SPS 371.21(1)(a)(a) Access.
Components shall be accessible for required routine maintenance without trespassing on adjoining property or disassembling any major portion of the solar energy system, building or dwelling.
Components within 10 feet horizontally of a chimney or vent shall be at least 2 feet below the top of the chimney or vent.
The location of components may not interfere with the operation of required doors, windows or other building components.
SPS 371.21 Note
Note: Components may be subject to local zoning requirements.
Combustible materials may not be exposed to components having maximum operating temperatures that can cause ignition. Clearances to combustible materials specified in the component listing or by the component manufacturer shall be maintained.
Clearance between combustible materials and unlisted components shall be maintained in accordance with Table 371.21-A.
Clearance Between Combustible Materials and
- See PDF for table
1If approved insulation protects the component, the required clearance may be reduced by 50%.
(2) Material tests and standards.
The installation of, as well as all materials used in the construction of, solar energy systems shall meet the applicable requirements specified in chs. SPS 320
, and 381
and this chapter. Where different chapters specify different requirements, the most restrictive material test and installation standard shall apply.
SPS 371.21(3)(a)(a) General.
Insulation of piping, ducts and thermal storage containers shall be of a type satisfactory for its intended purpose and installed in accordance with recognized standards and practices.
1. `Flame spread rating.'
The flame spread rating for all insulation materials may not exceed the following values:
Plastic foam: 75
Other insulation materials: 150
2. `Compressive loads.'
Insulation shall be protected against compressive loads from pipe and duct supports and storage tanks.
3. `Exterior insulation.'
Exterior insulation shall be capable of withstanding moisture, ultraviolet radiation, and environmental exposure.
Pipes of nominal size of one and one-half inch or larger shall be insulated to a thermal resistance value of R-4 or greater. All other piping in the solar energy system shall be insulated to a thermal resistance value of R-3 or greater. A vapor barrier, if installed, shall be located on the warm side of the insulation.
Ductwork located in unheated spaces shall be insulated to a thermal resistance value of R-11 or greater, where space permits. Ductwork in heated spaces shall be insulated to a thermal resistance value of R-3 or greater. A vapor barrier, if installed, shall be located on the warm side of the insulation.
SPS 371.21(3)(d)1.1. `Thermal storage - liquid systems.'
Thermal storage for liquid systems located in unheated spaces shall be insulated to an overall thermal resistance value of R-16 or greater. Thermal storage for liquid systems installed in heated spaces shall be insulated to an overall thermal resistance value of R-11 or greater.
2. `Thermal storage - air systems.'
Thermal storage for air systems located in unheated spaces shall be insulated to an overall thermal resistance value of R-38 or greater. Thermal storage for air systems installed in heated spaces shall be insulated to an overall thermal resistance value of R-11 or greater.
SPS 371.21(4)(a)(a) Protection against vermin.
All penetrations of the building or dwelling by components shall be properly sealed with noncombustible material to prevent the entrance of vermin.
(b) Protection against vehicular or pedestrian traffic.
Components exposed to vehicular or pedestrian traffic shall be protected against impact damage.
(c) Protection against water penetration.
All penetrations by components into a building or dwelling from the outside shall be properly sealed and waterproofed with approved materials to prevent leaks, insects and drafts from entering the building or dwelling. All penetrations shall be made using weatherproof devices which will allow for expansions and contractions.
(d) Protection against decay and termites.
Wood used in the construction of the collector or mounting, and exposed to outdoor conditions shall be pressure-treated with preservative or shall be a naturally durable, decay resistant species of lumber and shall be protected against termites.
(e) Protection from heated components.
Components which are maintained at temperatures above 170° F shall be protected from human contact. The protections may be in the form of insulation, metal or plastic guards.
(5) Smoke detectors.
All dwellings that contain air systems with wood-frame collectors shall be provided with smoke detectors as specified in s. SPS 321.09
(6) Fire protection.
The design and installation of the solar energy system and components shall provide a level of fire safety consistent with chs. SPS 320
for one- and 2-family dwellings, or chs. SPS 361
for commercial buildings.
SPS 371.21(6)(a)1.1. `Existing buildings.'
An existing building's vents, pipes, and ducts, installed for the operation of the solar energy system, shall comply with chs. SPS 361
2. `Existing dwellings.'
Existing dwellings shall be provided with draftstopping at openings around vents, pipes and ducts installed for the operation of the solar energy system. Draftstopping materials may not be less than 1/2 -inch gypsumboard, 3/8 -inch plywood, mineral-based insulation or other approved materials.
A collector intended for installation integral with or forming a part of the building or dwelling roof structure and its associated roof covering material, may not reduce or impair the fire resistance of the designated roof covering material.
The structural design of the solar energy system, including connections and supporting structural elements, shall be based on loads anticipated during the design life of the solar energy system. Roof loading due to the following loading effects shall be included in the design of all structural elements influenced by these loads:
SPS 371.21(7)(a)1.1. `Collector.'
The collector and supporting structure, including building components, shall be designed and constructed to support the weight of the collector, other components and heat transfer fluids.
2. `Thermal storage.'
The thermal storage and supporting structure shall be designed and constructed to support the weight of the storage container, components, heat transfer fluids and storage medium.
SPS 371.21(7)(b)1.1. `Use.'
Surfaces that must support maintenance personnel shall resist a load of 250 pounds distributed over a 4-inch square area.
2. `Wind, snow and seismic.'
The collector, including any mounting hardware and building components, shall be designed and constructed to resist the wind and snow loads specified in chs. SPS 320
for one- and 2-family dwellings, or the wind, snow and seismic loads specified in chs. SPS 361
for commercial buildings.
SPS 371.21 History
Cr. Register, June, 1986, No. 366
, eff. 7-1-86; CR 01-139
: am. (2), (5), (6) (intro.), r. and recr. (7) (b) 2., r. (7) (b) 3. Register June 2002 No. 558
, eff. 7-1-02; correction in (6) (a) 1. made under s. 13.93 (2m) (b) 7., Stats., Register June 2002 No. 558
; correction in (1) (c) 2., (2), (5), (6) (intro.), (a) 1., (7) (b) 2. made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672
General mechanical requirements. SPS 371.22(1)(1)
When a solar energy system and an auxiliary energy system are interconnected, the design temperature or design pressure of either system may not be exceeded. The interconnection may not compromise or bypass any required safety devices on either system. Auxiliary equipment shall be compatible with the solar energy system output, including but not limited to, temperatures, pressures and heat transfer fluid type.
(2) Identification of materials.
Components and materials used in solar energy systems shall be permanently marked or labeled by the manufacturer as to the component's limitations. All listed components shall have the seal of the listing agency permanently affixed to the component.
All components of the solar energy system having valves capable of isolating heat generating or heat transfer components shall be provided with an approved, adequately sized pressure relief valve. The installation of the relief valve discharge shall be in accordance with s. SPS 382.40 (5)
The pressure relief valve shall be set at a pressure not to exceed the design pressure of the solar energy system or component or 150 psig, whichever is lesser. The relief valve settings may not exceed the recommendations of the valve manufacturer.
Temperature relief valves shall be of adequate relief rating expressed in Btu/hr for the components served.
Temperature relief valves shall be installed in thermal storage so that the temperature sensing element is immersed within the top 6 inches of a storage tank that contains liquid. The temperature relief valve shall be set to open at 210° F or less.
(d) Combination pressure-temperature relief valves.
Combination pressure-temperature relief valves shall comply with all the requirements of the separate pressure and temperature relief valves.
(e) Entrapped air.
Except for drainback systems, the solar energy system shall provide means for removing air at the highest point of the system when liquid heat transfer fluids are used.
Except as provided in par. (b)
, wherever potable water is interfaced with toxic heat transfer fluids, a double wall heat exchanger, with positive leak detection vented to the atmosphere, shall be provided. The vent shall be located at the lowest part of the heat exchanger or as approved by the department.
Where air is the heat transfer fluid, a single wall heat exchanger may be used. Where potable water is the heat transfer fluid, direct connection to the potable water system is allowed or a single wall heat exchanger may be used.
Solar energy systems using liquid heat transfer fluids shall have a label attached to the thermal storage indicating the heat transfer fluid's name, freezing point and pH, and the system designer's recommendations for checking and maintaining the heat transfer fluid.
The heat transfer fluid contained in a non-draindown or non-drainback system shall be able to withstand temperatures of at least -35ºF before freezing.
Only heat transfer fluids recommended by the system designer for use in the solar energy system shall be used. Ethylene glycol may not be used for solar energy systems in one- and 2-family dwellings, but may be used in buildings.
The heat transfer fluid shall be capable of withstanding design temperatures without rapid thermal degradation.
The flash point of the heat transfer fluid shall exceed, by 50ºF, the maximum operating temperature of the solar energy system.
Drains and other designated heat transfer fluid discharge or fill points in solar energy systems at which toxic, combustible or high temperature heat transfer fluids may be discharged shall be labeled with a warning describing the identification and hazardous properties of the fluid, instructions concerning the safe handling of the fluid, and emergency first aid procedures.
Controls, dampers and valves shall be marked to identify their function. Any control that serves as an emergency shutdown device shall be so identified by a conspicuous and permanent label.
Automatic control of the heat transfer fluid circulation between the collector and thermal storage or load shall be used to limit operations to conditions when useful energy can be collected.
Fail-safe controls shall be designed so that in the event of a power failure, or a failure of any component in the solar energy system, the temperature or pressure or both developed in the solar energy system, will not damage the component or the building or present a danger to the occupants.
Controls shall be selected and installed so that the solar energy system and auxiliary energy system will operate together and independently.
Space heating and control thermostats shall be installed in accordance with the manufacturer's or system designer's instructions. Space heating thermostats shall be located away from drafts, heat sources and exterior walls. Mercury bulb thermostats shall be leveled to assure satisfactory operation. Thermostats mounted outdoors shall be suitable for outdoor environmental exposure.
Controls shall be installed to prevent component damage from thermal shock.
Controls shall include provisions for manual bypass, adjustment or override of automatic controls as is required to facilitate installation, startup, shutdown and maintenance.
All materials used in the solar energy system shall be compatible. All components in contact with the heat transfer fluid used in the solar energy system shall be compatible with the heat transfer fluid.
All metal parts, including screws, bolts, and washers, which are not inherently corrosion resistant and are exposed to atmospheric conditions, shall be protected from corrosion by painting, plating, or similar means.
Metallic parts which provide protection to either electrical components or internal building structures shall be galvanically compatible and protected from corrosion.
SPS 371.22 History
Cr. Register, June, 1986, No. 366
, eff. 7-1-86; corrections in (3) (a) and (b) made under s. 13.93 (2m) (b) 7., Stats., Register June 2002 No. 558
; correction in (3) (a) 1., (b) made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672
Collector certification requirements.
After January 1, 1987, all collectors shall be certified by the Solar Rating and Certification Corporation (SRCC), the Air Conditioning and Refrigeration Institute (ARI) or equivalent. This provision does not apply to home-built systems, custom-built systems and small manufacturers. As used in this subsection:
"Home-built system" means an owner-installed solar energy system incorporating a collector assembled by the system owner from components, but does not include manufactured collectors supplied as an integral unit and installed by the owner.
"Custom-built system" means a one-of-a-kind solar energy system incorporating a collector fabricated at the installation site from components, but does not include modular systems in which the modular components are assembled at the installation site.
"Small manufacturer" means a business that builds or assembles less than 2500 square feet of collector per year and elects not to list with SRCC or ARI.
SPS 371.23 Note
Certification of collectors by the SRCC and the ARI is based on the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards 93-77 and 95-1981
. Further information can be obtained from the Solar Rating and Certification Corporation, 1001 Connecticut Avenue, N.W., Suite 800, Washington, D.C. 20036, or the Air-Conditioning and Refrigeration Institute, 1501 Wilson Boulevard, 6th Floor, Arlington, VA 22209.
(2) Collector tilt and orientation.
Collectors shall be installed as close to the optimum tilt angle as conditions allow and within 45º of due south.
SPS 371.23(3)(a)(a) Transmission losses due to outgassing.
Outgassing of volatiles from components may not reduce the collector performance below the declared collector performance when the collector is exposed to the temperatures and pressures that will occur in actual service.