1、Designation: C 421 08Standard Test Method forTumbling Friability of Preformed Block-Type and PreformedPipe-Covering-Type Thermal Insulation1This standard is issued under the fixed designation C 421; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This tes
3、t 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 the standard. The val
4、ues in parentheses are provided forinformation only.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 establish appro-priate safety and health practices and determine the applica-bility of
5、 regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 168 Terminology Relating to Thermal InsulationC 302 Test Method for Density and Dimensions of Pre-formed Pipe-Covering-Type Thermal InsulationC 303 Test Method for Dimensions and Density of Pre-formed Block and BoardTy
6、pe Thermal Insulation3. Terminology3.1 DefinitionsDefinitions pertaining to thermal insulat-ing materials are defined in Terminology C 168.4. Significance and Use4.1 Several test methods for measuring mass loss by abra-sion and impact of preformed block-type and preformedpipe-covering-type thermal i
7、nsulation 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 gives reproducible results. It is used for com-paring the mass loss by tumbl
8、ing 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 712 by 734 by 734 in. (190 by 197 by 197 mm),mounted rigidly at the center of one 734 by 734 in. (197 by 197mm) e
9、nd, 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/min.5.2 CubesTwenty-four room-dry, solid oak,34 6132-in.(19
10、 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.NOTE 1Number each group of wood cubes 1 through 24. At the endof every 600-revolution test, remove one “used” cube (follow the number
11、sequence 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 curvature is greater than116 in.(1.6 mm) or the cu
12、bes 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-tooth band saw) into 1 6116-in. (25.4 6
13、 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 be used.6.3 Dry and condition
14、specimens prior to test, followingapplicable specifications for the material. If the material isadversely 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 specific
15、ations, dry specimens in an oven at215 to 250F (102 to 121C) to constant mass, and hold in a1This test method is under the jurisdiction ofASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.32 on MechanicalProperties.Current edition approved April 15, 2008. P
16、ublished May 2008. Originallyapproved in 1958. Last previous edition approved in 2005 as C 421 05.2For 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 Docu
17、ment Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.desiccator to cool to room temperature before testing. Wherecircumstances or requirements preclude compliance with theseconditioning procedures, exc
18、eptions agreed upon by the pur-chaser and the manufacturer are acceptable, but they shall bespecifically listed in the test report.7. Procedure7.1 Conduct the test in the Standard LaboratoryAtmosphereat 73.4 6 1.8F (23 6 1C) and 50 6 5 % relative humidity.NOTE 2Other specimen conditioning procedures
19、 or test conditionsmay be selected to simulate actual-use conditions, upon agreementbetween the purchaser and the manufacturer.7.2 Weigh the twelve conditioned test specimens on abalance to within 6 1%.7.3 Place the twelve specimens together with the 24 oakcubes in the clean test box and secure the
20、lid tightly.7.4 Rotate the box at 60 6 2 r/min for 600 6 3 revolutions.7.5 Immediately after the test period, carefully empty thecontents of the box onto a38-in. (9.5-mm) mesh screen and tapgently to remove dust and small particles. Carefully remove thetwelve largest pieces of insulation from the sc
21、reen and weighpromptly.7.6 Clean out the box between runs.7.7 If an additional test period is to be run, replace thetwelve weighed pieces into the box and repeat steps 7.3-7.5.8. Calculation8.1 Calculate the percent mass loss to two significant figuresusing Eq 1:Mass loss, % 5 M12 M2!/M1# 3 100 (1)w
22、here:M1= original mass, andM2= final mass.9. Report9.1 The report shall include the following:9.1.1 Complete description of the material tested, includingtype, source, and density, in accordance with Test MethodsC 302 and C 303, and special surfaces if any,9.1.2 Conditioning or drying procedures fol
23、lowed and spe-cial conditions employed in the test, if any,9.1.3 Date of test,9.1.4 Percent mass loss, and9.1.5 Comments on the mode and extent of abrasion,erosion, crumbling, cracking, etc.10. Precision and Bias310.1 PrecisionThe precision of this test method is givenin Table 1.10.1.1 Repeatability
24、 The difference between successiveresults obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialswould exceed the values given for repeatability in Table 1 onlyin one case in twenty.10.1.2 Reproducibility The difference between two singlea
25、nd independent results obtained by different operators work-ing in different laboratories on identical material would exceedthe values given for reproducibility in Table 1 only in one casein twenty.10.2 BiasNo information can be presented on the bias ofthe procedure in this test method because no ma
26、terial having anaccepted reference value is available.11. Keywords11.1 mass loss; thermal insulating materialsblock/board; tumbling friabilityASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of thi
27、s standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five yea
28、rs andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical commit
29、tee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942
30、8-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).3Supporting data have been filed at AST
31、M Headquarters. Request ResearchReport RR:C16-1006.TABLE 1 PrecisionMaterialMassLoss (%)Repeatability Reproducibility6 2.0 Sr6 2.0 Sr(%)6 2.0 SR6 2.0SRA(%)Rigid cellular A 0.11 0.34 309 0.40 364plastic B 1.00 0.65 65.0 0.83 83.0(Specimens = 3, C 5.3 1.6 30.9 4.2 79.3Laboratories = 6) D 31.4 2.6 8.2
32、8.5 27.1E 48.9 4.5 9.1 11.3 23.2F 49.6 5.3 10.7 10.8 21.8Calcium silicate15 lb/ft3(240 kg/m3)maximum(Specimen = 6,Laboratories = 4). 9.3 1.3 14.0 1.1 11.8Perlite14 lb/ft3(224 kg/m3)maximum(Specimens = 3,Laboratories = 5). 54.4 4.2 7.6 9.5 17.5ASr=repeatability standard deviationSR=reproducibility standard deviationC421082
