1、Designation:E208806(Reapproved 2015)Standard Practice forSelecting,Preparing,Exposing,and Analyzing WitnessSurfaces for Measuring Particle Deposition in Cleanroomsand Associated Controlled Environments1This standard is issued under the fixed designation E2088;the number immediately following the des
2、ignation 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 practice is intended to assist
3、in the selection,preparation,exposure,and analysis of witness surfaces for thepurpose of characterizing particle deposition rates in clean-rooms and associated controlled environments,particularly foraerospace applications.1.2 Requirements may be defined in terms of particle sizedistribution and cou
4、nt,percent area coverage,or productperformance criteria such as optical transmission or scatter.Several choices for witness surfaces are provided.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purp
5、ort 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents(Note 1)2.1 ASTM Standards:
6、2E1216 Practice for Sampling for Particulate Contaminationby Tape LiftF24 Test Method for Measuring and Counting ParticulateContamination on SurfacesF312 Test Methods for Microscopical Sizing and CountingParticles from Aerospace Fluids on Membrane Filters2.2 ISO Standard:ISO 14644-1 Cleanrooms and A
7、ssociated ControlledEnvironmentsPart 1:Classification of Air Cleanliness32.3 Government Standards:Fed-Std-209 Airborne Particulate Cleanliness Classes inCleanrooms and Clean Zones4IEST-STD-CC1246 Product Cleanliness Levels and Con-tamination Control Program5NOTE1The Institute of Environmental Scienc
8、es and Technology hasseveral Recommended Practices which may also be useful.3.Terminology3.1 Definitions:3.1.1 bidirectionalreflectancedistributionfunction(BRDF)the scattering properties of light reflected offsurfaces,expressed as the ratio of differential outputs ofradiance divided by differential
9、inputs of radiance.Surfacecontaminants scatter the incident radiation in all directions andwith variable intensities.The BRDF is a method to quantify thespatial distribution of the scattered energy.3.1.2 cleanliness levelan established maximum allowableamount of contamination in a given area or volu
10、me,or on acomponent.3.1.3 cleanrooman environmentally conditioned area inwhich temperature,humidity,and airborne contaminants arecontrolled by design and operation.High-efficiency particulateair(HEPA)filters or better are usually required to achieve theair cleanliness level.Air particulate cleanline
11、ss is classified inaccordance with Fed-Std-209 or ISO 14644-1.3.1.4 contaminantunwanted molecular and particulatematter that could affect or degrade the performance of thecomponents upon which they reside.1This practice is under the jurisdiction of ASTM Committee E21 on SpaceSimulation and Applicati
12、ons of Space Technology and is the direct responsibility ofSubcommittee E21.05 on Contamination.Current edition approved May 1,2015.Published June 2015.Originallyapproved in 2000.Last previous edition approved in 2011 as E2088 06(2011).DOI:10.1520/E2088-06R15.2For referenced ASTM standards,visit the
13、 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.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http
14、:/www.ansi.org.4Although Fed-Std-209 has been cancelled,it still may be used and designationsin Fed-Std-209 may be used in addition to the ISO designations.5Available from Institute of Environmental Sciences and Technology(IEST),Arlington Place One,2340 South Arlington Heights Road,Suite 100,Arlingt
15、onHeights,IL 60005-4516,http:/www.iest.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.5 contaminationa process of contaminating.3.1.6 contamination controlorganized action to controlthe level of contamination.3.1.7 controlled are
16、aan environmentally controlled area,operated as a cleanroom,but without the final stage of HEPA(or better)filters used in cleanrooms.3.1.8 critical surfaceany surface of an item or productwhich is required to meet established cleanliness level require-ments.3.1.9 demonstrated equivalencethe condition in which amethod of measurement has passed a series of tests to showthat it gives equivalent results to those of a standard measure-ment.3.1.10 environmentally controlled areacleanrooms,con-trolled
