ASTM_E_1573_-_09.pdf

Designation:E157309Standard Test Method forEvaluating Masking Sound in Open Offices UsingA-Weighted and One-Third Octave Band Sound PressureLevels1This standard is issued under the fixed designation E1573;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.INTRODUCTIONThis test method is one of a set of standards for evaluating the acoustical performance ofcomponents or systems in an open office.The other standards in this set deal with the measurementof the sound attenuation between work stations provided by partial height space dividers,verticalsurfaces,and acoustical ceiling systems;speech privacy;and the evaluation of masking sound.1.Scope1.1 This test method specifies the procedures that can beused to evaluate the spatial and temporal uniformity ofmasking sound in open offices using A-weighted sound levels.It also specifies the procedure for evaluating the masking soundspectrum and level using one-third octave band sound pressurelevels.1.2 The results of this test method can be used to determineif the masking sound meets a particular specification for spatialand temporal uniformity if that specification is written in termsof A-weighted sound levels and if the masking sound meets aparticular spectrum shape and level in the office area.1.3 This test method must not be used to evaluate theacoustical environment in an office space.It is intended only toevaluate the masking sound in an office.This test method,forinstance,does not evaluate the low frequency rumble noisefound in some offices.1.4 This standard does not purport to address all of thesafety problems,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:2C634 Terminology Relating to Building and EnvironmentalAcousticsE1374 Guide for Open Office Acoustics and ApplicableASTM Standards2.2 ANSI Standards:3S1.11 2004 Specification for Octave-Band and Fractional-Octave Band Analog and Digital FiltersS1.43 1997(R 2007)Specifications for integrating averag-ing sound level metersIEC 61672 2002 Electroacoustics-Sound Level meters-part1:specifications3.Terminology3.1 DefinitionsThe acoustical terminology used in thistest method is consistent with the definitions in TerminologyC634.3.2 Definitions of Terms Specific to This Standard:3.2.1 masking soundsound within an office that reducesthe intelligibility of intruding speech and the distraction fromactivity noise.Masking sound may be produced by a masking1This test method is under the jurisdiction ofASTM Committee E33 on Buildingand Environmental Acoustics and is the direct responsibility of SubcommitteeE33.02 on Speech Privacy.Current edition approved April 1,2009.Published April 2009.Originallyapproved in 1993.Last previous edition approved in 2002 as E157302.DOI:10.1520/E1573-09.2For 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 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 sound system,heating,ventilating,and air conditioning(HVAC)sources,or other sources.3.2.2 masking sound systemthe electronic equipment andloudspeakers used to generate,distribute,and produce maskingsound throughout an office space.3.2.3 spatial uniformitya condition where the sound pres-sure levels throughout a defined space do not vary significantlyfrom the arithmetic mean sound pressure level.The amount ofallowable variation is specified by others such as a consultant,designer,or owner.3.2.4 temporal uniformityat a given position,a conditionwhere the average sound pressure level measured over a shorttime interval does not differ significantly from the averagesound pressure level measured over a long time interval.Theamount of allowable variation is specified by others such as aconsultant,designer,or owner.4.Summary of Test Method4.1 The spatial uniformity of the masking sound in an openoffice is determined by measuring the A-weighted averagesound level with a sound level meter or real time analyzer atseveral locations and comparing these values to the arithmeticmean sound level or to a specified level.The temporaluniformity of the masking sound is determined by measuringtheA-weighted sound levels over an extended period of time atone or more locations.The masking sound spectrum and levelis determined by measuring the one-third octave band soundp