ASTM D7200-2012 red 9375 Standard Practice for Sampling and Counting Airborne Fibers Including Asbestos Fibers in Mines and Quarries by Phase Contrast Microscopy and Transmission E.pdf

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1、Designation: D7200 06 D7200 12Standard Practice forSampling and Counting Airborne Fibers, Including AsbestosFibers, in Mines and Quarries, by Phase ContrastMicroscopy and Transmission Electron Microscopy1This standard is issued under the fixed designation D7200; the number immediately following the

2、designation indicates 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 practice2 describes t

3、he determination of the concentration of fibers, expressed as the number of such fibers per millilitreof air, using phase contrast microscopy and optionally transmission electron microscopy to evaluate particulate material collectedon a membrane filter in the breathing zone of an individual or by ar

4、ea sampling in a specific location. This practice is based onthe core procedures provided in the International Organization for Standardization (ISO) Standard ISO 8672(1)3, the NationalInstitute for Occupational and Health (NIOSH) Manual of Analytical Methods, NIOSH 7400 (2), and the Occupational Sa

5、fety andHealth Administration (OSHA) Method ID 160 (3). This practice indicates the important points where these methods differ, andprovides information regarding the differences. However, selecting portions of procedures from different published methodsgenerally requires a user to report that they

6、have used a modification to a method rather than claim they have used the method aswritten. This practice further gives guidance on how differential counting techniques may be used to indicate where a populationof fibers may be asbestos.1.2 The practice is used for routine determination of an index

7、of occupational exposure to airborne fibers in mines, quarries,or other locations where ore may be processed or handled. The method gives an index of airborne fiber concentration. The methodprovides an estimate of the fraction of counted fibers that may be asbestos. This practice should be used in c

8、onjunction withelectron microscopy (See Appendix X1) for assistance in identification of fibers.1.3 This practice specifies the equipment and procedures for sampling the atmosphere in the breathing zone of an individual andfor determining the number of fibers accumulated on a filter membrane during

9、the course of an appropriately-selected samplingperiod. The method may also be used to sample the atmosphere in a specific location in a mine or in a room of a building (areasampling).1.4 The ideal working range of this practice extends from 100 fibers/mm2 to 1300 fibers/mm2 of filter area. For a 10

10、00-L airsample, this corresponds to a concentration range from approximately 0.04 to 0.5 fiber/mL (or fiber/cm3). Lower and higher rangesof fiber concentration can be measured by reducing or increasing the volume of air collected. However, when this practice isapplied to personal sampling in mines a

11、nd quarries, the level of total suspended particulate may impose an upper limit to thevolume of air that can be sampled if the filters produced are to be of appropriate particulate loading for fiber counting.1.5 Users should determine their own limit of detection using the procedure in Practice D662

12、0. For reference, the NIOSH 7400method gives the limit of detection as 7 fibers/mm2 of filter area. For a 1000-L air sample, this corresponds to a limit of detectionof 0.0027 fiber/mL (or fiber/cm3). For OSHA ID 160 the limit of detection is given as 5.5 fibers/mm2 of filter area. For a 1000-Lair sa

13、mple, this corresponds to a limit of detection of 0.0022 fiber/mL (or fiber/cm3).1.6 If this practice yields a fiber concentration that does not exceed one-half the permissible exposure limit or threshold limitvalue for the particular regulated fiber variety, no further action may be necessary. If t

14、he fiber concentration exceeds one-half ofthe regulated permissible exposure limit or threshold limit value for the particular regulated fiber variety, it is necessary to examinethe data to determine if more than 50 % 50 % of the counted fibers may be bundles, fibers longer than 10 m, or fibers are

15、thinnerthan 1.0 m. If these counts exceed 50 % of the total count, then there is an increased possibility that asbestos is present in thesample. Use the optional method specified in m, Appendix X1 to measure the concentration or proportion of the fibers counted1 This practice is under the jurisdicti

16、on of ASTM Committee D22 on Air Quality and is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.Current edition approved June 1, 2006Oct. 15, 2012. Published July 2006November 2012. DOI: 10.1520/D7200-06.Originally approved in 2006. Last previous editionapproved in 2006 as D

17、7200 06. DOI:10.1520/D7200-06.2 This test method is based on NIOSH 7400, OSHA Method ID 60, and ISO 8672. Users of this ASTM standard are cautioned that if they wish to comply with one ofthese specific procedures exactly they should follow that procedure, otherwise they should document the modificat

18、ion.3 Boldface numbers in parentheses refer to the list of references appended to this method.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically poss

19、ible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, We

20、st Conshohocken, PA 19428-2959. United States1that is of the regulated variety. If asbestos fibers are identified by this method, the mine/quarry operator should conduct a geologicalsurvey of the property to identify the source of the fibers. or thicker but with an appearance of asbestos (curvature,

21、 splayed ends,or the appearance of a bundle).1.7 The mounting medium used in this practice has a refractive index of approximately 1.45. Fibers with refractive indices inthe range of 1.4 to 1.5 will exhibit reduced contrast, and may be difficult to detect.1.8 Fibers less than approximately 0.2 m in

22、diameter may not be detected by this practice. (4)1.9 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address allof the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate

23、safetyand health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements,see Section 7.2. Referenced Documents2.1 ASTM Standards:4D257 Test Methods for DC Resistance or Conductance of Insulating MaterialsD1356 Terminology Relating to Sa

24、mpling and Analysis of AtmospheresD1357 Practice for Planning the Sampling of the Ambient AtmosphereD3670 Guide for Determination of Precision and Bias of Methods of Committee D22D5337 Practice for Flow Rate Adjustment of Personal Sampling PumpsD6620 Practice for Asbestos Detection Limit Based on Co

25、unts2.2 Other StandardsNIOSH 7400 National Institute of Occupational Health and Safety (Revised 1994).5(RTM 1) Asbestos International Association (AIA), Recommended Technical Method No.1.6ID 160 Occupational Safety and Health Administration (OSHA).ISO 8672 International Organization for Standardizat

26、ion.3. Terminology3.1 Description of terms specific to this practice, in addition to those found in Terminology D1356:3.1.1 asbestosa term applied to six specific silicate minerals belonging to the serpentine and amphibole groups, which havecrystallized in the asbestiform habit, causing them to be e

27、asily separated into long, thin, flexible, strong fibers when crushed orprocessed (5). The Chemical Abstracts Service Registry Numbers of the most common asbestos varieties are: chrysotile(12001-29-5), riebeckite asbestos (crocidolite) (12001-28-4), grunerite asbestos (Amosite) (12172-73-5), anthoph

28、yllite asbestos(77536-67-5), tremolite asbestos (77536-68-6) and actinolite asbestos (77536-66-4).The precise chemical composition of each species varies with the location from which it was mined. Other amphibole mineralswhich exhibit the characteristics of asbestos have also been observed (6).The n

29、ominal compositions of the most common asbestos varieties are:Chrysotile Mg3Si2O5(OH)4Crocidolite Na2 Fe32+Fe23+ Si8O22(OH)2Amosite (Mg,Fe)7 Si8O22 (OH)2Anthophyllite (Mg,Fe)7 Si8O22 (OH)2Tremolite Ca2(Mg,Fe)5 Si8O22 (OH)2 Mg/(Mg + Fe2+) 0.9 1.0Actinolite Ca2(Mg,Fe)5 Si8O22 (OH)2 Mg/(Mg + Fe2+) 0.5

30、0.9NOTE 1Actinolite compositions in which Mg/(Mg + Fe2+) is between 0 and 0.5 are referred to as ferroactinolite. See Ref. (7) for the full namingconventions specified by the International Mineralogical Association.3.1.2 area samplean air sample collected so as to represent the concentration of airb

31、orne dust in a specific mine location, orarea, or room of a workplace.3.1.3 asbestiforma specific type of fibrous mineral growth habit in which the fibers and fibrils exhibit a polyfilamentousgrowth habit and possess high tensile strength and flexibility. All materials regulated as asbestos are asbe

32、stiform, but not allasbestiform minerals are classified as asbestos. Characteristics such as tensile strength and flexibility cannot be ascertained frommicroscopic evaluation.3.1.4 asbestos fibera fiber of asbestos that meets the criteria specified below for “fiber.” Phase Contrast Microscopy (PCM)d

33、oes not identify fibers unequivocally as asbestos. Under the light microscope, a population of asbestos fibers may appear as amixture of fiber agglomerates, fiber bundles (polyfilamentous growth, unique to asbestiform fibers) fibers with split ends, andsingle fibers, the relative occurrence and freq

34、uency of each type depending on the situation.4 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.5 This stand

35、ard is available from US Department of Health and Human Services, 4676 Columbia Parkway, Cincinnati, OH 45226.6 Available from Asbestos International Association, 68 Gloucester Place, London, W1H 3HL, EnglandD7200 1223.1.5 aspect ratiothe ratio of the length of a fiber to its width.3.1.6 cleavage fr

36、agmentsmineral particles, normally formed by comminution of minerals, which often are characterized byparallel sides and a moderate aspect ratio (usually less than 20:1). Non-asbestiform cleavage fragments do not exhibit fibrillarbundling at any level of examination.3.1.7 limit of detectionthe numbe

37、r of fibers necessary to be 95 % confident that the result is greater than zero.3.1.8 differential countinga term applied to the practice of excluding certain kinds of fibers from the fiber count because theydo not appear to be morphologically consistent with fibers of a specific variety thus modify

38、ing the definition of fiber given below.3.1.9 fiberan elongated particle that is longer than 5.0 m, with a minimum aspect ratio of 3:1, and sometimes also classifiedas having a maximum width of 3.0 m as this latter dimension may equate to the size of fiber of the density of many silicateminerals cap

39、able of penetrating the lung. An asbestos fiber should further exhibit the asbestiform habit, although analysis ofairborne fibers by PCM may not be sufficient in itself to determine asbestiform habit.3.1.10 fibrila single fiber of asbestos that cannot be further separated longitudinally into smaller

40、 components without losingits fibrous properties or appearances.3.1.11 fibrousa mineral that is composed of parallel, radiating, or interlaced aggregates of fibers, from which the fibers aresometimes separable. A crystalline aggregate may be referred to as fibrous even if it is not composed of separ

41、able fibers, but hasthat distinct appearance. The term “fibrous” in mineralogy is used to describe aggregates of grains that crystallize in a needle-likehabit and appear to be composed of fibers. Asbestos minerals are fibrous, exhibiting a specific type of fibrous habit termedasbestiform. However, n

42、ot all minerals having fibrous habit are asbestos.3.1.12 field (of view)the area within the graticule circle that is superimposed on the microscope image.3.1.13 habitthe characteristic crystal growth form or combination of these forms of a mineral, including characteristicirregularities.3.1.14 perso

43、nal samplea sample taken by a collection apparatus (membrane filter) positioned in the breathing zone of thesubject (near the nose and mouth) such that the collected particles are representative of airborne dust that is likely to enter therespiratory system of the subject in the absence of respirato

44、ry protection.3.1.15 seta group of samples that are collected, submitted to the laboratory, and analyzed for a report that is generated.3.1.16 RIB Graticulean eyepiece graticule specifically designed for asbestos fiber counting. It consists of a circle with anominal projected diameter of 100 m (nomi

45、nal area of 0.00785 mm2) with a cross-hair having dash lines 5-m long and 0.5-mwide in one direction and 5-m long and 1-m wide in the orthogonal direction. There are also examples around the periphery ofthe circle to illustrate specific sizes and shapes of fibers. This design of the graticule is sho

46、wn in Fig. A1.1. The graticule is placedin one of the microscope eyepieces so that the design is superimposed on the field of view.3.1.17 Walton Beckett Graticulean eyepiece graticule specifically designed for asbestos fiber counting. It consists of a circlewith a nominal projected diameter of 100 m

47、 (nominal area of 0.00785 mm2) with a cross-hair having tick-marks at 3 m intervalsin one direction and 5 m intervals in the orthogonal direction. There are also examples around the periphery of the circle toillustrate specific sizes and shapes of fibers. This design of the graticule is shown in Fig

48、. A1.2. The graticule is placed in one ofthe microscope eyepieces so that the design is superimposed on the field of view.3.1.18 HSE/NPL7 test slidea calibration slide designed to determine the limit of visibility of a PCM and an observer.4. Summary of Practice4.1 The sample is collected by drawing

49、air through a 25-mm diameter, mixed cellulose ester (MCE) membrane filter, housedin a conductive polypropylene cassette. After sampling, a sector of the membrane filter is converted to an optically transparenthomogeneous gel. Fibers longer than 5 m are counted by observing them with a Phase Contrast Microscope (PCM) at amagnification between 400 and 500.4.2 Divide the total count into three groups: 1) bundles, fibers with splayed ends, or fibers with curvature; 2) fibers longer than10 m or fibers thinner than 1.0 m; 3) all other fibers l