1、Designation:D782112(Reapproved 2018)Standard Test Method forField Test Determination of Urea Concentration in DieselExhaust Fluid(DEF)1This standard is issued under the fixed designation D7821;the number immediately following the designation indicates the year oforiginal adoption or,in the case of r
2、evision,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.Scope1.1 This test method covers a technique for field testing theconcentration of aqueous urea-based diesel exh
3、aust fluid(DEF)prescribed for use in diesel engines equipped with selectivecatalytic reduction technology and is not intended to circum-vent or replace the more accurate determination of urea contentby refractive index laboratory method,described in ISO22241-2,Annex C.1.2 This test method is designe
4、d solely as a quantitative testto determine the concentration of urea in DEF and does notpurport to determine the quality of DEF nor to detect trace orother contaminants therein.Biuret content of DEF creates aknown bias in this test method.See section 9.2.1 for details.1.3 UnitsThe values stated in
5、SI units are to be regardedas the standard.No other units of measurement are included inthis standard.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,health,an
6、d environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 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
7、Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ISO Standard:2ISO 22241 Diesel enginesNOx reduction agent AUS 323.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 American Petroleum Ins
8、titute(API),na nonprofittrade association that licenses diesel exhaust fluid(DEF)marketers to use the API Diesel Exhaust Fluid CertificationMark.A marketer may be licensed to use the API Mark if itsDEF is in compliance with the most recent and applicableedition of ISO 22241.3.1.2 diesel exhaust flui
9、d,DEF,npreparation of aqueousurea(NH2)2CO,containing 32.5%by weight of technicallypure urea in high-purity water with quality characteristicsdefined by ISO 22241.3.1.3 refractive index,nfundamental physical property ofa substance that is related to the ratio of the velocity of light inair,to its vel
10、ocity in the substance under examination,at aspecified temperature and wavelength.3.1.4 refractometer,noptical instrument that measures therefractive index of a substance and can be used to characterizethe concentration or mixture ratio of various substances.3.1.5 biuret,nchemical compound which app
11、ears as acharacteristic impurity in aqueous urea solutions.3.1.6 AUS 32,nISO designation for DEF also known asNOx reduction agent AUS 32(aqueous urea solution).4.Summary of Test Method4.1 A digital refractometer with a special scale specific tothe percent by weight of urea is used to measure the con
12、cen-tration of a DEF sample.34.2 To determine DEF concentration,the refractometer shallfirst be zero set to distilled water.Next,a sample of DEF isplaced on the measuring surface of the refractometer and thetemperature of the instrument,fluid,and ambient environmentis allowed to equilibrate.A readin
13、g is taken by pressing abutton,and the unit of measure and concentration are directlyread from a digital display.1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and Related Fluids and is the direct responsibility of SubcommitteeD15.25 on Diesel Exhaust Fluid.Curre
14、nt edition approved Sept.1,2018.Published September 2018.Originallyapproved in 2012.Last previous edition approved in 2012 as D782112.DOI:10.1520/D782112R18.2Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.3Sources for DEF refra
15、ctometers used to establish the precision and bias of thismethod:MISCO Refractometer,6275 Cochran Road,Solon,OH 44139,andReichert Technologies,3362 Walden Avenue,Suite 100,Depew,NY 14043.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis
16、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 5.Apparatus5.1 RefractometerArefractometer is an optical instrumentused to measure the physical properties of a solution.Refrac-tometers suitable for use in this test method shall possess t