IEC 62021-2:2007

Insulating liquids - Determination of acidity - Part 2: Colourimetric titration

Describes a procedure for determination of the acidity of unused and used electrical mineral insulating oils. The method may be used to indicate relative changes that occur in a mineral insulating oil during use under oxidizing conditions that may or may not be shown by other properties of the resulting mineral oil. The acidity can be used in the quality control of unused mineral oil. As a variety of oxidation products present in used mineral oil contribute to acidity and these products vary widely in their corrosion properties, the test cannot be used to predict corrosiveness of a mineral oil under service conditions.

Liquides isolants - Détermination de l'acidité - Partie 2: Titrage colorimétrique

Décrit une procédure pour la détermination de l'acidité des huiles isolantes minérales électriques neuves et usagées. La méthode peut être utilisée pour indiquer des modifications relatives qui se produisent dans une huile minérale isolante pendant l'utilisation dans des conditions d'oxydation qui peuvent être ou peuvent ne pas être révélées par d'autres propriétés de l'huile minérale résultante. L'acidité peut être utilisée dans le contrôle de la qualité des huiles minérales neuves. Comme divers produits d'oxydation présents dans l'huile minérale usagée contribuent à l'acidité et comme ces produits varient largement du point de vue de leurs propriétés de corrosion, l'essai ne peut pas être utilisé pour prévoir la corrosivité d'une huile minérale dans des conditions de service.

General Information

• Status: Published
• Publication Date: 14-May-2007
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.040.10 - Insulating oils
• Technical Committee: TC 10 - Fluids for electrotechnical applications
• Drafting Committee: WG 17 - TC 10/WG 17
• Current Stage: PPUB - Publication issued
• Start Date: 15-Jul-2007
• Completion Date: 15-May-2007

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
CEI
62021-2
NORME
First edition
INTERNATIONALE
Première édition
2007-05
Insulating liquids –
Determination of acidity
Part 2:
Colourimetric titration
Liquides isolants –
Détermination de l’acidité
Partie 2:
Titrage colorimétrique
Reference number
Numéro de référence
IEC/CEI 62021-2:2007
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INTERNATIONAL IEC
STANDARD
CEI
62021-2
NORME
First edition
INTERNATIONALE
Première édition
2007-05
Insulating liquids –
Determination of acidity
Part 2:
Colourimetric titration
Liquides isolants –
Détermination de l’acidité
Partie 2:
Titrage colorimétrique
PRICE CODE
P
CODE PRIX
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
Pour prix, voir catalogue en vigueur

– 2 – 62021-2 © IEC:2007
CONTENTS
FOREWORD.3
INTRODUCTION.5

1 Scope.6
2 Normative references .6
3 Terms and definitions .7
4 Principle .7
5 Reagents.7
5.1 Titration reagent.7
5.2 Titration solvent.8
5.3 Potassium hydrogen phthalate, primary standard .8
5.4 Standard hydrochloric acid solution .8
5.5 Alkali Blue 6B indicator solution .8
5.6 Cobalt nitrate solution .8
6 Apparatus.8
6.1 Titration vessel.8
6.2 Stirrer.8
6.3 Burette .8
7 Sampling .8
8 Procedure .9
8.1 Standardization of alcoholic potassium hydroxide solution.9
8.2 Blank titration .9
8.3 Sample titration .10
9 Calculation of results .10
10 Precision .10
10.1 Repeatability .10
10.2 Reproducibility .11
11 Report .11

Annex A (informative) Determination of acidity in electrical insulating oils by
photometric titration .12

Figure A.1 – Molecular structure of para-naphtolbenzein indicator in (I) acidic media
and (II) basic media .15
Figure A.2 – UV spectra of para-naphthol-benzein indicator in toluene/2-
propanol/water solution in (a) acidic media, (b) basic media .16

62021-2 © IEC:2007 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
INSULATING LIQUIDS –
DETERMINATION OF ACIDITY –
Part 2: Colourimetric titration

FOREWORD
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International Standard IEC 62021-2 has been prepared by IEC technical committee 10: Fluids
for electrotechnical applications.
The text of this standard is based on the following documents:
FDIS Report on voting
10/692/FDIS 10/696/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – 62021-2 © IEC:2007
A list of all parts of IEC 62021 series, under the general title Insulating liquids – Determination
of acidity can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
62021-2 © IEC:2007 – 5 –
INTRODUCTION
The standardized method given in IEC 62021-1 is a method for measurement of acidity in
used and unused mineral oil and is a potentiometric titration requiring special instrumentation
for measurement of acidity. Historically, acidity of insulating oil was measured by
colourimetric titration as described in IEC 60296, 1982 edition. With the revision of IEC 60296,
the colourimetric titration was deleted as that method used high volumes of sample and
solvent, generating undesirable volumes of waste.
However, there is still a market requirement for having colourimetric titration as many labs
use this method.
Health and safety
This International Standard does not purport to address all the safety problems associated
with its use. It is the responsibility of the user of the Standard to establish appropriate health
and safety practices and determine the applicability of regulatory limitations prior to use.
The mineral oils which are the subject of this standard should be handled with due regard to
personal hygiene. Direct contact with eyes may cause slight irritation. In the case of eye
contact, irrigation with copious quantities of clean running water should be carried out and
medical advice sought.
Some of the tests specified in this standard involve the use of processes that could lead to a
hazardous situation. Attention is drawn to the relevant standard for guidance.
This standard involves mineral oils, chemicals and used sample containers. The disposal of
these items should be carried out in accordance
...