ASTM_D_7961_-_17.pdf

Designation:D796117Standard Practice forCalibrating U-tube Density Cells over Large Ranges ofTemperature and Pressure1This standard is issued under the fixed designation D7961;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.Scope*1.1 This practice outlines procedures for the calibration ofU-tube density cells.It is applicable to instruments capable ofdetermining fluid density at temperatures in the range 10 Cto 200 C and pressures from just greater than the saturationpressure to 140 MPa.The practice refers to density cells asthey are utilized to make measurements of fluids primarily inthe compressed-liquid state.Examples of substances for whichthe density can be determined with a calibrated U-tube densitymeter include:crude oils,gasoline and gasoline-oxygenateblends,diesel and jet fuels,hydraulic fluids,and lubricatingoils.1.2 This practice specifies a procedure for the determinationof the expanded uncertainty of the density measurement.1.3 This practice pertains to fluids with viscosities 1 Pas(1000 centipoise)at ambient conditions.1.4 4 The values listed in SI units are regarded as thestandard,unless otherwise stated.The SI unit for mass densityis kilograms per cubic metre(kgm-3)and can be given asgrams per cubic centimetre(gcm-3).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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4052 Test Method for Density,Relative Density,and APIGravity of Liquids by Digital Density MeterD5002 Test Method for Density and Relative Density ofCrude Oils by Digital Density AnalyzerD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing LaboratoriesD7483 Test Method for Determination of Dynamic Viscosityand Derived Kinematic Viscosity of Liquids by Oscillat-ing Piston ViscometerD7578 Guide for Calibration Requirements for ElementalAnalysis of Petroleum Products and LubricantsD7740 Practice for Optimization,Calibration,and Valida-tion of Atomic Absorption Spectrometry for Metal Analy-sis of Petroleum Products and Lubricants3.Terminology3.1 Definitions:3.1.1 calibration,nset of operations that establishes therelationship between the reference density of standards and thecorresponding density reading of the instrument.D40523.1.2 certified reference material(CRM),nreference ma-terial one or more of whose property values are certified by atechnically valid procedure,accompanied by a traceable cer-tificate or other documentation that is issued by a certifyingbody.D02.94 D6792,D02.03 D75783.1.3 density(),nmass per unit volume at a specifiedtemperature.D02.07 D74833.1.4 standard reference material(SRM),ntrademark forreference materials certified by NIST.D02.03 D77404.Summary of Practice4.1 This practice details the considerations and proceduresnecessary in order to complete a calibration of a U-tube densitymeter and an associated uncertainty analysis.The principalobjective of this practice is to provide the user with informationas to how different aspects of the calibration procedurecontribute to the overall uncertainty of related density mea-surements obtained with a U-tube density meter.5.Significance and Use5.1 This practice covers a series of methods offered to aidusers in calibrating U-tube density meters to provide a measureof density and an associated expanded uncertainty.The refer-ence density,as obtained from either an equation of state1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts,Liquid Fuels,and Lubricants and is the direct responsibility of Subcom-mittee D02.04 on Hydrocarbon Analysis.Current edition approved Jan.1,2017.Published January 2017.Originallyapproved in 2015.Last previous edition approved in 2015 as D7961 15.DOI:10.1520/D7961-17.2For 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1(EOS)or CRM has an uncertainty that arises from theuncertainty of