Electrostatics - Part 2-1: Measurement methods - Ability of materials and products to dissipate static electric charge

IEC 61340-2-1:2015 describes test methods for measuring the rate of dissipation of static charge of insulating and static dissipative materials and products. It includes a generic description of test methods and detailed test procedures for specific applications. The two test methods for measuring charge decay time, one using corona charging and one using a charged metal plate are different and may not give equivalent results. Nevertheless, each method has a range of applications for which it is best suited. The corona charging method is suitable for evaluating the ability of materials, e.g. textiles, packaging, etc., to dissipate charge from their own surfaces. The charged metal plate method is suitable for evaluating the ability of materials and objects such as gloves, finger cots, hand tools, etc. to dissipate charge from conductive objects placed on or in contact with them. The charged plate method may not be suitable for evaluating the ability of materials to dissipate charge from their own surfaces. In addition to its general application, this horizontal standard is also intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 108. This edition includes the following significant technical changes with respect to the previous edition:
a) the first edition supported requirements in IEC TR 61340-5-1, but with the revision of IEC TR 61340-5-1 into an International Standard, this support is no longer required; references to IEC 61340-5-1 have been removed;
b) the introduction gives additional information on when charge decay time measurements are appropriate, and the applications for which each of the two test methods are best suited;
c) procedures for performance verification of measuring instruments for the corona charging method have been added. It has the status of a horizontal standard in accordance with IEC Guide 108.

Electrostatique - Partie 2-1: Méthodes de mesure - Capacité des matériaux et des produits à dissiper des charges électrostatiques

L'IEC 61340-2-1:2015 décrit les méthodes d'essai pour mesurer le taux de dissipation de charge statique des matériaux et des produits isolants et électrostatiquement dissipatifs. Elle comprend une description générique des méthodes d'essai et les procédures d'essai détaillées pour des applications spécifiques. Les deux méthodes d'essai pour mesurer le temps de décroissance de la charge, l'une utilisant la charge par effet de couronne et l'autre utilisant une plaque de métal chargée sont différentes et peuvent ne pas donner des résultats équivalents. Néanmoins, chaque méthode comporte une plage d'applications pour lesquelles elle est la plus adaptée. La méthode de la charge par effet de couronne convient à l'évaluation de l'aptitude des matériaux (p. ex.: textiles, emballages, etc.) à dissiper la charge de leurs propres surfaces. La méthode de la plaque de métal chargée convient à l'évaluation de l'aptitude des matériaux et objets (p. ex.: gants, doigtiers, outils à main, etc.) à dissiper la charge des objets conducteurs placés sur eux ou en contact avec eux. La méthode de la plaque de métal chargée peut ne pas convenir à l'évaluation de l'aptitude des matériaux à dissiper la charge de leurs propres surfaces. Outre son application générale, cette norme horizontale est également destinée à l'usage des comités d'études dans la préparation des normes, conformément aux principes établis dans le Guide 108 de l'IEC. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) la première édition prenait en charge les exigences de l'IEC TR 61340-5-1, mais avec la révision de l'IEC TR 61340-5-1 pour en faire une Norme internationale cette prise en charge n'est plus exigée; les références à l'IEC 61340-5-1 ont été supprimées;
b) l'introduction donne des informations complémentaires sur le moment où les mesures du temps de décroissance de la charge sont appropriées, ainsi que les applications pour lesquelles chacune des deux méthodes d'essai est la plus adaptée;
c) des procédures ont été ajoutées pour vérifier les performances des instruments de mesure dans le cadre de la méthode de charge par effet de couronne. Elle a le statut de norme horizontale conformément au Guide IEC 108.

General Information

Status
Published
Publication Date
27-Aug-2015
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
28-Aug-2015
Ref Project

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IEC 61340-2-1
Edition 2.0 2015-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
HORIZONTAL STANDARD
NORME HORIZONTALE
Electrostatics –
Part 2-1: Measurement methods – Ability of materials and products to dissipate
static electric charge
Électrostatique –
Partie 2-1: Méthodes de mesure – Capacité des matériaux et des produits à
dissiper des charges électrostatiques
IEC 61340-2-1:2015-08(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61340-2-1
Edition 2.0 2015-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
HORIZONTAL STANDARD
NORME HORIZONTALE
Electrostatics –
Part 2-1: Measurement methods – Ability of materials and products to dissipate
static electric charge
Électrostatique –
Partie 2-1: Méthodes de mesure – Capacité des matériaux et des produits à
dissiper des charges électrostatiques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.99; 29.020 ISBN 978-2-8322-2877-7

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 61340-2-1:2015 © IEC 2015
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms and definitions ...................................................................................................... 7

4 Method of measurement of charge decay ........................................................................ 8

4.1 Principles ................................................................................................................ 8

4.2 Environmental conditions ........................................................................................ 9

4.3 Apparatus for measurement of corona charge decay ............................................. 10

4.3.1 Physical design features ................................................................................ 10

4.3.2 Containment of test material .......................................................................... 11

4.3.3 Corona charge deposition .............................................................................. 11

4.3.4 Fieldmeter ..................................................................................................... 11

4.4 Apparatus for measurement of contact charge decay ............................................ 12

4.4.1 Physical design features ................................................................................ 12

4.4.2 Charge decay time (t ) ................................................................................ 13

5 Practical application of test methods and procedures .................................................... 14

5.1 General ................................................................................................................. 14

5.2 Charge decay test for textile materials .................................................................. 14

5.2.1 Selection of test method ................................................................................ 14

5.2.2 Test surface preparation ................................................................................ 14

5.2.3 Testing .......................................................................................................... 14

5.2.4 Results .......................................................................................................... 15

5.2.5 Test report ..................................................................................................... 15

5.3 Charge decay test via gloves, finger cots or tools ................................................. 15

5.3.1 Selection of test method ................................................................................ 15

5.3.2 Common steps in testing ............................................................................... 15

5.3.3 Test procedure for charge decay properties of finger cots as worn ................ 16

5.3.4 Test procedure for the charge decay properties of gloves as worn ................. 16

5.3.5 Test report for finger cots or gloves ............................................................... 16

5.3.6 Test procedure for the charge decay properties of tools ................................. 17

5.3.7 Test report for tools ....................................................................................... 17

5.4 Null test for CPM................................................................................................... 17

Annex A (normative) Performance verification of measuring instrumentation........................ 19

A.1 Verification of corona charge decay measuring instrumentation ............................ 19

A.1.1 Aspects to be verified .................................................................................... 19

A.1.2 Surface potential sensitivity verification ......................................................... 19

A.1.3 Decay time verification .................................................................................. 19

A.1.4 Verification procedure .................................................................................... 19

A.2 Methods for verification of the capacitance of an isolated conductive plate ........... 20

A.2.1 General ......................................................................................................... 20

A.2.2 Capacitance meter method ............................................................................ 20

A.2.3 Charge measuring method ............................................................................. 20

A.2.4 Charge-sharing method ................................................................................. 21

Bibliography .......................................................................................................................... 22

---------------------- Page: 4 ----------------------
IEC 61340-2-1:2015 © IEC 2015 – 3 –

Figure 1 – Example of an arrangement for measurement of dissipation of charge using

corona charging .................................................................................................................... 10

Figure 2 – Example of an arrangement for measurement of dissipation of charge using

a charged plate ..................................................................................................................... 12

Figure 3 – Charged plate detail ............................................................................................. 13

Figure 4 – Charge decay time (tsd) and offset voltage (U0) ................................................... 13

Figure A.1 – Equivalent circuit for CPM and reference capacitor ........................................... 21

---------------------- Page: 5 ----------------------
– 4 – IEC 61340-2-1:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROSTATICS –
Part 2-1: Measurement methods –
Ability of materials and products
to dissipate static electric charge
FOREWORD

1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising

all national electrotechnical committees (IEC National Committees). The object of IEC is to promote

international co-operation on all questions concerning standardization in the electrical and electronic fields. To

this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,

Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC

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governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely

with the International Organization for Standardization (ISO) in accordance with conditions determined by

agreement between the two organizations.

2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international

consensus of opinion on the relevant subjects since each technical committee has representation from all

interested IEC National Committees.

3) IEC Publications have the form of recommendations for international use and are accepted by IEC National

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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in

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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

6) All users should ensure that they have the latest edition of this publication.

7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and

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other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and

expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC

Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

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

International Standard IEC 61340-2-1 has been prepared by IEC technical committee 101:

Electrostatics.

This second edition cancels and replaces the first edition published in 2002. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:
---------------------- Page: 6 ----------------------
IEC 61340-2-1:2015 © IEC 2015 – 5 –

a) the first edition supported requirements in IEC TR 61340-5-1, but with the revision of IEC

TR 61340-5-1 into an International Standard, this support is no longer required; references

to IEC 61340-5-1[1] have been removed;

b) the introduction gives additional information on when charge decay time measurements

are appropriate, and the applications for which each of the two test methods are best

suited;

c) procedures for performance verification of measuring instruments for the corona charging

method have been added.
The text of this standard is based on the following documents:
CDV Report on voting
101/446/CDV 101/462/RVC

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.

It has the status of a horizontal standard in accordance with IEC Guide 108[3].

A list of all the parts in the IEC 61340 series, published under the general title Electrostatics,

can be found on the IEC website.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC website 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.
___________
Numbers in square brackets refer to the Bibliography.
---------------------- Page: 7 ----------------------
– 6 – IEC 61340-2-1:2015 © IEC 2015
INTRODUCTION

Measurements of the rate of dissipation of static charge belong to the essential measurement

techniques in the field of electrostatics.

For homogeneous conductive materials, this property can be evaluated indirectly by

measuring resistance or resistivity parameters. Care should be exercised when determining

the homogeneity of materials, as some materials that appear homogenous do exhibit non-

homogeneous electrical characteristics. If the homogeneity of materials is not known and

cannot be otherwise verified, resistance measurements may not be reliable or may not give

enough information. Resistance measurements may also not be reliable when evaluating

materials in the dissipative or insulative range and especially for high ohmic materials

including conductive fibres (e.g. textiles with a metallic grid). In such cases, the rate of

dissipation of static charge should be measured directly.
---------------------- Page: 8 ----------------------
IEC 61340-2-1:2015 © IEC 2015 – 7 –
ELECTROSTATICS –
Part 2-1: Measurement methods –
Ability of materials and products
to dissipate static electric charge
1 Scope

This part of IEC 61340 describes test methods for measuring the rate of dissipation of static

charge of insulating and static dissipative materials and products.

It includes a generic description of test methods and detailed test procedures for specific

applications.

The two test methods for measuring charge decay time, one using corona charging and one

using a charged metal plate are different and may not give equivalent results. Nevertheless,

each method has a range of applications for which it is best suited. The corona charging

method is suitable for evaluating the ability of materials, e.g. textiles, packaging, etc., to

dissipate charge from their own surfaces. The charged metal plate method is suitable for

evaluating the ability of materials and objects such as gloves, finger cots, hand tools, etc. to

dissipate charge from conductive objects placed on or in contact with them. The charged plate

method may not be suitable for evaluating the ability of materials to dissipate charge from

their own surfaces.

In addition to its general application, this horizontal standard is also intended for use by

technical committees in the preparation of standards in accordance with the principles laid

down in IEC Guide 108.

One of the responsibilities of a technical committee is, wherever applicable, to make use of

horizontal standards in the preparation of its publications. The contents of this horizontal

standard shall not apply unless specifically referred to or included in the relevant publications.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and

are indispensable for its application. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any
amendments) applies.

IEC 61340-4-6, Electrostatics – Part 4-6: Standard test methods for specific applications –

Wrist straps

IEC 61340-4-7, Electrostatics – Part 4-7: Standard test methods for specific applications –

Ionization
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
---------------------- Page: 9 ----------------------
– 8 – IEC 61340-2-1:2015 © IEC 2015
3.1
charge decay

migration of charge across or through a material leading to a reduction of charge density or

surface potential at the area where the charge was deposited
3.2
charge decay time
time from an initial voltage to a set fraction of the initial voltage

Note 1 to entry: 1/e and 10 % are appropriate fractions (e is the base of natural logarithms, equal to 2,718). If the

initial voltage is low, the accuracy of decay time measurements to a small fraction of the initial voltage may be

susceptible to the noise level of the fieldmeter.
3.3
charged plate monitor
CPM

instrument using a charged metal plate of a defined capacitance and geometry which is

discharged in order to measure charge dissipation/neutralization properties of products or

materials
Note 1 to entry: This note only applies to the French language.
3.4
corona
corona discharge
generation of ions of either polarities by a high electric field
3.5
static dissipative material

material which allows charge to migrate over its surface and/or through its volume in a time

which is short compared to the time scale of the actions creating the charge, or short

compared to the time within which this charge will cause an electrostatic problem

Note 1 to entry: Materials that may be considered conductive in other contexts are included within this definition

for the purposes of this part of IEC 61340.
3.6
initial voltage

< corona charge decay> surface potential at a time after the end of charge deposition that is a

sensible match to the time it takes material surfaces to separate in practical situations

Note 1 to entry: A time of 100 ms is appropriate for manual tribocharging actions.

3.7
initial voltage

voltage applied to the conductive plate of a charged plate monitor

3.8
insulator

material with very low mobility of charge so that any charge on the surface will remain there

for a time which is long compared to the time scale of the actions creating the charge

4 Method of measurement of charge decay
4.1 Principles
Two methods are described.

The first method determines the dissipation of charge deposited on the surface of the material

by a corona discharge. The resulting decrease in surface potential is observed using a

---------------------- Page: 10 ----------------------
IEC 61340-2-1:2015 © IEC 2015 – 9 –

fieldmeter or other equivalent equipment. This method is applicable to measurement of

charge dissipation from surfaces and materials.

The second method determines the dissipation of charge from a charged plate through an

object under test by applying a potential to the metallic plate, disconnecting the voltage

source and observing the decrease in potential of the plate by means of a fieldmeter or other

equivalent equipment. This method is applicable to measurement of charge dissipation via

products such as finger cots, gloves and hand tools.

NOTE There are more methods to charge materials other than the charging methods described here (for example

tribocharging or inductive charging) but they are not relevant for this standard.

CAUTION The test methods specified in this International Standard involve the use of high-voltage power

supplies that may present hazards if handled incorrectly, particularly by unqualified or inexperienced personnel.

Users of this International Standard are encouraged to carry out proper risk assessments and pay due regard to

local regulations before undertaking any of the test procedures.
4.2 Environmental conditions

The electrical properties of materials vary with temperature and the absorption of moisture.

Unless otherwise agreed, the atmosphere for conditioning and testing shall be (23 ± 2) °C and

(12 ± 3) % relative humidity, and the conditioning time prior to testing shall be at least 48 h.

For measurements in practical situations the ambient temperature and relative humidity shall

be recorded.
---------------------- Page: 11 ----------------------
– 10 – IEC 61340-2-1:2015 © IEC 2015
4.3 Apparatus for measurement of corona charge decay
4.3.1 Physical design features
Dimensions in millimetres with a tolerance of ± 1 mm.
1 2
>5 >5
∅50
1 2
∅50
IEC
Key
Array of corona points, the tips of which form a circle
1 5 Sample
(10 ± 1) mm in diameter
2 Fieldmeter sensing aperture 6 Metal plate (open backing)
3 Movable plate: 7 Aperture through which the movable plate is
withdrawn
– insulating plate to mount corona points (resistance
8 Air dam
to ground > 10 Ω)
9 Metal plate (earthed backing)
– earthed top surface to shield fieldmeter
4 Earthed casing
Figure 1 – Example of an arrangement for measurement
of dissipation of charge using corona charging

A typical arrangement and relevant dimensions of the test apparatus are shown in Figure 1.

Other equipment giving similar results may be used.
>25
---------------------- Page: 12 ----------------------
IEC 61340-2-1:2015 © IEC 2015 – 11 –

The test aperture for deposition and measurement of deposited charge shall be (50 ± 1) mm

diameter or an equivalent area quasi-square aperture. An array of corona points is mounted

on a movable plate above the centre of the test aperture. The fieldmeter sensing aperture

shall be (25 ± 1) mm above the centre of the test area. When the plate with the corona points

is moved fully away, the test area shall be clear up to the plane of the fieldmeter sensing

aperture.
4.3.2 Containment of test material

With an installed material, the test aperture in the instrument base plate shall rest directly on

its surface. Sheet or flexible materials shall be supported as follows:

a) for testing materials with open backing, the material shall be rested against an earthed

metal plate with an aperture aligned with the instrument test aperture and with a width of

at least 5 mm extending beyond the aperture. A shield over the reverse side of the test

area shall be earthed and be at least 25 mm away over the whole test area;

b) for testing materials against an earthed backing, the material shall be mounted between

the instrument base plate and a flat earthed metal plate.

NOTE If charge moves more readily through the bulk test material than across its surface, then placing an

earthed metal plate immediately behind the test area can increase the rate of charge dissipation. On the other

hand, if charge moves more readily across the surface of the test material, then the rate of charge dissipation can

decrease if an earthed metal plate is used because its presence will increase the capacitive loading. To gain a full

understanding of charge dissipation from the test material, it is desirable to make measurements both with and

without an earthed metal plate backing the test area.

In practical terms, earthed backing represents a material in intimate contact with an earthed surface, for example,

a garment fitted close to the body of the wearer, or a work surface on top of a metal bench. Open-backed

measurements represent the other practical extreme where materials are separated from earthed surfaces, for

example, the bottom edge of a coat or smock which hangs away from the body of the wearer.

4.3.3 Corona charge deposition

Corona charging is achieved with at least five corona points, the tips of which form a

(10 ± 1) mm diameter circle, (10 ± 1) mm above the centre of the test area. The corona points

shall be made from non-corrosive metal wire of a diameter in the range 0,1 mm to 0,5 mm.

The exact size and distribution of charge on the material is not well defined, particularly with

the more conductive surfaces, but the arrangement provides a consistent pattern of deposited

charge and decay time measurements.
NOTE 1 Typical voltages for corona charging equipment are between 5 kV
...

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