1、Designation:C42108(Reapproved 2014)Standard Test Method forTumbling Friability of Preformed Block-Type and PreformedPipe-Covering-Type Thermal Insulation1This standard is issued under the fixed designation C421;the number immediately following the designation indicates the year oforiginal adoption o
2、r,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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1
3、This test method covers determination of the mass lossof preformed block-type and preformed pipe-covering-typethermal insulation as a result of a combination of abrasion andimpact produced by a laboratory tumbling mechanism.1.2 The values stated in inch-pound units are to be regardedas standard.The
4、values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 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 standard to est
5、ablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C168 Terminology Relating to Thermal InsulationC302 Test Method for Density and Dimensions of Pre-formed Pipe-Covering-Type Thermal Insula
6、tionC303 Test Method for Dimensions and Density of Pre-formed Block and BoardType Thermal Insulation3.Terminology3.1 DefinitionsDefinitions pertaining to thermal insulat-ing materials are defined in Terminology C168.4.Significance and Use4.1 Several test methods for measuring mass loss by abra-sion
7、and impact of preformed block-type and preformedpipe-covering-type thermal insulation have been used previ-ously.It is believed that no single test method completelycovers all factors involving such forces for different kinds ofmaterials,but this test method is intended to provide aprocedure that gi
8、ves reproducible results.It is used for com-paring the mass loss by tumbling before and after a specifictreatment of the insulation,as agreed upon by the purchaserand the manufacturer.5.Apparatus5.1 BoxA cubical box of oak wood,having inside dimen-sions of 712by 734by 734in.(190 by 197 by 197 mm),mo
9、unted rigidly at the center of one 734by 734in.(197 by 197mm)end,so that the axis normal to a face of the box is that ofa rotatable horizontal shaft.One side of the box shall be hingedas a door and shall be gasketed to be dust-tight.The box shaftshall be motor driven at a constant speed of 60 6 2 r/
10、min.5.2 CubesTwenty-four room-dry,solid oak,346132-in.(19 6 0.8-mm)cubes shall be placed in the box with the testspecimens.The specific gravity of the oak cubes shall beapproximately 0.65;white oak meets this requirement.NOTE1Number each group of wood cubes 1 through 24.At the endof every 600-revolu
11、tion test,remove one“used”cube(follow the numbersequence and remove the oldest cube)and replace with a correspondinglynumbered“new”cube.In this manner,cube wear is eliminated as anuncontrolled variable in the test method.When the corners of the woodcubes have been worn so that the radius of curvatur
12、e is greater than116in.(1.6 mm)or the cubes have become altered so as not to be comparablewith new cubes,they shall be discarded and new ones used.A conven-tional machinists radius gage is used for checking the edge wear.6.Test Specimens6.1 Cut the insulation with a fine-tooth saw(similar to a16-too
13、th band saw)into 1 6116-in.(25.4 6 1.6-mm)cubes.6.2 Test twelve cubes at a time cut from one piece ofinsulation.When flat insulation has special surfaces due totreatment or molding,cut each cube to include such specialsurfaces as one face,except that the edges and corners of theinsulation shall not
14、be used.6.3 Dry and condition specimens prior to test,followingapplicable specifications for the material.If the material is1This test method is under the jurisdiction ofASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.32 on MechanicalProperties.Current ed
15、ition approved April 1,2014.Published April 2014.Originallyapproved in 1958.Last previous edition approved in 2008 as C421 08.DOI:10.1520/C0421-08R14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards
16、 volume 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 adversely affected by oven temperatures,then condition speci-mens for not less than 40 h at 73.46 1.8F(23 6 1C),and 506 5%relative humidity before testing.In the absence ofdefinitive drying specifications,dry specimens in an oven at215 to 250F(102 to 121C)to constant mass,and hold in adesiccator to cool t
