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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This test method covers measurement techniques for calorimetrically determining the ratio of solar absorptance to hemispherical emittance using a steady-state method, and for calorimetrically determining the total hemispherical emittance using a transient technique. The main elements of the apparatus include a vacuum system, a cold shroud within the vacuum chamber, instrumentation for temperature measurement, and a solar simulator. Any type of coating may be tested by this test method provided its structure remains stable in vacuum over the temperature range of interest. The substrate shall be machined from flat stock and to a size proportioned to the working area of the chamber.1.1 This test method covers measurement techniques for calorimetrically determining the ratio of solar absorptance to hemispherical emittance using a steady-state method, and for calorimetrically determining the total hemispherical emittance using a transient technique.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.

定价： 590元 / 折扣价： 502 元 加购物车

4.1 Although this practice is intended for evaluating solar absorber materials and coatings used in flat-plate collectors, no single procedure can duplicate the wide range of temperatures and environmental conditions to which these materials may be exposed during in-service conditions.4.2 This practice is intended as a screening test for absorber materials and coatings. All conditions are chosen to be representative of those encountered in solar collectors with single cover plates and with no added means of limiting the temperature during stagnation conditions.4.3 This practice uses exposure in a simulated collector with a single cover plate. Although collectors with additional cover plates will produce higher temperatures at stagnation, this procedure is considered to provide adequate thermal testing for most applications.NOTE 1: Mathematical modeling has shown that a selective absorber, single glazed flat-plate solar collector can attain absorber plate stagnation temperatures as high as 226 °C (437 °F) with an ambient temperature of 37.8 °C (100 °F) and zero wind velocity, and a double glazed one as high as 245 °C (482 °F) under these conditions. The same configuration solar collector with a nonselective absorber can attain absorber stagnation temperatures as high as 146 °C (284 °F) if single glazed, and 185 °C (360 °F) if double glazed, with the same environmental conditions (see “Performance Criteria for Solar Heating and Cooling Systems in Commercial Buildings,” NBS Technical Note 1187).44.4 This practice evaluates the thermal stability of absorber materials. It does not evaluate the moisture stability of absorber materials used in actual solar collectors exposed outdoors. Moisture intrusion into solar collectors is a frequent occurrence in addition to condensation caused by diurnal breathing.4.5 This practice differentiates between the testing of spectrally selective absorbers and nonselective absorbers.4.5.1 Testing Spectrally Selective Absorber Coatings and Materials—Spectrally selective solar absorptive coatings and materials require testing in a covered enclosure that contains a selectively coated sample mounting plate, such that the enclosure and mounting plate simulate the temperature conditions of a selective flat-plate collector exposed under stagnation conditions.4.5.2 Testing Nonselective Coatings and Materials—Spectrally nonselective solar absorptive coatings and materials require testing in a covered enclosure that contains a nonselective coated sample mounting plate, such that the enclosure and mounting plate simulate the temperature conditions of a covered, nonselective flat-plate collector exposed under stagnation conditions.1.1 This practice covers a test procedure for evaluating absorptive solar receiver materials and coatings when exposed to sunlight under cover plate(s) for long durations. This practice is intended to evaluate the exposure resistance of absorber materials and coatings used in flat-plate collectors where maximum non-operational stagnation temperatures will be approximately 200 °C (392 °F).1.2 This practice shall not apply to receiver materials used in solar collectors without covers (unglazed) or in evacuated collectors, that is, those that use a vacuum to suppress convective and conductive thermal losses.1.3 The values stated in SI units are to be regarded as the standard.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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3.1 This practice describes a weathering box test fixture and provides uniform exposure guidelines to minimize the variables encountered during outdoor exposure testing.3.2 This practice may be useful in comparing the performance of different materials at one site or the performance of the same material at different sites, or both.3.3 Since the combination of elevated temperature and solar radiation may cause some solar collector cover materials to degrade more rapidly than either alone, a weathering box that elevates the temperature of the cover materials is used.3.4 This practice is intended to assist in the evaluation of solar collector cover materials in the operational, not stagnation mode. Insufficient data exist to obtain exact correlation between the behavior of materials exposed according to this practice and actual in-service performance.3.5 Means of evaluation of effects of weathering are provided in Practice E781, and in other ASTM test methods that evaluate material properties.3.6 Tests 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 which comprise weather. Exposure conditions are complex and changeable. Important factors are solar radiation, temperature, moisture, time of year, presence of pollutants, etc. These factors vary from site to site and should be considered in selecting locations for exposure. Control samples must always be used in weathering tests for comparative analysis. Outdoor exposure for at least two years is required to make evident changes, such as surface degradation without the use of sophisticated analytical equipment.3.7 Temperature conditions attained with this box may not exactly duplicate those that occur under operational conditions with fluid flow. Dependent on environmental exposure conditions, the cover plate temperatures obtained with this box may be higher or lower than those obtained under operational conditions. Additional testing under stagnation conditions, although not covered by this practice, should be conducted.NOTE 1: Research has shown that exposure outdoors at sites having the combination of high levels of humidity, solar energy, and ambient temperature can cause more severe degradation of some polymeric cover materials (for example, microcracking and leaching of UV radiation screening additives) than exposure in arid climates.NOTE 2: Stagnation conditions are a normal occurrence for solar collectors, for example, during operation when the storage is fully charged; when the collectors are initially installed, before system start-up; or when the system is shut down for maintenance or seasonal considerations such as heating only systems in the summer.1.1 This practice provides a procedure for the exposure of cover materials for flat-plate solar collectors to the natural weather environment at temperatures that are elevated to approximate operating conditions.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 or photovoltaics.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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5.1 The solar reflectance of a building envelope surface affects surface temperature and near-surface ambient air temperature. Surfaces with low solar reflectance absorb a high fraction of the incoming solar energy. Sunlight absorbed by a roof or by other building envelope surfaces can be conducted into the building, increasing cooling load and decreasing heating load in a conditioned building, or raising indoor temperature in an unconditioned building. It can also warm the outside air by convection. Determination of solar reflectance can help designers and consumers choose appropriate materials for their buildings and communities.5.1.1 The solar reflectance of a new building envelope surface often changes within one to two years through deposition and retention of soot and dust; microbiological growth; exposure to sunlight, precipitation, and dew; and other processes of soiling and weathering. For example, light-colored “cool” envelope surfaces with high initial reflectance can experience substantial reflectance loss as they are covered with dark soiling agents. Current product rating programs require roofing manufacturers to report values of solar reflectance and thermal emittance measured after three years of natural exposure (2, 3). A rapid laboratory process for soiling and weathering that simulates the three-year-aged radiative properties of roof and other building envelope surface materials expedites the development, testing, and introduction to market of such products.5.2 Thermal emittance describes the efficiency with which a surface exchanges thermal radiation with its environment. High thermal emittance enhances the ability of a surface to stay cool in the sun. The thermal emittance of a bare metal surface is initially low, and often increases as it is soiled or oxidized (4). The thermal emittance of a typical non-metal surface is initially high, and remains high after soiling (5).5.3 This practice allows measurement of the solar reflectance and thermal emittance of a roofing specimen after the application of the simulated field exposure.5.4 This practice is intended to be referenced by another standard, such as ANSI/CRRC S100, that specifies practices for specimen selection and methods for radiative measurement.1.1 Practice D7897 applies to simulation of the effects of field exposure on the solar reflectance and thermal emittance of roof surface materials including but not limited to field-applied coatings, factory-applied coatings, single-ply membranes, modified bitumen products, shingles, tiles, and metal products. The solar reflectance and thermal emittance of roof surfacing materials can be changed by exposure to the outdoor environment. These changes are caused by three factors: deposition and retention of airborne pollutants, microbiological growth, and changes in physical or chemical properties. This practice applies to simulation of changes in solar reflectance and thermal emittance induced by deposition and retention of airborne pollutants and, to a limited extent, changes caused by microbiological growth.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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5.1 To overcome the inadequacies of conventional spectrophotometric measurement techniques when nonhomogeneous materials are measured, a large integrating sphere may be used.4,5 Since the beam employed in such spheres is large in comparison to the disparaties of the materials being tested, the nonisotropic nature of the specimen being measured is essentially averaged, or integrated out of the measurement, in a single experimental determination.5.2 Solar and photopic optical properties may be measured either with monofunctional spheres individually tailored for the measurement of either transmittance5 or reflectance, or may be measured with a single multifunctional sphere that is employed to measure both transmittance and reflectance.45.3 A multifunctional sphere is used for making total solar transmittance measurements in both a directional-hemispherical and a directional-directional mode. The solar absorptance can be evaluated in a single measurement as one minus the sum of the directional hemispherical reflectance and transmittance. When a sample at the center of the sphere is supported by its rim, the sum of the reflectance and transmittance can be measured as a function of the angle of incidence. The solar absorptance is then one minus the measured absorptance plus transmittance.1.1 This test method covers the measurement of the absolute total solar or photopic reflectance, transmittance, or absorptance of materials and surfaces. Although there are several applicable test methods employed for determining the optical properties of materials, they are generally useful only for flat, homogeneous, isotropic specimens. Materials that are patterned, textured, corrugated, or are of unusual size cannot be measured accurately using conventional spectrophotometric techniques, or require numerous measurements to obtain a relevant optical value. The purpose of this test method is to provide a means for making accurate optical property measurements of spatially nonuniform materials.1.2 This test method is applicable to large specimens of materials having both specular and diffuse optical properties. It is particularly suited to the measurement of the reflectance of opaque materials and the reflectance and transmittance of semitransparent materials including corrugated fiber-reinforced plastic, composite transparent and translucent samples, heavily textured surfaces, and nonhomogeneous materials such as woven wood, window blinds, draperies, etc.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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. (For specific safety hazards, see Note 1.)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.

定价： 515元 / 折扣价： 438 元 加购物车

This practice provides guidance for making adequate thermal balance tests of spacecraft and components where solar simulation has been determined to be the applicable method. Careful adherence to this practice should ensure the adequate simulation of the radiation environment of space for thermal tests of space vehicles. This practice also provides the proper test environment for systems-integration tests of space vehicles. However, there is no discussion herein of the extensive electronic equipment and procedures required to support such tests. This practice does not apply to or provide incomplete coverage of the following types of tests: launch phase or atmospheric reentry of space vehicles; landers on planet surfaces; degradation of thermal coatings; increased friction in space of mechanical devices, sometimes called "cold welding"; sun sensors; man in space; energy conversion devices; and tests of components for leaks, outgassing, radiation damage, or bulk thermal properties.1.1 Purpose: 1.1.1 The primary purpose of this practice is to provide guidance for making adequate thermal balance tests of spacecraft and components where solar simulation has been determined to be the applicable method. Careful adherence to this practice should ensure the adequate simulation of the radiation environment of space for thermal tests of space vehicles.1.1.2 A corollary purpose is to provide the proper test environment for systems-integration tests of space vehicles. An accurate space-simulation test for thermal balance generally will provide a good environment for operating all electrical and mechanical systems in their various mission modes to determine interferences within the complete system. Although adherence to this practice will provide the correct thermal environment for this type of test, there is no discussion of the extensive electronic equipment and procedures required to support systems-integration testing.1.2 Nonapplicability—This practice does not apply to or provide incomplete coverage of the following types of tests:1.2.1 Launch phase or atmospheric reentry of space vehicles,1.2.2 Landers on planet surfaces,1.2.3 Degradation of thermal coatings,1.2.4 Increased friction in space of mechanical devices, sometimes called “cold welding,”1.2.5 Sun sensors,1.2.6 Man in space,1.2.7 Energy conversion devices, and1.2.8 Tests of components for leaks, outgassing, radiation damage, or bulk thermal properties.1.3 Range of Application: 1.3.1 The extreme diversification of space-craft, design philosophies, and analytical effort makes the preparation of a brief, concise document impossible. Because of this, various spacecraft parameters are classified and related to the important characteristic of space simulators in a chart in 7.6.1.3.2 The ultimate result of the thermal balance test is to prove the thermal design to the satisfaction of the thermal designers. Flexibility must be provided to them to trade off additional analytical effort for simulator shortcomings. The combination of a comprehensive thermal-analytical model, modern computers, and a competent team of analysts greatly reduces the requirements for accuracy of space simulation.1.4 Utility—This practice will be useful during space vehicle test phases from the development through flight acceptance test. It should provide guidance for space simulation testing early in the design phase of thermal control models of subsystems and spacecraft. Flight spacecraft frequently are tested before launch. Occasionally, tests are made in a space chamber after a sister spacecraft is launched as an aid in analyzing anomalies that occur in space.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.

定价： 843元 / 折扣价： 717 元 加购物车

2.1 In many geographic areas there is concern about the effect of falling hail upon solar collector covers. This practice may be used to determine the ability of flat-plate solar collector covers to withstand the impact forces of hailstones. In this practice, the ability of a solar collector cover plate to withstand hail impact is related to its tested ability to withstand impact from ice balls. The effects of the impact on the material are highly variable and dependent upon the material.2.2 This practice describes a standard procedure for mounting the test specimen, conducting the impact test, and reporting the effects.2.2.1 The procedures for mounting cover plate materials and collectors are provided to ensure that they are tested in a configuration that relates to their use in a solar collector.2.2.2 The corner locations of the four impacts are chosen to represent vulnerable sites on the cover plate. Impacts near corner supports are more critical than impacts elsewhere. Only a single impact is specified at each of the impact locations. For test control purposes, multiple impacts in a single location are not permitted because a subcritical impact may still cause damage that would alter the response to subsequent impacts.2.2.3 Resultant velocity is used to simulate the velocity that may be reached by hail accompanied by wind. The resultant velocity used in this practice is determined by vector addition of a 20 m/s (45 mph) horizontal velocity to the vertical terminal velocity.2.2.4 Ice balls are used in this practice to simulate hailstones because natural hailstones are not readily available to use, and ice balls closely approximate hailstones. However, no direct relationship has been established between the effect of impact of ice balls and hailstones. Hailstones are highly variable in properties such as shape, density, and frangibility.2 These properties affect factors such as the kinetic energy delivered to the cover plate, the period during which energy is delivered, and the area over which the energy is distributed. Ice balls, with a density, frangibility, and terminal velocity near the range of hailstones, are the nearest hailstone approximation known at this time. Perhaps the major difference between ice balls and hailstones is that hailstones are much more variable than ice balls. However, ice balls can be uniformly and repeatedly manufactured to ensure a projectile with known properties.2.2.5 A wide range of observable effects may be produced by impacting the various types of cover plate materials. The effects may vary from no effect to total destruction. Some changes in the cover material may be visible when there is no apparent functional impairment of the cover plate material. All effects of each impact must be described in the report so that an estimate of their significance can be made.2.3 Data generated using this practice may be used: (1) to evaluate impact resistance of a single material or collector, (2) to compare the impact resistance of several materials or collectors, (3) to provide a common basis for selection of cover materials or collectors for use in various geographic areas, or (4) to evaluate changes in impact resistance due to environmental factors such as weather.2.4 This practice does not state the size(s) of ice ball(s) to be used in making the impact. Either the person requesting the test or the person performing the test must determine ice ball size to be used in the testing. Choice of ice ball size may relate to the intent of the testing.2.4.1 If the testing is being performed to evaluate impact resistance of a single material or collector, or several materials or collectors, it may be desirable to repeat the test using several sizes of ice balls. In this manner the different effects of various sizes of ice balls may be determined.2.4.2 The size and frequency of hail varies significantly among various geographic areas. If testing is being performed to evaluate materials or collectors intended for use in a specific geographic area, the ice ball size should correspond to the level of hail impact resistance required for that area. Information on hail size and frequency may be available from local historical weather records or may be determined from the publications listed in Appendix X1.2.5 The hail impact resistance of materials may change as the materials are exposed to various environmental factors. This practice may be used to generate data to evaluate degradation by comparison of hail impact resistance data measured before and after exposure to such aging.1.1 This practice covers a procedure for determining the ability of cover plates for flat-plate solar collectors to withstand impact forces of falling hail. Propelled ice balls are used to simulate falling hailstones. This practice is not intended to apply to photovoltaic cells or arrays.1.2 This practice defines two types of test specimens, describes methods for mounting specimens, specifies impact locations on each test specimen, provides an equation for determining the velocity of any size ice ball, provides a method for impacting the test specimens with ice balls, and specifies parameters that must be recorded and reported.1.3 This practice does not establish pass or fail levels. The determination of acceptable or unacceptable levels of ice-ball impact resistance is beyond the scope of this practice.1.4 The size of ice ball to be used in conducting this test is not specified in this practice. This practice can be used with various sizes of ice balls.1.5 The categories of solar collector cover plate materials to which this practice may be applied cover the range of:1.5.1 Brittle sheet, such as glass,1.5.2 Semirigid sheet, such as plastic, and1.5.3 Flexible membrane, such as plastic film.1.6 Solar collector cover materials should be tested as:1.6.1 Part of an assembled collector (Type 1 specimen), or1.6.2 Mounted on a separate test frame cover plate holder (Type 2 specimen).1.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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.

定价： 590元 / 折扣价： 502 元 加购物车

Exposure in a nonoperational mode provides for conditioning and assessment of the physical appearance of a solar collector resulting from moderately severe solar irradiation, ambient temperature, and effects of moisture on the various materials or construction.This practice describes actual exposure conditions that have a high probability of occurring sometime during the installation of a solar collector, or during operation, or malfunction of a solar energy system.This practice shall be considered to be a limited aging test in that it does not address those aging effects resulting from fluid-to-collector interfaces.This practice applies to all solar thermal collector types.1.1 This practice defines the procedure to expose a solar thermal collector to an outdoor or simulated outdoor environment in a nonoperational model. The procedure provides for periodic inspections and a post-exposure disassembly and inspection of the collector.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 and health practices and determine the applicability of regulatory limitations prior to use.

定价： 0元 / 折扣价： 0 元

This specification establishes the general requirements for two types, two classes, and seven grades of rubber seals used in solar energy systems employing air-heat transport, such as duct and damper seals. Particular applications may necessitate other requirements that would take precedence over these requirements when specified. The design requirement stated herein pertains only to permissible deflections of the rubber during thermal expansion or contraction of the seal in use and the tolerances in dimensions of molded and extruded seals. This specification does not address the requirements pertaining to the fabrication or installation of the seals. Type C seals are intended for use in cold climates, while Type W seals are intended for use in warm climates. Grade designations (Grades 2 to 8) represent differing degrees of hardness. Finally, Class PS are preformed rubber seals, while Class SC are sealing compounds. Each class shall conform to individually specified values of the following requirements: ultimate elongation; compression set at specified times and temperatures; resistance to heating (hardness and ultimate elongation change, and volatiles lost); resistance to ozone; resistance to low temperature; and adhesion loss.1.1 This specification covers the general requirements for the rubber seals used in solar energy systems employing air-heat transport. Examples are duct and damper seals. Particular applications may necessitate other requirements that would take precedence over these requirements when specified.NOTE 1: Rubber seals for the collector are covered in Specifications D3667 and D3771.1.2 Design requirement pertains only to permissible deflections of the rubber during thermal expansion or contraction of the seal in use and the tolerances in dimensions of molded and extruded seals.1.3 This specification does not include requirements pertaining to the fabrication or installation of the seals.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 The following safety hazards caveat pertains only to the test methods portion, Section 10, of this specification: 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.

定价： 515元 / 折扣价： 438 元 加购物车

1.1 These tables define the solar constant and zero air mass solar spectral irradiance for use in thermal analysis, thermal balance testing, and other tests of spacecraft and spacecraft components and materials. Typical applications include the calculation of solar absorptance from spectral reflectance data, the specification of solar UV exposure of materials during simulated space radiation testing, and the rating of photovoltaic cells deployed in space.1.2 These tables are based upon data from experimental measurements made mostly from spacecraft, with minor contributions from observations made on high-altitude aircraft, or from the earth's surface.1.3 These tables are representative of periods when the sun’s activity is average or moderate. The sun’s activity tends to modify its spectrum almost exclusively in the UV and extreme UV spectral regions (below 0.1 µm).1.4 Units—The values stated in SI units are to be regarded as standard. Other units of measurement are included for information purposes 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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4.1 Solar transmittance is an important factor in the admission of energy through fenestration, collector glazing, and protective envelopes. This test method provides a means of measuring this factor under fixed conditions. While the data may be of assistance to designers in the selection and specification of glazing materials, the solar transmittance is not sufficient to define the rate of net heat transfer without information on other important factors.4.2 This test method has been found practical for both transparent and translucent materials, as well as for those with transmittance reduced by highly reflective coatings. This test method is particularly applicable to the measurement of transmittance of inhomogeneous, fiber reinforced, patterned, or corrugated materials since the transmittance is averaged over a large area.4.3 This test method may be used to measure transmittance of glazing materials at angles up to 60° off normal incidence.NOTE 1: A technique similar to the one described but using a pyrheliometer has been used for the measurement of specular solar reflectance; however, there is insufficient experience with this technique for standardization at present.1.1 This test method covers the measurement of solar transmittance (terrestrial) of materials in sheet form by using a pyranometer, an enclosure, and the sun as the energy source.1.2 This test method also allows measurement of solar transmittance at angles other than normal incidence.1.3 This test method is applicable to sheet materials that are transparent, translucent, textured, or patterned.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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The rain spray test described in 8.1 as Method A is based upon Test Method E 331 which is intended for use in the evaluation of exterior windows, curtain walls, and doors. This test method is intended to supplement the water spray test in Practice E 823 that does not include the effects of wind-driven rain. This method includes the use of a pressure differential to enhance the penetration of water into the assembly being tested. This type of pressure differential can occur with many types of solar collector mounting configurations. In the case of solar collectors that form a building element, for example, a roof, this pressure differential will be caused by differences of pressure inside and outside the building. In the case of solar collectors mounted on standoffs or racks, this pressure differential will be caused by positive and negative wind forces acting simultaneously on faces of the collector.Water leakage due to joint expansion can be influenced by several factors, including: the specific collector design and materials used, the test specimen temperature, and the water spray temperature (Note 1), in addition to the pressure differential. The temperature conditions will vary in outdoor exposure. The test temperatures should be selected to be representative of outdoor conditions where the collectors will be used.Note 1—Water spray temperatures are likely to range from 4.5°C to 29.4°C (40 to 85°F).1.1 This test method covers the determination of the resistance of flat plate solar collectors to water penetration when water is applied to their outer surfaces with a static air pressure at the outer surface higher than the pressure at the interior of the collector.1.2 This test method is applicable to any flat plate solar collector.1.3 The proper use of this test method requires a knowledge of the principles of pressure and deflection measurement.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 and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary information is contained in Section 6.

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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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