ASTM D2144-07
(Test Method)Standard Practices for Examination of Electrical Insulating Oils by Infrared Absorption
Standard Practices for Examination of Electrical Insulating Oils by Infrared Absorption
SIGNIFICANCE AND USE
The infrared spectrum of an electrical insulating oil is a record of the absorption of infrared energy over a range of wavelengths. The spectrum indicates the general chemical composition of the test specimen.
Note 2—The infrared spectrum of a pure chemical compound is probably the most characteristic property of that compound. However, in the case of oils, multicomponent systems are being examined whose spectra are the sum total of all the spectra of the individual components. Because the absorption bands of the components may overlap, the spectrum of the oil is not as sharply defined as that for a single compound. For these reasons, these practices may not in every case be suitable for the quantitative estimation of the components of such a complex mixture as mineral oil.
SCOPE
1.1 These practices are to be used for the recording and interpretation of infrared absorption spectra of electrical insulating oils from 4000 to 400 cm-1 (2.5 to 25 μm). Note 1 - While these practices are specific to ratio recording or optical null double-beam dispersive spectrophotometers, single-beam and HATR (horizontal attenuated total reflectance), Fourier-transform rapid scan infrared spectrophotometers may also be used. By computerized subtraction techniques, ratio methods can be used. Any of these types of equipment may be suitable if they comply with the specifications described in Practice E 932.
1.2 Two practices are covered, a Reference Standard Practice and a Differential Practice.
1.3 These practices are designed primarily for use as rapid continuity tests for identifying a shipment of oil from a supplier by comparing its spectrum with that obtained from previous shipments, or with the sample on which approval tests were made. They also may be used for the detection of certain types of contamination in oils, and for the identification of oils in storage or service, by comparison of the spectra of the unknown and known oils. The practices are not intended for the determination of the various constituents of an oil.
1.4 Warning-Infrared absorption is a tool of high resolving power. Conclusions as to continuity of oil quality should not be drawn until sufficient data have been accumulated so that the shipment-to-shipment variation is clearly established, for example.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
General Information
Standards Content (Sample)
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Designation: D2144 − 07
StandardPractices for
Examination of Electrical Insulating Oils by Infrared
1
Absorption
This standard is issued under the fixed designation D2144; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
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1.1 These practices are to be used for the recording and 2.1 ASTM Standards:
interpretation of infrared absorption spectra of electrical insu- D923Practices for Sampling Electrical Insulating Liquids
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lating oils from 4000 to 400 cm (2.5 to 25 µm). E131Terminology Relating to Molecular Spectroscopy
E168Practices for General Techniques of Infrared Quanti-
NOTE 1—While these practices are specific to ratio recording or optical
tative Analysis
null double-beam dispersive spectrophotometers, single-beam and HATR
E932PracticeforDescribingandMeasuringPerformanceof
(horizontal attenuated total reflectance), Fourier-transform rapid scan
infrared spectrophotometers may also be used. By computerized subtrac-
Dispersive Infrared Spectrometers
tion techniques, ratio methods can be used. Any of these types of
equipment may be suitable if they comply with the specifications 3. Terminology
described in Practice E932.
3.1 Definitions—For definitions of terms and symbols, refer
1.2 Two practices are covered, a Reference Standard Prac-
to Terminology E131.
tice and a Differential Practice.
4. Summary of Practices
1.3 These practices are designed primarily for use as rapid
4.1 The infrared absorption spectrum may be recorded on
continuitytestsforidentifyingashipmentofoilfromasupplier
the spectrophotometer by either of the two practices outlined
by comparing its spectrum with that obtained from previous
below.Inbothpracticesdifferencesinwavelengthorfrequency
shipments, or with the sample on which approval tests were
and intensity of the absorption bands are observed and mea-
made.They also may be used for the detection of certain types
sured.
of contamination in oils, and for the identification of oils in
4.1.1 Reference Standard Practice —An infrared cell filled
storage or service, by comparison of the spectra of the
with the insulating oil test specimen is placed in the sample
unknownandknownoils.Thepracticesarenotintendedforthe
beam of the spectrophotometer. With the shutter of the refer-
determination of the various constituents of an oil.
ence beam open, the infrared absorption spectrum is recorded
1.4 Warning—Infrared absorption is a tool of high resolv-
over the entire range of the instrument. The absorption spec-
ing power. Conclusions as to continuity of oil quality should
trum of the test specimen is compared with a reference
not be drawn until sufficient data have been accumulated so
spectrumobtainedwithoilfromaprevioustestspecimenorthe
that the shipment-to-shipment variation is clearly established,
qualification oil.
for example.
4.1.2 Differential Practice—Two cells having the same
1.5 This standard does not purport to address all of the
sample path length are filled, one with the test specimen and
safety concerns, if any, associated with its use. It is the
the other with the reference oil.The filled cells are then placed
responsibility of the user of this standard to establish appro-
in the paths of the sample and reference beams, respectively,
priate safety and health practices and determine the applica-
and the differential absorption spectrum recorded. This spec-
bility of regulatory limitations prior to use.
trum is then compared with the reference differential spectrum
obtainedinasimilarmannerwiththesamecellsfilledwiththe
reference oil.
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These practices are under the jurisdiction of ASTM Committee D27 on
Electrical Insulating Liquids and Gases and are the direct responsibility of
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Subcommittee D27.03 on Analytical Tests. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved May 1, 2007. Published June 2007. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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approved in 1963. Last previous edition approved in 2001 as D2144–01 . DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D2144-07. the ASTM website.
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D2144 − 07
5. Significance and Use dissipated from the sample. For heavy cable oils, gently tilt or
invert the sample container and swirl the fluid several times
5.1 The infrared spectrum of an electrical insulating oil is a
and then permit it to stand undisturbed for
...
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