ASTM_D_6552_-_06_2011.pdf

Designation:D655206(Reapproved 2011)Standard Practice forControlling and Characterizing Errors in Weighing CollectedAerosols1This standard is issued under the fixed designation D6552;the number immediately following the 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 Assessment of airborne aerosol hazards in the occupa-tional setting entails sampling onto a collection mediumfollowed by analysis of the collected material.The result isgenerally an estimated concentration of a possibly hazardousmaterial in the air.The uncertainty in such estimates dependson several factors,one of which relates to the specific type ofanalysis employed.The most commonly applied method foranalysis of aerosols is the weighing of the sampled material.Gravimetric analysis,though apparently simple,is subject toerrors from instability in the mass of the sampling medium andother elements that must be weighed.An example is providedby aerosol samplers designed to collect particles so as to agreewith the inhalable aerosol sampling convention(see ISO TR7708,Guide D6062,and EN 481).For some sampler types,filter and cassette are weighed together to make estimates.Therefore,if the cassette,for example,absorbs or loses waterbetween the weighings required for a concentration estimation,then errors may arise.This practice covers such potential errorsand provides solutions for their minimization.1.2 The values given in SI units are to be regarded asstandard.1.3 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1356 Terminology Relating to Sampling and Analysis ofAtmospheresD4096 Test Method for Determination of Total SuspendedParticulate Matter in theAtmosphere(HighVolume Sam-pler Method)D4532 Test Method for Respirable Dust in Workplace At-mospheres Using Cyclone SamplersD6062 Guide for Personal Samplers of Health-RelatedAero-sol Fractions2.2 International Standards:3EN 481 Workplace AtmospheresSize Fraction Definitionsfor Measurement of Airborne Particles in the WorkplaceEN 482 Workplace AtmospheresGeneral Requirementsfor Performance of Procedures for the Measurement ofChemical AgentsprEN 13205 Workplace AtmospheresAssessment of Per-formance of Instruments for Measurement of AirborneParticle Concentrations2.3 ISO Standards:4ISO TR 7708 Air QualityParticle Size Fraction Defini-tions for Health-related SamplingISO GUM Guide to the Expression of Uncertainty in Mea-surement(1993)ISO 20988 Air QualityGuidelines for Estimating Mea-surement Uncertainty3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice,refer toTerminology D1356.3.2 Definitions of Terms Specific to This Standard:3.2.1 blank substratea collection medium or substratecoming from the same batch as the sampling medium,butunexposed.3.2.2 equilibration timeFor the purposes of this practice,atime constant(seconds)characterizing an approximate expo-nentially damped approach of the mass of an aerosol collectionmedium to a constant value.The constant can be defined as the1This practice is under the jurisdiction ofASTM Committee D22 on Air Qualityand is the direct responsibility of Subcommittee D22.04 on Workplace Air Quality.Current edition approved Oct.1,2011.Published October 2011.Originallyapproved in 2000.Last previous edition approved in 2006 as D6552-06.DOI:10.1520/D6552-06R11.2For 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.3Available from CEN Central Secretariat:rue de Stassart 36,B-1050 Brussels,Belgium.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 mean difference of the mass from equilibrium per mean massloss or gain rate as measured over a finite time interval.3.2.2.1 DiscussionThere may be important instances inwhich several time constants are required to describe theapproach to equilibrium.3.2.3 estimated overall uncertainty(U)2 estimated stan-dard deviation of estimated mass,in the case of negligibleuncorrectable bias(see EN 482).3.2.4 field blanka blank substrate that undergoes the samehandling as the sample substrate,generally including condi-tioning and loading into the samplers or transport containers,aswell as transportation to the sampling site,but without beingexposed.3.2.4.1 DiscussionIf blanks are not