ASTM D1534-95(2017)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D1534 − 95 (Reapproved 2017)
Standard Test Method for
Approximate Acidity in Electrical Insulating Liquids by
Color-Indicator Titration
This standard is issued under the fixed designation D1534; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Summary of Test Method
3.1 To determine whether the acidity is greater or less than
1.1 This test method describes the determination of the
a specified arbitrary value, a fixed volume of liquid to be tested
approximate total acid value of used electrical insulating
is added to a graduated cylinder, together with a small amount
liquidshavingviscositieslessthan24cStat40°C.Itisasimple
of indicator (phenolphthalein) and the appropriate quantity of
procedure that can be applied in the field. Where a quantitative
standard potassium hydroxide solution. The mixture is shaken
neutralization value is required, use Test Method D664 or Test
and allowed to separate. The color of the aqueous layer at the
Method D974. These test methods should be applied in the
bottom of the container when testing mineral oils, or at the top
laboratory.
when testing askarels, determines whether the acidity is less
1.2 The values stated in SI units are to be regarded as
than or greater than the arbitrary value chosen.
standard. No other units of measurement are included in this
3.2 To determine the approximate total acidity, the proce-
standard.
dure is the same as described in 3.1 except that the potassium
1.3 This standard does not purport to address all of the
hydroxide solution is added in small increments until the color
safety concerns, if any, associated with its use. It is the
of the aqueous layer, after shaking and settling, is a faint pink.
responsibility of the user of this standard to establish appro-
The volume of standard potassium hydroxide solution used
priate safety and health practices and determine the applica-
determines the approximate total acid value.
bility of regulatory limitations prior to use.
1.4 This international standard was developed in accor- 4. Significance and Use
dance with internationally recognized principles on standard-
4.1 The approximate acidity of used electrical insulating
ization established in the Decision on Principles for the
oils is an estimate of the total acid value of the oil. As acid
Development of International Standards, Guides and Recom-
values increase, oil quality decreases. This is usually due to
mendations issued by the World Trade Organization Technical
oxidation of the oil while in service. In general, acidic
Barriers to Trade (TBT) Committee.
by-products produce increased dielectric loss, increased
corrosivity, and may cause thermal difficulties attributable to
2. Referenced Documents
insoluble components called “sludge.” This test method is
adapted to a specific volume of oil; total acid values of 0.05 to
2.1 ASTM Standards:
0.5mgofpotassiumhydroxidepergramofoilisarangewhich
D664 Test Method for Acid Number of Petroleum Products
is functionally significant.
by Potentiometric Titration
D974 Test Method for Acid and Base Number by Color-
5. Apparatus
Indicator Titration
D1193 Specification for Reagent Water
5.1 Graduated Cylinder, 50 mL, stoppered.
5.2 Medicine Dropper, calibrated at 1-mL intervals.
5.3 Calibrated Pipet, 1-mL capacity, calibrated to deliver
This test method is under the jurisdiction of ASTM Committee D27 on
0.05-mL increments.
Electrical Insulating Liquids and Gases and is the direct responsibility of Subcom-
mittee D27.06 on Chemical Test.
Current edition approved June 1, 2017. Published June 2017. Originally
6. Reagents and Materials
approved in 1958. Last previous edition approved in 2008 as D1534– 95(2008).
DOI: 10.1520/D1534-95R17.
6.1 Purity of Reagents—Use reagent grade chemicals in all
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
tests. Unless otherwise indicated, it is intended that all reagents
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
shall conform to the specifications of the Committee on
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Analytical Reagents of theAmerican Chemical Society, where
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D1534 − 95 (2017)
such specifications are available. Other grades may be used, allow to settle, and observe the aqueous layer. If it is free of
provided it is first ascertained that the reagent is of sufficiently pink, the acidity is greater than the specified value.
high purity to permit its use without lessening the accuracy of
7.3 To determine the approximate total acidity, add KOH
the determination.
solution in increments of 0.5 mLuntil the color of the aqueous
6.2 Purity of Water—Unless otherwise indicated, references layer, after shaking and settling, is a pale pink.
to water shall be understood to mean reagent water (see Note
8. Calculation
1) conforming to S
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