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ASTM E861-94(2007)

(Practice)

Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors

Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors

SIGNIFICANCE AND USE
The exposure conditions in solar collectors, especially under stagnation conditions, may degrade the performance of thermal insulation materials. This practice sets forth a methodology for evaluating the degree of degradation, if any, of the thermal insulation materials after exposure to simulated in-service conditions.
This practice is also intended to aid in the assessment of long-term performance by comparative testing of insulation materials. However, correlations between performance under laboratory and actual in-service conditions have not been established.
This practice also sets forth criteria that shall be considered in the selection and specification of thermal insulation materials. One such criterion is surface burning characteristics (Test Method E 84), which is used by many code officials as a reference. This practice does not represent that the numerical values obtained in any way reflect the anticipated performance of the thermal insulation under actual fire conditions.
SCOPE
1.1 This practice sets forth a testing methodology for evaluating the properties of thermal insulation materials to be used in solar collectors with concentration ratios of less than 10. Tests are given herein to evaluate the pH, surface burning characteristics, moisture adsorption, water absorption, thermal resistance, linear shrinkage (or expansion), hot surface performance, and accelerated aging. This practice provides a test for surface burning characteristics but does not provide a methodology for determining combustibility performance of thermal insulation materials.
1.2 The tests shall apply to blanket, rigid board, loose-fill, and foam thermal insulation materials used in solar collectors. Other thermal insulation materials shall be tested in accordance with the provisions set forth herein and should not be excluded from consideration.
1.3 The assumption is made that elevated temperature, moisture, and applied stresses are the primary factors contributing to the degradation of thermal insulation materials used in solar collectors.
1.4 Solar radiation is not considered a contributing factor since insulating materials are not normally exposed to it.
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.

General Information

Status
Historical
Publication Date
28-Feb-2007
ICS
27.160 - Solar energy engineering
Technical Committee
E44 - Solar, Geothermal and Other Alternative Energy Sources
Current Stage
Ref Project

Relations

Replaces
ASTM E861-94(2001) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors
Effective Date
01-Mar-2007

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ASTM E861-94(2007) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar CollectorsASTM E861-94(2007) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors
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ASTM E861-94(2007) - Standard Practice for Evaluating Thermal Insulation Materials for Use in Solar Collectors
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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: E861 − 94(Reapproved 2007)
Standard Practice for
Evaluating Thermal Insulation Materials for Use in Solar
Collectors
This standard is issued under the fixed designation E861; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope C177Test Method for Steady-State Heat Flux Measure-
ments and Thermal Transmission Properties by Means of
1.1 This practice sets forth a testing methodology for
the Guarded-Hot-Plate Apparatus
evaluating the properties of thermal insulation materials to be
C209Test Methods for Cellulosic Fiber Insulating Board
used in solar collectors with concentration ratios of less than
C356Test Method for Linear Shrinkage of Preformed High-
10. Tests are given herein to evaluate the pH, surface burning
Temperature Thermal Insulation Subjected to Soaking
characteristics, moisture adsorption, water absorption, thermal
Heat
resistance, linear shrinkage (or expansion), hot surface
C411Test Method for Hot-Surface Performance of High-
performance, and accelerated aging. This practice provides a
Temperature Thermal Insulation
test for surface burning characteristics but does not provide a
C518Test Method for Steady-State Thermal Transmission
methodology for determining combustibility performance of
Properties by Means of the Heat Flow Meter Apparatus
thermal insulation materials.
C553Specification for Mineral Fiber BlanketThermal Insu-
1.2 The tests shall apply to blanket, rigid board, loose-fill,
lation for Commercial and Industrial Applications
and foam thermal insulation materials used in solar collectors.
C687Practice for Determination of Thermal Resistance of
Otherthermalinsulationmaterialsshallbetestedinaccordance
Loose-Fill Building Insulation
withtheprovisionssetforthhereinandshouldnotbeexcluded
D2842Test Method for Water Absorption of Rigid Cellular
from consideration.
Plastics
E84Test Method for Surface Burning Characteristics of
1.3 The assumption is made that elevated temperature,
moisture, and applied stresses are the primary factors contrib- Building Materials
utingtothedegradationofthermalinsulationmaterialsusedin
solar collectors. 3. Summary of Practice
1.4 Solar radiation is not considered a contributing factor 3.1 The following factors, in most cases, should be consid-
since insulating materials are not normally exposed to it. ered when evaluating insulation materials for use in solar
collectors. Design considerations should dictate priorities in
1.5 This standard does not purport to address all of the
material test evaluations:
safety concerns, if any, associated with its use. It is the
Factor Reference
responsibility of the user of this standard to establish appro-
Section
priate safety and health practices and determine the applica-
pH 7.2
bility of regulatory limitations prior to use.
Surface Burning Characteristics 7.3
Moisture Adsorption 7.4
Water Absorption 7.5
2. Referenced Documents
Thermal Resistance 7.6
Linear Shrinkage (or Expansion) 7.7
2.1 ASTM Standards:
Hot Surface Performance 7.8
Chemical Compatibility 7.9
Outgassing 7.10
Durability 7.11
These test methods are under the jurisdiction of ASTM Committee E44 on
Solar, Geothermal and Other Alternative Energy Sources and is the direct respon-
4. Significance and Use
sibility of Subcommittee E44.05 on Solar Heating and Cooling Systems and
Materials.
4.1 The exposure conditions in solar collectors, especially
Current edition approved March 1, 2007. Published April 2007. Originally
under stagnation conditions, may degrade the performance of
approved in 1982. Last previous edition approved in 2001 as E861–94(2001).
DOI: 10.1520/E0861-94R07.
thermal insulation materials. This practice sets forth a meth-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
odology for evaluating the degree of degradation, if any, of the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
thermal insulation materials after exposure to simulated in-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. service conditions.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E861 − 94 (2007)
4.2 Thispracticeisalsointendedtoaidintheassessmentof 7.5 Water Absorption— Determine the water absorption of
long-term performance by comparative testing of insulation the insulation material in accordance with Methods C209 or
materials. However, correlations between performance under Test Method D2842 as applicable. Express the quantity of
laboratory and actual in-service conditions have not been water absorbed by the insulation material as a percentage by
established. mass and by volume.
4.3 This practice also sets forth criteria that shall be con-
7.6 Thermal Resistance—Determine the thermal resistance
sidered in the selection and specification of thermal insulation
of the insulation material in accordance with Test Methods
materials. One such criterion is surface burning characteristics
C518, C177, or Practice C687, as applicable.
(Test Method E84), which is used by many code officials as a
7.7 Linear Shrinkage— Determine the linear shrinkage (or
reference. This practice does not represent that the numerical
expansion) of the insulation material in accordance with Test
values obtained in any way reflect the anticipated performance
Method C356, at the expected maximum in-service
of the thermal insulation under actual fire conditions.
temperature, including stagnation conditions.
5. Sampling and Test Specimens
NOTE 1—Maximum in-service temperatures, including stagnation con-
5.1 Representative specimens shall be selected at random ditions must be determined by testing the solar collector design under
consideration.
from the original sample lot for each test condition.
7.8 Hot Surface Performance—Determine the hot surface
5.2 At least three representative specimens shall be mea-
performance in accordance with Test Method C411. Test
sured for each property tested unless otherwise stipulated in a
materials at the expected maximum in-service temperature,
particular test.
including stagnation conditions. See Note 1.
5.3 Thesizeandshapeoftherepresentativespecimensshall
be as specified in the property measurement test.
7.9 Chemical Compatibility with Adjoining Material:
7.9.1 Cut samples of adjoining materials to be evaluated to
5.4 A separate set of test specimens shall be prepared for
100 by 40 mm (3.7 by 1.5 in.) from stock materials and wash
each test.
thoroughly with cr grade isopropyl alcohol. After drying
6. Conditioning
overnight in a desiccator, weigh the samples to at least four
significant figures. Then photograph the specimens at a mag-
6.1 Unless otherwise specified, maintain the test specimens
nification of 200×.
in a condi
...

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FIG. 1 Hot Spot Effect  
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FIG. 2 Bypass Diode Effect  
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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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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.  
4.5.1 Testing Spectrally Selective...
SCOPE
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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SIGNIFICANCE AND USE
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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.  
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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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