ASTM_E_1038_-_10_2015.pdf

Designation:E103810(Reapproved 2015)Standard Test Method forDetermining Resistance of Photovoltaic Modules to Hail byImpact with Propelled Ice Balls1This standard is issued under the fixed designation E1038;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method provides a procedure for determiningthe ability of photovoltaic modules to withstand impact forcesof falling hail.Propelled ice balls are used to simulate fallinghailstones.1.2 This test method defines test specimens and methods formounting specimens,specifies impact locations on each testspecimen,provides an equation for determining the velocity ofany size ice ball,provides a method for impacting the testspecimens with ice balls,provides a method for determiningchanges in electrical performance,and specifies parametersthat 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 iceball impact resistance is beyond the scope of this test method.1.4 The size of the ice ball to be used in conducting this testis not specified.This test method can be used with various sizesof ice balls.1.5 This test method may be applied to concentrator andnonconcentrator modules.1.6 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.7 This standard does not purport to address all of thesafety problems,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specificprecautionary statements,refer to 5.1,Section 6,Note 8,andNote 9.2.Referenced Documents2.1 ASTM Standards:2E772 Terminology of Solar Energy ConversionE822 Practice for Determining Resistance of Solar CollectorCovers to Hail by Impact With Propelled Ice BallsE1036 Test Methods for Electrical Performance of Noncon-centrator Terrestrial Photovoltaic Modules and ArraysUsing Reference CellsE1462 Test Methods for Insulation Integrity and GroundPath Continuity of Photovoltaic Modules3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,see Terminology E772.3.2 SymbolsThe following symbols are used in this testmethod.m=ice ball mass,g,d=ice ball diameter,mm,andr=ice ball radius,mm.3.2.1 Speed:Vt=ice ball terminal,m s1,Vw=wind,m s1,andVr=ice ball resultant,m s1.4.Significance and Use4.1 In many geographic areas,there is concern about theeffect of falling hail upon photovoltaic modules.This testmethod may be used to determine the ability of photovoltaicmodules to withstand the impact forces of hailstones.In thistest method,the ability of a photovoltaic module to withstandhail impact is related to its tested ability to withstand impactfrom ice balls.The effects of impact may be either physical orelectrical degradation of the module.1This test method is under the jurisdiction of ASTM Committee E44 on Solar,Geothermal and OtherAlternative Energy Sources and is the direct responsibility ofSubcommittee E44.09 on Photovoltaic Electric Power Conversion.Current edition approved March 1,2015.Published April 2015.Originallyapproved in 1985.Last previous edition approved in 2010 as E1038 10.DOI:10.1520/E1038-10R15.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at service astm.org.For Annual Book of ASTMStandardsvolume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.2 This test method describes a standard procedure formounting the test specimen,conducting the impact test,andreporting the effects.4.2.1 The procedures for mounting the test specimen areprovided to assure that modules are tested in a configurationthat relates to their use in a photovoltaic array.4.2.2 Six or more impact locations are chosen to representvulnerable sites on modules and general locations are listed inTable 1.Only a single impact is specified at each of the impactlocations.4.2.3 Resultant speed is used to simulate the speed that maybe reached by hail accompanied by wind.The resultant speedused in this test method is determined by vector addition ofhorizontal wind velocity plus vertical ice ball terminal velocity.4.2.4 Ice balls are used in this test method to simulatehailstones.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 asthe duration and magnitude of the impulsive force acting on themodule and the area over which the impulse is distributed.Iceb