1、Designation:D720012Standard 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 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 practice2describes the determination of the
3、 con-centration of fibers,expressed as the number of such fibers permillilitre of air,using phase contrast microscopy and optionallytransmission electron microscopy to evaluate particulate mate-rial collected on a membrane filter in the breathing zone of anindividual or by area sampling in a specifi
4、c location.Thispractice is based on the core procedures provided in theInternational Organization for Standardization(ISO)StandardISO 8672(1)3,the National Institute for Occupational andHealth(NIOSH)Manual of Analytical Methods,NIOSH 7400(2),and the Occupational Safety and Health Administration(OSHA
5、)Method ID 160(3).This practice indicates the impor-tant points where these methods differ,and provides informa-tion regarding the differences.However,selecting portions ofprocedures from different published methods generally re-quires a user to report that they have used a modification to amethod r
6、ather than claim they have used the method as written.This practice further gives guidance on how differential count-ing techniques may be used to indicate where a population offibers may be asbestos.1.2 The practice is used for routine determination of anindex of occupational exposure to airborne f
7、ibers in mines,quarries,or other locations where ore may be processed orhandled.The method gives an index of airborne fiber concen-tration.The method provides an estimate of the fraction ofcounted fibers that may be asbestos.This practice should beused in conjunction with electron microscopy(See App
8、endixX1)for assistance in identification of fibers.1.3 This practice specifies the equipment and procedures forsampling the atmosphere in the breathing zone of an individualand for determining the number of fibers accumulated on afilter membrane during the course of an appropriately-selectedsampling
9、 period.The method may also be used to sample theatmosphere in a specific location in a mine or in a room of abuilding(area sampling).1.4 The ideal working range of this practice extends from100 fibers/mm2to 1300 fibers/mm2of filter area.For a 1000-Lair sample,this corresponds to a concentration ran
10、ge fromapproximately 0.04 to 0.5 fiber/mL(or fiber/cm3).Lower andhigher ranges of fiber concentration can be measured byreducing or increasing the volume of air collected.However,when this practice is applied to personal sampling in mines andquarries,the level of total suspended particulate may impo
11、se anupper limit to the volume of air that can be sampled if the filtersproduced are to be of appropriate particulate loading for fibercounting.1.5 Users should determine their own limit of detectionusing the procedure in Practice D6620.For reference,theNIOSH 7400 method gives the limit of detection
12、 as 7 fibers/mm2of filter area.For a 1000-L air sample,this corresponds toa limit of detection of 0.0027 fiber/mL(or fiber/cm3).ForOSHA ID 160 the limit of detection is given as 5.5 fibers/mm2of filter area.For a 1000-L air sample,this corresponds to alimit of detection of 0.0022 fiber/mL(or fiber/c
13、m3).1.6 If this practice yields a fiber concentration that does notexceed one-half the permissible exposure limit or thresholdlimit value for the particular regulated fiber variety,no furtheraction may be necessary.If the fiber concentration exceedsone-half of the regulated permissible exposure limi
14、t or thresh-old limit value for the particular regulated fiber variety,it isnecessary to examine the data to determine if more than 50%of the counted fibers are thinner than 1.0 m,or thicker butwith an appearance of asbestos(curvature,splayed ends,or theappearance of a bundle).1.7 The mounting mediu
15、m used in this practice has arefractive index of approximately 1.45.Fibers with refractiveindices in the range of 1.4 to 1.5 will exhibit reduced contrast,and may be difficult to detect.1This practice is under the jurisdiction ofASTM Committee D22 on Air Qualityand is the direct responsibility of Su
16、bcommittee D22.04 on Workplace Air Quality.Current edition approved Oct.15,2012.Published November 2012.Originallyapproved in 2006.Last previous edition approved in 2006 as D7200 06.DOI:10.1520/D7200-06.2This test method is based on NIOSH 7400,OSHA Method ID 60,andISO 8672.Users of this ASTM standard are cautioned that if they wish to complywith one of these specific procedures exactly they should follow that procedure,otherwise they should document the modification.3Boldface numbers in parenthe
