ASTM E1038-10(2015)
(Test Method)Standard Test Method for Determining Resistance of Photovoltaic Modules to Hail by Impact with Propelled Ice Balls
Standard Test Method for Determining Resistance of Photovoltaic Modules to Hail by Impact with Propelled Ice Balls
SIGNIFICANCE AND USE
4.1 In many geographic areas, there is concern about the effect of falling hail upon photovoltaic modules. This test method may be used to determine the ability of photovoltaic modules to withstand the impact forces of hailstones. In this test method, the ability of a photovoltaic module to withstand hail impact is related to its tested ability to withstand impact from ice balls. The effects of impact may be either physical or electrical degradation of the module.
4.2 This test method describes a standard procedure for mounting the test specimen, conducting the impact test, and reporting the effects.
4.2.1 The procedures for mounting the test specimen are provided to assure that modules are tested in a configuration that relates to their use in a photovoltaic array.
4.2.2 Six or more impact locations are chosen to represent vulnerable sites on modules and general locations are listed in Table 1. Only a single impact is specified at each of the impact locations.
4.2.3 Resultant speed is used to simulate the speed that may be reached by hail accompanied by wind. The resultant speed used in this test method is determined by vector addition of horizontal wind velocity plus vertical ice ball terminal velocity.
4.2.4 Ice balls are used in this test method to simulate hailstones. Hailstones are variable in properties such as shape, density, and frangibility (for fracture characteristics, see Ref (10) in Practice E822). These properties affect factors such as the duration and magnitude of the impulsive force acting on the module and the area over which the impulse 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. Ice balls generally are harder and denser than hailstones; therefore, an ice ball simulates the worst case hailstone. Perhaps the major difference between ice balls and hailstones is that hailstones are more variable than ice balls....
SCOPE
1.1 This test method provides a procedure for determining the ability of photovoltaic modules to withstand impact forces of falling hail. Propelled ice balls are used to simulate falling hailstones.
1.2 This test method defines test specimens and 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, provides a method for determining changes in electrical performance, and specifies parameters that must be recorded and reported.
1.3 This test method 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 test method.
1.4 The size of the ice ball to be used in conducting this test is not specified. This test method can be used with various sizes of ice balls.
1.5 This test method may be applied to concentrator and nonconcentrator modules.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety problems, 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 specific precautionary statements, refer to 5.1, Section 6, Note 8, and Note 9.
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Designation: E1038 − 10 (Reapproved 2015)
Standard Test Method for
Determining Resistance of Photovoltaic Modules to Hail by
Impact with Propelled Ice Balls
This standard is issued under the fixed designation E1038; 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 2. Referenced Documents
1.1 This test method provides a procedure for determining 2.1 ASTM Standards:
the ability of photovoltaic modules to withstand impact forces E772Terminology of Solar Energy Conversion
of falling hail. Propelled ice balls are used to simulate falling E822PracticeforDeterminingResistanceofSolarCollector
hailstones. Covers to Hail by Impact With Propelled Ice Balls
E1036Test Methods for Electrical Performance of Noncon-
1.2 Thistestmethoddefinestestspecimensandmethodsfor
centrator Terrestrial Photovoltaic Modules and Arrays
mounting specimens, specifies impact locations on each test
Using Reference Cells
specimen,providesanequationfordeterminingthevelocityof
E1462Test Methods for Insulation Integrity and Ground
any size ice ball, provides a method for impacting the test
Path Continuity of Photovoltaic Modules
specimens with ice balls, provides a method for determining
changes in electrical performance, and specifies parameters
3. Terminology
that must be recorded and reported.
3.1 Definitions—For definitions of terms used in this test
1.3 This test method does not establish pass or fail levels.
method, see Terminology E772.
The determination of acceptable or unacceptable levels of ice
3.2 Symbols—The following symbols are used in this test
ball impact resistance is beyond the scope of this test method.
method.
1.4 Thesizeoftheiceballtobeusedinconductingthistest
m =ice ball mass, g,
isnotspecified.Thistestmethodcanbeusedwithvarioussizes d =ice ball diameter, mm, and
of ice balls. r =ice ball radius, mm.
3.2.1 Speed:
1.5 This test method may be applied to concentrator and
−1
V =ice ball terminal, m s ,
t
nonconcentrator modules.
−1
V =wind, m s , and
w
1.6 The values stated in SI units are to be regarded as −1
V =ice ball resultant, m s .
r
standard. No other units of measurement are included in this
standard.
4. Significance and Use
1.7 This standard does not purport to address all of the
4.1 In many geographic areas, there is concern about the
safety problems, if any, associated with its use. It is the
effect of falling hail upon photovoltaic modules. This test
responsibility of the user of this standard to establish appro-
method may be used to determine the ability of photovoltaic
priate safety and health practices and determine the applica-
modules to withstand the impact forces of hailstones. In this
bility of regulatory limitations prior to use. For specific
test method, the ability of a photovoltaic module to withstand
precautionary statements, refer to 5.1, Section 6, Note 8, and
hail impact is related to its tested ability to withstand impact
Note 9.
from ice balls. The effects of impact may be either physical or
electrical degradation of the module.
This test method is under the jurisdiction of ASTM Committee E44 on Solar,
GeothermalandOtherAlternativeEnergySourcesandisthedirectresponsibilityof
Subcommittee E44.09 on Photovoltaic Electric Power Conversion. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2015. Published April 2015. Originally contactASTM Customer Service at service @astm.org. For Annual Book of ASTM
approved in 1985. Last previous edition approved in 2010 as E1038–10. DOI: Standardsvolume information, refer to the standard’s Document Summary page on
10.1520/E1038-10R15. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1038 − 10 (2015)
4.2 This test method describes a standard procedure for repeatable conditions for before and after tests are required for
mounting the test specimen, conducting the impact test, and determining electrical changes.
reporting the effects. 4.3.2 A range of observable effects may be produced by
4.2.1 The procedures for mounting the test specimen are impacting various types of photovoltaic modules. Physical
provided to assure that modules are tested in a configuration effects on modules may vary from no effect to penetration by
that relates to their use in a photovoltaic array. the ice ball. Some physical changes in the module may be
4.2.2 Six or more impact locations are chosen to represent visible when there is no apparent electrical degradation of the
vulnerable sites on modules and general locations are listed in module.
Table 1. Only a single impact is specified at each of the impact 4.3.3 Electrical changes may vary from no effect to no
locations. output. All effects of the impacts must be described in the
4.2.3 Resultantspeedisusedtosimulatethespeedthatmay report so that an estimate of their significance can be made.
be reached by hail accompanied by wind. The resultant speed
4.4 This test method does not specify the size or velocity of
used in this test method is determined by vector addition of
ice balls or maximum number of impacts to be used in making
horizontalwindvelocityplusverticaliceballterminalvelocity.
the test. These determinations will be based on frequency and
4.2.4 Ice balls are used in this test method to simulate
severity of expected hail occurrences and the intent of the
hailstones. Hailstones are variable in properties such as shape,
testing.
density, and frangibility (for fracture characteristics, see Ref
4.4.1 If the testing is being performed to evaluate impact
(10) in Practice E822). These properties affect factors such as
resistance of a single module, or several modules, it may be
thedurationandmagnitudeoftheimpulsiveforceactingonthe
desirable to repeat the test using several sizes and velocities of
module and the area over which the impulse is distributed. Ice
ice balls. In this manner, the different effects of various sizes
balls(withadensity,frangibility,andterminalvelocitynearthe
and velocities of ice balls may be determined. However, no
range of hailstones) are the nearest hailstone approximation
point shall be impacted more than once (see 7.10).
known at this time. Ice balls generally are harder and denser
4.4.2 The size and frequency of hail varies significantly
than hailstones; therefore, an ice ball simulates the worst case
among various geographic areas. If testing is being performed
hailstone. Perhaps the major difference between ice balls and
to evaluate modules intended for use in a specific geographic
hailstonesisthathailstonesaremorevariablethaniceballs.Ice
area, the ice ball size should correspond to the level of hail
balls can be uniformly and repeatedly manufactured to assure
impact resistance required for that area. Information on hail
a projectile with known properties.
size and frequency can be found in Appendix X1 of Practice
4.2.5 Ice balls are directed normal to the surface of a test
E822 and footnotes 3 and 4 of this test method, or may be
specimen,whichtransfersthegreatestkineticenergytothetest
available from local historical weather records.
specimen, unlike a non-normal impact at a glancing angle.
4.4.3 When testing modules that are designed to be in a
4.3 Data generated using this test method may be used for stowedpositionduringhailstorms,additionalimpactlocations
the following: (1) to evaluate impact resistance of a module, should be chosen accordingly.
(2) to compare the impact resistance of several modules, (3)to
4.5 The hail impact resistance of modules may change as
provide a common basis for selection of modules for use in
the materials are exposed to various environmental factors.
various geographic areas, or (4) to evaluate changes in impact
This test method may be used to evaluate degradation by
resistance of modules due to other environmental factors, such
comparisonofhailimpactresistancedatameasuredbeforeand
as weathering.
after exposure to other such environmental factors.
4.3.1 This test method requires analysis of visual effects, as
well as electrical measurements. Visual effects are generally
5. Apparatus
more sensitive than the electrical measurements; therefore, the
5.1 Launcher,capableofpropellingaselectediceballatthe
absolute values for voltage and current are not critical, but
specified speed within 65%. The aiming accuracy of the
launcher must be sufficient for the ice ball to strike the
specified impact area, or the surrounding area must be masked
TABL
...
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: E1038 − 10 E1038 − 10 (Reapproved 2015)
Standard Test Method for
Determining Resistance of Photovoltaic Modules to Hail by
Impact with Propelled Ice Balls
This standard is issued under the fixed designation E1038; 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 test method provides a procedure for determining the ability of photovoltaic modules to withstand impact forces of
falling hail. Propelled ice balls are used to simulate falling hailstones.
1.2 This test method defines test specimens and 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, provides a method for determining changes in electrical performance, and specifies parameters that must
be recorded and reported.
1.3 This test method 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 test method.
1.4 The size of the ice ball to be used in conducting this test is not specified. This test method can be used with various sizes
of ice balls.
1.5 This test method may be applied to concentrator and nonconcentrator modules.
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.7 This standard does not purport to address all of the safety problems, 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 specific precautionary statements, refer to 5.1, Section 6, Note 8, and Note 9.
2. Referenced Documents
2.1 ASTM Standards:
E772 Terminology of Solar Energy Conversion
E822 Practice for Determining Resistance of Solar Collector Covers to Hail by Impact With Propelled Ice Balls
E1036 Test Methods for Electrical Performance of Nonconcentrator Terrestrial Photovoltaic Modules and Arrays Using
Reference Cells
E1462 Test Methods for Insulation Integrity and Ground Path Continuity of Photovoltaic Modules
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, see Terminology E772.
3.2 Symbols—The following symbols are used in this test method.
m = ice ball mass, g,
d = ice ball diameter, mm, and
r = ice ball radius, mm.
3.2.1 Speed:
−1
V = ice ball terminal, m s ,
t
−1
V = wind, m s , and
w
−1
V = ice ball resultant, m s .
r
This test method is under the jurisdiction of ASTM Committee E44 on Solar, Geothermal and Other Alternative Energy Sources and is the direct responsibility of
Subcommittee E44.09 on Photovoltaic Electric Power Conversion.
Current edition approved Nov. 1, 2010March 1, 2015. Published November 2010April 2015. Originally approved in 1985. Last previous edition approved in 20052010
as E1038 – 05.E1038 – 10. DOI: 10.1520/E1038-10.10.1520/E1038-10R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service @astm.org. For Annual Book of ASTM
Standardsvolume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1038 − 10 (2015)
4. Significance and Use
4.1 In many geographic areas, there is concern about the effect of falling hail upon photovoltaic modules. This test method may
be used to determine the ability of photovoltaic modules to withstand the impact forces of hailstones. In this test method, the ability
of a photovoltaic module to withstand hail impact is related to its tested ability to withstand impact from ice balls. The effects of
impact may be either physical or electrical degradation of the module.
4.2 This test method describes a standard procedure for mounting the test specimen, conducting the impact test, and reporting
the effects.
4.2.1 The procedures for mounting the test specimen are provided to assure that modules are tested in a configuration that relates
to their use in a photovoltaic array.
4.2.2 Six or more impact locations are chosen to represent vulnerable sites on modules and general locations are listed in Table
1. Only a single impact is specified at each of the impact locations.
4.2.3 Resultant speed is used to simulate the speed that may be reached by hail accompanied by wind. The resultant speed used
in this test method is determined by vector addition of horizontal wind velocity plus vertical ice ball terminal velocity.
4.2.4 Ice balls are used in this test method to simulate hailstones. Hailstones are variable in properties such as shape, density,
and frangibility (for fracture characteristics, see Ref (10) in Practice E822). These properties affect factors such as the duration and
magnitude of the impulsive force acting on the module and the area over which the impulse 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. Ice balls
generally are harder and denser than hailstones; therefore, an ice ball simulates the worst case hailstone. Perhaps the major
difference between ice balls and hailstones is that hailstones are more variable than ice balls. Ice balls can be uniformly and
repeatedly manufactured to assure a projectile with known properties.
4.2.5 Ice balls are directed normal to the surface of a test specimen, which transfers the greatest kinetic energy to the test
specimen, unlike a non-normal impact at a glancing angle.
4.3 Data generated using this test method may be used for the following: (1) to evaluate impact resistance of a module, (2) to
compare the impact resistance of several modules, (3) to provide a common basis for selection of modules for use in various
geographic areas, or (4) to evaluate changes in impact resistance of modules due to other environmental factors, such as
weathering.
4.3.1 This test method requires analysis of visual effects, as well as electrical measurements. Visual effects are generally more
sensitive than the electrical measurements; therefore, the absolute values for voltage and current are not critical, but repeatable
conditions for before and after tests are required for determining electrical changes.
4.3.2 A range of observable effects may be produced by impacting various types of photovoltaic modules. Physical effects on
modules may vary from no effect to penetration by the ice ball. Some physical changes in the module may be visible when there
is no apparent electrical degradation of the module.
4.3.3 Electrical changes may vary from no effect to no output. All effects of the impacts must be described in the report so that
an estimate of their significance can be made.
4.4 This test method does not specify the size or velocity of ice balls or maximum number of impacts to be used in making the
test. These determinations will be based on frequency and severity of expected hail occurrences and the intent of the testing.
4.4.1 If the testing is being performed to evaluate impact resistance of a single module, or several modules, it may be desirable
to repeat the test using several sizes and velocities of ice balls. In this manner, the different effects of various sizes and velocities
of ice balls may be determined. However, no point shall be impacted more than once (see 7.10).
4.4.2 The size and frequency of hail varies significantly among various geographic areas. If testing is being performed to
evaluate modules intended for use in a specific geographic area, the ice ball size should correspond to the level of hail impact
TABLE 1 Candidate Locations and Suggested Order for Impact
Points
Location number Description
1 Centers of cells
2 Edges of cells, especially near electrical
contacts
3 Points of minimum spacing between cells
4 Points of maximum distance from points of
support in 6
Corners and edges of the module
5 Points of support for any superstrate material
6 Back of module, if exposed in stowed
orientation
7 Electrical terminals and leads
8 Centers of lenses approximately 50 mm from
lens support points
E1038 − 10 (2015)
resistance required for that area. Information on hail size and frequency can be found in Appendix X1 of Practice E822 and
footnotes 3 and 4 of this test method, or may be availa
...
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