EN 61340-4-7:2017

SLOVENSKI STANDARD
01-maj-2017
Elektrostatika - 4-7. del: Standardne preskusne metode za posebno uporabo -
Ionizacija (IEC 61340-4-7:2017)
Electrostatics - Part 4-7: Standard test methods for specific applications - Ionization (IEC
61340-4-7:2017)
Electrostatique - Partie 4-7: Méthodes d'essai normalisées pour des applications
spécifiques - Ionisation (IEC 61340-4-7:2017)
Ta slovenski standard je istoveten z: EN 61340-4-7:2017
ICS:
17.220.99 Drugi standardi v zvezi z Other standards related to
elektriko in magnetizmom electricity and magnetism
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61340-4-7

NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2017
ICS 17.200.99; 29.020
English Version
Electrostatics - Part 4-7: Standard test methods for specific
applications - Ionization
(IEC 61340-4-7:2017)
Électrostatique - Partie 4-7: Méthodes d'essai normalisées Elektrostatik - Teil 4-7: Standard-Prüfverfahren für spezielle
pour des applications spécifiques - Ionisation Anwendungen - Ionisation
(IEC 61340-4-7:2017) (IEC 61340-4-7:2017)
This European Standard was approved by CENELEC on 2017-02-10. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61340-4-7:2017 E
European foreword
The text of document 101/521/FDIS, future edition 2 of IEC 61340-4-7, prepared by IEC/TC 101
"Electrostatics" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
(dop) 2017-11-10
• latest date by which the document has to be implemented at
national level by publication of an identical national
standard or by endorsement
• latest date by which the national standards conflicting with (dow) 2020-02-10
the document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
Endorsement notice
The text of the International Standard IEC 61340-4-7:2017 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following note has to be added for the standard indicated :
IEC/TR 61340-5-2 NOTE Harmonized as CLC/TR 61340-5-2

IEC 61340-4-7 ®
Edition 2.0 2017-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Electrostatics –
Part 4-7: Standard test methods for specific applications – Ionization

Électrostatique –
Partie 4-7: Méthodes d'essai normalisées pour des applications spécifiques –

Ionisation
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.200.99; 29.020 ISBN 978-2-8322-3775-5

– 2 – IEC 61340-4-7:2017  IEC 2017
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Test fixture and instrumentation . 9
5 Specific requirements for equipment categories . 11
5.1 Specific requirements for all ionization equipment . 11
5.2 Room ionization . 12
5.3 Laminar flow hood ionization . 14
5.4 Work surface ionization . 16
5.5 Compressed gas ionizers – Guns and nozzles . 19
Annex A (informative) Theoretical background and additional information on the
standard test method for the performance of ionizers . 21
A.1 Introductory remarks . 21
A.2 Air ions . 21
A.3 Mobility and ion current . 21
A.4 Neutralization current . 21
A.5 Neutralization rate . 22
A.6 Ion depletion and field suppression . 22
A.7 Charged plate monitor and charge neutralization . 22
A.8 Relationship between charged plate monitor decay time and actual object . 23
A.9 Offset voltage . 23
A.10 Preparation of test area . 23
A.11 Ion transport in airflow . 24
A.12 Obstruction of airflow around the charged plate monitor . 24
A.13 Effect of “air blanket” . 24
A.14 Sources of measurement error . 25
A.14.1 Typical decay time variability . 25
A.14.2 Plate isolation . 25
A.14.3 Charging voltage . 25
A.14.4 Materials near the plate . 25
A.14.5 Other field-producing devices in test area . 25
A.14.6 Effect of offset voltage on decay time . 25
A.15 Importance of ionization equipment maintenance . 26
Annex B (normative) Method of measuring the capacitance of an isolated conductive

plate . 27
B.1 Method . 27
B.2 Equipment . 27
B.3 Procedure . 27
B.4 Example. 27
B.5 Sources of error . 28
B.5.1 Measuring equipment . 28
B.5.2 Poor plate isolation . 28
B.5.3 Objects in the environment . 29
B.5.4 Stray capacitance . 29
Annex C (informative) Safety considerations . 30

IEC 61340-4-7:2017  IEC 2017 – 3 –
C.1 General . 30
C.2 Electrical . 30
C.3 Ozone . 30
C.4 Radioactive . 30
C.5 X-ray . 30
C.6 Installation . 30
Bibliography . 31

Figure 1 – Charged plate monitor components for non-contacting plate measurement . 10
Figure 2 – Charged plate monitor components for contacting plate measurement . 10
Figure 3 – Conductive plate detail for the non-contacting CPM . 11
Figure 4 – Conductive plate detail for the voltage follower CPM . 11
Figure 5 – Test locations for room ionization – AC grids and DC bar systems . 13
Figure 6 – Test locations for room ionization – Single polarity emitter systems . 13
Figure 7 – Test locations for room ionization – Dual DC line systems . 14
Figure 8 – Test locations for room ionization – Pulsed DC emitter systems . 14
Figure 9 – Test locations for vertical laminar flow hood – Top view . 15
Figure 10 – Test locations for vertical laminar flow hood – Side view . 15
Figure 11 – Test locations for horizontal laminar flow hood – Top view . 16
Figure 12 – Test locations for horizontal laminar flow hood – Side view . 16
Figure 13 – Test locations for benchtop ionizer – Top view . 17
Figure 14 – Test locations for benchtop ionizer – Side view . 18
Figure 15 – Test locations for overhead ionizer – Top view . 18
Figure 16 – Test locations for overhead ionizer – Side view . 19
Figure 17 – Test locations for compressed gas ionizer (gun or nozzle) – Side view . 20

Table 1 – Test set-ups and test locations/points (TP) . 12
Table B.1 – Example measurement data . 28

– 4 – IEC 61340-4-7:2017  IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROSTATICS –
Part 4-7: Standard test methods for specific applications –
Ionization
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
in the subject dealt with may participate in this preparatory work. International, governmental and non-
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
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
members of its technical committees and IEC National Committees for any personal injury, property damage or
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 61340-4-7 has been prepared by IEC technical committee 101:
Electrostatics.
This second edition cancels and replaces the first edition, published in 2010, and constitutes
a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– the use of contacting plate voltage measurements in addition to the previous non-
contacting plate voltage measurements has been added. Charged plate monitors (CPMs)
using this technology have been in use in the industry for many years.

IEC 61340-4-7:2017  IEC 2017 – 5 –
The text of this standard is also based on the following documents:
FDIS Report on voting
101/521/FDIS 101/524/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.
A list of all 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.
– 6 – IEC 61340-4-7:2017  IEC 2017
INTRODUCTION
Grounding is the primary method used to limit static charge when protecting electrostatic
discharge sensitive items in the work environment. However, grounding methods are not
effective in removing static charges from the surfaces of non-conductive (insulative) or
isolated conductive materials. Air ionization techniques, by means of ionizer systems, can be
utilized to reduce this charge.
The preferred way of evaluating the ability of an ionizer to neutralize a static charge is to
directly measure the rate of charge decay. Charges to be neutralized may be located on
insulators as well as on isolated conductors. It is difficult to charge an insulator reliably and
repeatably. Charge neutralization is more easily evaluated by measuring the rate of decay of
the voltage of an isolated conductive plate. The measurement of this decay should not
interfere with or change the nature of the actual decay. Four practical methods of air
ionization are addressed in this document:
a) radioactive emission;
b) high-voltage corona from a.c. electric fields;
c) high-voltage corona from d.c. electric fields;
d) soft X-ray emission.
This part of IEC 61340 provides test methods and procedures that can be used when
evaluating ionization equipment. The objective of the test methods is to generate meaningful,
reproducible data. The test methods are not meant to be a recommendation for any particular
ionizer configuration. The wide variety of ionizers, and the environments within which they are
used, will often require test methods different from those described in this document. Users of
this document should be prepared to adapt the test methods as required to produce
meaningful data in their own application of ionizers.
Similarly, the test conditions chosen in this document do not represent a recommendation for
acceptable ionizer performance. There is a wide range of item sensitivities to static charge.
There is also a wide range of environmental conditions affecting the operation of ionizers.
Performance specifications should be agreed upon between the user and manufacturer of the
ionizer in each application. Users of this document should be prepared to establish
reasonable performance requirements for their own application of ionizers.
Annex B provides a method for measuring capacitance of the isolated conductive plate.

IEC 61340-4-7:2017  IEC 2017 – 7 –
ELECTROSTATICS –
Part 4-7: Standard test methods for specific applications –
Ionization
1 Scope
This part of IEC 61340 provides test methods and procedures for evaluating and selecting air
ionization equipment and systems (ionizers).
This document establishes measurement techniques, under specified conditions, to determine
offset voltage (ion balance) and decay (charge neutralization) time for ionizers.
This document does not include measurements of electromagnetic interference (EMI), or the
use of ionizers in connection with ordnance, flammables, explosive items or electrically
initiated explosive devices.
As contained in this document, the test methods and test conditions can be used by
manufacturers of ionizers to provide performance data describing their products. Users of
ionizers are urged to modify the test methods and test conditions for their specific application
in order to qualify ionizers for use, or to make periodic verifications of ionizer performance.
The user will decide the extent of the data required for each application.
CAUTION: Procedures and equipment described in this document can expose personnel to hazardous electrical
and non-electrical conditions. Users of this document are responsible for selecting equipment that complies with
applicable laws, regulatory codes and both external and internal policy. Users are cautioned that this document
cannot replace or supersede any requirements for personnel safety.
2 Normative references
There are no normative references in this document.
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:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
air conductivity
ability of air to conduct (pass) an electric current under the influence of an electric field
3.2
air ions
molecular clusters of about ten molecules (water, impurities, etc.) bound by polarization
forces to a singly charged oxygen or nitrogen molecule

– 8 – IEC 61340-4-7:2017  IEC 2017
3.3
charge decay
decrease and/or neutralization of a net electrostatic charge
3.4
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 applies to the French language only.
3.5
compressed gas ionizer
ionization device that can be used to neutralize charged surfaces and/or remove surface
particles with pressurized gas
Note 1 to entry: This type of ionizer may be used to ionize the gas within production equipment.
3.6
corona
production of positive or negative ions by a very localized high electric field
Note 1 to entry: The field is normally established by applying a high voltage to a conductor in the shape of a
sharp point or wire.
3.7
decay rate
decrease of charge or voltage per unit time
3.8
decay time
time necessary for a voltage (due to an electrostatic charge) to decay from an initial value to
some chosen final value
3.9
emitter
conducting sharp object, usually a needle or wire, which will cause a corona discharge when
kept at a high potential
3.10
horizontal laminar flow
non-turbulent airflow in a horizontal direction
3.11
ionizer
device designed to generate positive and/or negative air ions
3.12
isolated conductor
non-grounded conductor
3.13
laminar flow hood ionization
device or systems that provide local area ionization coverage in vertical or horizontal laminar
flow hoods or benches
IEC 61340-4-7:2017  IEC 2017 – 9 –
3.14
non-contacting voltage measurement
measurement technique using an electrostatic fieldmeter or voltmeter to monitor the voltage
induced on an isolated conductive plate where there is no direct connection from the
measurement sensor to the isolated conductive plate
3.15
offset voltage
ion balance
observed voltage on the isolated conductive plate of a charged plate monitor (CPM) that has
been placed in an ionized environment
3.16
peak offset voltage
for pulsed ionizers, maximum value of the offset voltage for each polarity, as the ionizer
cycles between positive and negative ion outputs
3.17
room ionization
ionization systems that provide large area coverage with air ions
3.18
work surface ionization
ionization devices or systems used to control static charges at a work surface
Note 1 to entry: This type includes benchtop ionizers, overhead work surface ionizers and laminar flow hood
ionizers.
3.19
vertical laminar flow
non-turbulent airflow in a vertical direction
3.20
contacting voltage measurement
measurement technique using high input impedance circuitry used to monitor the voltage
induced on an isolated conductive plate where there is a direct connection from the circuitry to
the conductive plate
4 Test fixture and instrumentation
4.1 The instrument described in this document to make performance measurements on air
ionization equipment is the charged plate monitor (CPM); refer to Figure 1 and Figure 2. The
conductive plate shall be (15,0 ± 0,1) cm × (15,0 ± 0,1) cm and the total capacitance of the
test circuit, with plate, while the instrument is in its normal operating mode, shall be
20 pF ± 2 pF (refer to Annex B). See Figure 3 and Figure 4. The instrument described in this
document may also be used for compliance verification of air ionizers.
4.2 For the isolated conductive plate design shown in Figure 3, there shall be no objects,
grounded or otherwise, closer than dimension "A" of the conductive plate, except the
supporting insulators or plate voltage contacts, as shown in Figure 3 (refer to Annex B). For
the conductive plate assembly shown in Figure 4, there shall be no objects, grounded or
otherwise, within 2,54 cm of the plate assembly in any direction, other than a support
structure (e.g. a tripod) located below the ground plate of the assembly.
4.3 The conductive plate, when charged to the desired test voltage, shall not decay more
than 10 % of the test voltage within 5 min, in the absence of ionization.

– 10 – IEC 61340-4-7:2017  IEC 2017
4.4 The voltage on the conductive plate shall be monitored in such a way that the system
conforms to 4.1, 4.2 and 4.3. The response time of the monitoring device shall be sufficient to
accurately measure changing plate voltages.
For safety reasons (see Clause C.1), the voltage source used to charge the plate should be
current limited.
Probe
See NOTE
Switch
Conductive plate
Insulator
Ground plate
Ground
High voltage
power supply -
current limited
Non-contacting
voltmeter or
electrometer
Decay timer
IEC
NOTE See Figure 3.
Figure 1 – Charged plate monitor components for non-contacting plate measurement
+HV
Threshold
A/D detector and
decay timer
20pF –HV
–HV +HV
IEC
Figure 2 – Charged plate monitor components for contacting plate measurement

IEC 61340-4-7:2017  IEC 2017 – 11 –
(15,0 ± 0,1) cm × (15,0 ± 0,1) cm
Conductive plate
Dimension A
Insulator
Ground plate
Ground
≥ 15 cm
IEC
Figure 3 – Conductive plate detail for the non-contacting CPM
(15,0 ± 0,1) cm × (15,0 ± 0,1) cm
Conductive plate assembly
Insulator
Driven shield
Insulator
Ground plate
≥ 15 cm
IEC
Figure 4 – Conductive plate detail for the voltage follower CPM
5 Specific requirements for equipment categories
5.1 Specific requirements for all ionization equipment
For the types of ionization equipment listed in 5.2, 5.3, 5.4 and 5.5, the following specific
requirements apply:
a) Decay time test – The conductive plate of the test fixture shall be charged to an initial test
voltage and allowed to decay to 10 % of the initial test voltage. The time required shall be
monitored and recorded for both polarities of initial charge. This time is referred to as the
decay time (refer to 4.1 and Figure 1).
b) Offset voltage test – The conductive plate shall be momentarily grounded to remove any
residual charges and to verify zero of the voltage monitoring device. The plate is then
monitored within the ionized environment, per the procedure described for each
equipment category. The resulting observed voltage is referred to as the offset voltage.
c) Locations – The decay time and offset voltage shall be measured for each test
location/point (TP) described in the test location figures (see Table 1).
d) Same conditions – Decay time and offset voltage shall be measured under the same
conditions without any equipment adjustments. If ionizers from different categories are to
be compared, the same test voltages shall be used for all tests.
e) Peak offset voltage – In the case of pulsed ionizers, offset voltage shall be measured and
reported in peak values using the test equipment described in 4.1.
f) Other parameters – Application specific parameters such as humidity, temperature, air
speed, etc., shall be recorded.

– 12 – IEC 61340-4-7:2017  IEC 2017
Table 1 – Test set-ups and test locations/points (TP)
Charged plate
Offset voltage
Equipment Figure Number of test initial voltage
measurement
category references locations (both polarities)
time interval
V
Room ionization
Grids, AC 5 2 (1 to 5) min 1 000
Bars, pulsed and DC 5 2 (1 to 5) min 1 000
Single polarity emitter 6 3 (1 to 5) min 1 000
Dual DC line 7 3 (1 to 5) min 1 000
Pulsed DC emitter 8 2 (1 to 5) min 1 000
Laminar flow hood
Vertical 9 and 10 8 (1 to 5) min 1 000
Horizontal 11 and 12 6 (1 to 5) min 1 000
Work surface ionization
Benchtop 13 and 14 12 (1 to 5) min 1 000
Overhead 15 and 16 12 (1 to 5) min 1 000
Compressed gas ionization
Guns and nozzles 17 1 10 s to 1 min 1 000

5.2 Room ionization
5.2.1 The area around the charged plate monitor should be cleared for a horizontal
distance of 1,5 m in all directions. The ionization system should be operated for a minimum of
30 min to stabilize conditions in the test area.
5.2.2 To avoid affecting the test, the test technician should be grounded and stand outside
the 1,5 m cleared area.
5.2.3 Decay time from a 1 000 V initial voltage to a 100 V final voltage shall be measured
for both positive (+) and negative (-) polarities.
5.2.4 The air speed at the test location shall be recorded.
5.2.5 Measurements should be taken with the charged plate monitor at a distance of 1,5 m
from the ionizer under test. Since installed ionizer heights can vary, a consistent
measurement height should be selected for the evaluation of different systems. This height
and the ionizer mounting height shall be recorded in the test results.
5.2.6 The minimum number of test locations is determined by the type of system (see
Table 1 and refer to Figures 5 through 8.)
5.2.7 Decay time as described in 5.1, point a), shall be measured at each test location.
Offset voltage as described in 5.1, points b) and e) shall be determined at each test location.
Offset voltage shall be measured after a period of at least 1 min to allow the reading to
stabilize (5 min maximum).
IEC 61340-4-7:2017  IEC 2017 – 13 –
Charged plate
DC bars (or) AC grids
TP1
TP2
IEC
NOTE 1 Example for AC grids (shaded areas, less than 100 % coverage) and pulsed or steady-state DC bars.
NOTE 2 TP1 is directly under grid or bar while TP2 is centred between grids or bars.
Figure 5 – Test locations for room ionization – AC grids and DC bar systems
Charged plate Emitter
TP1
TP3
TP2
IEC
Three measurement locations required.
Figure 6 – Test locations for room ionization – Single polarity emitter systems

– 14 – IEC 61340-4-7:2017  IEC 2017
Charged plate Emitter
TP1
TP2
TP3
IEC
Three measurement locations required.
Figure 7 – Test locations for room ionization – Dual DC line systems
Charged plate Emitter
TP1
TP2
IEC
Two measurement locations required.
Figure 8 – Test locations for room ionization – Pulsed DC emitter systems
5.3 Laminar flow hood ionization
5.3.1 The test should be performed on a surface that does not contain obstructions to
airflow. Unless otherwise specified, the test surface should be static dissipative or conductive
and properly grounded.
5.3.2 To avoid affecting the test, the test technician should be properly grounded.
5.3.3 Decay time from a 1 000 V initial voltage to a 100 V final voltage shall be measured
for both positive (+) and negative (-) polarities.
5.3.4 The air speed at test location TP4, as shown in Figures 9 and 11, should be
recorded.
5.3.5 For a vertical laminar flow hood, the test set-up is shown in Figures 9 and 10. Data
shall be taken at test positions TP1 through TP8 as shown in Figure 9.

IEC 61340-4-7:2017  IEC 2017 – 15 –
5.3.6 For a horizontal laminar flow hood, the test set-up is shown in Figures 9 and 10. Data
shall be taken at test positions TP1 through TP6 as shown in Figure 11.
5.3.7 Decay time as described in 5.1, point a), shall be measured at each test location.
5.3.8 Offset voltage as described in 5.1, points b) and e) shall be determined at each test
location. Offset voltage shall be measured after a period of at least 1 min, or as necessary to
allow the reading to stabilize (5 min maximum).
15 cm 15 cm
Rear
TP6 TP7
Centre line
TP3 TP4 TP5
of test points
Charged plate
TP1 TP8 TP2
Front edge
Centre line
of test points
IEC
Eight measurement locations required, all dimensions nominal.
Figure 9 – Test locations for vertical laminar flow hood – Top view
HEPA filter
Ionizing grid or bar
Charged plate
IEC
All dimensions nominal.
Figure 10 – Test locations for vertical laminar flow hood – Side view

15 cm
Air flow
60 cm
15 cm
– 16 – IEC 61340-4-7:2017  IEC 2017
15 cm 15 cm
Rear
HEPA filter
Ionizing grid or bar
TP3 TP4 TP5
Charged plate
TP1 TP6 TP2
Front edge
Centre line
of test points
IEC
Six measurement locations required, all dimensions nominal.
Figure 11 – Test locations for horizontal laminar flow hood – Top view
38 cm
Charged plate
Air flow
Rear
IEC
All dimensions nominal.
Figure 12 – Test locations for horizontal laminar flow hood – Side view
5.4 Work surface ionization
5.4.1 The test should be performed on a surface that does not contain obstructions to
airflow. Unless otherwise specified the test surface should be static dissipative or conductive
and properly grounded.
5.4.2 To avoid affecting the test, the test technician should be properly grounded.
15 cm
Air flow
Ionizing grid or bar
38 cm
HEPA filter
IEC 61340-4-7:2017  IEC 2017 – 17 –
5.4.3 Decay time from a 1 000 V initial voltage to a 100 V final voltage shall be measured
for both positive (+) and negative (-) polarities.
5.4.4 The unit shall be measured with the heater on and off, if so equipped. The unit shall
be tested with any filters in place if so equipped. Measurements shall be made at both
minimum and maximum airflows for units with variable airflow. The air speed shall be
measured and included in the test results. End users should test ionizers with the same
configuration of operating heaters and filters that they intend to use.
5.4.5 For benchtop units, the ionizer shall be placed as shown in Figures 13 and 14.
Airflow shall be directed at test location TP2 and measured at test locations TP2 and TP5.
The charged plate monitor shall face the ionizer. Measurements with the charged plate
monitor shall be made at test locations TP1 through TP12 as shown in Figure 13.
5.4.6 For overhead units, the ionizer shall be placed as shown in Figures 15 and 16.
Airflow shall be measured at test locations TP5 and TP8. Measurements with the charged
plate monitor shall be made at test locations TP1 through TP12 as shown in Figure 15.
5.4.7 Decay time as described in 5.1, point a), shall be measured at each test location.
5.4.8 Offset voltage as described in 5.1, points b) and e) shall be determined at each test
location. Offset voltage shall be measured after a period of at least 1 min, or as necessary to
allow the reading to stabilize (5 min maximum).
Charged plate
TP1 TP4 TP7 TP10
TP2 TP5 TP8 TP11
Air flow
TP3 TP6 TP9 TP12
30 cm 30 cm 30 cm 30 cm
IEC
Twelve measurement locations required, all dimensions nominal.
Figure 13 – Test locations for benchtop ionizer – Top view
Bench top
ionizer
30 cm 30 cm
– 18 – IEC 61340-4-7:2017  IEC 2017
Charged plate
Bench top
Air flow
ionizer
IEC
All dimensions nominal.
Figure 14 – Test locations for benchtop ionizer – Side view
Overhead ionizer centred
Charged plate
above test area
TP1 TP4 TP7 TP10
TP2 TP5 TP8 TP11
TP3 TP6 TP9 TP12
40 cm 40 cm 40 cm
IEC
Twelve measurement locations required, all dimensions nominal.
Figure 15 – Test locations for overhead ionizer – Top view
30 cm 30 cm
15 cm
IEC 61340-4-7:2017  IEC 2017 – 19 –
Centre line
of test points
60 cm
Overhead ionizer
Charged plate
IEC
All dimensions nominal.
Figure 16 – Test locations for overhead ionizer – Side view
5.5 Compressed gas ionizers – Guns and nozzles
5.5.1 The test should be performed on a surface that does not contain obstructions to
airflow. Unless otherwise specified, the test surface should be static dissipative or conductive
and properly grounded.
5.5.2 To avoid affecting the test, the test technician should be properly grounded.
5.5.3 Decay time from a 1 000 V initial voltage to a 100 V final voltage shall be measured
for both positive (+) and negative (-) polarities.
5.5.4 Unless otherwise specified, the input pressure shall be 200 kPa. End users should
test compressed gas ionizers in the same configuration of input pressure and distance that
they intend to use.
5.5.5 The tests shall be performed using the test set-up shown in Figure 17.
5.5.6 Decay time as described in 5.1, point a), shall be measured at the test location.
5.5.7 Offset voltage as described in 5.1, points b) and e) shall be determined at the test
location. Offset voltage shall be measured after a period of at least 10 s or as necessary to
allow the reading to stabilize (1 min maximum).
Air flow
15 cm 45 cm
– 20 – IEC 61340-4-7:2017  IEC 2017
Charged plate
15 cm
Gas flow
IEC
One measurement location required, all dimensions nominal.
Figure 17 – Test locations for compressed gas ionizer (gun or nozzle) – Side view

15 cm
IEC 61340-4-7:2017  IEC 2017 – 21 –
Annex A
(informative)
Theoretical background and additional information on
the standard test method for the performance of ionizers
A.1 Introductory remarks
The field from static charges, located on insulators or isolated conductors, can be neutralized
by oppositely charged air ions depositing on the charged bodies.
A.2 Air ions
Air ions are molecular clusters consisting of about ten molecules (often water) around a
(singly) charged oxygen or nitrogen molecule. Normally, relatively few ions are present in the
air. Typically, the number is less than 1 000 per cm . These "natural" ions are usually formed
by radiation from radioactive materials in the air, in the ground or in building materials.
For neutralization purposes, much higher ion concentrations are needed. Although
radioactivity can also be employed in such situations, the most common ion production
method is by collision between neutral molecules and electrons accelerated in an electric field
with field strengths exceeding 3 MV/m (at atmospheric pressure). This is generally referred to
as high voltage corona ionization.
A.3 Mobility and ion current
If an ion is exposed to an electric field E, it will move with an average drift speed (v)
proportional to E, i.e.
v = kE (A.1)
where k = the mobility of the ion.
–4 2 –1 –1 2
Ordinary air ions have mobilities in the range of 1 to 2 × 10 m V s (metre per volt-
second).
If the air has a concentration n of positive ions with the mobility k, and charge e, an electric
field E will cause an electric current to flow in the direction of E with the density j.
j = enkE = λ E (A.2)
The constant λ (enk) is called the positive conductivity of the air (or more precisely, the polar
conductivity due to the positive ions). Negative ions will move in the opposite direction of the
field, but Equation (A.2) can still be used to calculate the current density from negative ions,
when e is taken as the numerical value of the ion charge. The current density from negative
ions will thus also be in the direction of the field.
A.4 Neutralization current
If a body completely surrounded by ionized air is given a charge q, an electric field is
established around the body and charges will flow towards it and away from it. The field will
vary from point to point, but is always proportional to the charge q. The current towards the
body is carried by the ions of polarity opposite to that of q, and is known as the neutralization

– 22 – IEC 61340-4-7:2017  IEC 2017
current. The neutralization current is proportional to the charge q and to the relevant opposite
conductivity of the surrounding air.
A.5 Neutralization rate
If the conductivity does not change, the relative rate of charge neutralization is constant and
the charge will decay exponentially with a time constant τ equal to the permittivity of the air e
o
divided by the conductivity λ.
τ = e /λ (A.3)
o
It should be noted that it is the conductivity not the ion concentration itself that determines the
neutralizing ability of the air. If the particle concentration of the air is increased, by smoke for
example, the average mobility of the ions, and thus the conductivity, can decrease by a factor
of ten or more. The number of charged particles per unit volume of air, i.e. the ion
concentration, can still be more or less constant.
A.6 Ion depletion and field suppression
The conditions for fulfilling Equation (A.3) are almost never met.
It was assumed that the conductivity was not affected by the neutralization process. In the
case of room ionization, for example, the field from th
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