ASTM D1534-95

NOTICE: This standard has either been superseded and replaced by a new version or
withdrawn. Contact ASTM International (www.astm.org) for the latest information.
Designation: D 1534 – 95
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Approximate Acidity in Electrical Insulating Liquids by
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Color-Indicator Titration
This standard is issued under the fixed designation D 1534; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Significance and Use
1.1 This test method describes the determination of the 4.1 The approximate acidity of used electrical insulating
approximate total acid value of used electrical insulating oils is an estimate of the total acid value of the oil. As acid
liquids having viscosities less than 24 cSt at 40°C. It is a simple values increase, oil quality decreases. This is usually due to
procedure that can be applied in the field. Where a quantitative oxidation of the oil while in service. In general, acidic
neutralization value is required, use Test Method D 664 or by-products produce increased dielectric loss, increased corro-
D 974. These test methods should be applied in the laboratory. sivity, and may cause thermal difficulties attributable to in-
1.2 This standard does not purport to address all of the soluble components called “sludge.” This test method is
safety concerns, if any, associated with its use. It is the adapted to a specific volume of oil; total acid values of 0.05 to
responsibility of the user of this standard to establish appro- 0.5 mg of potassium hydroxide per gram of oil is a range which
priate safety and health practices and determine the applica- is functionally significant.
bility of regulatory limitations prior to use.
5. Apparatus
5.1 Graduated Cylinder, 50-mL, stoppered.
2. Referenced Documents
5.2 Medicine Dropper, calibrated at 1-mL intervals.
2.1 ASTM Standards:
5.3 Calibrated Pipet, 1-mL capacity, calibrated to deliver
D 664 Test Method for Acid Number of Petroleum Products
0.05-mL increments.
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by Potentiometric Titration
D 974 Test Method for Acid and Base Number by Color- 6. Reagents and Materials
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Indicator Titration
6.1 Purity of Reagents—Use reagent grade chemicals in all
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D 1193 Specification for Reagent Water
tests. Unless otherwise indicated, it is intended that all reagents
shall conform to the specifications of the Committee on
3. Summary of Test Method
Analytical Reagents of the American Chemical Society, where
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3.1 To determine whether the acidity is greater or less than
such specifications are available. Other grades may be used,
a specified arbitrary value, a fixed volume of liquid to be tested
provided it is first ascertained that the reagent is of sufficiently
is added to a graduated cylinder, together with a small amount
high purity to permit its use without lessening the accuracy of
of indicator (phenolphthalein) and the appropriate quantity of
the determination.
standard potassium hydroxide solution. The mixture is shaken
6.2 Purity of Water—Unless otherwise indicated, references
and allowed to separate. The color of the aqueous layer at the
to water shall be understood to mean reagent water (see Note
bottom of the container when testing mineral oils, or at the top
1) conforming to Specification D 1193.
when testing askarels, determines whether the acidity is less
NOTE 1—Any grades of water listed in Specification D 1193 are
than or greater than the arbitrary value chosen.
deemed satisfactory for the purpose of this test method.
3.2 To determine the approximate total acidity, the proce-
6.3 Ethyl or Isopropyl Alcohol, reagent grade.
dure is the same as described in 3.1 except that the potassium
6.4 Phenolphthalein Indicator Solution (100 g/L)—
hydroxide solution is added in small increments until the color
Dissolve 10 g of phenolphthalein in 100 mL of denatured
of the aqueous layer, after shaking and settling, is a faint pink.
alcohol by slight warming.
The volume of standard potassium hydroxide solution used
6.5 Potassium Hydroxide, Standard Solution (0.031 6
determines the approximate total acid value.
0.003 N)—Prepare a 0.031 6 0.003 N solution of potassium
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This test method is under the jurisdiction of ASTM Committee D-27 on
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Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom- Reagent Chemicals, American Chemical Society Specifications, American
mittee D27.06 on Chemical Test. Chemical Society, Washington, DC. For suggestions on the testing of reagents not
Current edition approved Sept. 10, 1995. Published November 1995. Originally listed by the American Chemical Society, see Analar Standards for Laboratory
publish
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