ASTM_D_2879_-_18.pdf

Designation:D287918Standard Test Method forVapor Pressure-Temperature Relationship and InitialDecomposition Temperature of Liquids by Isoteniscope1This standard is issued under the fixed designation D2879;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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the vaporpressure of pure liquids,the vapor pressure exerted by mixturesin a closed vessel at 40%6 5%ullage,and the initial thermaldecomposition temperature of pure and mixed liquids.It isapplicable to liquids that are compatible with borosilicate glassand that have a vapor pressure between 133 Pa(1.0 torr)and101.3 kPa(760 torr)at the selected test temperatures.The testmethod is suitable for use over the range from ambient to623 K.The temperature range may be extended to includetemperatures below ambient provided a suitable constant-temperature bath for such temperatures is used.NOTE1The isoteniscope is a constant-volume apparatus and resultsobtained with it on other than pure liquids differ from those obtained in aconstant-pressure distillation.1.2 Most petroleum products boil over a fairly wide tem-perature range,and this fact shall be recognized in discussionof their vapor pressures.Even an ideal mixture followingRaoults law will show a progressive decrease in vaporpressure as the lighter component is removed,and this is vastlyaccentuated in complex mixtures such as lubricating oilscontaining traces of dewaxing solvents,etc.Such a mixturemay well exert a pressure in a closed vessel of as much as 100times that calculated from its average composition,and it is theclosed vessel which is simulated by the isoteniscope.Formeasurement of the apparent vapor pressure in open systems,Test Method D2878,is recommended.1.3 The values stated in SI units are to be regarded asstandard.The values given in parentheses after SI units areprovided for information only and are not considered standard.1.4 WARNINGMercury has been designated by manyregulatory agencies as a hazardous substance that can causeserious medical issues.Mercury,or its vapor,has been dem-onstrated to be hazardous to health and corrosive to materials.Use Caution when handling mercury and mercury-containingproducts.See the applicable product Safety Data Sheet(SDS)for additional information.The potential exists that sellingmercury or mercury-containing products,or both,is prohibitedby local or national law.Users must determine legality of salesin their location.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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.For specific warning statements,see 6.10,6.12,and AnnexA2.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D2878 Test Method for Estimating Apparent Vapor Pres-sures and Molecular Weights of Lubricating OilsE230 Specification for Temperature-Electromotive Force(emf)Tables for Standardized Thermocouples3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ullagethat percentage of a closed system which isfilled with vapor.3.1.1.1 DiscussionSpecifically,on Fig.1,that portion ofthe volume of the isoteniscope to the right of point A that isfilled with vapor.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.L0.07 on Engineering Sciences of High Performance Fluids andSolids(Formally D02.1100).Current edition approved Dec.1,2018.Published December 2018.Originallyapproved in 1970.Last previous edition approved in 2010 as D2879 10.DOI:10.1520/D2879-18.2For 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,Gu