ASTM_D_6897_-_16.pdf

Designation:D689716Standard Test Method forVapor Pressure of Liquefied Petroleum Gases(LPG)(Expansion Method)1This standard is issued under the fixed designation D6897;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 test method covers the use of automatic vaporpressure instruments to determine the vapor pressure of lique-fied petroleum gas products at a temperature of 37.8 C,vaporto liquid ratio of 0.5:1,and pressures from 200 kPa to 1550 kPaon a sample volume of 3.33 mL.1.2 This test method is applicable to the determination ofvapor pressures of liquefied petroleum gas products at tem-peratures from 37.8 C to 70 C,vapor to liquid ratios of 0.1:1to 4:1,and pressures up to 3500 kPa;however,the precision ofthe test method(see Section 15)has only been determined fora vapor to liquid ratio of 0.5:1,at a temperature of 37.8 C,anda pressure range from 300 kPa to 1500 kPa.NOTE1This test method is not intended to determine the true vaporpressure of LPG samples,but rather determine and report the vaporpressure of LPG at the 37.8 C temperature and 0.5:1 vapor to liquid ratioas the Test Method D1267 method.NOTE2This test method is not a true vapor pressure method and willnot measure the full contribution from any dissolved gases such asnitrogen or helium if they are present.The contribution of light gases tothe measured vapor pressure is highly dependent on the test temperature,type of gas,and V/L ratio of the test.1.3 The values stated in SI units are to be regarded asstandard.1.3.1 ExceptionNon-SI units are included in parenthesesfor information only.1.4 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.For specificwarning statements,see Appendix X2.2.Referenced Documents2.1 ASTM Standards:2D1265 Practice for Sampling Liquefied Petroleum(LP)Gases,Manual MethodD1267 Test Method for Gage Vapor Pressure of LiquefiedPetroleum(LP)Gases(LP-Gas Method)D2892 Test Method for Distillation of Crude Petroleum(15-Theoretical Plate Column)D3700 Practice for Obtaining LPG Samples Using a Float-ing Piston CylinderD5191 Test Method for Vapor Pressure of Petroleum Prod-ucts(Mini Method)D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance2.2 Energy Institute Standards:3IP 181 Sampling Petroleum Gases3.Terminology3.1 Definitions:3.1.1 liquefied petroleum gases(LPG),nnarrow boilingrange hydrocarbon mixtures,consisting mainly of propane orpropylene,or both(WarningExtremely flammable.Harmfulif inhaled),butanes and butylenes,or both;in which theconcentration of hydrocarbon compounds with boiling pointgreater than 0 C is less than 5%by liquid volume,and whosevapor pressure at 37.8 C(100 F)is not greater than 1550 kPa.3.1.2 platinum resistance thermometer,ntemperaturemeasuring device with platinum wire,whose electrical resis-tance changes in relation to temperature.3.1.3 vapor-liquid ratio(V/L),nof a liquid,the ratio of thevapor volume to the liquid volume of specimen,in equilibrium,under specified conditions.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.08 on Volatility.Current edition approved July 15,2016.Published August 2016.Originallyapproved in 2003.Last previous edition approved in 2009 as D6897 09.DOI:10.1520/D6897-16.2For 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 Energy Institute,61 New Cavendish St.,London,WIG 7AR,U.K.,http:/www.energyinst.org.uk.*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 States1 3.2 Definitions of Terms Specific to This Standard:3.2.1 total vapor pressure(Ptot),nthe absolute vaporpressure(relative to vacuum)exerted by the specimen at thespecified temperature and vapor-liquid ratio.3.2.2 true vapor pressure,nthe physical property of agiven liquid which specifies the maximum pressure at which avapor phase can coexist with the liquid phase at a givenequilibrium temperature condition.3.2.3 vapor pressure of LPG,nthe total pressure correctedrelative to normal barometric pressure.3.3 Abbreviations:3.3.1 LPGliquefied petroleum gas3.3.2 V/Lvapor liquid ratio4.Summary of Test Method4.1 Employing a measuring chamber