ISO 14309:2011

Rubber, vulcanized or thermoplastic — Determination of volume and/or surface resistivity

ISO 14309:2011 specifies a method for the determination of the volume and the surface resistivity of vulcanized or thermoplastic rubbers. The method can be applied to materials with a resistivity from 101 ohm metres to 1017 ohm metres.

Caoutchouc vulcanisé ou thermoplastique — Détermination de la résistivité transversale et/ou superficielle

General Information

• Status: Withdrawn
• Publication Date: 11-Sep-2011
• Withdrawal Date: 11-Sep-2011
• ICS: 83.060 - Rubber
• Technical Committee: ISO/TC 45/SC 2 - Testing and analysis
• Drafting Committee: ISO/TC 45/SC 2/WG 1 - Physical properties
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 03-Jul-2019

Relations

• Revised: ISO 14309:2019 - Rubber, vulcanized or thermoplastic — Determination of volume and/or surface resistivity
• Effective Date: 10-Dec-2016

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 14309
First edition
2011-09-15
Rubber, vulcanized or thermoplastic —
Determination of volume and/or surface
resistivity
Caoutchouc vulcanisé ou thermoplastique — Détermination de la
résistivité transversale et/ou superficielle
Reference number
ISO 14309:2011(E)
ISO 2011
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ISO 14309:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s

member body in the country of the requester.
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Published in Switzerland
ii © ISO 2011 – All rights reserved
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ISO 14309:2011(E)
Contents Page

Foreword ............................................................................................................................................................................iv

Introduction ........................................................................................................................................................................v

1 Scope ...................................................................................................................................................................... 1

2 Normative references ......................................................................................................................................... 1

3 Terms and definitions ......................................................................................................................................... 1

4 Principle ................................................................................................................................................................. 2

5 Apparatus .............................................................................................................................................................. 2

6 Calibration ............................................................................................................................................................. 5

7 Test pieces ............................................................................................................................................................ 5

7.1 Form of test piece ............................................................................................................................................... 5

7.2 Number of test pieces ........................................................................................................................................ 6

8 Conditioning ......................................................................................................................................................... 6

9 Test conditions ..................................................................................................................................................... 6

9.1 Temperature and humidity ................................................................................................................................ 6

9.2 Applied voltage .................................................................................................................................................... 6

10 Test procedure ..................................................................................................................................................... 6

11 Expression of results ......................................................................................................................................... 7

11.1 Volume resistivity ................................................................................................................................................ 7

11.2 Surface resistivity ............................................................................................................................................... 7

12 Test report ............................................................................................................................................................. 8

Annex A (informative) Electrode materials .................................................................................................................. 9

Annex B (informative) Suitable range of test conditions .......................................................................................10

Annex C (normative) Calibration schedule................................................................................................................12

Bibliography .....................................................................................................................................................................14

© ISO 2011 – All rights reserved iii
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ISO 14309:2011(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International

Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 14309 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee

SC 2, Testing and analysis.
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ISO 14309:2011(E)
Introduction

Rubber materials are widely used in many industries, either as the major material or forming a part of the product,

because of their unique physical properties which can be tailored by compounding to match the particular

requirements of the product specification. Although rubbers are generally regarded as insulating materials,

they can be made electrically conductive or dissipative by compounding with a certain amount of carbon black

or ionizable ingredients. Hence, the range of electrical resistance to be measured is very wide. It is difficult,

however, to obtain high accuracy for measurements in the high-resistance range due to a number of factors.

In this International Standard, the guarded-electrode system is used to determine the resistivity of rubber

test pieces since it is considered a good compromise between minimizing the errors by shunting away stray

currents and using more unwieldy measurement instruments (see also IEC 60093).

ISO 1853, on the other hand, covers rubber materials with medium to low resistance, i.e. resistivities of

10 Ω⋅m or below. It specifies three methods for determining volume resistivity which minimize or eliminate

contact resistance.

The methods specified in this International Standard were originally designed for the determination of both

surface and volume resistivity of insulating rubber materials, but their use can be extended to cover the range

from high to low resistivity.

It is known that the test results are sensitive to the test conditions, such as temperature and humidity, and to

heat and strain history.
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INTERNATIONAL STANDARD ISO 14309:2011(E)
Rubber, vulcanized or thermoplastic — Determination of volume
and/or surface resistivity

WARNING — Persons using this International Standard should be familiar with normal laboratory

practice. This standard 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

ensure compliance with any national regulatory conditions.

IMPORTANT — Certain procedures specified in this International Standard 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 International Standard specifies a method for the determination of the volume and the surface resistivity

of vulcanized or thermoplastic rubbers. The method can be applied to materials with a resistivity from

1 17
10 Ω⋅m to 10 Ω⋅m.
2 Normative references

The following referenced documents are indispensable for the application 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 1382, Rubber — Vocabulary
ISO 18899:2004, Rubber — Guide to the calibration of test equipment

ISO 23529, Rubber — General procedures for preparing and conditioning test pieces for physical test methods

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1382 and the following apply.

3.1
volume resistance

quotient of a direct-current voltage applied between two electrodes in contact with opposite faces of a test

piece and the current between the electrodes, excluding current along the surface

NOTE It is expressed in ohms (Ω).
3.2
surface resistance

quotient of a direct-current voltage applied between two electrodes on the same surface of a test piece and

the current between the electrodes
NOTE It is expressed in ohms (Ω).
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ISO 14309:2011(E)
3.3
volume resistivity
measured volume resistance calculated to apply to a cube of unit side
NOTE It is expressed in ohm metres (Ω⋅m).
3.4
surface resistivity
measured surface resistance calculated to apply to a square
NOTE It is expressed in ohms (Ω) and the size of the square is immaterial.
3.5
guarded-electrode system

electrode system composed of three electrodes, a guard, and a guarded and an unguarded electrode to reduce

measurement errors by protecting the current-measuring electrode from the interfering influences of voltages

other than the test voltage, and of stray conductances

NOTE Guarding depends on interposing, in all critical insulated parts, guard electrodes which intercept all stray

currents that might otherwise cause errors. The guard electrodes are connected together, constituting the guard system

and forming with the measurement terminals a three-terminal network. When suitable connections are made, stray currents

from spurious external voltages are shunted away from the measurement circuit by the guard system, the insulation

resistance from either measurement terminal to the guard system shunts a circuit element which should be of very much

lower resistance, and the specimen resistance constitutes the only direct path between the measurement terminals. By

this technique, the probability of error is considerably reduced (see 5.3 of IEC 60093:1980 for more details).

4 Principle

The volume and surface resistances of a rubber test piece are determined, using a suitable arrangement

of electrodes, from the current flowing when a voltage is applied. The volume and surface resistivities are

calculated from the measured resistances, which include the contact resistance.
5 Apparatus

The test equipment consists of a power supply, current-measuring equipment and electrodes, as follows:

5.1 Stabilized direct-current power supply, capable of applying a voltage of 1 V to 1 000 V to the test piece.

5.2 Voltmeter, capable of measuring the applied voltage with an accuracy of ±2 %.

5.3 Ammeter or other current-measuring device, capable of measuring a current of 0,01 pA to 100 mA,

depending on the resistivity of the test piece to be measured. The accuracy of the current-measuring device

shall be better than 5 %.
5.4 Electrodes, as follows:
5.4.1 Guarded-electrode system
Three electrodes shall be applied to the test piece:
— a main electrode (circular);
— a ring electrode (annular);
— an opposed electrode (circular).
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ISO 14309:2011(E)
5.4.2 Shapes and dimensions of electrodes

The main (smallest) electrode is circular and is surrounded by the ring electrode. The third electrode is circular

and placed on the opposite side of the test piece to the main electrode. The arrangement of the electrodes is

shown schematically in Figure 1. The dimensions of the electrodes shall comply with following requirements:

— The diameter D of the main electrode shall be at least ten times the test piece thickness h.

— The gap g between the main electrode and the ring electrode shall be uniform in width. For the measurement

of volume resistivity, it should preferably be as narrow as possible so that surface leakage does not cause any

error in the measurement. In practice, it is usually 1 mm or larger. For the measurement of surface resistivity,

it shall be at least twice the test piece thickness so that the effect of the volume resistance can be ignored.

— The width of the ring electrode shall be greater than the test piece thickness h.

— The diameter D of the opposed electrode shall be greater than the outer diameter D of the ring electrode.

4 3
A typical example is as follows:
D (50 ± 0,5) mm
D (70 ± 0,5) mm
D (80 ± 0,5) mm
D (83 ± 2) mm
Figure 1 — Arrangement of electrodes
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ISO 14309:2011(E)
5.4.3 Electrode materials

Electrodes shall be of a conducting material capable of being intimately applied to the test piece. If they are

applied before conditioning, the material shall be moisture-permeable. Electrodes other than of rigid metal

shall be supplemented by rigid metal backing plates.
NOTE Suitable electrode materials are considered in Annex A.
5.4.4 Electrical circuits
Suitable circuits for testing are shown in Figures 2 and 3.
1 12
8 6
Key
1 guarded electrode (main electrode)
2 guard electrode (ring electrode)
3 test piece
4 unguarded electrode (opposed electrode)
5 direct-current supply
6 switch
7 connection for short-circuiting electrodes (to discharge test piece)
8 connection for measurement circuit
9 ammeter
10 earth
11 measurement current
12 guard current
Figure 2 — Circuit configuration for volume resistivity
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ISO 14309:2011(E)
4 7
Key
1 guarded electrode (main electrode)
2 ung
...