ASTM F312-2008 Standard Test Methods for Microscopical Sizing and Counting Particles from Aerospace Fluids on Membrane Filters《膜滤器上航空流体中颗粒微观大小的测定及计数的标准试验方法》.pdf
《ASTM F312-2008 Standard Test Methods for Microscopical Sizing and Counting Particles from Aerospace Fluids on Membrane Filters《膜滤器上航空流体中颗粒微观大小的测定及计数的标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM F312-2008 Standard Test Methods for Microscopical Sizing and Counting Particles from Aerospace Fluids on Membrane Filters《膜滤器上航空流体中颗粒微观大小的测定及计数的标准试验方法》.pdf(4页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: F 312 08Standard Test Methods forMicroscopical Sizing and Counting Particles fromAerospace Fluids on Membrane Filters1This standard is issued under the fixed designation F 312; the number immediately following the designation indicates the year oforiginal adoption or, in the case of rev
2、ision, 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 These test methods cover the determination of the sizedistribution and quantity of particulate matt
3、er contaminationfrom aerospace fluids isolated on a membrane filter. Themicroscopical techniques described may also be applied toother properly prepared samples of small particles. Two testmethods are described for sizing particles as follows:1.1.1 Test Method AParticle sizes are measured as thediam
4、eter of a circle whose area is equal to the projected area ofthe particle.1.1.2 Test Method BParticle sizes are measured by theirlongest dimension.1.2 The test methods are intended for application to particlecontamination determination of aerospace fluids, gases, sur-faces, and environments.1.3 The
5、values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 These test methods do not provide for sizing particlessmaller than 5 m.NOTE 1Results of these methods are subject to variables inherent inany statistical method. The use of these m
6、ethods as a standard for initiallyestablishing limits should be avoided unless ample tolerances are permis-sible.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate sa
7、fety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2F 302 Practice for Field Sampling of Aerospace Fluids inContainersF 303 Practices for Sampling for Particles in AerospaceFluids and ComponentsF311 Practice for
8、 ProcessingAerospace Liquid Samples forParticulate Contamination Analysis Using Membrane Fil-tersF 314 Method of Test for Identification of Metallic andFibrous Contaminants in Aerospace Fluids3F 318 Practice for Sampling Airborne Particulate Contami-nation in Cleanrooms for Handling Aerospace Fluids
9、3. Terminology3.1 Definitions:3.1.1 unit areathe area selected for counting particles.This may be the area of a reticle grid or some subdivisionthereof, the area of one imprinted membrane grid, or any otheraccurately calibrated area.3.1.2 effective filter areathe area of the membrane whichentraps th
10、e particles to be counted.3.1.3 particle sizethe size of a particle as defined by areacomparison or by its longest dimension.4. Summary of Test Methods4.1 The membrane is examined through a microscope andthe particles counted according to size or size categories usinga calibrated reticle. The total
11、number of particles present isestimated by statistical methods from the actual number ofparticles counted. Either sizing Test Method A or B may beselected according to the preference and results expected.5. Significance and Use5.1 Reported particle size measurement is a function of boththe actual pa
12、rticle dimension and shape factor as well as theparticular physical or chemical properties of the particle beingmeasured. Caution is required when comparing data frominstruments operating on different physical or chemical param-eters or with different particle size measurement ranges.1These test met
13、hods are under the jurisdiction of ASTM CommitteeE21 onSpace Simulation andApplications of Space Technology are the direct responsibilityof Subcommittee E21.05 on ContaminationCurrent edition approved Nov. 1, 2008. Published December 2008. Originallyapproved in 1969. Last previous edition approved i
14、n 2003 as F 312 97(2003).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 Document Summary page onthe ASTM website.3Withdrawn. The last approved versio
15、n of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Sample acquisition, handling and preparation can also affectthe reported particle size results.6. Apparatus6.1 Microscope, cap
16、able of resolving the smallest particlesto be counted and producing a flat field of view.6.1.1 The following optic combinations are recommended:Magnification Ocular ObjectiveMinimumNumericalAperture503 103 53 0.151003 103 103 0.252003 103 203 0.50Similar ocular-objective combinations resulting in ma
17、gnifi-cations of 50 6 103, 100 6 103, and 200 6 203 may beused. The optimum equipment is a compound binocularmicroscope. Conventional stereo microscopes will not meetthese requirements.6.2 Mechanical Stage, capable of traversing the entireeffective filter area.6.3 Stage Micrometer, with 0.1 and 0.01
18、-mm subdivisions.6.4 Provisions for variable high-intensity external obliqueincident illumination and for a focusing condenser. A flexibleor jointed arm is desirable.6.5 Reticles, inscribed with reference markings that can becalibrated to represent the following dimensions:Magnification Size, m Tole
19、rance, m200 6 203 5 60.815 61.2100 6 103 15 61.525 62.050 6 103 50 62.550 62.5100 65.06.5.1 The reticles shall be as follows:6.5.1.1 Reticle A, Globe and Circle Pattern, provides ameans for correlation of the microscopic method with auto-matic counter methods. Reticle A uses the diameter of a circle
20、for its comparison of a particle, and automatic counter methodsuse either a particle volume, projected area, or particle areameasurements which are all directly related to the diameter.6.5.1.2 Reticle B, Linear Scale, provides for measurementof the longest linear dimension technique.NOTE 2Some retic
21、les combine both patterns in one reticle.6.6 Tally Counter, hand operated, for recording particlecounts.6.7 Video imaging and software packages are allowedprovided they meet the calibration requirements of 6.5.7. Sampling7.1 Collect and process the sample in accordance with theapplicable methods of
22、the American Society for Testing andMaterials, as follows: Practice F 302, Practice F311, PracticeF 318, and Practices F 303.8. Calibration8.1 The sizing reticle shall be calibrated at each magnifica-tion by comparing the reference divisions noted in 6.3 with therulings on the stage micrometer. Deta
23、iled calibration proce-dures and a discussion of errors are given in Appendix X1.8.2 The area extrapolation factor used for statistical count-ing is determined by the ratio of the area counted to the totaleffective area of the membrane filter.8.2.1 Unit AreaMeasure the size of the appropriate unitar
24、ea with the stage micrometer or previously calibrated reticleand calculate its area.8.2.2 Effective Filter Area (Note 3)Measure the diameterof the effective filter area with a scale, caliper, or calibratedmechanical stage and calculate the total area. Area = pr2,where r is the radius of the effectiv
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