1、Designation: E1038 10Standard 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
2、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 with
3、stand 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, provid
4、es 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 level
5、s 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 va
6、lues 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 s
7、afety 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 Relating to Solar Energy ConversionE822 Practice for Determ
8、ining Resistance of Solar Collec-tor Covers 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 Photovoltai
9、c 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,
10、 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 meth
11、od, 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.4.2 This test method describes a standard procedure formounting the test specimen,
12、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 mod
13、ules and general locations are listed inTable 1. Only a single impact is specified at each of the impactlocations.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 Photov
14、oltaic Electric Power Conversion.Current edition approved Nov. 1, 2010. Published November 2010. Originallyapproved in 1985. Last previous edition approved in 2005 as E1038 05. DOI:10.1520/E1038-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
15、at service astm.org. For Annual Book of ASTMStandardsvolume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.3 Resultant speed is used to simulate the sp
16、eed 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 properti
17、es 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. Iceballs (with a density, frangibi
18、lity, and terminal velocity near therange of hailstones) are the nearest hailstone approximationknown at this time. Ice balls generally are harder and denserthan hailstones; therefore, an ice ball simulates the worst casehailstone. Perhaps the major difference between ice balls andhailstones is that
19、 hailstones are more variable than ice balls. Iceballs can be uniformly and repeatedly manufactured to assurea projectile with known properties.4.2.5 Ice balls are directed normal to the surface of a testspecimen, which transfers the greatest kinetic energy to the testspecimen, unlike a non-normal i
20、mpact at a glancing angle.4.3 Data generated using this test method may be used forthe following: (1) to evaluate impact resistance of a module,(2) to compare the impact resistance of several modules, (3)toprovide a common basis for selection of modules for use invarious geographic areas, or ( 4) to
21、 evaluate changes in impactresistance of modules due to other environmental factors, suchas weathering.4.3.1 This test method requires analysis of visual effects, aswell as electrical measurements. Visual effects are generallymore sensitive than the electrical measurements; therefore, theabsolute va
22、lues for voltage and current are not critical, butrepeatable conditions for before and after tests are required fordetermining electrical changes.4.3.2 A range of observable effects may be produced byimpacting various types of photovoltaic modules. Physicaleffects on modules may vary from no effect
23、to penetration bythe ice ball. Some physical changes in the module may bevisible when there is no apparent electrical degradation of themodule.4.3.3 Electrical changes may vary from no effect to nooutput. All effects of the impacts must be described in thereport so that an estimate of their signific
24、ance can be made.4.4 This test method does not specify the size or velocity ofice balls or maximum number of impacts to be used in makingthe test. These determinations will be based on frequency andseverity of expected hail occurrences and the intent of thetesting.4.4.1 If the testing is being perfo
25、rmed to evaluate impactresistance of a single module, or several modules, it may bedesirable to repeat the test using several sizes and velocities ofice balls. In this manner, the different effects of various sizesand velocities of ice balls may be determined. However, nopoint shall be impacted more
26、 than once (see 7.10).4.4.2 The size and frequency of hail varies significantlyamong various geographic areas. If testing is being performedto evaluate modules intended for use in a specific geographicarea, the ice ball size should correspond to the level of hailimpact resistance required for that a
27、rea. Information on hailsize and frequency can be found in Appendix X1 of PracticeE822 and footnotes 3 and 4 of this test method, or may beavailable from local historical weather records.4.4.3 When testing modules that are designed to be in astowed position during hail storms, additional impact loca
28、tionsshould be chosen accordingly.4.5 The hail impact resistance of modules may change asthe materials are exposed to various environmental factors.This test method may be used to evaluate degradation bycomparison of hail impact resistance data measured before andafter exposure to other such environ
29、mental factors.5. Apparatus5.1 Launcher, capable of propelling a selected ice ball at thespecified speed within 65 %. The aiming accuracy of thelauncher must be sufficient for the ice ball to strike thespecified impact area, or the surrounding area must be maskedfor protection from inadvertent impac
30、ts.NOTE 1Launchers that have proven suitable utilize a compressed airsupply, an accumulator tank, a large diameter quick-opening valve, andinterchangeable barrels to accommodate different sizes of ice balls3 ,4(seeRef (14) of Practice E822). Another launcher that has been used is atable-mounted slin
31、gshot with an adjustable hand rest.5.2 Speed Meter, for measuring ice ball speed to within62%.5.3 Test BaseArigid mount for supporting the test modulein a fashion that simulates actual mounting applications.5.4 Molds, for casting spherical ice balls of appropriatediameter.NOTE 2Molds made from silic
32、one rubber or expanded polystyrenehave been found suitable.5.5 Freezer, for making ice balls in the molds, controlledat106 5C.3Moore, D., and Wilson, A., “Photovoltaic Solar Panel Resistance to SimulatedHail,” Low-Cost Solar Array Project Report 5101-62, Jet Propulsion Laboratory,Pasadena, CA, 1978.
33、 Available from National Technical Information Service, 5285Port Royal Road, Springfield, VA 22161-0001.4Jenkins, D. R., and Mathey, R. G., “Hail Impact Testing Procedure for SolarCovers,” NBSIR 82-2487, National Bureau of Standards, April 1982. Availablefrom National Technical Information Service,
34、5285 Port Royal Road, Springfield,VA 22161-0001.TABLE 1 Candidate Locations and Suggested Order for ImpactPointsLocation number Description1 Centers of cells2 Edges of cells, especially near electricalcontacts3 Points of minimum spacing between cells4 Points of maximum distance from points ofsupport
35、 in 6Corners and edges of the module5 Points of support for any superstrate material6 Back of module, if exposed in stowedorientation7 Electrical terminals and leads8 Centers of lenses approximately 50 mm fromlens support points9E1038 1025.6 Storage ContainerAn ice chest or an ice water/saltmixture
36、and a bag for the ice balls capable of maintainingtemperature of 4 6 2C.5.7 Balance, for determining ice ball mass to within 6 1%.5.8 Ring Gages or Equivalent, for determining ice ball size.6. Hazards6.1 The operation of the equipment described in Section 5may expose personnel to risk of injury from
37、 propelled orrebounded ice balls, fragments of the broken test specimen, andfrom the noise that may develop. Eye and ear protection shallbe considered as minimum protection for the operator.7. Procedure7.1 Determine the ice ball size to be used in the test.NOTE 3The size of the ice balls shall be sp
38、ecified in 10-mmincrements by the sponsor of the test or the test director.d,mm m,g15 1.625 7.535 20.645 43.955 80.165 132.275 20385 296m = 0.00385 r3.7.2 Using the ice mold(s), make sufficient quantities of iceballs of the prescribed size(s). Examine for cracks, size, andweight. An acceptable ball
39、shall meet the following criteria:7.2.1 CracksNo cracks visible to the unaided eye.7.2.2 SizeWithin 65 % of specified diameter, and7.2.3 MassWithin 65 % of nominal value listed.7.3 Calculate the resultant speed corresponding to the iceball diameter and selected wind speed using the followingequation
40、s:Vr5 =Vt21 Vw2(1)where:Vt5 4.44 =d (2)7.3.1 The wind speed is selected from the following table bythe sponsor of the test or the test director.ms-10152030NOTE 4Considerations for appropriate wind speeds may be found infootnote 4.7.4 Electrical Tests:7.4.1 Perform an insulation current leakage test
41、on the testmodule according to 7.1 of Test Methods E1462.7.4.2 Measure the open-circuit voltage and short-circuitcurrent of the module. As acceptable procedure is given inMethods E1036.NOTE 5Because damage to a module that results from ice ball impactis usually catastrophic, it is only necessary to
42、determine if the Vocand Iscsurvive the impact test. Thus, a simple measurement of Vocand Iscusinga voltmeter and an ammeter while the module is illuminated is permis-sible.7.5 Select a minimum of six target impact points identifiedin Table 1.7.6 Document visual features in the impact areas that mayb
43、e affected by the ice balls. Photographs may be used.7.7 Mount the test module on a suitable test base to simulatean actual installation of the module. The specified impactpoints shall not be obstructed by the mounting fixtures.7.8 The test module temperature shall be stable and theambient temperatu
44、re shall be 20 6 10C.7.9 Position the module to assure that the path of thepropelled ice ball at impact will be perpendicular (90 6 5) tothe surface at the target point.NOTE 6The apparatus may be designed so that the path of the ice ballis at any angle, for example, horizontal or vertical, as long a
45、s the otherrequirements of the test are met.7.10 Aim the launcher at a target impact point that has notpreviously been impacted. Each point shall be impacted onetime only.7.11 Position the speed meter such that the ice ball speedwill be measured between the launcher and the test specimen.The ice bal
46、l should exit the speed meter not more than 1.0 min front of the impact location. Prepare the speed meter for thetest.NOTE 7Testing of the apparatus may be done by impacting ice ballson a simulated target placed in front of the module.NOTE 8A shield may be placed around the impact point for protec-t
47、ion.7.12 Set the launcher controls to assure that the ball will bepropelled at the speed determined in 7.3.7.13 Remove an ice ball from the storage container.7.14 Place the ice ball in the launcher.7.15 Launch the ice ball. Measure and record the speed ofthe ice ball. Ice balls shall impact the test
48、 specimen within 60s of removal from the storage container.NOTE 9Caution: Personnel protective equipment may be requiredduring this step (see 6.1).7.16 Mark the ice ball impact location.7.17 Record all visual effects of the impact.7.18 Repeat 7.8-7.16, until one of the following occurs:7.18.1 All se
49、lected target points have been impacted, or7.18.2 Severe damage of the module occurs.7.19 At the completion of the test, repeat the electrical testsin 7.4.8. Report8.1 Report, as a minimum, the following information:8.1.1 Module manufacturer and type,8.1.2 Module description that includes the following items:8.1.2.1 Major dimensions,8.1.2.2 Substrate material and thickness,8.1.2.3 Superstrate material and thickness, and8.1.2.4 Cell material,8.1.3 A line drawing or photograph of the module withimpact sites marked,8.1.4 Aline drawing or photograph of the mod
