ASTM_D_2144_-_07_2013.pdf

Designation:D214407(Reapproved 2013)Standard Practices forExamination of Electrical Insulating Oils by InfraredAbsorption1This standard is issued under the fixed designation D2144;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.Scope1.1 These practices are to be used for the recording andinterpretation of infrared absorption spectra of electrical insu-lating oils from 4000 to 400 cm1(2.5 to 25 m).NOTE1While these practices are specific to ratio recording or opticalnull double-beam dispersive spectrophotometers,single-beam and HATR(horizontal attenuated total reflectance),Fourier-transform rapid scaninfrared spectrophotometers may also be used.By computerized subtrac-tion techniques,ratio methods can be used.Any of these types ofequipment may be suitable if they comply with the specificationsdescribed in Practice E932.1.2 Two practices are covered,a Reference Standard Prac-tice and a Differential Practice.1.3 These practices are designed primarily for use as rapidcontinuity tests for identifying a shipment of oil from a supplierby comparing its spectrum with that obtained from previousshipments,or with the sample on which approval tests weremade.They also may be used for the detection of certain typesof contamination in oils,and for the identification of oils instorage or service,by comparison of the spectra of theunknown and known oils.The practices are not intended for thedetermination of the various constituents of an oil.1.4 WarningInfrared absorption is a tool of high resolv-ing power.Conclusions as to continuity of oil quality shouldnot be drawn until sufficient data have been accumulated sothat the shipment-to-shipment variation is clearly established,for example.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.6 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.2.Referenced Documents2.1 ASTM Standards:2D923 Practices for Sampling Electrical Insulating LiquidsE131 Terminology Relating to Molecular SpectroscopyE168 Practices for General Techniques of Infrared Quanti-tative AnalysisE932 Practice for Describing and Measuring Performance ofDispersive Infrared Spectrometers3.Terminology3.1 DefinitionsFor definitions of terms and symbols,referto Terminology E131.4.Summary of Practices4.1 The infrared absorption spectrum may be recorded onthe spectrophotometer by either of the two practices outlinedbelow.In both practices differences in wavelength or frequencyand intensity of the absorption bands are observed and mea-sured.4.1.1 Reference Standard Practice An infrared cell filledwith the insulating oil test specimen is placed in the samplebeam of the spectrophotometer.With the shutter of the refer-ence beam open,the infrared absorption spectrum is recordedover the entire range of the instrument.The absorption spec-trum of the test specimen is compared with a referencespectrum obtained with oil from a previous test specimen or thequalification oil.4.1.2 Differential PracticeTwo cells having the samesample path length are filled,one with the test specimen andthe other with the reference oil.The filled cells are then placedin the paths of the sample and reference beams,respectively,and the differential absorption spectrum recorded.This spec-trum is then compared with the reference differential spectrumobtained in a similar manner with the same cells filled with thereference oil.1These practices are under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and are the direct responsibility ofSubcommittee D27.03 on Analytical Tests.Current edition approved Nov.1,2013.Published December 2013.Originallyapproved in 1963.Last previous edition approved in 2007 as D2144 07.DOI:10.1520/D2144-07R13.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Significance and Use5.1 The infrared spectrum of an electrical insulating oil is arecord of the absorption of infrared energy over a range ofwavelengths.The spectrum indicates the general chemicalcomposition of the test specimen.NOTE2The infrared spectrum of a pure chemical compound isprobably the most characteristic property of that compound.However,inthe case of oils,multicomponent systems are being examined whosespe