IEC TS 61340-4-2:2013

IEC/TS 61340-4-2 ®
Edition 1.0 2013-06
TECHNICAL
SPECIFICATION
SPÉCIFICATION
TECHNIQUE
colour
inside
Electrostatics –
Part 4-2: Standard test methods for specific applications – Electrostatic
properties of garments
Électrostatique –
Partie 4-2: Méthodes d’essai normalisées pour des applications spécifiques –
Propriétés électrostatiques des vêtements

IEC/TS 61340-4-2:2013
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IEC/TS 61340-4-2 ®
Edition 1.0 2013-06
TECHNICAL
SPECIFICATION
SPÉCIFICATION
TECHNIQUE
colour
inside
Electrostatics –
Part 4-2: Standard test methods for specific applications – Electrostatic

properties of garments
Électrostatique –
Partie 4-2: Méthodes d’essai normalisées pour des applications spécifiques –

Propriétés électrostatiques des vêtements

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX XA
ICS 17.220.99; 29.020 ISBN 978-2-83220-891-5

– 2 – TS 61340-4-2 © IEC:2013
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 8
4 Atmosphere for conditioning and testing . 8
5 Preparation of samples and test materials . 9
5.1 Samples . 9
5.2 Test equipment and materials . 9
6 Test methods. 9
6.1 General . 9
6.2 Resistance and resistivity . 10
6.2.1 Selection of the appropriate resistance measurement test method . 10
6.2.2 Conversion to resistivity values . 11
6.3 Charge decay time . 11
6.3.1 Selection of the appropriate charge decay time test method . 11
6.3.2 Corona charging method . 12
6.3.3 Induction charging method . 12
6.3.4 Charge decay by conduction through a garment to a human body . 12
6.3.5 Surface potential suppression of isolated garments . 12
6.4 Measurement of electrostatic discharges . 12
6.5 Field suppression . 13
6.6 Tribocharging tests . 13
6.6.1 General . 13
6.6.2 Tribocharging by removal of garments . 14
6.6.3 Tribocharging the outer surface of garments . 14
6.6.4 Tribocharging using seats . 14
6.7 Clinging tests . 14
6.8 Capacitance loading . 14
Annex A (normative) Tribocharging by removal of garments. 16
Annex B (normative) Tribocharging using seats . 20
Annex C (normative) Test of chargeability . 25
Annex D (normative) Capacitance loading . 37
Annex E (informative) Simple tribocharging tests . 49
Bibliography . 50

Figure A.1 – Test equipment for measuring body voltage and charge on removed
garments . 17
Figure B.1 – Example of test equipment set up for measuring body voltage when rising
from a seat . 22
Figure B.2 – Typical body voltage recordings . 24
Figure C.1 – Diagram of the test stand with a mannequin . 26
Figure C.2 – Measuring scheme with a mannequin and Faraday cage . 27
Figure C.3 – Measuring scheme with a mannequin and net table . 27
Figure C.4 – Net table used to measure the charging level of clothes . 28

TS 61340-4-2 © IEC:2013 – 3 –
Figure C.5 – Measuring scheme with a test person and net table . 29
Figure C.6 – Possible ways of taking off clothes from the mannequin trunk or from the
test person . 32
Figure C.7 – Diagram of the stand for testing mechanical tribocharging on the outer
surface of clothing . 34
Figure C.8 – Diagram of the system for measurement of the test person charging level
resulting from manual rubbing of its clothing . 35
Figure D.1 – Example of an arrangement for measurement of corona charge decay
and arrangements for ‘open backing’ and ‘earthed backing’ . 38
Figure D.2 – Equipment for charge decay time calibration . 40
Figure D.3 – Arrangement for measuring received charge . 41
Figure D.4 – Example of variation of capacitance loading with quantity of corona . 45
Figure D.5 – Adjustment of factor for matching induction to conduction measurements . 48

Table 1 – Suitability of test methods for garments and garment materials . 10
Table 2 – Test method standards for resistance measurements . 10

– 4 – TS 61340-4-2 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROSTATICS –
Part 4-2: Standard test methods for specific applications –
Electrostatic properties of garments

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
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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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
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
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
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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.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
This document is being issued in the Technical Specification series of publications
(according to the ISO/IEC Directives, Part 1, 3.1.1.1) as a “prospective standard for
provisional application” in the field of determination of the electrostatic properties of garments
and garment materials because there is an urgent need for guidance on how standards in this
field should be used to meet an identified need.

TS 61340-4-2 © IEC:2013 – 5 –
This document is not to be regarded as an “International Standard”. It is proposed for
provisional application so that information and experience of its use in practice may be
gathered. Comments on the content of this document should be sent to the IEC Central
Office.
A review of this technical specification will be carried out not later than 3 years after its
publication with the options of: extension for another 3 years; conversion into an
International Standard; or withdrawal.
IEC 61340-4-2, which is a technical specification, has been prepared by IEC technical
committee 101: Electrostatics.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
101/374/DTS 101/388/RVC
Full information on the voting for the approval of this technical specification can be found in
the report on voting indicated in the above table.
The French version of this standard has not been voted upon.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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 web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International Standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – TS 61340-4-2 © IEC:2013
INTRODUCTION
The garments worn by most people in their everyday lives are not usually designed to
dissipate static electricity. Some natural fibres, such as cotton or linen, have sufficient
retained moisture to provide some degree of conductivity and may dissipate charge at an
acceptable rate. However, synthetic fibres, such as polyester or polyamide, or natural fibres
under low humidity conditions are not able to dissipate charge quickly. If electrostatic charge
builds up on a garment it may cause a number of effects:
a) dust and airborne contaminants can be attracted to the surface of charged garments;
b) light-weight garments can cling to the body of the wearer;
c) the electric field associated with charge on garments can damage or disrupt sensitive
electronic systems or components;
d) electrostatic discharges from garments can ignite flammable or explosive materials and
can damage or disrupt sensitive electronic systems or components;
e) charge on garments induces a potential on the body of an isolated person wearing the
garments and this can lead to damaging or hazardous spark discharges from the body.
Some of the effects can often be tolerated but in many situations the presence of these
effects is unacceptable. In order to evaluate whether or not there is a potential problem, it is
necessary to determine the propensity of garments to acquire charge or produce electrostatic
discharges, or to determine their ability to dissipate charge within an acceptable time. If
normal garments are found to be unacceptable, they are replaced with garments specifically
designed and manufactured to prevent the undesirable effects of static electricity, i.e. static
control garments. Suitable test methods are required both to evaluate the extent of potential
problems and to determine the effectiveness of charge dissipation mechanisms in static
control garments.
TS 61340-4-2 © IEC:2013 – 7 –
ELECTROSTATICS –
Part 4-2: Standard test methods for specific applications –
Electrostatic properties of garments

1 Scope
This part of IEC 61340, which is a technical specification, describes test methods and
procedures that can be used to evaluate the electrostatic charging and discharging
propensity, field suppression properties and charge dissipation properties of garments and
materials from which garments are constructed.
The test methods described are suitable for evaluating garments worn on or about the upper
and lower body, including headwear, but excluding footwear, which is covered in other parts
of IEC 61340 (see IEC 61340-4-3 and IEC 61340-4-5)[1] , and excluding gloves and finger
cots.
The test methods described may not be suitable for evaluating garments and garment
materials in relation to safety of personnel.
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/TR 61340-1:2012, Electrostatics – Part 1: Electrostatic phenomena – Principle and
measurements
IEC 61340-2-1:2002, Electrostatics – Part 2-1: Measurement methods – Ability of materials
and products to dissipate static electric charge
IEC/TR 61340-2-2, Electrostatics – Part 2-2: Measurement methods – Measurement of
chargeability
IEC 61340-2-3:2000, Electrostatics – Part 2-3: Methods of test for determining the resistance
and resistivity of solid planar materials used to avoid electrostatic charge accumulation
IEC 61340-4-9, Electrostatics – Part 4-9: Standard test methods for specific applications –
Garments
ISO 3175-2, Textiles – Professional care, drycleaning and wetcleaning of fabrics and
garments – Part 2: Procedure for testing performance when cleaning and finishing using
tetrachloroethene
ISO 3175-3, Textiles – Professional care, drycleaning and wetcleaning of fabrics and
garments – Part 3: Procedure for testing performance when cleaning and finishing using
hydrocarbon solvents
—————————
Numbers in square brackets refer to the Bibliography.

– 8 – TS 61340-4-2 © IEC:2013
ISO 6330, Textiles – Domestic washing and drying procedures for textile testing
ISO 15797, Textiles – Industrial washing and finishing procedures for testing of workwear
AATCC Test Method 115, Electrostatic Clinging of Fabrics: Fabric-to-Metal Test
BS 7506-1:1995, Methods for measurement in electrostatics – Part 1: Guide to basic
electrostatics
EN 1149-3:2004, Protective clothing – Electrostatic properties – Part 3: Test methods for
measurement of charge decay
EN 1149-5, Protective clothing – Electrostatic properties – Part 5: Material performance and
design requirements
NT ELEC 036:2006, Fabrics and inhomogeneous materials: Measurement of a direct
discharge from an ESD protective material, such as an ESD garment/fabric
NT ELEC 037:2006, Protective garments: Measurement of the charge decay time of ESD-
protective garments
3 Terms and definitions
For the purposes of this document, the following terms and definitions, as well as those given
in IEC/TR 61340-1:2012 apply. Additional definitions given in the references listed in Clause 2
also apply where relevant to this standard.
3.1
capacitance loading
measure of the degree to which surface potential is suppressed compared to an insulator and
is calculated as the surface potential achieved per unit quantity of charge for a thin film of a
good insulator divided into the surface potential achieved per unit of charge with a similar
surface charge distribution on the test material
3.2
field suppression
attenuation of static electric field emanating from charged undergarments
3.3
induction charging
generation of potential difference on a test material by the influence of an electric field from a
nearby charged electrode
4 Atmosphere for conditioning and testing
As the electrostatic properties of materials are influenced by temperature and relative
humidity, it is important that measurements are made under controlled conditions where
possible.
If conditions are not otherwise specified, in product standards for example, the conditions
specified in the test methods referenced in this part of IEC 61340 may be used, or may be
adjusted to be suitable for specific applications. The most appropriate conditions and the time
of conditioning before measurements are made shall be selected with regard to the type of
—————————
American Association of Textile Chemists and Colorists.

TS 61340-4-2 © IEC:2013 – 9 –
material, the intended application and the expected conditions of use. It is recommended that
at least two sets of measurements be made, one at the lowest expected relative humidity and
one at the highest expected relative humidity.
If environmental control is not possible, a record of the temperature and relative humidity at
the time of measurement shall be made. If the conditions during the 24 h preceding the
measurements are known, the range of these conditions shall also be recorded.
The atmosphere for conditioning and testing shall be included in the test report for all
measurements made in accordance with this part of IEC 61340.
5 Preparation of samples and test materials
5.1 Samples
New garments may have been treated with topical finishes to help reduce charging or
increase charge dissipation. Even if such finishes are not deliberately applied, there may be
residual processing finishes present that have similar effects. Residual processing finishes
and some deliberately applied finishes may not be permanent and their effects will diminish
with use and with cleaning. It may be necessary when evaluating garments and garment
materials for longterm use to ensure that temporary finishes are removed by cleaning prior to
testing.
Samples may be tested before and after cleaning in order to evaluate the effects of the
cleaning procedures.
Unless otherwise specified in product standards or by agreement between interested parties,
cleaning to remove temporary finishes, if required, shall be carried out in accordance with
international standards such as ISO 6330 (domestic washing), ISO 15797 (industrial washing)
or ISO 3175-2 or ISO 3175-3 (dry cleaning). Cleaning procedures (including number of cycles,
wash temperature, detergent, etc.) shall be selected with regard to the type of material,
manufacturer’s recommended cleaning procedures, the intended application, and the
expected conditions of use.
Full details of any cleaning procedures used prior to testing shall be included in test reports.
5.2 Test equipment and materials
Test equipment and materials that come into contact with samples, particularly during
tribocharging tests, shall be maintained in a clean condition and shall be free of contaminants
that might influence test results.
6 Test methods
6.1 General
Test methods for making suitable measurements on garments and garment materials are
summarized in Table 1.
– 10 – TS 61340-4-2 © IEC:2013
Table 1 – Suitability of test methods for garments and garment materials
Measurement Standard/ Clause in Suitable for
Technical IEC/TS 61340-4-2
Garments Materials Compliance
specification (this technical
verification
specification)
IEC 61340-2-3
Resistance 6.2 Yes Yes Yes
IEC 61340-4-9
IEC 61340-2-1 6.3.2 Yes Yes Yes
EN 1149-3 6.3.3 Yes Yes Yes
Charge decay
time
NT ELEC 037 6.3.4 Yes Yes Yes
NT ELEC 037 6.3.5 Yes Yes Yes
Size of
electrostatic NT ELEC 036 6.4 No Yes No
discharges
Field suppression EN 1149-3 6.5 Yes Yes Yes
6.6.3
IEC/TS 61340-4-2
(this technical Annex A Yes Yes Yes
specification)
Clause C.2
IEC/TS 61340-4-2
6.6.4
(this technical Yes Yes Yes
Triboelectric
Clause C.3
specification)
charging
IEC/TS 61340-4-2
6.6.5
(this technical Yes Yes Yes
Annex B
specification)
IEC/TS 61340-4-2
(this technical Annex E Yes No Yes
specification)
Clinging AATCC 115 6.7 No Yes No
IEC/TS 61340-4-2
6.8
Capacitance
(this Technical Yes Yes Yes
loading
Annex D
Specification)
NOTE Compliance verification includes daily and pre-use checks. Test methods may require modifying to suit
the application.
6.2 Resistance and resistivity
6.2.1 Selection of the appropriate resistance measurement test method
Resistance measurements on garment materials and garments shall be carried out using the
procedures specified in Table 2.
Table 2 – Test method standards for resistance measurements
Test samples Parameter Standard
Surface resistance
Garment materials Volume resistance
Point-to-point resistance IEC 61340-2-3
Surface resistance
Volume resistance
Garments Point-to-point resistance
Sleeve-to-sleeve resistance IEC 61340-4-9
Resistance to groundable point

TS 61340-4-2 © IEC:2013 – 11 –

If the garment under test is of sufficient size, three measurements of surface resistance
and/or volume resistance shall be made at different locations on a single sample.
Alternatively, one measurement can be made on each of three separate garments. The latter
option shall be used for any garment that is too small to accommodate three measurement
locations.
Measurements using the electrodes specified in IEC 61340-2-3 are impractical on garments
smaller than 80 mm in any direction. In such cases, measurements shall be made on larger
samples of material from which the garment under test is constructed. If this is not possible,
smaller electrodes may be used provided they are fully described in the test report.
Volume resistance measurements on garments are usually made between the inside and
outside surfaces. To achieve this on areas such a sleeves or trouser legs, or on items such as
gloves, it is necessary to insert the bottom electrode (described as probe 2 in IEC 61340-2-3)
inside the garment. If, as in the example of gloves, the bottom electrode is too large to fit
inside the garment, the garment shall be cut open, or smaller electrodes shall be used
provided they are fully described in the test report.
6.2.2 Conversion to resistivity values
When required, surface resistance and volume resistance values shall be converted to
surface resistivity and volume resistivity, respectively, using the formulae specified in Clause
9 of IEC 61340-2-3:2000.
NOTE 1 It is common for the surface resistivity of textile materials to be calculated using a different formula to
that specified in 9.1 of IEC 61340-2-3:2000. A typical example is EN 1149-1:1996 [3]. The difference in the values
calculated by the two different formulae is 3,3 % of the smaller value for the electrodes specified in
IEC 61340-2-3:2000.
NOTE 2 Resistivity values can only be defined if the garment material is electrically homogeneous, i.e. material in
which all the constituent components have similar electrical properties, or in which components of differing
electrical properties are uniformly blended to produce a material that has macroscopically uniform electrical
properties.
6.3 Charge decay time
6.3.1 Selection of the appropriate charge decay time test method
The principle of a charge decay time test is to deposit or generate charge on, or in a material
and observe the rate at which that charge is dissipated. Test methods vary mainly in the
procedure used to deposit or generate charge. In this part of IEC 61340, different methods
are described, each one with a different means of charging the test material. Charge is not
measured directly but dissipation of charge is determined by measurement of related
parameters. In three of the procedures, the rate of charge dissipation is observed using a
charged plate monitor (CPM) to measure electric potential, and in the other three procedures
a field meter is used to observe the change in electric field caused by charge dissipation.
Selection of the most appropriate method to use is made by considering the nature of the
garment under test, the way in which it may become charged in use, and the way in which it is
required to dissipate charge. Some of the methods described are generally suitable for a
range of different applications, whilst others are suitable for more specific applications. For
example, the corona charging method can be used to evaluate most types of garment material
for a wide range of applications. The charged metal plate method, as another example, is best
suited for evaluating the ability of materials to dissipate charge from conductors that come
into contact with them, such as the dissipation of charge from hand tools via gloves.
The point at which timing is started and stopped is specified in some of the test methods
referenced in this part of IEC 61340. If no other values are specified, in product standards for
example, these timing points may be used, or may be adjusted to be suitable for specific
applications. The start point and end point of any charge decay time measurement made in

– 12 – TS 61340-4-2 © IEC:2013
accordance with this part of IEC 61340 shall be included in the test report in a format
appropriate to the test method used.
NOTE 1 Although charge decay time may be presented in the same format for different test methods, the results
may not be directly comparable because of differences in the test procedures.
NOTE 2 If more than one material or material combination is involved in the charge decay, more than one time
constant is present. This is the main reason why different methods give different results, since defining the initial
potential value is crucial.
6.3.2 Corona charging method
The ability of a garment or garment material to dissipate charge deposited or generated on its
surface can be evaluated using the method described in 4.3 and Clause A.1 of IEC 61340-2-
1:2002.
6.3.3 Induction charging method
The ability of a garment or garment material to dissipate charge deposited or generated on its
surface can be evaluated using the method described in EN 1149-3:2004, test method 2. This
test method uses an electrode positioned close to the garment or material under test.
Although charge is not applied directly, the movement of charge within the test sample
induced by the field from the charged electrode is related to the ability of the sample to
dissipate charge. The EN 1149 series of standards have been developed for evaluating
personal protective clothing for use in hazardous explosive environments. The performance
requirements specified in EN 1149-5 shall be used for evaluating garments and garment
materials intended for such applications. For other applications, the test method can be used
but careful consideration shall be given to the applicability of the related performance
requirements.
6.3.4 Charge decay by conduction through a garment to a human body
The ability of all parts of a garment to dissipate charge to ground via the body of the wearer
can be evaluated using the method described in NT ELEC 037. The test parameters specified
in NT ELEC 037 are applicable to garments intended for use in electrostatic discharge
protected areas (EPA). If the test procedures are used to evaluate garments intended for
other applications, careful consideration shall be given to the relevance of the test parameters
to the specific application. Test parameters may be adjusted to suit specific applications.
The test procedure described in NT ELEC 037 relies on charge being applied via a conductive
clamp in direct contact with the garment under test. The conductive clamp may not achieve
good electrical contact with embedded conductive or dissipative elements that are
incorporated in some garment materials. In such cases, the corona charging method
described in 6.3.2, or the induction charging method described in 6.3.3 can be used to
evaluate the ability of the garment to dissipate charge.
6.3.5 Surface potential suppression of isolated garments
The test method described in 6.3.5 can be used to evaluate garments that are worn with at
least part of the garment in good electrical contact with the skin of the wearer, either directly
or via conductive or dissipative undergarments. The test procedure described in the Appendix
of NT ELEC 037:2006 can be used to evaluate the ability of a garment to suppress surface
potential as charge is distributed over the garment and forms a capacitance with the grounded
body of the wearer. This test procedure is useful for evaluating garments that are worn over
other clothing that prevents good electrical contact with the body of the wearer.
6.4 Measurement of electrostatic discharges
Perhaps the greatest risk from charged garments is the possibility of an electrostatic
discharge (ESD) from the garment material itself, particularly when garments hang away from
the body of the wearer, or when they are removed. Such discharges can damage or disrupt
sensitive electrical or electronic components or systems and can cause the ignition of

TS 61340-4-2 © IEC:2013 – 13 –
flammable and explosive materials. One way to evaluate the risk of ESD from charged
garment materials is to generate, capture and measure ESD directly.
The test method described in NT ELEC 036 can be used to measure direct ESD from
garments and garment materials. A procedure is described for testing garment materials. Full
garments can be tested using the same basic procedure, using a suitable support for the
garment. Alternatively, measurements can be made on garments whilst they are worn.
The acceptance and rejection criteria specified in 6.9 of NT ELEC 036:2006 are only
applicable for garments intended for use in EPA where components or systems susceptible to
damage by ESD greater than or equal to 100 V human body model (HBM) are handled. For
other applications, the acceptance and rejection criteria shall be re-evaluated to ensure they
are valid for the applications in question.
NOTE Subclause 6.9 of NT ELEC 036:2006 states that the maximum measured peak current shall be less than
300 mA. For equivalence to 100 V human body model, the correct limit is 67 mA. Equivalence in respect to peak
current does not necessarily imply equivalence in other aspects of the discharge waveform.
6.5 Field suppression
One property of static control garments that is required in some applications is the ability to
attenuate the net electric field from any charged undergarments. In many cases, although
undergarments may charge by rubbing against the body or other clothing, the net field
remains close to zero because opposite polarity layers of charge are effectively balanced. In
other cases, either owing to asymmetric charging or to partial dissipation of charge from one
layer, a net charge may exist on undergarments; hence a net electric field will be present.
Test method 2 described in EN 1149-3:2004 can be used to evaluate the field suppression
properties of garments and garment materials.
NOTE EN 1149-3:2004, test method 2, is only concerned with the suppression of electric field associated with
static electric charge. It does not address other electromagnetic phenomena, e.g. electromagnetic interference
caused by ESD.
6.6 Tribocharging tests
6.6.1 General
Tribocharging is a useful means of generating charge on the surface of garments and garment
materials as a precursor to charge decay time measurements. It is also useful as a test
method in its own right, to evaluate the propensity of garments and garment materials to
acquire charge when contacting and rubbing against other materials. Even if materials have
low-charging properties they may still retain some charge for a significant period of time,
which can be measured using one or more of the methods described in 6.6.2 to 6.6.4.
In many applications, daily checks are made on static control items to ensure correct
functioning prior to use. For items that provide a conductive path to earth, simple resistance
measurements can be made. Examples include wristband or footwear check stations that are
required to be used before entering ESD controlled areas. Similar checks can be made on
garments that form part of the personnel earthing system. However, there are applications in
which garments are not part of the earthing system and are not required to be earthed, but
nevertheless are required to be low charging. A simple tribocharging test can be used as a
daily check for this type of garment.
Annex E describes simple tribocharging tests that can be used for daily checks on garments.
These simple tests are unlikely to be suitable for qualification purposes, but they can provide
a means of screening out garments that exhibit high levels of charging.
If the tests described in Annex E are used as a screening check prior to use, the tests shall
be carried out in a safe area where the generation of static electricity does not present a risk
to personnel, components or systems.

– 14 – TS 61340-4-2 © IEC:2013
6.6.2 Tribocharging by removal of garments
The propensity of garments and full garment assemblies to acquire charge when contacting
and rubbing against other materials can be evaluated using the method described in Annex A
or Clause C.2.
Although the removal of garments is generally prohibited in EPA and hazardous explosive
area, the test methods described in Annex A and Clause C.2 provide a relatively simple but
controlled procedure for tribocharging full garments and assemblies of garments.
6.6.3 Tribocharging the outer surface of garments
The propensity of garments and full garment assemblies to acquire charge when contacting
and rubbing against other materials can be evaluated using the method described in Clause
C.3.
6.6.4 Tribocharging using seats
The propensity of garments and full garment assemblies to acquire charge when contacting
and rubbing against other materials can be evaluated using the method described in Annex B.
The test method described in Annex B can be used as an alternative to that described in
Annex A for evaluating tribocharging in general. It can also be used to evaluate tribocharging
in specific applications that involve personnel and seats (e.g. car seats, fork lift truck seats,
work station chairs, etc.).
6.7 Clinging tests
The propensity for lightweight garment materials to acquire charge by tribocharging and the
ability for the materials to lose charge by surface leakage can be evaluated using a clinging
test method such as that described in AATCC Test Method 115.
The principle of the clinging test is to suspend a charged test specimen from the top edge of
an angled metal plate that is connected to earth. If the test specimen has acquired sufficient
charge after tribocharging, it will cling to the metal plate. As charge leaks away from the test
specimen through the earthed metal plate, there will come a time when there is insufficient
charge to cause the test specimen to cling and it will then hang freely. A measure of the test
material’s ability to dissipate charge can be obtained by recording the time taken for the test
specimen to stop clinging.
Clingi
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