile Iron AWWA C115, AWWA C151 AWWA C110 , AWWA C153
    Steel ASTM A53, ASTM A106, ASTM A254 ASME B16.5, ASME B16.9, ASME B16.11, ASTM A420
    Gray Iron ASTM A126
    Malleable Iron ASME B16.3
    Acrylonitrile Butadiene Styrene (ABS) ASTM D1527
    Chlorinated Polyvinyl Chloride (CPVC) ASTM D2846, ASTM F441, ASTM F442 ASTM D2846, ASTM F437, ASTM F438, ASTM F439, ASTM F1970
    Polyethylene (PE) ASTM D1693, ASTM D2513, ASTM D2683, ASTM D2837, ASTM D3035, ASTM D3350, ASTM F1055, CSA B137.1 ASTM D2609, ASTM D2683, ASTM D3261, ASTM F1055, CSA B137.1
    Cross-Linked Polyethylene (PEX) ASTM F876, ASTM F877, CSA B137.5 ASSE 1061, ASTM F877, ASTM F1807, ASTM F1960, ASTM F1961, ASTM F2080, ASTM F2159, ASTM F2735, CSA B137.5
    Polypropylene (PP) ASTM F2389 ASTM F2389
    Polyvinyl Chloride (PVC) ASTM D1785, ASTM D2241 ASTM D2464, ASTM D2466, ASTM D2467, ASTM F1970
    Raised Temperature Polyethylene (PE-RT) ASTM F2623, ASTM F2769 ASTM F1807, ASTM F2159, ASTM F2735, ASTM F2769
    Cross-Linked Polyethylene/Aluminum/Cross-Linked Polyethylene (PEX-AL-PEX) ASTM F1281, ASTM F2262, CSA B137.10 ASTM F1281, ASTM F1974, ASTM F2434, CSA B137.10
    Polyethylene/Aluminum/Polyethylene (PE-AL-PE) ASTM F1282, CSA B137.9 ASTM F1282, ASTM F1974, CSA B137.9
    Stainless Steel ASTM A269, ASTM A312

     

    Notes:

    Ductile and gray iron.

    Only Type K, L, or M shall be permitted to be installed.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.3   Safety Devices.

    S-13.3.1   Pressure Relief Valves.

    Solar thermal energy system components containing pressurized fluids shall be protected against pressures exceeding design limitations with a pressure relief valve. Each section of the system in which excessive pressures are capable of developing shall have a relief device located so that a section cannot be isolated from a relief device. Pressure and temperature relief valves shall be installed in accordance with the terms of their listing and the manufacturer's installation instructions.

    (Ord. 2016-0055 § 20, 2016: Ord. 2013-0050 § 22, 2013.)

    S-13.3.2   Pressurized Vessels.

    Pressurized vessels shall be provided with overpressure protection by means of a listed pressure relief valve installed in accordance with the manufacturer's installation instructions.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.3.3   Discharge Piping.

    The discharge piping serving a temperature relief valve, pressure relief valve, or combination of both shall have no valves, obstructions, or means of isolation and shall comply with the following:

    (1)

    The discharge pipe shall equal the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and shall point downward;

    (2)

    Materials shall be rated at not less than the operating temperature of the system and approved for such use;

    (3)

    The discharge pipe shall discharge independently by gravity through an air gap into the drainage system or outside of the building with the end of the pipe not exceeding 2 feet (610 mm) and not less than 6 inches (152 mm) above the ground and pointing downward;

    (4)

    The discharge pipe shall discharge in such a manner that does not cause personal injury or structural damage;

    (5)

    No part of such discharge pipe shall be trapped or subject to freezing;

    (6)

    The terminal end of the pipe shall not be threaded; and

    (7)

    Discharge from a relief valve into a water heater pan is prohibited.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.3.4   Vacuum Relief Valves.

    System components that are subjected to a vacuum while in operation or during shutdown shall be protected with vacuum relief valves. Where the piping configuration, equipment location, and valve outlets are located below the storage tank elevation, the system shall be equipped with a vacuum relief valve at the highest point.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.3.5   Temperature Regulation.

    Where a system is capable of providing potable water at temperatures that exceed 140°F (60°C), a thermostatic mixing valve that is in accordance with ASSE 1017 shall be provided to limit the water supplied to the potable hot water distribution system to a temperature of 140°F (60°C) or less.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4   Protection of System Components.

    S-13.4.1   Materials.

    System components in contact with heat-transfer mediums shall be approved for such use. Components installed outdoors shall be resistant to ultraviolet radiation.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.2   Corrosion.

    Solar thermal energy systems and components subject to corrosion shall be protected in an approved manner. Metal parts exposed to atmospheric conditions shall be of corrosion-resistant material.

    (Ord. 2016-0055 § 20, 2016: Ord. 2013-0050 § 22, 2013.)

    S-13.4.3   Mechanical Damage.

    Portions of a solar thermal energy system installed where subjected to mechanical damage shall be guarded against such damage by being installed behind approved barriers or, where located within a garage, by being elevated or located out of the normal path of a vehicle.

    (Ord. 2016-0055 § 20, 2016: Ord. 2013-0050 § 22, 2013.)

    S-13.4.4   Freeze Protection.

    Unless designed for such conditions, solar thermal systems and components that contain liquid as the heat transfer medium shall be protected from freezing, by means of fail-safe freeze protection in accordance with this Section, where the ambient temperature may be less than 46°F (8°C).

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.4.1   Antifreeze.

    Antifreeze shall be used in accordance with the solar thermal system manufacturer's instructions.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.4.2   Drainback.

    Drainback systems shall drain by gravity and shall be permitted to be installed in applications where the ambient temperature may not be less than -60°F (-51°C).

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.4.3   Integral Collector Storage.

    Integral collector storage systems shall be permitted to be installed in applications where the ambient temperature may not be less than 23°F (-5°C) and the duration of below-freezing episodes exceeding 18 hours. Exposed piping in a solar thermal system shall be protected with insulation having a thermal resistance of not less than R-5.0.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.4.4   Indirect Thermosiphon.

    Indirect thermosiphon systems shall be permitted to be installed in applications where the ambient temperature may not be less than 23°F (-5°C). Exposed piping in a solar thermal system shall be protected with insulation having a thermal resistance of not less than R-5.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.4.5   Air Heating Systems.

    Air solar heating systems shall be permitted to be used in accordance with the manufacturer's instructions.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.4.6   Labeling.

    A label indicating the method of freeze protection for the system shall be attached to the system in a visible location.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.4.7   Piping.

    Fittings, pipe slope, and collector shall be designed to allow for manual gravity draining and air filling of solar thermal system components and piping. Pipe slope for gravity draining shall be not less than 1?4 inch per foot (20.8 mm/m) of horizontal length. Collector header pipes or absorber plate riser tubes internal to the collector shall be sloped in accordance with the manufacturer's instructions. Where a means to drain the system is provided, a drain valve shall be installed.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.5   Water Hammer Protection.

    Solar thermal systems where quick-acting valves are installed shall be provided with water hammer arrester(s) to absorb high pressures resulting from the quick closing of these valves. Water hammer arrestors shall be approved mechanical devices in accordance with the applicable standard(s) referenced in this Code and shall be installed as close as possible to quick-acting valves.

    (Ord. 2016-0055 § 20, 2016: Ord. 2013-0050 § 22, 2013.)

    S-13.4.6   Heat Transfer Medium.

    Solar thermal piping shall be identified with an orange background with black uppercase lettering, with the words "CAUTION: HEAT TRANSFER MEDIUM, DO NOT DRINK." Each solar thermal system shall be identified to designate the medium being conveyed. The minimum size of the letters and length of the color field shall comply with Table S-13.4.6.

    Each outlet on the solar thermal piping system shall be posted with black uppercase lettering as follows:

    "CAUTION: HEAT TRANSFER MEDIUM, DO NOT DRINK."

    TABLE S-13.4.6
    Minimum Length of Color Field and Size of Letters

    Outside Diameter of Pipe or
    Covering (inches)
    Minimum Length of Color Field (inches) Minimum Size of Letters (inches)
    ½ to 1¼ 8 ½
    1½ to 2 8 3/4;
    2½ to 6 12
    8 to 10 24
    Over 10 32

     

    For SI units: 1 inch = 25.4 mm

    (Ord. 2013-0050 § 22, 2013.)

    S-13.4.7   Insulation.

    S-13.4.7.1   General.

    The temperature of surfaces within reach of building occupants shall not exceed 140°F (60°C) unless the surfaces are protected by insulation. Where sleeves are installed, the insulation shall continue full size through them. Coverings and insulation used for piping shall be of material approved for the operating temperature of the system and the installation environment. Where installed in a plenum, the insulation, jackets and lap-seal adhesives, including pipe coverings and linings, shall have a flame spread index not to exceed 25 and a smoke-developed index not to exceed 50 where tested in accordance with ASTM E84 or UL 723.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.7.2   Heat Loss.

    Piping, storage tanks, and circulating air ductwork shall be insulated. Ductwork and piping shall be permitted to not be insulated where exposed in conditioned spaces, and the heat loss from such ducts or piping does not otherwise contribute to the heating or cooling load within such space.

    Exception: Low temperature, aboveground piping installed for swimming pools, spas, and hot tubs in accordance with the manufacturer's installation instructions unless such piping is located within a building.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.7.3   Piping.

    Pipes and fittings, other than unions, flanges, or valves, shall be insulated. Insulation material shall be approved for continuous operating temperatures of not less than 220°F (104°C). [See Table S-13.4.7.3(1) through Table S-13.4.7.3(4)].

    (Ord. 2016-0055 § 20, 2016.)

    Table S-13.4.7.3(1)
    MINIMUM PIPE INSULATION

    FLUID TEMPERATURE RANGE (°F) PIPE DIAMETER (inches)
    1 AND LESS 1.25 - 2 2.5 - 4 5 - 6 8 AND LARGER
    R-VALUE
    306-460 10 10 12 14 14
    251-305 8 10 10 12 12
    201-250 6 6 8 8 8
    105-200 2 4 6 6 6

     

    (Ord. 2016-0055 § 20, 2016.)

    Table S-13.4.7.3(2)
    IRON PIPE AND COPPER TUBING INSULATION THICKNESS

    T28_S_13.4.7.3_2_1.png

    T28_S_13.4.7.3_2_2.png

    For SI units: 1 inch = 25.4 mm, °C = (°F-32)/1.8, 1000 British thermal units per hour = 0.293kW

    *T = Thickness (inches), HL = Heat loss (Btu/h)

    (Ord. 2016-0055 § 20, 2016.)

    Table S-13.4.7.3(3)
    UNIVERSAL PIPE INSULATION THICKNESS
    BASED ON RADIUS AND IRON PIPE SIZE

    T28_S_13.4.7.3_3_1.png

    T28_S_13.4.7.3_3_2.png

    For SI units: 1 inch = 25.4 mm, 1 square inch = 0.000645 m2

    *A = Area (square inches), r1 = Inside radius (inches), r 2 = Outside radius (inches)

    (Ord. 2016-0055 § 20, 2016.)

    Table S-13.4.7.3(4)
    DESIGN VALUES FOR THERMAL CONDUCTIVITY (k) OF INDUSTRIAL INSULATION 3, 4, 5

    T28_S_13.4.7.3_4_1.png

    T28_S_13.4.7.3_4_2.png

    For SI units: °C = (°F-32)/1.8, 1 pound per cubic foot = 16.01846 kg/m , 1 inch = 25.4 mm, 1 British thermal unit inch per hour square foot degree fahrenheit = 0.1 [W/(m•K)]

    Notes:

     These temperatures are generally accepted as maximum. Where operating temperature approaches these limits, follow the manufacturer's recommendations.

     Values are for aged board stock.

     Representative values for dry materials as selected by ASHRAE TC 4.4, Insulation and Moisture Barriers. They are intended as design (not specification values for materials of building construction for normal use). For thermal resistance of a particular product, use the value supplied by the manufacturer or by unbiased tests.

     Some polyurethane foams are formed by means that produce a stable product (with respect to k), but most are blown with refrigerant and will change with time.

     Thermal conductivity (k) of industrial insulation shall be expressed in British thermal unit inch per hour square foot degree fahrenheit [Btu•in/(h•ft •°F)] [W/(m•K)].

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.7.4   Fittings.

    Fittings shall be insulated with mitered sections, molded fittings, insulating cement, or flexible insulation.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.7.5   Installation.

    Insulation shall be finished with a jacket or facing with the laps sealed with adhesives or staples so as to secure the insulation on the pipe. Insulation jacket seams shall be on the underside of the piping and shall overlap in accordance with the manufacturer's installation instructions. Joints and seams shall be sealed with a sealant that is approved for both the material and environmental conditions. In lieu of jackets, molded insulation shall be permitted to be secured with 16 gauge galvanized wire ties not exceeding 9 inches (229 mm) on center.

    (Ord. 2016-0055 § 20, 2016.)

    S-13.4.7.5.1   Exterior Applications.

    Insulation for exterior applications shall be finished with an approved jacket or facing with the surfaces and laps sealed. Jacketing, facing, and tape used for exterior applications shall be designed for such use. Where flexible insulation is used, it shall be wrapped and sealed against water penetration. Insulation used for exterior applications shall be resistant to extreme temperatures, UV exposure, and moisture.

(Ord. 2016-0055 § 20, 2016.)