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ASTM E927-04a

(Specification)

Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing

Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing

SCOPE
1.1 This specification provides means for classifying solar simulators intended for indoor testing of photovoltaic devices (solar cells or modules), according to their spectral match to a reference spectral irradiance, non-uniformity of spatial irradiance, and temporal instability of irradiance.
1.2 Testing of photovoltaic devices may require the use of solar simulators. Test Methods that require specific classification of simulators as defined in this specification include Test Methods E 948, E 1036, and E 1362.
1.3 This standard is applicable to both pulsed and steady state simulators and includes recommended test requirements used for classifying such simulators.
1.4 A solar simulator usually consists of three major components: (1) light source(s) and associated power supply; (2) any optics and filters required to modify the output beam to meet the classification requirements in Section ; and (3) the necessary controls to operate the simulator, adjust irradiance, etc.
1.5 A light source that does not meet all of the defined requirements for classification presented in this document may not be referred to as a solar simulator.
1.6 Spectral irradiance classifications are provided for Air Mass 1.5 direct and global (as defined in Tables G 173), or Air Mass 0 (AM0, as defined in Standard E 490).
1.7 The classification of a solar simulator is based on the size of the test plane; simulators with smaller test plane areas have tighter specifications for non-uniformity of spatial irradiance.
1.8 The data acquisition system may affect the ability to synchronize electrical measurements with variations in irradiance and therefore may be included in this specification. In all cases, the manufacturer must specify with the temporal instability classification: (1) how the classification was determined; and (2) the conditions under which the classification was determined.
1.9 The classification of a solar simulator does not provide any information about electrical measurement errors that are related to photovoltaic performance measurements obtained with a classified solar simulator. Such errors are dependent on the actual instrumentation and procedures used.
1.10 There is no similar or equivalent ISO standard.
1.11 UnitsThe values stated in SI are to be regarded as standard. No other units of measurement are included in this standard.
The following precautionary caveat pertains only to the hazards portion, Section , 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 and health practices and determine the applicability of regulatory requirements prior to use.

General Information

Status
Historical
Publication Date
31-Aug-2004
ICS
27.160 - Solar energy engineering
Technical Committee
E44 - Solar, Geothermal and Other Alternative Energy Sources
Drafting Committee
E44.09 - Photovoltaic Electric Power Conversion
Current Stage
Ref Project

Relations

Replaces
ASTM E927-04 - Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing
Effective Date
01-Sep-2004
Replaced By
ASTM E927-05 - Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing
Effective Date
01-Apr-2005
Referred By
ASTM G214-23 - Standard Test Method for Integration of Digital Spectral Data for Weathering and Durability Applications
Effective Date
01-Sep-2004
Referred By
ASTM E1125-16(2020) - Standard Test Method for Calibration of Primary Non-Concentrator Terrestrial Photovoltaic Reference Cells Using a Tabular Spectrum
Effective Date
01-Sep-2004
Referred By
ASTM E1036-15(2019) - Standard Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using Reference Cells
Effective Date
01-Sep-2004
Referred By
ASTM E2236-10(2019) - Standard Test Methods for Measurement of Electrical Performance and Spectral Response of Nonconcentrator Multijunction Photovoltaic Cells and Modules
Effective Date
01-Sep-2004
Referred By
ASTM E1021-15(2019) - Standard Test Method for Spectral Responsivity Measurements of Photovoltaic Devices
Effective Date
01-Sep-2004
Referred By
ASTM E1362-15(2019) - Standard Test Methods for Calibration of Non-Concentrator Photovoltaic Non-Primary Reference Cells
Effective Date
01-Sep-2004
Referred By
ASTM E772-15(2021) - Standard Terminology of Solar Energy Conversion
Effective Date
01-Sep-2004
Referred By
ASTM E2848-13(2023) - Standard Test Method for Reporting Photovoltaic Non-Concentrator System Performance
Effective Date
01-Sep-2004
Referred By
ASTM E948-16(2020) - Standard Test Method for Electrical Performance of Photovoltaic Cells Using Reference Cells Under Simulated Sunlight
Effective Date
01-Sep-2004
Referred By
ASTM E2481-12(2023) - Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules
Effective Date
01-Sep-2004

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ASTM E927-04a - Standard Specification for Solar Simulation for Terrestrial Photovoltaic TestingASTM E927-04a - Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing
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ASTM E927-04a - Standard Specification for Solar Simulation for Terrestrial Photovoltaic Testing
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E 927 – 04a
Standard Specification for
1
Solar Simulation for Photovoltaic Testing
This standard is issued under the fixed designation E 927; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope related to photovoltaic performance measurements obtained
with a classified solar simulator. Such errors are dependent on
1.1 This specification provides means for classifying solar
the actual instrumentation and procedures used.
simulators intended for indoor testing of photovoltaic devices
1.10 There is no similar or equivalent ISO standard.
(solar cells or modules), according to their spectral match to a
1.11 Units—The values stated in SI are to be regarded as
reference spectral irradiance, non-uniformity of spatial irradi-
standard. No other units of measurement are included in this
ance, and temporal instability of irradiance.
standard.
1.2 Testing of photovoltaic devices may require the use of
1.12 Thefollowingprecautionarycaveatpertainsonlytothe
solar simulators. Test Methods that require specific classifica-
hazards portion, Section 6, of this specification. This standard
tion of simulators as defined in this specification include Test
does not purport to address all of the safety concerns, if any,
Methods E 948, E 1036, and E 1362.
associated with its use. It is the responsibility of the user of this
1.3 This standard is applicable to both pulsed and steady
standard to establish appropriate safety and health practices
state simulators and includes recommended test requirements
and determine the applicability of regulatory requirements
used for classifying such simulators.
prior to use.
1.4 A solar simulator usually consists of three major com-
ponents: (1) light source(s) and associated power supply; (2)
2. Referenced Documents
any optics and filters required to modify the output beam to
2
2.1 ASTM Standards:
meet the classification requirements in Section 4; and (3) the
E 490 Standard Solar Constant and Air Mass Zero Solar
necessary controls to operate the simulator, adjust irradiance,
Spectral Irradiance Tables
etc.
E 772 Terminology Relating to Solar Energy Conversion
1.5 A light source that does not meet all of the defined
E 948 Test Method for Electrical Performance of Photovol-
requirements for classification presented in this document may
taicCellsUsingReferenceCellsUnderSimulatedSunlight
not be referred to as a solar simulator.
E 1036 Test Methods for Electrical Performance of Non-
1.6 Spectral irradiance classifications are provided for Air
concentrator Terrestrial Photovoltaic Modules and Arrays
Mass 1.5 direct and global (as defined in Tables G 173), orAir
Using Reference Cells
Mass 0 (AM0, as defined in Standard E 490).
E 1328 Terminology Relating to Photovoltaic Solar Energy
1.7 The classification of a solar simulator is based on the
Conversion
size of the test plane; simulators with smaller test plane areas
E 1362 Test Method for Calibration of Non-Concentrator
have tighter specifications for non-uniformity of spatial irradi-
Photovoltaic Secondary Reference Cells
ance.
G 138 Test Method for Calibration of a Spectroradiometer
1.8 The data acquisition system may affect the ability to
Using a Standard Source of Irradiance
synchronize electrical measurements with variations in irradi-
G 173 Tables for Reference Solar Spectral Irradiances:
ance and therefore may be included in this specification. In all
Direct Normal and Hemispherical on 37° Tilted Surface
cases, the manufacturer must specify with the temporal insta-
2.2 IEC Standard:
bility classification: (1) how the classification was determined;
IEC 60904-9 Photovoltaic Devices—Part 9: Solar Simula-
and (2) the conditions under which the classification was
tor Performance Requirements
determined.
1.9 The classification of a solar simulator does not provide
3. Terminology
any information about electrical measurement errors that are
3.1 Definitions—Definitions of terms used in this specifica-
tion may be found in Terminologies E 772 and E 1328.
1
This specification is under the jurisdiction ofASTM Committee E44 on Solar,
2
Geothermal and OtherAlternative Energy Sources and is the direct responsibility of For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Subcommittee E44.09 on Photovoltaic Electric Power Conversion. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved September 1, 2004. Published September 2004. Standards volume information, refer to the standard’s Document Summary page on
Originally approved in 1983. Last previous edition approved in 2004 as E 927 – 04. the AST
...

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ASTM E2481-12(2023)(Test Method)
Standard Test Method for Hot Spot Protection Testing of Photovoltaic Modules

SIGNIFICANCE AND USE
4.1 The design of a photovoltaic module or system intended to provide safe conversion of the sun's radiant energy into useful electricity must take into consideration the possibility of partial shadowing of the module(s) during operation. This test method describes a procedure for verifying that the design and construction of the module provides adequate protection against the potential harmful effects of hot spots during normal installation and use.  
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4.3 Hot spot heating occurs in a module when its operating current exceeds the reduced short-circuit current (ISC) of a shadowed or faulty cell or group of cells. When such a condition occurs, the affected cell or group of cells is forced into reverse bias and must dissipate power, which can cause overheating.
Note 1: The correct use of bypass diodes can prevent hot spot damage from occurring.  
4.4 Fig. 1 illustrates the hot spot effect in a module of a series string of cells, one of which, cell Y, is partially shadowed. The amount of electrical power dissipated in Y is equal to the product of the module current and the reverse voltage developed across Y. For any irradiance level, when the reverse voltage across Y is equal to the voltage generated by the remaining (s-1) cells in the module, power dissipation is at a maximum when the module is short-circuited. This is shown in Fig. 1 by the shaded rectangle constructed at the intersection of the reverse I-V characteristic of Y with the image of the forward I-V characteristic of the (s-1) cells.
FIG. 1 Hot Spot Effect  
4.5 Bypass diodes, if present, as shown in Fig. 2, begin conducting when a series-connected string in a module is in reverse bias, thereby limiting the power dissipation in the reduced-output cell.  
FIG. 2 Bypass Diode Effect  
Note 2: If the ...
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1.1 This test method provides a procedure to determine the ability of a photovoltaic (PV) module to endure the long-term effects of periodic “hot spot” heating associated with common fault conditions such as severely cracked or mismatched cells, single-point open circuit failures (for example, interconnect failures), partial (or nonuniform) shadowing, or soiling. Such effects typically include solder melting or deterioration of the encapsulation, but in severe cases could progress to combustion of the PV module and surrounding materials.  
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ASTM E2939-13(2023)(Practice)
Standard Practice for Determining Reporting Conditions and Expected Capacity for Photovoltaic Non-Concentrator Systems

SIGNIFICANCE AND USE
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4.1 Environmental stress tests, such as those listed in 1.2, are normally used to evaluate module designs prior to production or purchase. These test methods rely on performing electrical tests and visual inspections of modules before and after stress testing to determine the effects of the exposures.  
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5.1 Because there are a number of choices in this test method that depend on different applications and system configurations, it is the responsibility of the user of this test method to specify the details and protocol of an individual system power measurement prior to the beginning of a measurement.  
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1.1 This test method provides measurement and analysis procedures for determining the capacity of a specific photovoltaic system built in a particular place and in operation under natural sunlight.  
1.2 This test method is used for the following purposes:  
1.2.1 Acceptance testing of newly installed photovoltaic systems,  
1.2.2 Reporting of dc or ac system performance, and  
1.2.3 Monitoring of photovoltaic system performance.  
1.3 This test method should not be used for:  
1.3.1 Testing of individual photovoltaic modules for comparison to nameplate power ratings,  
1.3.2 Testing of individual photovoltaic modules or systems for comparison to other photovoltaic modules or systems, and  
1.3.3 Testing of photovoltaic systems for the purpose of comparing the performance of photovoltaic systems located in different places.  
1.4 In this test method, photovoltaic system power is reported with respect to a set of reporting conditions (RC) including solar irradiance in the plane of the modules, ambient temperature, and wind speed (see Section 6). Measurements under a variety of reporting conditions are allowed to facilitate testing and comparison of results.  
1.5 This test method assumes that the solar cell temperature is directly influenced by ambient temperature and wind speed; if not the regression results may be less meaningful.  
1.6 The capacity measured according to this test method should not be used to make representations about the energy generation capabilities of the system.  
1.7 This test method is not applicable to concentrator photovoltaic systems; as an alternative, Test Method E2527 should be considered for such systems.  
1.8 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.9 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...

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ASTM E781-86(2023)(Practice)
Standard Practice for Evaluating Absorptive Solar Receiver Materials When Exposed to Conditions Simulating Stagnation in Solar Collectors with Cover Plates

SIGNIFICANCE AND USE
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).4  
4.4 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.  
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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.  
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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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ASTM E822-92(2023)(Practice)
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SIGNIFICANCE AND USE
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 ...
SCOPE
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, and  
1.5.3 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), or  
1.6.2 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 internatio...

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ASTM
ASTM E881-92(2022)(Practice)
Standard Practice for Exposure of Solar Collector Cover Materials to Natural Weathering Under Conditions Simulating Stagnation Mode

SIGNIFICANCE AND USE
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 req...
SCOPE
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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ASTM
ASTM E782-95(2022)(Practice)
Standard Practice for Exposure of Cover Materials for Solar Collectors to Natural Weathering Under Conditions Simulating Operational Mode

SIGNIFICANCE AND USE
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 und...
SCOPE
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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