5.1 Solar reflectance and thermal emittance are important factors affecting surface and near-surface ambient air temperature. Surfaces with low solar reflectance, absorb a high fraction of the incoming solar energy. A fraction of this absorbed energy is conducted into ground and buildings, a fraction is convected to air (leading to higher air temperatures), and a fraction is radiated to the sky. For equivalent conditions, the lower the emissivity of a surface the higher its steady-state temperature. Surfaces with low emissivity cannot effectively radiate to the sky and, therefore, get hot. Determination of solar reflectance and thermal emittance, and subsequent calculation of the relative temperature of the surfaces with respect to black and white reference temperature (defined as Solar Reflectance Index, SRI), may help designers and consumers to choose the proper materials to make their buildings and communities energy efficient. The method described here gives the SRI of surfaces based on measured solar reflectances and thermal emissivities of the surfaces.1.1 This practice covers the calculation of the Solar Reflectance Index (SRI) of horizontal and low-sloped opaque surfaces at standard conditions. The method is intended to calculate SRI for surfaces with emissivity greater than 0.1.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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At this time, none of these tests has been demonstrated to correlate with field service. It is essential that consideration be given to the appropriate pairing of metal and fluid since these procedures do not restrict the selection of either the containment material or the fluid for testing. Likewise, knowledge of the corrosion protection mechanism and the probable mode of failure of a particular metal is helpful in the selection of test conditions and the observation, interpretation, and reporting of test results. The design of solar heating and cooling systems strongly affects the applicability of the results of the laboratory screening tests. Therefore, the results of these laboratory procedures should be confirmed by component and systems testing under actual or simulated service conditions. Table 1 is provided to assist in an orderly consideration of the important factors in testing. It is expected that the user of the test procedure will investigate a range of test times and temperatures for the containment material in a metal/fluid pair, and adjust the time and temperature of testing as necessary. Note 1—Corrosion, whether general or localized, is a time-dependent phenomenon. This time dependence can show substantial nonlinearity. For example, formation of a protective oxide will diminish corrosion with time, while certain forms of localized attack accelerate with time. The minimum time required for a test to provide a corrosion rate that can be extrapolated for the prediction of long-term performance varies widely, depending on the selection of metal and fluid, and on the form of corrosion attack. Therefore, it is not possible to establish a single minimum length of test applicable to all materials and conditions. However, it is recommended that for the tests described in this practice, a test period of no less than 30 days be used. Furthermore, it is recommended that the effect of time of testing be evaluated to detect any significant time dependence of corrosion attack. It is essential for the meaningful application of these procedures that the length of the test be adequate to detect changes in the nature of the fluid that might significantly alter the corrosivity of the fluid. For example, exhaustion of chemical inhibitor or chemical breakdown of the fluid may occur after periods of months in selected cycles of operation. Note 2—Many fluids that may be considered for solar applications contain additives to minimize the corrosivity of the fluid. Many such additives are useful only within a specific concentration range, and some additives may actually accelerate corrosion if the concentration falls below a critical level. Depletion kinetics can be a strong function of the exposed metal surface area. Therefore, for tests involving fluids with such additives, consideration must be given to the ratio of metal surface area to fluid volume as it may relate to an operating system. TABLE 1 Significant Variables in Evaluation of Containment Material/Heat Transfer Fluid PairsA Test AspectVariable TemperatureFlow Rate I.Operating Conditions of System: A. Operating, full flow B. Stagnant, fullnormal operating fluid boiling point without pressurization or no-flow temperature with pressurization normal operating convection C. Stagnant, partial fill D. Stagnant, emptysame as stagnant, full no-flow temperature convection not applicable II.Test Specimen Design A. flat metal couple B. metal couple with crevice C. dissimilar metal couple D. dissimilar metal couple with crevice III.Fluid TypeA. fluid intended for use in system B. fluid pretreated by thermal exposure or chemical contamination IV.Test CycleA. long time, constant temperature B. cycles of heating, holding, and cooling C. cycles of operating full flow, and stagnation D. cycles of wetting and drying A In this table, the subdivisions are not necessarily related in correspondence to their lettering.1.1 This practice covers several laboratory test procedures for evaluating corrosion performance of metallic containment materials under conditions similar to those that may occur in solar heating and cooling systems. All test results relate to the performance of the metallic containment material only as a part of a metal/fluid pair. Performance in these laboratory test procedures, taken by itself, does not necessarily constitute an adequate basis for acceptance or rejection of a particular metal/fluid pair in solar heating and cooling systems, either in general or in a particular design. This practice is not intended to preclude the use of other screening tests, particularly when those tests are designed to more closely simulate field service conditions. 1.2 This practice describes apparatus and procedures for several tests, any one or more of which may be used to evaluate the deterioration of the metallic containment material in a metal/fluid pair. The procedures are designed to permit simulation, heating, and cooling systems including (1) operating full flow, (2) stagnant full, (3) stagnant partial fill, and (4) stagnant empty. Particular attention should be directed to properly reflecting whether the system is open or closed to atmosphere. 1.3 This practice covers the following six tests: Practice ABasic Immersion Test at Atmospheric Pressure Practice BHeat-Rejecting Surface Test at Atmospheric Pressure Practice CHigh-Pressure Test Practice DRepeated Dip Dry Test at Atmospheric Pressure Practice ECrevice Test at Atmospheric Pressure Practice FTube Loop Test at Atmospheric Pressure 1.4 Practice A is concerned with the interaction of metal and fluid when both are at the same temperature with no heat transfer from one to the other. It is regarded as useful for plumbing, pumps, tanking, etc., but of less significance, taken by itself, for collector panels. Practices B and F are concerned with the deterioration of the metal when there is transfer of heat from the metal into the heat transfer fluid. These practices are especially applicable to the collector panel. Practice C permits a variety of tests but is especially useful in relation to systems that experience high temperatures, or are closed to the atmosphere. Practices D and E evaluate specific corrosion problems that may be associated with particular metal/fluid pairs and particular designs of systems and components. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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4.1 The methods in this practice are intended to aid in the assessment of long-term performance by comparative testing of absorptive materials. The results of the methods, however, have not been shown to correlate to actual in-service performance.4.2 The testing methodology in this practice provides two testing methods, in accordance with Fig. 1.FIG. 1 Outline of Test Method Options4.2.1 Method A, which aims at decreasing the time required for evaluation, uses a series of individual tests to simulate various exposure conditions.4.2.2 Method B utilizes a single test of actual outdoor exposure under conditions simulating thermal stagnation.4.2.3 Equivalency of the two methods has not yet been established.1.1 This practice covers a testing methodology for evaluating absorptive materials used in flat plate or concentrating collectors, with concentrating ratios not to exceed five, for solar thermal applications. This practice is not intended to be used for the evaluation of absorptive surfaces that are (1) used in direct contact with, or suspended in, a heat-transfer liquid, (that is, trickle collectors, direct absorption fluids, etc.); (2) used in evacuated collectors; or (3) used in collectors without cover plate(s).1.2 Test methods included in this practice are property measurement tests and aging tests. Property measurement tests provide for the determination of various properties of absorptive materials, for example, absorptance, emittance, and appearance. Aging tests provide for exposure of absorptive materials to environments that may induce changes in the properties of test specimens. Measuring properties before and after an aging test provides a means of determining the effect of the exposure.1.3 The assumption is made that solar radiation, elevated temperature, temperature cycles, and moisture are the primary factors that cause degradation of absorptive materials. Aging tests are described for exposure of specimens to these factors.NOTE 1: For some geographic locations, other factors, such as salt spray and dust erosion, may be important. They are not evaluated by this practice.1.4 The values stated in SI units are to be regarded as the standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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At this time none of these practices have been demonstrated to correlate with field service. Because these procedures do not restrict the selection of either the containment material or the fluid for testing, it is essential that consideration be given to the appropriate pairing of metal and fluid. Likewise, knowledge of the corrosion protection mechanism and the probable mode of failure of a particular metal is helpful in the selection of test conditions and the observation, interpretation, and reporting of test results. It is important that consideration be given to each of the permitted variables in test procedure so that the results will be meaningfully related to field performance. It is especially important that the time of testing selected be adequate to correctly measure the rate of corrosion of the containment material. Note 1—Corrosion, whether general or localized, is a time-dependent phenomenon. This time dependence can show substantial nonlinearity. For example, formation of a protective oxide will diminish corrosion with time, while certain forms of localized attack accelerate corrosion with time. The minimum time required for a test to provide a corrosion rate that can be extrapolated for the prediction of long-term performance varies widely, depending on the selection of metal and fluid, and on the form of corrosion attack. Therefore, it is not possible to establish a single minimum length of test applicable to all materials and conditions. However, it is recommended that for the tests described in these practices, a test period of no less than 6 months be used. Furthermore, it is recommended that the effect of time of testing be evaluated to detect any significant time dependence of corrosion attack. It is essential for the meaningful application of these procedures that the length of test be adequate to detect changes in the nature of the fluid that might significantly alter the corrosivity of the fluid. For example, exhaustion of chemical inhibitor or chemical breakdown of the fluid may occur after periods of months in selected cycles of operation. Note 2—Many fluids that may be considered for solar applications contain additives to minimize the corrosivity of the fluid. Many such additives are useful only within a specific concentration range, and some additives may actually accelerate corrosion if the concentration falls below a critical level. Depletion kinetics can be a strong function of the exposed metal surface area. Therefore, for tests involving fluids with such additives, consideration must be given to the ratio of metal surface area to fluid volume as it may relate to an operating system.1.1 These practices cover test procedures simulating field service for evaluating the performance under corrosive conditions of metallic containment materials in solar heating and cooling systems. All test results relate to the performance of the metallic containment material only as a part of a metal/fluid pair. Performance in these test procedures, taken by itself, does not necessarily constitute an adequate basis for acceptance or rejection of a particular metal/fluid pair in solar heating and cooling systems, either in general or in a particular design. 1.2 These practices describe test procedures used to evaluate the resistance to deterioration of metallic containment materials in the several conditions that may occur in operation of solar heating and cooling systems. These conditions include: (1) operating full flow; (2) stagnant empty vented; (3) stagnant, closed to atmosphere, non-draindown; and (4) stagnant, closed to atmosphere, draindown. 1.3 The recommended practices cover the following three tests: 1.3.1 Practice A—Laboratory Exposure Test for Coupon Specimens. 1.3.2 Practice B—Laboratory Exposure Test of Components or Subcomponents. 1.3.3 Practice C—Field Exposure Test of Components or Subcomponents. 1.4 Practice A provides a laboratory simulation of various operating conditions of solar heating and cooling systems. It utilizes coupon test specimens and does not provide for heating of the fluid by the containment material. Practice B provides a laboratory simulation of various operating conditions of a solar heating and cooling system utilizing a component or a simulated subcomponent construction, and does provide for heating of the fluid by the containment material. Practice C provides a field simulation of various operating conditions of solar heating and cooling systems utilizing a component or a simulated subcomponent construction. It utilizes controlled schedules of operation in a field test. 1.5 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For a specific safety precaution statement see Section 6.

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This specification covers the general requirements for materials used in preformed rubber seals that contact the circulating liquid in solar energy systems. Rubber seal can be classified into types, grades and classes. It has two kinds according to what climate they should be used: Type C which is intended for use in cold climates and Type W which is intended for use in warm climates. Its grade designations represent differing degrees of hardness such as Grade 3, Grade 4, Grade 5, Grade 6, Grade 7 and Grade 8. As for the classes, it should be determined into 3 kinds. Class A for seals used with aqueous liquid at a certain maximum service temperature. Class AT for seals used with aqueous liquids at an above maximum service temperature and class N for use with nonaqueous liquids. Different tests shall be conducted in order to determine the following properties of rubber seals in liquid heat-transport systems: compression, resistance to heating, hardness, ultimate elongation, volume, resistance to ozone, resistance to low temperature, and resistance to liquid.1.1 This specification covers the general requirements for materials used in preformed rubber seals that contact the circulating liquid in solar energy systems. Particular applications may necessitate other requirements that would take precedence over these requirements when specified.1.2 This specification does not include requirements pertaining to the design, fabrication, or installation of the seals.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 This guide is intended for on-site assessment of in-service operation by short term measurement of appropriate system functions under representative operating conditions.4.2 Primary application is for residential systems and medium-size multi-family units or commercial buildings. Use of back-up conventional DHW heating system is assumed to augment solar heating.4.3 This guide is intended for use by suppliers, installers, consultants and homeowners in evaluating on-site operation of an installed system. Emphasis is placed on simplified measurements that do not require special skills, intrusive instrumentation, system modification or interruption of service to the purchaser.4.4 The purpose of this guide is to verify that the system is functioning. Copies of all data and reports must be submitted by the testing group to the owner or his or her designated agent.4.5 Data and reports from these procedures and tests may be used to compare the system performance over time, but should not be used to compare different systems or installations.4.6 Test is for a newly installed system and also for periodic checking.1.1 This guide covers procedures and test methods for conducting an on-site inspection and acceptance test of an installed domestic hot water system (DHW) using flat plate, concentrating-type collectors or tank absorber systems.1.2 It is intended as a simple and economical acceptance test to be performed by the system installer or an independent tester to verify that critical components of the system are functioning and to acquire baseline data reflecting overall short term system heat output.1.3 This guide is not intended to generate accurate measurements of system performance (see ASHRAE standard 95-1981 for a laboratory test) or thermal efficiency.1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 Solar-energy transmittance and reflectance are important factors in the heat admission through fenestration, most commonly through glass or plastics. (See Appendix X3.) These methods provide a means of measuring these factors under fixed conditions of incidence and viewing. While the data may be of assistance to designers in the selection and specification of glazing materials, the solar-energy transmittance and reflectance are not sufficient to define the rate of heat transfer without information on other important factors. The methods have been found practical for both transparent and translucent materials as well as for those with transmittances reduced by highly reflective coatings. Method B is particularly suitable for the measurement of transmittance of inhomogeneous, patterned, or corrugated materials since the transmittance is averaged over a large area.1.1 These test methods cover the measurement of solar energy transmittance and reflectance (terrestrial) of materials in sheet form. Method A, using a spectrophotometer, is applicable for both transmittance and reflectance and is the referee method. Method B is applicable only for measurement of transmittance using a pyranometer in an enclosure and the sun as the energy source. Specimens for Method A are limited in size by the geometry of the spectrophotometer while Method B requires a specimen 0.61 m2 (2 ft2). For the materials studied by the drafting task group, both test methods give essentially equivalent results.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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1.1 This terminology pertains to the conversion of solar energy into other forms of energy by various means, including thermal absorption (i.e., solar thermal) and the photovoltaic effect (i.e., photovoltaics).1.2 This terminology also pertains to instrumentation used to measure solar radiation.1.3 This terminology also pertains to glass for solar energy applications.1.4 Fundamental terms associated with electromagnetic radiation that are indicates as derived units in Standard IEEE/ASTM SI 10 are not repeated in this terminology.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 As with any accelerated test, the increase in rate of weathering compared to in-service exposure is material dependent. Therefore, no single acceleration factor can be used to relate two different types of outdoor weathering exposures. The weather resistance rankings of coatings provided by these two procedures may not agree when coatings differing in composition are compared. These two procedures should not be used interchangeably.5.2 The procedures described in this practice are designed to provide greater degradation rates of coatings than those provided by fixed-angle, open-rack, outdoor exposure racks. For many products, fixed angle exposures will produce higher degradation rates than the normal end use of the material.5.2.1 The use of Procedure A (Black Box) instead of an open-rack direct exposure is a more realistic test for materials with higher temperature end use service conditions. For many coatings, this procedure provides greater rates of degradation than those provided by 5°, equator-facing, open-rack exposures because the black box produces higher specimen temperatures during irradiation by daylight and longer time of specimen wetness. The black box specimen temperatures are comparable to those encountered on the hoods, roofs, and deck lids of automobiles parked in sunlight. The relative rates of gloss loss and color change produced in some automotive coatings by exposures in accordance with Procedure A are given in ASTM STP 781.45.2.2 The acceleration of degradation by weathering as described in Procedure C is produced by reflecting sunlight from ten mirrors onto an air-cooled specimen area. Approximately 1400 MJ/m2 of ultraviolet radiant exposure (295 to 385 nm) is received over a typical one-year period when samples are exposed on these devices in a central Arizona climate. This compares with approximately 333 MJ/m2 of ultraviolet radiant exposure from a central Arizona at-latitude exposure and 280 MJ/m2 of ultraviolet radiant exposure from a southern Florida at-latitude exposure over an equivalent time period. However, the test described by Procedure C reflects only direct beam radiation onto test specimens. The reflected direct beam of sunlight contains a lower percentage of short wavelength ultraviolet radiation than global daylight because short wavelength ultraviolet is more easily scattered by the atmosphere, and because mirrors are typically less efficient at shorter ultraviolet wavelengths. Ultraviolet radiant exposure levels should not be used to compute acceleration factors since acceleration is material dependent.5.3 The weather resistance of coatings in outdoor use can be very different depending on the geographic location of the exposure because of differences in ultraviolet (UV) radiation, time of wetness, temperature, pollutants, and other factors. Therefore, it cannot be assumed that results from one exposure in a single location will be useful for determining relative weather resistance in a different location. Exposures in several locations with different climates that represent a broad range of anticipated service conditions are recommended to determine weathering resistance and/or service life.5.4 Because of year-to-year climatological variations, results from a single exposure test cannot be used to predict the absolute rate at which a material degrades.NOTE 3: Three or more years of repeat exposures, starting at various times of the year, are typically needed to get an “average” test result for a given location.5.4.1 The degradation profile for many coatings is not a linear function of exposure time or radiant exposure. When short exposures are used as indications of weather resistance, the results obtained may not be representative of those from longer exposures.NOTE 4: Guide G141 provides information for addressing variability in exposure testing of nonmetallic materials. Guide G169 provides information for applying statistics to exposure test results.5.5 It is recommended that at least one control material be part of any exposure evaluation. Control materials are used for comparing the performance of the test materials relative to the controls when materials are not being ranked against one another. The control material used should be of similar composition and construction to the test materials and be of known weather resistance. It is preferable to use two control materials, one with relatively good weather resistance and one with poor weather resistance.1.1 This practice covers two accelerated outdoor exposure procedures for evaluating the exterior weather resistance of coatings applied to substrates.1.2 The two procedures are as follows:1.2.1 Procedure A—Black Box Exposure.1.2.2 Procedure C—Fresnel Reflector Rack Exposure.NOTE 1: Procedure B described a Heated Black Box procedure that is no longer in common use and has been removed as of the 2014 revision of this standard.1.3 This standard does not cover all the procedures that are available to the user for accelerating the outdoor exposure of coatings. Other procedures have been used in order to provide a particular effect; however, the two procedures described here are widely used.1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 This practice describes a weathering box test fixture and establishes limits for the heat loss coefficients. Uniform exposure guidelines are provided to minimize the variables encountered during outdoor exposure testing.4.2 Since the combination of elevated temperature and solar radiation may cause some solar collector cover materials to degrade more rapidly than either exposure alone, a weathering box that elevates the temperature of the cover materials is used.4.3 This practice may be used to assist in the evaluation of solar collector cover materials in the stagnation mode. No single temperature or procedure can duplicate the range of temperatures and environmental conditions to which cover materials may be exposed during stagnation conditions. To assist in evaluation of solar collector cover materials in the operational mode, Practice E782 should be used. Insufficient data exist to obtain exact correlation between the behavior of materials exposed in accordance with this practice and actual in-service performance.4.4 This practice may also be useful in comparing the performance of different materials at one site or the performance of the same material at different sites, or both.4.5 Means of evaluating the effects of weathering are provided in Practice E765, and in other ASTM test methods that evaluate material properties.4.6 Exposures of the type described in this practice may be used to evaluate the stability of solar collector cover materials when exposed outdoors to the varied influences that comprise weather. Exposure conditions are complex and changeable. Important factors are material temperature, climate, time of year, presence of industrial pollution, etc. Generally, because it is difficult to define or measure precisely the factors influencing degradation due to weathering, results of outdoor exposure tests must be taken as indicative only. Repeated exposure testing at different seasons over a period of more than one year is required to confirm exposure tests at any one location. Control samples must always be used in weathering tests for comparative analysis.1.1 This practice covers a procedure for the exposure of solar collector cover materials to the natural weather environment at elevated temperatures that approximate stagnation conditions in solar collectors having a combined back and edge loss coefficient of less than 1.5 W/(m2·°C).1.2 This practice is suitable for exposure of both glass and plastic solar collector cover materials. Provisions are made for exposure of single and double cover assemblies to accommodate the need for exposure of both inner and outer solar collector cover materials.1.3 This practice does not apply to cover materials for evacuated collectors, photovoltaic cells, flat-plate collectors having a combined back and edge loss coefficient greater than 1.5 W/(m2·°C), or flat-plate collectors whose design incorporates means for limiting temperatures during stagnation.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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1.1 The three radiant energy weathering procedures described in these test methods are intended to determine the effects of extended outdoor exposure-induced stress that may occur during service life of photovoltaic modules. 1.1.1 Because most accelerated weathering devices are not large enough to accept full-sized photovoltaic modules, the simulated weathering test procedures may be suitable only for smaller test modules. The construction of smaller test modules should be as close in design and function as possible to full-size modules. 1.2 The three solar weathering test methods are as follows: 1.2.1 Procedure A -Natural sunlight, real-time exposure testing, 1.2.2 Procedure B -Accelerated exposure testing concentrated natural sunlight, and 1.2.3 Procedure C -Accelerated exposure testing using simulated sunlight. 1.3 The test methods do not provide for weathering studies on individual components of photovoltaic modules. 1.4 There is no similar or equivalent ISO Standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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5.1 Solar-energy absorptance, reflectance, and transmittance are important in the performance of all solar energy systems ranging from passive building systems to central receiver power systems. This test method provides a means for determining these values under fixed conditions that represent an average that would be encountered during use of a system in the temperate zone.5.2 Solar-energy absorptance, reflectance, and transmittance are important for thermal control of spacecraft and the solar power of extraterrestrial systems. This test method also provides a means for determining these values for extraterrestrial conditions.5.3 This test method is designed to provide reproducible data appropriate for comparison of results among laboratories or at different times by the same laboratory and for comparison of data obtained on different materials.5.4 This test method has been found practical for smooth materials having both specular and diffuse optical properties. Materials that are textured, inhomogeneous, patterned, or corrugated require special consideration.5.4.1 Surface roughness may be introduced by physical or chemical processes, such as pressing, rolling, etching, or deposition of films or chemical layers on materials, resulting in textured surfaces.5.4.2 The magnitude of surface roughness with respect to the components of the spectrophotometer and attachments (light beam sizes, sphere apertures, sample holder configuration) can significantly affect the accuracy of measurements using this test method.5.4.3 Even if the repeatability, or precision of the measurement of textured materials is good, including repeated measurements at various locations within or orientations of the sample, the different characteristics of different spectrophotometers in different laboratories may result in significant differences in measurement results.5.4.4 In the context of 5.4.3, the term ‘significant’ means differences exceeding the calibration or measurement uncertainty, or both, established for the spectrophotometers involved, through measurement of or calibration with standard reference materials.5.4.5 The caveats of 5.4.3 and 5.4.4 apply as well to measurement of smooth inhomogeneous or diffusing materials, where incident light may propogate to the edge of the test material and be ‘lost’ with respect to the measurement.5.5 This test method describes measurements accomplished over wider spectral ranges than the Photopic response of the human eye. Measurements are typically made indoors using light sources other than natural sunlight, though it is possible to configure systems using natural sunlight as the illumination source, as in Practice E424. Practice E971 describes outdoor methods using natural sunlight over the spectral response range of the human eye.5.6 Light diffracted by gratings is typically significantly polarized. For polarizing samples, measurement data will be a function of the orientation of the sample. Polarization effects may be detected by measuring the sample with rotation at various angles about the normal to the samples.1.1 This test method covers the measurement of spectral absorptance, reflectance, and transmittance of materials using spectrophotometers equipped with integrating spheres.1.2 Methods of computing solar weighted properties from the measured spectral values are specified.1.3 This test method is applicable to materials having both specular and diffuse optical properties.1.4 This test method is applicable to material with applied optical coatings with special consideration for the impact on the textures of the material under test.1.5 Transmitting sheet materials that are inhomogeneous, textured, patterned, or corrugated require special considerations with respect to the applicability of this test method. Test Method E1084 may be more appropriate to determine the bulk optical properties of textured or inhomogeneous materials.1.6 For homogeneous materials this test method is preferred over Test Method E1084.1.7 This test method refers to applications using standard reference solar spectral distributions but may be applied using alternative selected spectra as long as the source and details of the solar spectral distribution and weighting are reported.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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This practice may be employed for a relative determination of the useful energy collected by different solar collectors tested side-by-side under the same operating and environmental parameters, in the same location, and on the same test day. Variations in inlet temperature and transfer fluid flow rate should be minimized for best results.Limitations: Caution should be exercised when comparing the all-day thermal performance data for collectors tested by this practice to the performance of other collectors not tested at the same time and the same location, or with the same test conditions. The data collected by this practice represent the behavior of the tested collectors only under the conditions occurring on the day of test and at the specific inlet temperature and fluid flow rate employed during the test.5.2.1 In the case of low-temperature collectors (operating below 100°C (212°F)), consideration must be given to the relationship of inlet temperature to ambient temperature when analyzing or interpreting the test data.Data collected in this test have not been shown to provide the overall comparison of collectors or collector concepts that would be required to support a nationally accepted rating or certification program.1.1 This practice covers a means of generating all-day thermal performance data for flat-plate collectors, concentrating collectors, and tracking collectors.1.2 The values stated in SI units are to be regarded as the standard. The values given in the parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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5.1 This test method is intended to provide test data essential to the prediction of the thermal performance of a collector in a specific system application in a specific location. In addition to the collector test data, such prediction requires validated collector and system performance simulation models that are not provided by this test method. The results of this test method therefore do not by themselves constitute a rating of the collector under test. Furthermore, it is not the intent of this test method to determine collector efficiency for comparison purposes since efficiency should be determined for particular applications.5.2 This test method relates collector thermal performance to the direct solar irradiance as measured with a pyrheliometer with an angular field of view between 5 and 6°. The preponderance of existing solar radiation data was collected with instruments of this type, and therefore is directly applicable to prediction of collector and system performance.5.3 This test method provides experimental procedures and calculation procedures to determine the following clear sky, quasi-steady state values for the solar collector:5.3.1 Response time,5.3.2 Incident angle modifiers,5.3.3 Near-normal incidence angular range, and5.3.4 Rate of heat gain at near-normal incidence angles.NOTE 4: Not all of these values are determined for all collectors. Table 1 outlines the tests required for each collector type and tracking arrangement.× = Required.⊗ = Required but method may not be practicable for point focus collectors—Safety precautions and technical precautions must be followed because of potential damage to equipment and subsequent damage to personnel due to high levels of solar irradiance on the receiver support structure.** = Optional test that may provide useful information on the effect of the accuracy of the manufacturer's tracking equipment on thermal performance.5.4 This test method may be used to evaluate the thermal performance of either (1) a complete system, including the tracking subsystems and the thermal collection subsystem, or (2) the thermal collection subsystem.5.4.1 When this test method is used to evaluate the complete system, the test shall be performed with the manufacturer's tracker and associated controls, and thus the effects of tracking error on thermal performance will be included in the results. Linear single-axis tracking systems may be supplemented with the test laboratory's tracking equipment to effect a two-axis tracking arrangement.5.4.2 When evaluating a thermal collection subsystem, the accuracy of the tracking equipment shall be maintained according to the restrictions in 10.3.5.5 This test method is to be completed at a single appropriate flowrate. For collectors designed to operate at variable flowrates to achieve controlled outlet temperatures, the collector performance shall be characterized by repeating this test method in its entirety for more than one flowrate. These flowrates should be typical of the actual operating conditions of the collectors.5.6 The response time is determined to establish the time required for quasi-steady state conditions to exist before each thermal performance test to assure valid test data, and to determine the length of time over which the quasi-steady state performance is averaged. The response time is calculated from transient temperature data resulting from step changes in intercepted solar irradiance with a given flow rate. Initial quasi-steady state conditions are established, the irradiance level is then increased or decreased suddenly, and the final quasi-steady state conditions are established. For most collectors covered by this test method, the difference in the response time determined by each of the two procedures will be small in terms of actual time. It is recognized that for some collectors, particularly those with long fluid residence times, the difference in the two values of response time may be large. However, the difference has not been found to influence the remainder of the test method.5.7 The incident angle modifier is measured for linear single-axis tracking collectors so that the thermal performance at arbitrary angles of incidence can be predicted from the thermal performance measured at near-normal incidence as required in this test method. This is necessary because, during actual daily operation, linear single-axis tracking collectors will usually be normal to the sun only once or twice.5.7.1 At non-zero angles of incidence, the thermal performance of a linear single-axis tracking collector may change for several reasons:5.7.1.1 Increased or decreased reflectance, transmittance, and absorptance at the concentrator and receiver surfaces, or5.7.1.2 Increased or decreased interception of the reflected or refracted solar radiant energy by the receiver.5.7.1.3 That part of the decreased interception that is due to loss of collected energy at the ends of the absorber can be calculated analytically from the collector geometry as an end effects factor (see Appendix X1).5.7.2 The preferred procedure for determining the incident angle modifier minimizes heat loss from the receiver by requiring that the working heat transfer fluid be the same as is used in the rest of the test method, and that it be maintained at an inlet temperature approximately equal to ambient temperature. It is realized, however, that this procedure may not be practical to perform as specified, since some heat transfer oils become too viscous near ambient temperatures to be pumped through the fluid test loop, or the fluid test loop cannot practicably cool the working fluid sufficiently to approximate the ambient temperatures that typically occur in the winter in cold climates. In these cases, either Alternative Procedure A or B may be used at the discretion of the manufacturer or supplier. Alternative Procedure A uses water as the working fluid at an inlet temperature approximately equal to ambient to minimize heat losses, but the procedure requires careful cleaning of the collector fluid passages, possibly use of a separate fluid test loop, and may cause corrosion if the collector fluid passages are incompatible with water. Alternative Procedure B uses the same heat transfer fluid as is used in the rest of the test method, but at an elevated temperature which is as close as practicable to ambient. Alternative Procedure B involves higher heat losses from the receiver which must be calculated and corrected for. An approximate correction for these heat losses is obtained in Alternative Procedure B by determining the nonirradiated heat loss for the same fluid inlet temperature.5.8 Determination of the angular range of near-normal incidence is required to establish the test conditions under which the measured thermal performance will adequately represent the thermal performance at true normal incidence.NOTE 5: Measurement of angular range of the near-normal incidence also provides data that can be used to evaluate the sensitivity of the thermal performance of the tracking accuracy.5.9 The thermal performance of the solar collector is determined under clear sky conditions and at near-normal incidence because these conditions are reproducible and lead to relatively stable performance.1.1 This test method covers the determination of thermal performance of tracking concentrating solar collectors that heat fluids for use in thermal systems.1.2 This test method applies to one- or two-axis tracking reflecting concentrating collectors in which the fluid enters the collector through a single inlet and leaves the collector through a single outlet, and to those collectors where a single inlet and outlet can be effectively provided, such as into parallel inlets and outlets of multiple collector modules.1.3 This test method is intended for those collectors whose design is such that the effects of diffuse irradiance on performance is negligible and whose performance can be characterized in terms of direct irradiance.NOTE 1: For purposes of clarification, this method shall apply to collectors with a geometric concentration ratio of seven or greater.1.4 The collector may be tested either as a thermal collection subsystem where the effects of tracking errors have been essentially removed from the thermal performance, or as a system with the manufacturer-supplied tracking mechanism.1.4.1 The tests appear as follows:  SectionLinear Single-Axis Tracking Collectors Tested as Thermal Collection Subsystems 11–13System Testing of Linear Single-Axis Tracking Collectors 14–16Linear Two-Axis Tracking and Point Focus Collectors Tested as Thermal Collection Subsystems 17–19System Testing of Point Focus and Linear Two-Axis Tracking Collectors 20–221.5 This test method is not intended for and may not be applicable to phase-change or thermosyphon collectors, to any collector under operating conditions where phase-change occurs, to fixed mirror-tracking receiver collectors, or to central receivers.1.6 This test method is for outdoor testing only, under clear sky, quasi-steady state conditions.1.7 Selection and preparation of the collector (sampling method, preconditioning, mounting, alignment, etc.), calculation of efficiency, and manipulation of the data generated through use of this standard for rating purposes are beyond the scope of this test method, and are expected to be covered elsewhere.1.8 This test method does not provide a means of determining the durability or the reliability of any collector or component.1.9 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.11 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 This standard does not purport to address the mean spectral irradiance incident on tilted or vertical fenestration or building-integrated systems over a day, a season, or a year. The spectral irradiance distributions have been chosen to represent a reasonable near-upper limit for solar radiation when these systems are exposed to clear-sky conditions similar to those used to calculate solar heat loads of buildings. The diffuse spectral irradiance distributions can also be used to represent conditions when these systems are shaded from the direct sun.5.2 Absorptance, reflectance, and transmittance of solar radiation are important factors in studies of light transmission through semi-transparent plates. These properties are normally functions of wavelength, which require that the spectral distribution of the solar flux be known before the solar-weighted property can be calculated.5.3 To compare the relative performance of competitive products by computerized simulations, or to compare the performance of products subjected to experimental tests in laboratory conditions, a reference standard solar spectral distribution for both direct and diffuse irradiance is desirable.5.4 The table provides appropriate standard spectral irradiance distributions for determining the relative optical performance of semi-transparent materials and other systems. The table may be used to evaluate components and materials for the purpose of solar simulation where the direct and the diffuse spectral solar irradiances are needed separately.5.5 The selected air mass value of 1.5 for a plane-parallel atmosphere above a flat earth corresponds to a zenith angle of 48.19°. The SMARTS2 computation of air mass accounts for atmospheric curvature and the vertical density profile of molecules, which results in a solar zenith angle of 48.236°, or an equivalent plane-parallel-atmosphere air mass of 1.50136. The angle of incidence computed by SMARTS for the direct beam irradiance incident on a 20°-tilted plane facing the sun is thus 28.236°. It is 41.764° for a 90°-tilted surface facing the sun.5.6 A plot of the SMARTS model output for the reference direct radiation on a 20° and 90° tilted surfaces is shown in Fig. 1. A similar plot, but for diffuse radiation, is shown in Fig. 2.5.7 The input needed by SMARTS to generate the spectra for the prescribed conditions and the 20°-tilted surface is provided in Table 1. The input file for the 90°-tilted surface differs only by one line. This modified line appears in Table 2.5.8 The total irradiance, integrated over the spectral range 280–4000 nm, is 791.07, 93.02, 97.96, and 889.03 W·m-2 for direct, sky diffuse, total diffuse and global radiation incident on the 20° tilted surface, respectively. It is 669.74, 58.66, 140.56, and 810.30 W·m-2 for direct, sky diffuse, total diffuse and global radiation incident on the 90° tilted surface, respectively.5.9 The availability of the adjunct standard computer software for SMARTS allows one to (a) reproduce the reference spectra, using the above input parameters; (b) compute test spectra to attempt to match measured data at a specified FWHM, and evaluate atmospheric conditions; (c) compute test spectra representing specific conditions for analysis vis-à-vis any one or all of the reference spectra; (d) obtain the sky diffuse and the ground-reflected diffuse spectra (whose sum appears in the table) separately; and (e) smooth the spectral results to different resolution and wavelength step by using the postprocessing options.1.1 This table provides terrestrial solar spectral irradiance distributions that may be employed as weighting functions to (1) calculate the broadband solar or light transmittance of fenestration from its spectral properties; or (2) evaluate the performance of building-integrated technologies such as photovoltaic electricity generators. Most of these systems are installed on vertical walls, but some are also installed on pitched roofs or on other tilted structures, such as sunspaces. Glazing transmittance calculations or measurements require information on both the direct and diffuse components of irradiance. The table provides separate information for direct and diffuse irradiance, and for two different tilt angles, 20° and 90° relative to the horizontal. All distributions are provided at 2002 wavelengths within the spectral range 280–4000 nm. The data contained in this table reflect reference spectra with uniform wavelength interval (0.5 nanometer (nm) below 400 nm, 1 nm between 400 and 1700 nm, an intermediate wavelength at 1702 nm, and 5 nm intervals from 1705 to 4000 nm). The data table represents reasonable cloudless atmospheric conditions favorable for the computerized simulation, comparative rating, or experimental testing of fenestration systems.1.2 The data contained in this table were generated using the SMARTS version 2.9.2 atmospheric transmission model developed by Gueymard (1, 2).1.3 The selection of the SMARTS radiative model to generate the spectral distributions is chosen for compatibility with previous standards (ASTM G173 and G177). The atmospheric and climatic conditions are identical to those in ASTM G173. The environmental conditions are also identical, with only one exception (see sections 4.3 and X1.2).1.4 The table defines four solar spectral irradiance distributions:1.4.1 Separate direct and diffuse solar spectral irradiance incident on a sun-facing, 20° tilted surface in the wavelength region from 280–4000 nm for air mass 1.5, at sea level.1.4.2 Separate direct and diffuse solar spectral irradiance incident on a sun-facing, 90° (vertical) tilted surface in the wavelength region from 280–4000 nm for air mass 1.5, at sea level.1.5 The diffuse spectral distribution on a vertical surface facing away from the sun (i.e., shaded), or at any prescribed azimuth away from the sun, may be computed using the model to obtain representative results (i.e., results that fall within an acceptable range of variance).1.6 The climatic, atmospheric, and geometric parameters selected reflect the conditions to provide a realistic set of spectral distributions appropriate for building applications under very clear-sky conditions, representative of near-maximum solar heat gains in buildings.1.7 A wide variety of orientations or local environmental conditions is possible for exposed surfaces. The availability of the SMARTS model (as an adjunct to this standard) used to generate the standard spectra allows users to evaluate spectral differences relative to the spectra specified here.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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