1、Designation: E3004 151Standard Specification forPreparation and Verification of Clay Blocks Used inBallistic-Resistance Testing of Torso Body Armor1This standard is issued under the fixed designation E3004; the number immediately following the designation indicates the year oforiginal adoption or, i
2、n 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.1NOTEEditorial corrections made throughout in August 2016.INTRODUCTIONAt the time when work on
3、 this specification was undertaken, different ballistic-resistant body armortest protocols required different impactors for verification of the clay blocks placed behind the testitems, and the lack of detailed guidance about the clay blocks resulted in different practices forpreparation and verifica
4、tion. To improve laboratory-to-laboratory consistency, major stakeholderssought to harmonize practices related to the preparation and verification of the clay blocks used fortesting of ballistic-resistant body armor.1. Scope1.1 The purpose of this specification is to provide a stan-dardized method f
5、or preparation and verification of backingassemblies used in ballistic-resistant torso body armor testingand to reduce variability within and between laboratories.1.2 The backing assembly is a clay block that containsROMA Plastilina No. 12clay as the backing material. Theclay serves as a witness mat
6、erial and provides a measurableindication of test item performance.1.3 This specification is primarily directed toward testlaboratories but may be applicable to body armormanufacturers, researchers, and end users performing ballistic-resistance testing of body armor.1.4 UnitsThe values stated in SI
7、units are to be regardedas standard. The values given in parentheses are mathematicalconversions to non-SI units that are provided for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this
8、 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E3005 Terminology for Body Armor2.2 NIST Standard:4NIST Special Publication 330 The International System ofUnits (SI), 20
9、08 Edition, Barry N. Taylor and AmblerThompson, Editors3. Terminology3.1 The terms and definitions of Terminology E3005 applyfor the following terms: backing assembly, backing fixture,backing material and test item.3.2 Definitions of Terms Specific to This Standard:3.2.1 backing assembly, na backing
10、 fixture filled withbacking material. For example, a clay block is a type of abacking assembly.3.2.2 backing fixture, nany apparatus designed to hold orcontain the backing material(s) for a specific test.3.2.3 backing material, nthe substance placed behind thetest item during testing which is intend
11、ed to be a witnessmaterial and which may provide a measurable indication of testitem performance.3.2.4 bridge gauge, nan assembly used for measuring thatconsists of a depth gauge and supports that rest on oppositesides of the backing fixture.1This specification is under the jurisdiction of ASTM Comm
12、ittee E54 onHomeland Security Applications and is the direct responsibility of SubcommitteeE54.04 on Personal Protective Equipment (PPE).Current edition approved Nov. 1, 2015. Published November 2015. DOI:10.1520/E300415E01.2U.S. Government standards require ROMA Plastilina No. 1, from SculptureHous
13、e, Inc., as the backing material for ballistic-resistance testing.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM web
14、site.4Available from National Institute of Standards and Technology (NIST), 100Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http:/www.nist.gov.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.5 clay block, na type of backing
15、 assembly in whichthe backing material is ROMA Plastilina No. 1 modelingclay. See Fig. 1.3.2.6 clay package, nthe smallest unit of wrapped andlabeled clay as received from the supplier.3.2.7 depth gauge, ninstrument (for example, caliper)used to measure the indentations in the backing material cause
16、dby the impactor.3.2.8 impactor, ncylindrical device, used during verifica-tion of the backing material, having specified dimensions andone hemispherical end.3.2.9 striking device, na device used on a clay block toestablish an appropriate, flat surface on the clay backingmaterial with respect to the
17、 backing fixture edges.3.2.10 test item, na single article intended for testing.Examples may include one panel, one plate, or one shoot pack.4. Significance and Use4.1 U.S. Department of Defense and U.S. Department ofJustice standards for assessing the performance of ballistic-resistant torso body a
18、rmor require the use of backing assem-blies made with Roma Plastilina No. 1. It can be demon-strated that the way the clay block is handled prior to andduring ballistic testing can have a significant influence ondeformation of the clay when a test item is struck by aprojectile during testing.4.2 At
19、the time when work on this specification wasundertaken, different ballistic-resistant body armor test proto-cols required different impactors for verification of the clayblocks placed behind the test items, and the lack of detailedguidance about the clay blocks resulted in different practicesfor pre
20、paration and verification. To improve laboratory-to-laboratory consistency, major stakeholders sought to harmo-nize practices related to the preparation and verification of theclay blocks used for testing of ballistic-resistant body armor.5. Equipment5.1 The equipment used for preparation and verifi
21、cation ofclay blocks shall be as described below:5.1.1 Backing FixtureThe backing fixture shall be a rigid,metal frame with a plywood bottom. The inside dimensions ofthe metal frame shall be 610 6 2 mm (24.0 6 0.08 in.) by 6106 2 mm (24.0 6 0.08 in.) with a depth of 140 6 2 mm (5.5 60.08 in.). The t
22、op and bottom edges of the metal frame shall beplanar. Plywood, of any grade, that is nominally “34 in.” or “18mm,” shall be attached to the outside of the metal frame toform the bottom of the fixture and shall be removable. See Fig.2.5.1.2 Backing Fixture LinerA liner, such as 0.08 to 0.13mm (3 to
23、5 mil) polyethylene sheeting, shall be inserted intothe backing fixture to prevent the clay oils from coming intocontact with the plywood. The liner shall be placed against theplywood bottom of the backing fixture and shall not extend upthe inside surfaces of the metal frame.NOTE 1The backing fixtur
24、e liner is intended to be a barrier betweenthe clay and the plywood and may be sheeting, a coating (for example,spray, paint, shellac), or any other barrier that prevents leaching of oil intothe plywood.5.1.3 Bridge GaugeThe bridge gauge shall be a rigidassembly that rests on two parallel strike fac
25、e edges of thebacking fixture and supports a depth gauge that can slide backand forth on the assembly to measure depths across the surfaceof the backing material. The bridge gauge (independent of thebacking fixture) shall have a resolution of 0.01 mm or betterwith an accuracy of 60.1 mm or better.5.
26、1.4 Conditioning ChamberThe chamber shall be tem-perature controlled, be sufficiently large, and have continuouscirculation of air with the intention of uniformly heating allclay blocks in the chamber.5.1.5 Impactor:5.1.5.1 The impactor shall be a steel, constant diametercylinder having a hemispheri
27、cal end of diameter equal to thecylinder diameter and a smooth transition from the hemispheri-cal end to the cylinder body. A drawing specifying thedimensions of the impactor is provided in Fig. 3.5.1.5.2 The impactor mass shall be 1.0 6 0.005 kg (2.20 60.01 lbm).NOTE 2To achieve the required mass,
28、the length of the entire impactorFIG. 1 Clay BlockNOTE 1The plywood bottom is shown larger than the metal frame forillustrative purposes only.FIG. 2 Backing FixtureE3004 1512will be approximately 90 mm (3.5 in.).5.1.6 Striking DeviceThe striking device shall be a metal,straight-edged blade capable o
29、f spanning two parallel strikeface edges of the backing fixture so that the backing fixtureserves as the reference for the clay block surface. The strikingdevice shall be sufficiently rigid to facilitate creation of a flatclay surface that is even with the strike face edges of thebacking fixture.5.1
30、.7 TemplateA circular template shall be used to markthe impact locations on the surface of the clay. The templateshall fit within the internal backing fixture dimensions. Theimpact location centers on the template shown in Fig. 4 arespaced approximately 50 mm (2 in.), 127 mm (5 in.), and 203mm (8 in
31、.) from the center and approximately 120 apart.5.1.7.1 The purpose of the template is to ensure that thethree impact locations meet the drop spacing requirementsbelow:(1) Minimum of 76 mm (3.0 in.) from backing fixture edgeto nearest indentation edge.(2) Minimum of 152 mm (6.0 in.) between impactori
32、ndentation centers.5.1.8 Test SetupThe test setup for clay block verificationshall consist of a guide tube through which the impactor isdropped (hemispherical end down) onto a clay block that restson a movable support. See Fig. 5 for an example test setupincluding guide tube dimensions and spacing b
33、etween theguide tube and the clay block surface.5.1.8.1 Guide TubeThe guide tube length shall be suchthat the impactor is within the tube prior to release and entirelyout of the tube at impact with the clay block surface. The guidetube length shall be sufficient to minimize yaw of the impactorat the
34、 clay surface. The guide tube inside diameter shall besized to allow the impactor to drop freely and minimize yaw.The guide tube shall be solidly mounted to a fixed surface.NOTE 3Holes or slots along the length of the guide tube may be usefulto limit effects of air on the impactor as it drops throug
35、h the tube.5.1.8.2 Movable SupportThe support upon which the clayblock rests shall allow positioning of the clay block to set theimpact locations, keep the clay block level, keep the dropdistance constant when the clay block is positioned fordifferent impact locations, and prevent the block from mov
36、ingvertically due to the impact from the impactor.5.1.9 Velocity Measurement EquipmentThe velocity mea-surement equipment shall be capable of measuring velocities inat least the range of interest with a resolution of 0.005 m/s orbetter and an accuracy of 0.01 m/s or better. See Appendix X1for Veloci
37、ty Measurement Guidance.6. Procedures6.1 Characterization of Clay Block Verification Test Setup:6.1.1 Perform the following steps at installation of a newtest setup (see 5.1.8) and periodically thereafter. These stepsshall be performed without the clay block or its movablesupport in the test setup.6
38、.1.1.1 Verify that the guide tube is straight, plumb, andrigid.6.1.1.2 Verify that the guide tube is solidly mounted so thatit remains in the verified position.6.1.1.3 To verify the performance of the test setup, thevelocity of the impactor at the clay surface is required to bebetween 6.15 to 6.27 m
39、/s. Perform an appropriate number ofFIG. 3 ImpactorFIG. 4 Template for Impact Locations FIG. 5 Example Test SetupE3004 1513impactor drops through the guide tube to determine the dropdistance at which a velocity in this range is achieved at theexpected point of impact. The drop distance shall be meas
40、uredfrom the impactor tip (rounded end) to the expected point ofimpact.6.1.1.4 Record the drop distance. The drop distance shall bewithin 2 6 0.02 m.NOTE 4If the measured drop distance does not meet this requirement,the test setup should be adjusted until the measured velocity and dropdistance are w
41、ithin the required ranges.6.1.2 The value of the measured drop distance shall be usedduring clay block verifications. The velocity is not required tobe measured during actual clay block verifications.NOTE 5Provision should be made to ensure that the impactor isdropped the determined drop distance ea
42、ch time, such as by the use of ahard stop at the top of the guide tube.6.2 Clay Block Preparation Procedures:6.2.1 New Clay Block Assembly:6.2.1.1 Fill the backing fixture with clay following the stepsbelow:(1) Open each clay package, and soften the clay by heatingit; working it with kneading, pound
43、ing, or tamping; or combi-nations thereof.(2) Press clay into the backing fixture, using a manualdevice (for example, mallet) or a machine (for example,hydraulic press or powered hammering tool), one layer at atime starting in the corners. One layer of flattened clay shouldbe added at a time, and th
44、en pressed and blended into theprevious layers to prevent voids.(3) Continue layering, pressing, and blending of clay untilthe depth of the clay exceeds the strike face edges of thebacking fixture.(4) Remove excess clay at the surface by drawing thestriking device at least once across the full lengt
45、h of paralleledges of the backing fixture.NOTE 6The striking device should be drawn across the same edgesthat the bridge gauge rests on during measuring and should be drawn inthe same direction every time.NOTE 7If the striking device is drawn more than once and inorthogonal directions, the resultant
46、 clay surface must be planar.(5) Visually verify that the clay surface is flat and flushwith the backing fixture strike face edges. If voids in thesurface are visible, fill those voids with additional clay, andrepeat steps (4) and (5) until the surface of the clay is flat withno visible voids.(6) St
47、ore the clay block indoors at room temperature or inthe conditioning chamber.6.2.2 Determination of Conditioning Chamber Tempera-ture:6.2.2.1 Set the conditioning chamber temperature at aninitial temperature chosen by the test laboratory.6.2.2.2 Place the clay block into the conditioning chamber.6.2
48、.2.3 Heat the clay block according to the requirementsbelow:(1) New clay blocks shall be heated for at least 24 hours.(2) Any clay block that has been out of the conditioningchamber for more than one hour shall be heated for at leastthree times the time out of the chamber. Every clay block shallbe h
49、eated for no less than three hours.6.2.2.4 Record the conditioning chamber temperature.6.2.2.5 Remove the clay block from the conditioning cham-ber and promptly perform the procedure specified in 6.3.6.2.2.6 Perform the procedure specified in 6.4.6.2.2.7 If necessary, adjust the temperature of the condition-ing chamber based on the indentation depth measurements inthe clay and repeat steps 6.2.2.2 6.2.2.7.6.2.3 Clay Block Temperature Conditioning Procedure:6.2.3.1 Prior to performing a clay block verificationprocedure, the clay block shall
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