ASTM_D_7624_-_22.pdf

Designation:D762422Standard Test Method forCondition Monitoring of Nitration in In-Service Petroleumand Hydrocarbon-Based Lubricants by Trend AnalysisUsing Fourier Transform Infrared(FT-IR)Spectrometry1This standard is issued under the fixed designation D7624;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 monitoring nitration in gasolineand natural gas engine oils as well as in other types oflubricants where nitration by-products may form due to thecombustion process or other routes of formation of nitrationcompounds.1.2 This test method uses FT-IR spectroscopy for monitor-ing build-up of nitration by-products in in-service petroleumand hydrocarbon-based lubricants as a result of normal ma-chinery operation.Nitration levels in gasoline and natural gasengine oils rise as combustion by-products react with the oil asa result of exhaust gas recirculation or a blow-by.This testmethod is designed as a fast,simple spectroscopic check formonitoringofnitrationinin-servicepetroleumandhydrocarbon-based lubricants with the objective of helpingdiagnose the operational condition of the machine based onmeasuring the level of nitration in the oil.1.3 Acquisition of FT-IR spectral data for measuring nitra-tion in in-service oil and lubricant samples is described inPractice D7418.In this test method,measurement and datainterpretation parameters for nitration using both direct trendanalysis and differential(spectral subtraction)trend analysisare presented.1.4 This test method is based on trending of spectralchanges associated with nitration in in-service petroleum andhydrocarbon-based lubricants.For direct trend analysis,valuesare recorded directly from absorption spectra and reported inunits of 100*absorbance per 0.1 mm pathlength(or equiva-lently absorbance units per centimetre).For differential trendanalysis,values are recorded from the differential spectra(spectrum obtained by subtraction of the spectrum of thereference oil from that of the in-service oil)and reported inunits of 100*absorbance per 0.1 mm pathlength(or equiva-lently absorbance units per centimetre).Warnings or alarmlimits can be set on the basis of a fixed maximum value for asingle measurement or,alternatively,can be based on a rate ofchange of the response measured(1).2In either case,suchmaintenance action limits should be determined through sta-tistical analysis,history of the same or similar equipment,round robin tests or other methods in conjunction with thecorrelation of nitration changes to equipment performance.NOTE1It is not the intent of this test method to establish orrecommend normal,cautionary,warning or alert limits for any machinery.Such limits should be established in conjunction with advice and guidancefrom the machinery manufacturer and maintenance group.1.5 This test method is for petroleum and hydrocarbon-based lubricants and is not applicable for ester-based oils,including polyol esters or phosphate esters.1.6 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6.1 ExceptionThe unit for wave numbers is cm-1.1.7 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.1.8 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:3D445 Test Method for Kinematic Viscosity of Transparent1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.96.03 on FTIR Testing Practices and Techniques Related toIn-Service Lubricants.Current edition approved Oct.1,2022.Published October 2022.Originallyapproved in 2010.Last previous edition approved in 2021 as D7624 21.DOI:10.1520/D7624-22.2The boldface numbers in parentheses refer to a list of references at the end ofthis standard.3For 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 Stat