ISO 2951:2019

INTERNATIONAL ISO
STANDARD 2951
Third edition
2019-05
Rubber, vulcanized rubber —
Determination of insulation resistance
Caoutchouc vulcanisé ou thermoplastique — Détermination de la
résistance d'isolement
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test equipment. 1
5 Calibration . 2
6 Electrodes . 2
6.1 General . 2
6.2 Conducting-paint electrodes (for flat plates, tubes and rods) . 2
6.3 Bar electrodes (for thin sheets and tapes) . 2
7 Test pieces . 2
7.1 Test pieces for conducting-paint electrodes . 2
7.2 Test pieces for bar electrodes. 2
7.3 Attachment of electrodes . 2
7.4 Conditioning . 3
7.5 Number of test pieces . 3
8 Procedure. 3
9 Expression of results . 3
9.1 Test pieces using conducting-paint electrodes . 3
9.2 Test pieces using bar electrodes . 3
10 Test report . 4
Annex A (informative) Cleaning and mounting of test pieces . 8
Annex B (normative) Calibration schedule . 9
Bibliography .11
Foreword
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electrotechnical standardization.
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This document was prepared by Technical Committee ISO/TC 45, Rubber and rubber products,
Subcommittee SC 2, Testing and analysis.
This third edition cancels and replaces the second edition (ISO 2951:2012), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— The normative references have been updated in Clause 2;
— The calibration schedule has been added as Annex B.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

Introduction
This document specifies an empirical method that gives a value for insulation resistance which includes,
without discrimination, both volume and surface resistance. This value can be used for the comparison
of the quality of different insulating rubbers. For general principles regarding measuring resistance,
general effects of temperature and humidity, applied voltage and time of electrification, see IEC 62631-
3-1, IEC 62631-3-2 and IEC 62631-3-3.
INTERNATIONAL STANDARD ISO 2951:2019(E)
Rubber, vulcanized rubber — Determination of insulation
resistance
WARNING 1 — Persons using this document should be familiar with normal laboratory practice.
This document does not purport to address all of the safety problems, if any, associated with its
use. It is the responsibility of the user to establish appropriate safety and health practices and to
determine the applicability of any other restrictions.
WARNING 2 — Certain procedures specified in this document might involve the use or generation
of substances, or the generation of waste, that could constitute a local environmental hazard.
Reference should be made to appropriate documentation on safe handling and disposal after use.
1 Scope
This document specifies a method for the determination of the insulation resistance of vulcanized and
thermoplastic rubbers without discrimination between the volume and surface resistances involved.
This method is applicable only to the test pieces with a resistance greater than 10 Ω.
NOTE Methods of test for test pieces with a lower resistance are described in ISO 1853 and ISO 2878.
Because the test pieces are simply and easily prepared, this method is particularly useful for rapidly
determining values which will give a general indication of quality when great accuracy is not required.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 18899:2013, Rubber — Guide to the calibration of test equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
insulation resistance
ratio of the direct
voltage applied to the electrodes to the total current between them at a given time after the application
of that voltage
Note 1 to entry: It is dependent upon both the volume and surface resistances of the test
...