1、Designation: D 6057 96 (Reapproved 2006)Standard Test Method forDetermining Concentration of Airborne Single-CrystalCeramic Whiskers in the Workplace Environment by PhaseContrast Microscopy1This standard is issued under the fixed designation D 6057; the number immediately following the designation i
2、ndicates the year oforiginal adoption or, in the case 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.1. Scope1.1 This test method covers the sampling m
3、ethods andanalysis techniques used to assess the airborne concentration ofsingle-crystal ceramic whiskers (SCCW), such as silicon car-bide and silicon nitride, which may occur in and around theworkplace where these materials are manufactured, processed,transported, or used. This test method is based
4、 on the collectionof fibers by filtration of a known quantity of air through a filter.The filter is subsequently evaluated with a phase contrastmicroscope (PCM) for the number of fibers meeting appropri-ately selected counting criteria. This test method cannotdistinguish among different types of fib
5、ers. This test methodmay be appropriate for other man-made mineral fibers(MMMF).1.2 This test method is applicable to the quantitation offibers on a collection filter that are greater than 5 m in length,less than 3 m in width, and have an aspect ratio equal to orgreater than 5:1. The data are direct
6、ly convertible to astatement of concentration per unit volume of air sampled.Thistest method is limited by the diameter of the fibers visible byPCM (typically greater than 0.25 m in width) and the amountand type of coincident interference particles.1.3 A more definitive analysis may be necessary to
7、confirmthe identity and dimensions of the fibers located with the PCM,especially where other fiber types may be present. Suchtechniques may include scanning electron microscopy (SEM)or transmission electron microscopy (TEM). The use of thesetest methods for the identification and size determination
8、ofSCCW is described in Practice D 6058 and Test MethodsD 6059 and D 6056.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its u
9、se. 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.2. Referenced Documents2.1 ASTM Standards:2D 1193 Specification for Reagent WaterD 1356 Terminology Relating to Sampl
10、ing and Analysis ofAtmospheresD 4532 Test Method for Respirable Dust in WorkplaceAtmospheresD 6056 Test Method for Determining Concentration ofAirborne Single-Crystal Ceramic Whiskers in the Work-place Environment by Transmission Electron MicroscopyD 6058 Practice for Determining Concentration ofAir
11、borneSingle-Crystal Ceramic Whiskers in the Workplace Envi-ronmentD 6059 Test Method for Determining Concentration ofAirborne Single-Crystal Ceramic Whiskers in the Work-place Environment by Scanning Electron MicroscopyE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision
12、of a Test Method3. Terminology3.1 Definitions:3.1.1 analytical sensitivity, nairborne fiber concentrationrepresented by a single fiber counted in the PCM.3.1.1.1 DiscussionAlthough the terms fiber and whiskerare, for convenience, used interchangeably in this test method,whisker is correctly applied
13、only to single-crystal fiberswhereas a fiber may be single- or poly-crystalline or may benoncrystalline.1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.04 on WorkplaceAtmospheres.Current edition approved Oct. 1, 200
14、6. Published October 2006. Originallyapproved in 1996. Last previous edition approved in 2001 as D 6057 - 96 (2001)e1.2For 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 t
15、o 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.3.1.2 aspect ratio, nthe ratio of the length of a fiber to itswidth.3.1.3 fiber, nfor the purpose of this test method,anelongate
16、d particle having a length greater than 5 m, a widthless than 3 m, and an aspect ratio equal to or greater than 5:1.3.1.4 man-made mineral fiber, nany inorganic fibrousmaterial produced by chemical or physical processes.3.1.5 single-crystal ceramic whisker, n a man-made min-eral fiber that has a sin
17、gle-crystal structure.3.2 For definitions of other terms used in this test method,see Terminology D 1356.4. Summary of Test Method4.1 The sample is collected on a mixed cellulose ester(MCE) filter by drawing air, using a sampling pump, throughan open-face 25-mm electrically conductive sampling casse
18、tteassembly (1,2).3Asection of the opaque filter is converted intoan optically transparent homogeneous specimen using anacetone vaporizer. The fibers are counted by PCM at amagnification of approximately 4003 using the criteria dis-cussed in Section 11. Results are expressed as a fiber concen-tratio
19、n per unit volume of air and a fiber loading per unit areaof filter. The airborne concentration is expressed as fibers permillilitre (f/mL) and the fiber loading is expressed as fibers persquare millimetre (f/mm2).5. Significance and Use5.1 The SCCWmay be present in the workplace atmospherewhere the
20、se materials are manufactured, processed, trans-ported, or used. This test method can be used to monitorairborne concentrations of fibers in these environments. It maybe employed as part of a personal or area monitoring strategy.5.2 This test method is based on dimensional considerationsonly.As such
21、, it does not provide a positive identification of thefibers counted. Analysis by SEM or TEM is required whenadditional fiber identification information is needed.NOTE 1This test method assumes that the analyst is familiar with theoperation of PCM instrumentation and the interpretation of data obtai
22、nedusing this technique.5.3 This test method is not appropriate for measurement offibers with diameters less than approximately 0.25 m due tovisibility limitations associated with PCM. The SEM or TEMmethods may be used to provide additional size information ofSCCW if needed (refer to Practice D 6058
23、 for additionalinformation on the use of these methods).5.4 Results from the use of this test method shall be reportedalong with 95 % confidence limits for the samples beingstudied. Individual laboratories shall determine their intralabo-ratory coefficient of variation and use it for reporting 95 %c
24、onfidence limits (1,3,4).6. Interferences6.1 All fibers meeting the dimensional criteria in Section 3are not necessarily of the same composition. Since the PCMmethod does not differentiate based on chemistry or morphol-ogy, all fibers in accordance with the definitions in Section 3shall be counted.6
25、.1.1 This test method has been designed to filter air for thedetermination of fiber concentration. However, filtration of airalso involves collection of extraneous particles. Extraneousparticles may obscure fibers by overlay or by discoloration ofthe filter. This situation can be managed by regulati
26、ng the airvolume sampled and thus the filter loading. Fibers shouldappear separated from other particles to ensure an adequateopportunity for their recognition as separate entities in thePCM and accurate counting. Some coincident particulateagglomeration does occur even with these guidelines. Analyz
27、ean alternate filter with a reduced loading if the obscuringcondition appears to exceed 15 % of the filter area (5).Redeposition of a portion of an overloaded filter is permittedonly in circumstances where an alternate filter is not availableand cannot be obtained through resampling (see 10.1.9).7.
28、Apparatus and Reagents7.1 Sampling CassetteUse a 25-mm, electrically conduc-tive cassette assembly such as a three-piece cassette with anextension cowl or retainer ring, or both, containing a 0.45-mpore size MCE filter and a support pad. Seal the cassetteassembly with shrink tape. Reloading of used
29、cassettes is notpermitted.7.2 Personal Sampling PumpUse a portable battery-operated pump for personal sampling. Each pump must becapable of operating within the range from 0.5 to 4 L/min andcontinuously over the chosen sampling period (1). The flowmust be free from pulsation.All pumps shall be calib
30、rated priorto use (6).7.3 Area Sampling PumpUse a personal sampling pumpor a non-portable high-volume pump for area sampling. Eachpump shall be capable of operating within the range from 0.5to 16 L/min and continuously over the chosen sampling period(1). The flow shall be free from pulsation. All pu
31、mps shall becalibrated prior to use (6).7.4 Vinyl Tubing, or equivalent.7.5 MicroscopePositive phase contrast light, with greenor blue filter, 8 to 103 eyepiece, and 40 to 453 phase objective(total magnification approximately 4003); numerical aper-ture = 0.65 to 0.75.7.6 Acetone VaporizerA device us
32、ed to clear the MCEfilter by exposure to a small amount of vaporized acetone.7.7 Graticule, with standardized 100-m diameter circularfield at the specimen plane (calibrated area 7.8 3 103mm2), with the capability to compare diameters and lengths at3 and 5 m, respectively, within the field of view.NO
33、TE 2The graticule is custom-made for each microscope. Specifydisk diameter needed to exactly fit the ocular of the microscope and thediameter (millimetres) of the circular counting area (see section 12.2.1).The Walton-Beckett Type G-24 graticule or other equivalent graticules arerecommended. Graticu
34、les designed for the NIOSH 7400 A rules, such asthe Walton-Beckett Type G-22, are not recommended.NOTE 3In some microscopes, adjustments of the interocular distancewill change the tube length and hence magnification of the microscope.Each analyst shall separately measure the diameter of his or her f
35、ield ofview and this value shall be used in all calculations.3The boldface numbers in parentheses refer to a list of references at the end ofthis test method.D 6057 96 (2006)27.8 Phase Shift Test Slide equivalent to HSE/NPL.47.9 Telescope, (ocular phase-ring centering) or Bertrandlens.7.10 Stage Mic
36、rometer, (0.01-mm divisions).7.11 Tweezers.7.12 Scalpel Blades.7.13 MCE Filters, 25 mm, 0.45 m and 0.22 m.7.14 Funnel/Filter Assembly,25mm.7.15 Triacetin (glycerol triacetate).7.16 Acetone.(WarningAcetone is a flammable liquidand requires precaution not to ignite it accidentally.)7.17 ASTM D1193 Typ
37、e II Water (particle free).7.18 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are availabl
38、e.5Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8. Sample Collection8.1 Collect samples of airborne SCCWon MCE filters usingsampling cassettes and pumps in accordance with
39、 Section 7.8.2 Remove the outlet plug from the sampling cassette andconnect it to a sampling pump by means of flexible,constriction-proof tubing.8.3 Perform a leak check of the sampling system byactivating the pump with the closed cassette and rotameter (orother flow measurement device) in line. Any
40、 flow indicates aleak that must be eliminated before starting the samplingoperation.8.4 Remove the inlet plug from the sampling cassette toeliminate any vacuum that may have accumulated during theleak test; then remove the entire inlet cap.8.5 Conduct personal and area sampling as follows:8.5.1 For
41、personal sampling, fasten the sampling cassette tothe workers lapel in the workers breathing zone and orient itface down. Adjust the calibrated flow rate to a value between0.5 and 4 L/min (1). Typically, a sampling rate between 0.5 and2.5 L/min is selected (2-5,7). Also see Test Method D 4532.8.5.2
42、Place area samples on an extension rod facing down ata 45 angle. Adjust the calibrated flow rate to a value between0.5 and 16 L/min (1). Typically, a sampling rate between 1 and10 L/min is selected (8).8.5.3 Set the sampling flow rate and time to produce anoptimum fiber loading between 100 and 1300
43、f/mm2(1,2). Thetime of sampling can be estimated by using the followingequation:t 5Ac! FL!Q! Ce! 103(1)where:Ac= active filter collection area (;385 mm2for 25-mmfilter),6t = time, min,FL= fiber loading, f/mm2,Q = sampling flow rate, L/min,Ce= estimated concentration of SCCW, f/mL, and103= conversion
44、 factor.NOTE 4While the desired minimum loading is 100 f/mm2, theminimum loading that has statistical significance is 7 f/mm2after blankcorrection (1).NOTE 5Experience has shown that the fiber loading should notexceed 1300 f/mm2(12 fibers/graticule area, average value for all countedfields) for the
45、majority of sampling situations (1).8.5.4 At a minimum, check the flow rate before and aftersampling. If the difference is greater than 10 % from the initialflow rate, the sample shall be rejected. Also see Test MethodD 4532.8.6 Carefully remove the cassette from the tubing at the endof the sampling
46、 period (ensure that the cassette is positionedupright before interrupting the pump flow). Replace the inletcap and inlet and outlet plugs, and store the cassette.NOTE 6Deactivate the sampling pump prior to disconnecting thecassette from the tubing.8.7 Submit at least one field blank (or a number eq
47、ual to10 % of the total samples, whichever is greater) for each set ofsamples. Remove the cap of the field blank briefly (approxi-mately 30 s) at the sampling site, then replace it. The fieldblank is used to monitor field sampling procedures. Fieldblanks shall be representative of filters used in sa
48、mple collec-tion (for example, same filter lot number).8.8 Submit at least one unused and unopened sealed blankwhich is used to monitor the supplies purchased as well asprocedures used in the laboratory. The sealed blank shall berepresentative of filters used in sample collection (for example,same f
49、ilter lot number).9. Transport of Samples9.1 Ship the samples in a rigid container with sufficientpacking material to prevent jostling or damage. Care shall betaken to minimize vibrations and cassette movement.NOTE 7Do not use shipping material that may develop electrostaticforces or generate dust.NOTE 8Shipping containers for 25-mm sampling cassettes are com-mercially available and their use is recommended.9.2 Include in the container a list of samples, their descrip-tions, and all other pertinent information.10. Specimen Preparation10.1 The o
