1、Designation: D6057 96 (Reapproved 2011)Standard Test Method forDetermining Concentration of Airborne Single-CrystalCeramic Whiskers in the Workplace Environment by PhaseContrast Microscopy1This standard is issued under the fixed designation D6057; the number immediately following the designation ind
2、icates 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the sampling meth
3、ods 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 on
4、 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 fibers
5、. 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 directly
6、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 con
7、firmthe 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 ofS
8、CCW is described in Practice D6058 and Test MethodsD6059 and D6056.1.4 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 use. It
9、 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:2D1193 Specification for Reagent WaterD1356 Terminology Relating to Sampling and
10、Analysis ofAtmospheresD4532 Test Method for Respirable Dust in WorkplaceAtmospheres Using Cyclone SamplersD6056 Test Method for Determining Concentration of Air-borne Single-Crystal Ceramic Whiskers in the WorkplaceEnvironment by Transmission Electron MicroscopyD6058 Practice for Determining Concent
11、ration of AirborneSingle-Crystal Ceramic Whiskers in the Workplace Envi-ronmentD6059 Test Method for Determining Concentration of Air-borne Single-Crystal Ceramic Whiskers in the WorkplaceEnvironment by Scanning Electron MicroscopyE691 Practice for Conducting an Interlaboratory Study toDetermine the
12、 Precision 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 correct
13、ly applied only to single-crystal fiberswhereas a fiber may be single- or poly-crystalline or may benoncrystalline.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,anelongated particle having a length greater than 5 m, a widthless
14、than 3 m, and an aspect ratio equal to or greater than 5:1.1This test method is under the jurisdiction of ASTM Committee D22 on AirQuality and is the direct responsibility of Subcommittee D22.04 on Workplace AirQuality.Current edition approved Oct. 1, 2011. Published October 2011. Originallyapproved
15、 in 1996. Last previous edition approved in 2006 as D6057 - 96 (2006).DOI: 10.1520/D6057-96R11.2For 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 Documen
16、t Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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-m
17、ade min-eral fiber that has a single-crystal structure.3.2 For definitions of other terms used in this test method,see Terminology D1356.4. 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 electr
18、ically conductive sampling cassetteassembly (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 ex
19、pressed as a fiber concen-tration 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 t
20、he workplace atmospherewhere these 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 dimens
21、ional considerationsonly.As such, 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
22、the interpretation of data obtainedusing 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
23、needed (refer to Practice D6058 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
24、 and use it for reporting 95 %confidence 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
25、 in Section 3shall be counted.6.1.1 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 situa
26、tion can be managed by regulating 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 eve
27、n with these guidelines. Analyzean 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 thro
28、ugh resampling (see 10.1.9).7. 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
29、shrink tape. Reloading of used 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 pul
30、sation.All pumps shall be calibrated 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
31、 be free from pulsation. All pumps 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
32、.6 Acetone VaporizerA device used 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, respective
33、ly, within the field of view.NOTE 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 gra
34、ticules arerecommended. Graticules 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 measu
35、re the diameter of his or her field ofview and this value shall be used in all calculations.7.8 Phase Shift Test Slide equivalent to HSE/NPL.47.9 Telescope, (ocular phase-ring centering) or Bertrandlens.3The boldface numbers in parentheses refer to a list of references at the end ofthis test method.
36、4The HSE/NPL Phase Shift Test Slide, Mark II.D6057 96 (2011)27.10 Stage Micrometer, (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 liqui
37、dand requires precaution not to ignite it accidentally.)7.17 ASTM D1193 Type 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 Reag
38、ents of the American Chemical Society wheresuch specifications are available.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 airbo
39、rne SCCWon MCE filters usingsampling cassettes and pumps in accordance with 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 c
40、losed cassette and rotameter (orother flow measurement device) in line. Any 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 en
41、tire inlet cap.8.5 Conduct personal and area sampling as follows:8.5.1 For 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 betwe
42、en 0.5 and2.5 L/min is selected (2-5,7). Also see Test Method D4532.8.5.2 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 f
43、low rate and time to produce anoptimum fiber loading between 100 and 1300 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
44、 rate, L/min,Ce= estimated concentration of SCCW, f/mL, and103= conversion 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/m
45、m2(12 fibers/graticule area, average value for all countedfields) for the 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 MethodD4532.8.
46、6 Carefully remove the cassette from the tubing at the endof the sampling 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 thecas
47、sette from the tubing.8.7 Submit at least one field blank (or a number equal 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 sampl
48、ing procedures. Fieldblanks shall be representative of filters used in sample 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
49、berepresentative of filters used in sample collection (for example,same filter 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-tio
