1、Designation: E 1038 05Standard Test Method forDetermining Resistance of Photovoltaic Modules to Hail byImpact with Propelled Ice Balls1This standard is issued under the fixed designation E 1038; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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 w
3、ithstand 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, pro
4、vides 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 le
5、vels 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 Thi
6、s 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 specificprecautio
7、nary statements, refer to 5.1, Section 6, Note 8, andNote 9.2. Referenced Documents2.1 ASTM Standards:2E 772 Terminology Relating to Solar Energy ConversionE 822 Practice for Determining Resistance of Solar Collec-tor Covers to Hail by Impact with Propelled Ice BallsE 1036 Test Methods for Electrica
8、l Performance of Non-concentrator Terrestrial Photovoltaic Modules and ArraysUsing Reference CellsE 1328 Terminology Relating to Photovoltaic Solar EnergyConversionE 1462 Test Methods for Insulation Integrity and GroundPath Continuity of Photovoltaic Modules3. Terminology3.1 DefinitionsFor definitio
9、ns of terms used in this testmethod, see Terminology E 772 and Terminology E 1328.3.2 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 Velocity:Vt= ice ball terminal, m s1,Vw= wind, m s1, andVr= ice ball resulta
10、nt, 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 pho
11、tovoltaic 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, conducting the impact te
12、st, 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 locatio
13、ns 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 Photovoltaic Electric Power S
14、ystems.Current edition approved April 1, 2005. Published May 2005. Originallyapproved in 1985. Last previous edition approved in 2004 as E 1038 98(2004).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at service astm.org. For Annual Book of ASTMS
15、tandardsvolume 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 velocity is used to simulate the velocity thatmay be reached by hail accompan
16、ied by wind. The resultantvelocity used in this test method is determined by vectoraddition of horizontal velocity to the vertical 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
17、fracture characteristics, see Ref(10) in Practice E 822). 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, frangibility, and terminal velocity near therange of ha
18、ilstones) 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 hailstones are more variable than ice balls. I
19、ceballs can be uniformly and repeatedly manufactured to assurea projectile with known properties.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
20、for selection of modules for use invarious geographic areas, or ( 4) to 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 generallymor
21、e sensitive than the electrical measurements; therefore, theabsolute values 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 ph
22、otovoltaic modules. Physicaleffects on modules may vary from no effect 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 impac
23、ts must be described in thereport so that an estimate of their significance 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 occur
24、rences and the intent of thetesting.4.4.1 If the testing is being performed 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
25、of ice balls may be determined. However, nopoint shall be impacted more 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 shou
26、ld correspond to the level of hailimpact resistance required for that area. Information on hailsize and frequency can be found in Appendix X1 of PracticeE 822 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 desig
27、ned to be in astowed position during hail storms, additional impact locationsshould 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
28、 resistance data measured before andafter exposure to other such environmental factors.5. Apparatus5.1 Launcher, capable of propelling a selected ice ball at thespecified velocity within 65 %. The aiming accuracy of thelauncher must be sufficient for the ice ball to strike thespecified impact area,
29、or the surrounding area must be maskedfor protection from inadvertent impacts.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
30、 Practice E 822). Another launcher that has been used is atable-mounted slingshot with an adjustable hand rest.5.2 Velocity Meter, for measuring ice ball velocity to within62%.5.3 Test BaseArigid mount for supporting the test modulein a fashion that simulates actual mounting applications.5.4 Molds,
31、for casting spherical ice balls of appropriatediameter.NOTE 2Molds made from silicone rubber or expanded polystyrenehave been found suitable.5.5 Freezer, for making ice balls in the molds, controlledat106 5C.5.6 Storage ContainerAn ice chest or an ice water/saltmixture and a bag for the ice balls ca
32、pable of maintainingtemperature of 4 6 2C.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. Available from National Technical Information Service, 5285Port Royal Road, Springf
33、ield, 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, 5285 Port Royal Road, Springfield,VA 22161-0001.TABLE 1 Candidate Locations and Sugg
34、ested 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 in 6Corners and edges of the module5 Points of support for any superstrate material
35、6 Back of module, if exposed in stowedorientation7 Electrical terminals and leads8 Centers of lenses approximately 50 mm fromlens support points9E10380525.7 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 o
36、f the equipment described in Section 5may expose personnel to risk of injury from 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
37、 ice ball size to be used in the test.NOTE 3The size of the ice balls shall be specified 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
38、 the prescribed size(s). Examine for cracks, size, andweight. An acceptable ball 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 velocity corre
39、sponding to the iceball diameter and selected wind speed. The resultant velocityshall be determined using the following equation: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 4Considerati
40、ons for appropriate wind speeds may be found infootnote 4.7.4 Electrical Tests:7.4.1 Perform an insulation current leakage test on the testmodule according to 7.1 of Test Methods E 1462.7.4.2 Measure the open-circuit voltage and short-circuitcurrent of the module. As acceptable procedure is given in
41、Methods E 1036.NOTE 5Because damage to a module that results from ice ball impactis usually catastrophic, it is only necessary to 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-sibl
42、e.7.5 Select a minimum of six target impact points identifiedin Table 1.7.6 Document visual features in the impact areas that maybe 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 impa
43、ctpoints shall not be obstructed by the mounting fixtures.7.8 The test module temperature shall be stable and theambient temperature 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.N
44、OTE 6The apparatus may be designed so that the path of the ice ballis at any angle, for example, horizontal or vertical, as long as 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
45、.7.11 Position the velocity meter such that the ice ballvelocity will be measured between the launcher and the testspecimen. The ice ball should leave the velocity meter notmore than 1.0 m (3.1 ft) in front of the impact location. Preparethe velocity meter for the test.NOTE 7Testing of the apparatus
46、 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-tion.7.12 Set the launcher controls to assure that the ball will bepropelled at the velocity determined in 7.3.7.13 Remove an ice ball from the stora
47、ge container.7.14 Place the ice ball in the launcher.7.15 Launch the ice ball. Measure and record the velocity ofthe ice ball. Ice balls shall impact the test specimen within 60s of removal from the storage container.NOTE 9Caution: Personnel protective equipment may be requiredduring this step (see
48、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 selected 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
49、 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 module mounting,8.1.5 Description of physical degradation, if any,8.1.6 Changes between pre and post electrical test results, ifany,8.1.7 Size, mas
