ASTM E881-92(2015)

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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 28-Feb-2015
• ICS: 27.160 - Solar energy engineering
• Technical Committee: E44 - Solar, Geothermal and Other Alternative Energy Sources
• Drafting Committee: E44.20 - Optical Materials for Solar Applications

Standards Content (Sample)

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: E881 − 92 (Reapproved 2015)
Standard Practice for
Exposure of Solar Collector Cover Materials to Natural
1
Weathering Under Conditions Simulating Stagnation Mode
This standard is issued under the fixed designation E881; 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 E765Practice for Evaluation of Cover Materials for Flat
3
Plate Solar Collectors (Withdrawn 1991)
1.1 This practice covers a procedure for the exposure of
E772Terminology of Solar Energy Conversion
solar collector cover materials to the natural weather environ-
E782Practice for Exposure of Cover Materials for Solar
ment at elevated temperatures that approximate stagnation
CollectorstoNaturalWeatheringUnderConditionsSimu-
conditionsinsolarcollectorshavingacombinedbackandedge
2 lating Operational Mode
loss coefficient of less than 1.5 W/(m ·°C).
G7Practice for Natural Weathering of Materials
1.2 This practice is suitable for exposure of both glass and 4
2.2 Other Documents:
plastic solar collector cover materials. Provisions are made for
Federal Specification HH-I-558B,Amendment 3, Insulation
exposure of single and double cover assemblies to accommo-
Blocks,Boards,Felts,Sleeving(PipeandTubeCovering),
date the need for exposure of both inner and outer solar
and Pipe Fitting CoveringThermal (Mineral Fiber, Indus-
collector cover materials.
trial Type) August 1976
1.3 This practice does not apply to cover materials for
3. Terminology
evacuated collectors, photovoltaic cells, flat-plate collectors
having a combined back and edge loss coefficient greater than
3.1 Definitions:
2
1.5 W/(m ·°C), or flat-plate collectors whose design incorpo-
3.1.1 For definitions of terms used in this practice, refer to
rates means for limiting temperatures during stagnation.
Terminology E772.
1.4 This standard does not purport to address all of the
4. Significance and Use
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4.1 Thispracticedescribesaweatheringboxtestfixtureand
priate safety, health, and environmental practices and deter- establishes limits for the heat loss coefficients. Uniform expo-
mine the applicability of regulatory limitations prior to use. sureguidelinesareprovidedtominimizethevariablesencoun-
1.5 This international standard was developed in accor- tered during outdoor exposure testing.
dance with internationally recognized principles on standard-
4.2 Sincethecombinationofelevatedtemperatureandsolar
ization established in the Decision on Principles for the
radiation may cause some solar collector cover materials to
Development of International Standards, Guides and Recom-
degrade more rapidly than either exposure alone, a weathering
mendations issued by the World Trade Organization Technical
boxthatelevatesthetemperatureofthecovermaterialsisused.
Barriers to Trade (TBT) Committee.
4.3 This practice may be used to assist in the evaluation of
solar collector cover materials in the stagnation mode. No
2. Referenced Documents
single temperature or procedure can duplicate the range of
2
2.1 ASTM Standards:
temperatures and environmental conditions to which cover
D1435Practice for Outdoor Weathering of Plastics
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
1
This practice is under the jurisdiction of ASTM Committee E44 on Solar,
data exist to obtain exact correlation between the behavior of
GeothermalandOtherAlternativeEnergySourcesandisthedirectresponsibilityof
materials exposed in accordance with this practice and actual
Subcommittee E44.20 on Optical Materials for Solar Applications.
in-service performance.
Current edition approved March 1, 2015. Published April 2015. Originally
approved in 1982. Last previous edition approved in 2009 as E881–92 (2009).
DOI: 10.1520/E0881-92R15.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or The last approved version of this historical standard is referenced on
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM www.astm.org.
4
Standards volume information, refer to the standard’s Document Summary page on Federal Specification HH-I-558B has several classes of insulation material
the ASTM website. intended for high-temperature use.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E881 − 92 (2015)
4.4 This practice may
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E881 − 92 (Reapproved 2009) E881 − 92 (Reapproved 2015)
Standard Practice for
Exposure of Solar Collector Cover Materials to Natural
1
Weathering Under Conditions Simulating Stagnation Mode
This standard is issued under the fixed designation E881; 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 (´) indicates an editorial change since the last revision or reapproval.
1. 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
2
of less than 1.5 W/(m · °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
2
combined back and edge loss coefficient greater than 1.5 W/(m ·° 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
D1435 Practice for Outdoor Weathering of Plastics
3
E765 Practice for Evaluation of Cover Materials for Flat Plate Solar Collectors (Withdrawn 1991)
E772 Terminology of Solar Energy Conversion
E782 Practice for Exposure of Cover Materials for Solar Collectors to Natural Weathering Under Conditions Simulating
Operational Mode
G7 Practice for Atmospheric Environmental Exposure Testing of Nonmetallic Materials
4
2.2 Other Documents:
Federal Specification HH-I-558B, Amendment 3, Insulation Blocks, Boards, Felts, Sleeving (Pipe and Tube Covering), and Pipe
Fitting Covering Thermal (Mineral Fiber, Industrial Type) August 1976
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this practice, refer to Terminology E772.
4. 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.
1
This practice is under the jurisdiction of ASTM Committee E44 on Solar, Geothermal and Other Alternative Energy Sources and is the direct responsibility of
Subcommittee E44.05 on Solar Heating and Cooling Systems and Materials.
Current edition approved April 1, 2009March 1, 2015. Published June 2009April 2015. Originally approved in 1982. Last previous edition approved in 20032009 as
E881–92(2003).E881–92(2009). DOI: 10.1520/E0881-92R09.10.1520/E0881-92R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
The last approved version of this historical standard is referenced on www.astm.org.
4
Federal Specification HH-I-558B has several classes of insulation material intended for high-temperature use.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E881 − 92 (2015)
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
...