1、Designation: D 2947 88 (Reapproved 2006)Standard Test Method forScreen Analysis of Asbestos Fibers1This standard is issued under the fixed designation D 2947; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio
2、n. 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 covers a dry screen analysis forasbestos fiber by means of a mechanical sieve shaker.1.2 This test method is lim
3、ited in its application to Group 4and shorter chrysotile asbestos fiber samples2as defined in TestMethod D 3639. However, some short amphibole asbestosfibers may be suitable for evaluation by this method.1.3 The values stated in SI units are standard. The inch-pound (customary) units in brackets are
4、 presented for informa-tion only.1.4 WarningBreathing of asbestos dust is hazardous.Asbestos and asbestos products present demonstrated healthrisks for users and for those with whom they come into contact.In addition to other precautions, when working with asbestos-cement products, minimize the dust
5、 that results. For informa-tion on the safe use of chrysoltile asbestos, refer to “Safe Useof Chrysotile Asbestos: A Manual on Preventive and ControlMeasures.”31.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the use
6、r of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific safetyhazard, see 1.4.2. Referenced Documents2.1 ASTM Standards:4D 2590 Test Method for Sampling Chrysotile AsbestosD 2946 Terminology for As
7、bestos and AsbestosCementProductsD 3639 Test Method for Classification of Asbestos byQuebec Standard TestD 3879 Test Method for Sampling Amphibole AsbestosE11 Specification for Wire Cloth and Sieves for TestingPurposesE 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3. Summa
8、ry of Method3.1 The procedure consists of screening a test specimenthrough a specified nest of sieves by means of a mechanicalsieve shaker that reproduces the circular and tapping motiongiven testing sieves in hand-sieving, but with a uniform,mechanical action, assuring more accurate and dependablet
9、ests.4. Significance and Use4.1 Test results give some indication of the apparent fiberlength distribution in the sample tested.4.2 Sieves are ideally suited to measure particle size andparticle size distribution when all three axes of the particle areequidimensional or the particle is of spherical
10、shape. Asbestosfibers differ considerably from these ideal conditions and,therefore, results depart from a true measure of fiber length andlength distribution.4.3 Characteristics that influence screening efficiency influ-ence test results. Among these are moisture content, degree offiberization, har
11、shness, and the tendency for fibers to clingtogether, and of short fibers and fines to cling to longer fibers.4.4 In spite of its shortcomings, this test method is particu-larly useful because of its simplicity and speed and satisfactoryreproducibility.4.5 The test is suitable for specification acce
12、ptance andmanufacturing control.5. Apparatus5.1 Sieve Shaker5for 200-mm (8-in.) diameter sieves thatimpart the screening and tapping action found necessary forthis asbestos application.1This method is under the jurisdiction of ASTM Committee C17 on Fiber-Reinforced Cement Products and is the direct
13、responsibility of SubcommitteeC17.03 on Asbestos-Cement Sheet Products and Accessories.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1971. Last previous edition approved in 2002 as D 2947 88 (2002)e1.2Quebec Asbestos Mining Assn. (QAMA) standard designation of chr
14、ysotileasbestos grades.3Available from The Asbestos Institute, http:/ 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 webs
15、ite.5The Tyler Ro-Tap has been found satisfactory for this purpose. The criteria,settings, and adjustments specified in 5.1.2 to 5.1.6 have been found to providereproducible results with this unit. Any other mechanical shaker that imparts to thenest of sieves a motion identical to that of this devic
16、e, and that can reproduce resultsachieved with the Ro-Tap would be acceptable as being equivalent thereto. If youare aware of alternative suppliers, please provide this information to ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible tech
17、nical committee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.1 The shaker shall be mounted on a suitable firmfoundation, preferably concrete.5.1.2 The eccentric shaft shall rotate at a speed of 285 6 5r/m
18、in. The machine shall be geared to give 152 taps/min whenthe eccentric shaft rotates at 285 r/min.5.1.3 The plate supporting the nest of sieves must be set togive a clearance of 2.4 6 0.8 mm (332 6132 in.) between thetop of the cast iron cover and the bottom of the stops on thecarrying plate (dimens
19、ion A in Fig. 1). This clearance issufficient to allow the nest of sieves to be easily set in place andto rotate freely when the shaker is in operation. It is importantthat this gap be checked periodically in order to maintainproper sieving action.5.1.4 The cast iron cover for the nest of sieves sha
20、ll be fittedwith a standard No. 9 rubber stopper made of neoprene or otherelastomer of equal elasticity.5.1.5 The height of the stopper above the top of the cast ironcover plate shall be 25.4 6 3.2 mm (1 618 in.) (dimension Aplus B in Fig. 1) measured with the hammer resting on thestopper. With a ne
21、w stopper this measurement should be takenonly after the machine has been in operation for a few hoursand should be set as closely as possible to the maximum settingof 28.6 mm (118 in.).5.1.6 The center of the hammer is a point in the center of theface 244.5 6 0.4 mm (958 6164 in.) from the center o
22、f thehammer pin. The hammer drop, measured from the center ofthe hammer in its highest position to the top of the stopper,shall be 34.9 6 3.2 mm (138 618 in.). The hammer drop maybe adjusted by adjustments in the top end of the push rod (Fig.2) or adjustments in the location of the push rod collar,
23、or byboth adjustments. A minimum clearance of 1.6 mm (116 in.)between the push rod and the hammer in its lower position(dimension E in Fig. 1) should be maintained.5.1.7 Automatic Timer or Timeswitch to energize the shakerwith an accuracy of 65 s, on periods extending from 10 to 30min.5.2 Sieves:5.2
24、.1 Standard 20 cm (8-in.) diameter covers, sieve frames,and pans shall be used. Sieve frames and pans shall be fullheight. Wire cloth of sieves, covers, frames and pans shallconform to Specification E11, except that stainless steel maybe used in place of sheet brass if desired. Alternatively,equival
25、ent Tyler Standard Sieves may be used.FIG. 1 Sieve ShakerFIG. 2 Adjustable Push RodD 2947 88 (2006)25.2.2 If calibration and standardization are desired, proceedas in the appendixes to Specification E11.6. Sampling6.1 Select samples in accordance with Test Method D 2590for chrysotile fibers or Test
26、Method D 3879 for amphibolefibers. If in doubt as to the type of fiber refer to the detaileddescriptions of chrysotile and of commercially importantamphibole fibers given in Terminology D 2946.(Warningsee 1.4.)7. Test Specimens, Screen Sizes and Test Duration7.1 The sample size, series of sieves, an
27、d test duration forthe particular grade to be tested are shown in Table 1.8. Procedure8.1 Select a series of sieves corresponding to the grade offiber to be tested as listed in Table 1.8.2 Nest the sieves in the order of decreasing opening sizeswith the coarsest size on top, and a pan at the bottom.
28、8.3 Weigh the specimen to the mass indicated in Table 1 andplace it on the uppermost sieve and close it with a sieve cover.8.4 Set the cast iron cover in place on top of the sieve cover.8.5 Place the sieve assembly in the shaker and lock it inposition.8.6 Start the sieve shaker and run it for the te
29、st durationspecified in Table 1.8.7 When the shaker has stopped, remove the sieves andweigh the contents of each to the nearest 0.1 g.9. Report9.1 Record the analysis in tabular form as the percentage bymass of material retained on each individual sieve and in thepan. Report the average of two accep
30、table results as defined in10.4.1.9.1.1 The particular sieve designation used or the nominalopening of each sieve shall be clearly indicated.9.2 In addition, results may also be presented as cumulativepercent retained, cumulative percent passing, or by graphicalrepresentation.9.3 Fully identify the
31、sample as to origin and grade desig-nation.9.4 If screen blinding or the formation of agglomerations ofany kind due to the shaking action are encountered, remarks tothis effect must be included in the report.10. Precision and Bias10.1 RepeatabilityThe single-operator, single apparatusrepeatability i
32、s presented in Table 2 based upon five and tworeplicates. The latter is significant because two replicates arecalled for by this test method.10.2 Reproducibility, (as defined in Practice E 177).10.2.1 The intralaboratory multiple operator, apparatus andsample variation between two test results shoul
33、d not exceed thevalues presented in Table 3 in 95 % of cases.10.2.2 During the period 1961 to 1975, a fifteen year annualintralaboratory reproducibility study was carried out on 15different samples of each of 91 chrysotile grades using multipleoperators and apparatus. The ranges of statistics presen
34、ted inTable 4 were obtained. The reproducibilities expressed ascoefficients of variation are presented in Table 5 for each sieveand for each group of fibre grades.10.3 Bias:10.3.1 Bias cannot be established on asbestos fiber for lackof a suitable referee method.10.3.2 Bias associated with each of th
35、e sieves used may bedetermined as described in the appendices to SpecificationE11.TABLE 1 Sieve Sizes, Specimen Mass and Test DurationGradeA4 5 6 and 7D 7 except 7DSieve series, mm 6.73 . . .4.76 4.76 . .3.36 3.36 3.36 3.361.68 1.68 1.68 . . 1.19 1.19Sieve series, m 841 841 841 841. . . 595420 420 4
36、20 420. 210 210 210pan pan pan panSpecimen Mass, g 50 6 0.05 50 6 0.05 100 6 0.05 100 6 0.05Test Duration, min 10 10 10 30Equivalent Sieve SeriesSI Sieve Openings US Standard Series AlternativeSieve DesignationTyler Series MeshDesignationmm m6.73 0.265 in. 34.76 No. 4 43.36 661.68 12 101.19 16 14. 8
37、41 20 20. 595 30 28. 420 40 35. 210 70 65AQuebec Asbestos Mining Association.D 2947 88 (2006)310.3.3 It has been observed that the retention of the fibers oneach sieve may be a function of the degree to which the screencloth is worn.10.4 Acceptance of Test Results:10.4.1 The acceptable variation in
38、the cumulative total ofthe fractions weighed may not exceed 61.0 %. In such a case,repeat the test.11. Keywords11.1 asbestos; fiber; fiber length distribution; Ro-Tapscreen; screen analysis; sievingTABLE 2 RepeatabilitySieve OpeningmmRepeatability, %Minimum Maximum5 Replicates2Replicates5 Replicates
39、 2 Replicates6.73 0.71 1.6 22.7 51.24.76 0.78 1.8 6.6 15.23.36 0.92 2.0 5.9 12.81.68 0.77 1.7 5.6 12.41.19 1.74 3.9 8.4 18.8841 m 0.82 1.8 4.4 9.7595 m 0.60 1.3 3.5 7.6420 m 0.33 0.7 0.8 1.7210 m 0.72 1.6 3.6 8.0TABLE 3 ReproducibilitySieveOpening, mmReproducibility, %Minimum Maximum5 Replicates 2 R
40、eplicates 5 Replicates 2 Replicates6.73 0.80 1.6 25.6 51.24.76 1.83 2.4 15.5 20.33.36 1.46 2.3 9.3 14.71.68 2.36 2.8 17.1 20.31, 19 1.19 3.7 5.8 18.0841 m 0.47 1.7 2.5 9.0595 m 1.66 2.0 9.6 11.6420 m 0.43 0.8 1.0 1.9210 m 1.35 2.0 6.7 9.9D 2947 88 (2006)4ASTM International takes no position respecti
41、ng the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this 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 stand
42、ard is subject to revision at any time by the responsible technical committee and must be reviewed every five years 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 Internation
43、al Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, 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.T
44、his standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,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
45、), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 4 Ranges of Reproducibility StatisticsGrades and Quantity of SamplesSieve MeshmmRange % retained Standard Deviation, % Variance range, %min max min max min maxGroup 4 6.73 1.2 3.7 0.7 2.0 54.0 90.014 samples 4.76 2.3 16.
46、1 0.6 3.25 14.9 61.53.36 9.6 21.7 1.5 2.7 7.4 26.51.68 29.4 42.6 1.0 8.3 2.4 28.2841 m 13.0 26.0 1.2 2.3 5.5 11.5420 m 4.6 15.8 0.7 2.0 7.6 17.8pan 4.4 11.6 0.8 2.6 13.7 25.6Group 5 4.76 0.4 3.8 0.4 2.3 44.4 79.722 samples 3.36 0.45 15.4 0.35 3.5 12.3 85.71.68 26.6 50.0 1.7 12.2 4.0 25.6841 m 14.4 3
47、6.7 1.3 7.8 5.4 28.0420 m 7.0 21.6 0.6 4.1 6.2 21.0210 m 2.5 5.5 0.3 1.1 7.3 22.4pan 3.4 14.4 0.7 2.9 14.0 28.1Group 6 and 7D 3.36 0.3 1.2 0.1 1.1 33.2 91.713 samples 1.68 8.6 27.4 1.9 6.2 13.8 36.51.19 14.6 26.8 1.1 2.6 5.8 14.4841 m 16.6 23.2 1.0 2.6 4.7 14.2420 m 20.7 33.6 2.0 3.0 6.7 13.0210 m 4
48、.5 9.4 0.7 1.7 10.4 28.9pan 5.1 16.9 0.8 3.5 11.1 38.9Group 7 except 7D 3.36 0 0 0 0 0 042 samples 1.19 0 3.6 0 2.8 0 120841 m 0 12.8 0 2.6 0 100595 m 0 28.8 0 3.8 0 100420 m 1.6 38.0 0.7 7.6 4.2 76210 m 7.3 64.8 0.7 9.7 4.9 26pan 11.9 67.7 1.5 9.8 2.6 28TABLE 5 Reproducibility as Coefficient of Var
49、iation, %Grades 4 5 6 and 7D 7 except 7D 7 floats All GradesNumber of Samples 14 22 13 33 9 916.73 mm 66.5 . . . . 66.54.76 mm 32.2 58.8 62.5 . . 42.33.36 mm 20.6 49.0 62.5 . . 41.91.68 mm 6.9 11.4 23.4 . . 13.91.19 mm . . 9.4 50.4 . 29.9841 m 8.6 11.3 8.8 30.4 44.0 20.6595 m . . . 18.3 57.5 37.9420 m 12.0 12.1 9.3 12.5 37.3 16.6210 m . 17.8 17.1 13.7 12.9 15.4pan 18.4 24.4 20.3 10.5 11.9 17.1D 2947 88 (2006)5
