1、Designation:D153495(Reapproved 2008)Standard Test Method forApproximate Acidity in Electrical Insulating Liquids byColor-Indicator Titration1This standard is issued under the fixed designation D1534;the number immediately following the designation indicates the year oforiginal adoption or,in the cas
2、e 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.Scope1.1 This test method describes the determination of theapproximate total acid value of used electrica
3、l insulatingliquids having viscosities less than 24 cSt at 40C.It is a simpleprocedure that can be applied in the field.Where a quantitativeneutralization value is required,use Test Method D664 or TestMethod D974.These test methods should be applied in thelaboratory.1.2 The values stated in SI units
4、 are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3 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
5、and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D664 Test Method for Acid Number of Petroleum Productsby Potentiometric TitrationD974 Test Method for Acid and Base Number by Color-Indicator TitrationD1193 Specification for Reagent Wat
6、er3.Summary of Test Method3.1 To determine whether the acidity is greater or less thana specified arbitrary value,a fixed volume of liquid to be testedis added to a graduated cylinder,together with a small amountof indicator(phenolphthalein)and the appropriate quantity ofstandard potassium hydroxide
7、 solution.The mixture is shakenand allowed to separate.The color of the aqueous layer at thebottom of the container when testing mineral oils,or at the topwhen testing askarels,determines whether the acidity is lessthan or greater than the arbitrary value chosen.3.2 To determine the approximate tota
8、l acidity,the proce-dure is the same as described in 3.1 except that the potassiumhydroxide solution is added in small increments until the colorof the aqueous layer,after shaking and settling,is a faint pink.The volume of standard potassium hydroxide solution useddetermines the approximate total ac
9、id value.4.Significance and Use4.1 The approximate acidity of used electrical insulatingoils is an estimate of the total acid value of the oil.As acidvalues increase,oil quality decreases.This is usually due tooxidation of the oil while in service.In general,acidicby-products produce increased diele
10、ctric loss,increased corro-sivity,and may cause thermal difficulties attributable to in-soluble components called“sludge.”This test method isadapted to a specific volume of oil;total acid values of 0.05 to0.5 mg of potassium hydroxide per gram of oil is a range whichis functionally significant.5.App
11、aratus5.1 Graduated Cylinder,50 mL,stoppered.5.2 Medicine Dropper,calibrated at 1-mL intervals.5.3 Calibrated Pipet,1-mL capacity,calibrated to deliver0.05-mL increments.6.Reagents and Materials6.1 Purity of ReagentsUse reagent grade chemicals in alltests.Unless otherwise indicated,it is intended th
12、at all reagentsshall conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society,wheresuch specifications are available.3Other grades may be used,1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and
13、is the direct responsibility of Subcom-mittee D27.06 on Chemical Test.Current edition approved May 1,2008.Published June 2008.Originallyapproved in 1958.Last previous edition approved in 2002 as D1534 95(2002)1.DOI:10.1520/D1534-95R08.2For referenced ASTM standards,visit the ASTM website,www.astm.or
14、g,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Reagent Chemicals,American Chemical Society Specifications,AmericanChemical Society,Washington,DC.For suggestions on the testing o
15、f reagents notlisted by the American Chemical Society,see Analar Standards for LaboratoryChemicals,BDH Ltd.,Poole,Dorset,U.K.,and the United States Pharmacopeiaand National Formulary,U.S.Pharmacopeial Convention,Inc.(USPC),Rockville,MD.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,W
16、est Conshohocken,PA 19428-2959.United States1 provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated,referencesto water shall be understood to mean reagent water(see Note1)conforming to Specification D1193.NOTE1Any grades of water listed in Specification D1193 are deemedsatisfactory for the purpose of this test method.6.3 Ethyl or Isopropyl Alchol,reagent gr
