IEC 60704-2-9:2024

IEC 60704-2-9 ®
Edition 2.0 2024-06
EXTENDED VERSION
INTERNATIONAL
STANDARD
colour
inside
This extended version of IEC 60704-2-9:2024 includes the content of the references made to
IEC 60704-1:2021
Household and similar electrical appliances – Test code for the determination of
airborne acoustical noise –
Part 2-9: Particular requirements for electric hair care appliances
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IEC 60704-2-9 ®
Edition 2.0 2024-06
EXTENDED VERSION
INTERNATIONAL
STANDARD
colour
inside
This extended version of IEC 60704-2-9:2024 includes the content of the references made to
IEC 60704-1:2021
Household and similar electrical appliances – Test code for the determination of
airborne acoustical noise –
Part 2-9: Particular requirements for electric hair care appliances
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 97.170, 17.140.20 ISBN 978-2-8322-9163-4

– 2 – IEC 60704-2-9:2024 EXV © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION to 60704-1:2021 . 7
INTRODUCTION to 60704-2-9:2024 . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Measurement methods and acoustical environments . 10
4.1 General . 10
4.2 Direct method . 11
4.3 Comparison method . 11
4.4 Acoustical environments . 12
4.4.1 General requirements and criterion for adequacy of the test
environment . 12
4.4.2 Criterion for background noise level . 12
4.4.3 Environmental conditions . 12
4.5 Measurement uncertainties . 12
4.5.1 General . 12
4.5.2 Standard deviations on repeatability and reproducibility and standard
deviations related to declaration and verification . 13
5 Instrumentation . 13
5.1 Instrumentation for measuring acoustical data . 13
5.2 Instrumentation for measuring climatic conditions . 13
5.3 Instrumentation for measuring operating conditions . 13
6 Operation and location of appliances under test . 14
6.1 Equipping and pre-conditioning of appliances . 14
6.2 Supply of electric energy and of water or gas . 14
6.3 Climatic conditions . 15
6.4 Loading and operating of appliances during tests . 15
6.5 Location and mounting of appliances . 15
7 Measurement of sound pressure levels . 18
7.1 Microphone array, measurement surface and RSS location for essentially
free field conditions over reflecting plane(s) . 18
7.2 Microphone array and RSS location in hard-walled test rooms . 21
7.3 Microphone array and RSS location in special reverberation test rooms . 21
7.4 Measurements . 22
8 Calculation of sound pressure and sound power levels . 22
8.1 General . 22
8.2 Corrections for background noise levels . 22
8.3 Corrections for the test environment . 23
8.4 Calculation of sound pressure level averaged over the microphone positions . 23
8.5 Calculation of sound power levels with the comparison method . 24
8.6 Calculation of sound power levels in free field conditions over a reflecting
plane . 24
8.7 Calculation of A-weighted sound power level with the direct method in
special reverberation test rooms . 25
9 Information to be recorded . 25
9.1 General data . 25

9.2 Description of appliance under test . 25
9.3 Measurement method . 26
9.4 Acoustical test environment . 26
9.5 Instrumentation . 26
9.6 Equipment and pre-conditioning of appliance under test . 26
9.7 Electric supply, water supply, etc. . 26
9.8 Climatic conditions . 26
9.9 Operation of the appliance under test . 27
9.10 Location and mounting of the appliance under test. 27
9.11 Microphone array . 27
9.12 Measurement data . 27
9.13 Calculated sound pressure and sound power levels . 28
9.14 Reporting . 28
10 Information to be reported . 28
10.1 General data . 28
10.2 Appliance under test . 28
10.3 Test conditions for the appliance . 28
10.4 Acoustical data . 29
Annex A (normative) Standard test table . 30
Annex B (normative) Test enclosure . 31
Annex C (informative) Guidelines for the design of simple test rooms with essentially
free field conditions. 32
Bibliography . 33

Figure 1 – Measurement surface – parallelepiped – with key microphone positions, for
floor free-standing appliances . 18
Figure 2 – Measurement surface – parallelepiped – with key microphone positions, for

floor standing appliances placed against a wall . 19
Figure 4 – Measurement surface – hemisphere – with key microphone positions, for
hand-held, table type and floor-treatment appliances . 20
Figure B.1 – Test enclosure . 31

Table 1 – Standard deviations of sound power levels . 13
Table 2 – Standard deviations for declaration and verification . 13

– 4 – IEC 60704-2-9:2024 EXV © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
TEST CODE FOR THE DETERMINATION OF
AIRBORNE ACOUSTICAL NOISE –
Part 2-9: Particular requirements for electric hair care appliances

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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This extended version (EXV) of the official IEC Standard provides the user with the
comprehensive content of the Standard.
made to IEC 60704-1:2021.
The specific content of IEC 60704-2-9:2024 is displayed on a blue background.

IEC 60704-2-9 has been prepared by subcommittee 59L: Small household appliances, of IEC
technical committee 59: Performance of household electrical appliances. It is an International
Standard.
This second edition cancels and replaces the first edition published in 2003. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Alignment with IEC 60704-1:2021.
The text of this International Standard is based on the following documents:
Draft Report on voting
59L/239/CDV 59L/253/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement,
available at www.iec.ch/members_experts/refdocs. The main document types developed by
IEC are described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 60704 series, published under the general title Household and
similar electrical appliances – Test code for the determination of airborne acoustical noise,
can be found on the IEC website.
This part 2-9 is intended to be used in conjunction with the fourth edition of IEC 60704-
1:2021: Household and similar electrical appliances – Test code for the determination of
airborne acoustical noise – Part 1: General requirements.
The relevant text of IEC 60704-1:2021 as amended by this standard establishes the test code
for electric hair care appliances.
This document supplements or modifies the corresponding clauses in IEC 60704-1:2021.
When a particular subclause of IEC 60704-1:2021 is not mentioned in this document, that
subclause applies as far as reasonable. Where this standard states "addition", "modification"
or "replacement", the relevant requirements, test specification or explanatory matter in
IEC 60704-1:2021 is adapted accordingly.
Subclauses or figures which are additional to those in IEC 60704-1:2021 are numbered
starting from 101. Additional annexes are lettered AA, BB, etc.

– 6 – IEC 60704-2-9:2024 EXV © IEC 2024
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IMPORTANT – The "colour inside" logo on the cover page of this document 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.
INTRODUCTION to 60704-1:2021
Although the noise emitted by household appliances does not generally present a hazard to
the hearing of the operator and other exposed persons, the need for standardization
procedures for the determination of the noise emitted has been recognized for a long time.
Such procedures should be specified, not only for special types of appliances, but also the
principles should be applicable to the majority of appliances in general use.
Generally, the determination of noise levels is only part of a comprehensive testing procedure
covering many aspects of the properties and performances of the appliance. It is therefore
important that the requirements for noise measurements (such as test environment,
instrumentation, and amount of labour involved) be kept at a modest level.
The results of noise measurements are used for many purposes, for example for noise
declaration, as well as for comparing the noise emitted by a specific appliance to the noise
emitted by other appliances of the same family. In other cases, the results are taken as a
basis for engineering action in the development stages of new pieces of equipment, or in
deciding on means for sound insulation. For all purposes, it is important to specify procedures
with known accuracy so that the results of measurements taken by different laboratories can
be compared.
These conditions have, as far as possible, been taken into account in the preparation of this
test code. The acoustic measuring methods are based on those described in
ISO 3743‑1:2010, ISO 3743-2:2018 and ISO 3744:2010.
The adoption of these methods permits the use of hemi-anechoic rooms, special reverberation
test rooms and hard-walled test rooms. The result of the measurements is the sound power
level of the appliance. Within the measuring uncertainty specific to these methods, the results
from the determination under free field conditions over a reflecting plane are equal to those
obtained in reverberant fields.
The use of intensity methods as described in ISO 9614-1:1993, ISO 9614-2:1996, and
ISO 9614-3:2002 is applicable under special conditions, which are described in specific parts
of the IEC 60704-2 series.
This test code is concerned with airborne noise only. In some cases, structure-borne noise,
for example transmitted to the adjoining room, can be of importance.
INTRODUCTION to 60704-2-9:2024
The measuring conditions specified in this document provide for sufficient accuracy in
determining the noise emitted and comparing the results of measurements taken by different
laboratories, whilst simulating as far as possible the practical use of hair care appliances.
It is recommended to consider the determination of noise levels as part of a comprehensive
testing procedure covering many aspects of the properties and performance of electric hair
care appliances.
NOTE As stated in the introduction to IEC 60704-1, this test code is concerned with airborne noise only.

– 8 – IEC 60704-2-9:2024 EXV © IEC 2024
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
TEST CODE FOR THE DETERMINATION
OF AIRBORNE ACOUSTICAL NOISE –

Part 1: General requirements
1 Scope
This part of IEC 60704 applies to electric hand-held hairdryers for household and similar use
supplied from mains, which operate with a flow of air.
These particular requirements can also be applied to analogous electrically operated devices
such as hairstyling appliances, which produce the airflow by a fan.
Helmet-type hairdryers are excluded from this document.
This document does not apply to hair care appliances with radiant heating.
For determining and verifying noise emission values declared in product specifications, see
IEC 60704-3.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 60704-2 (all parts), Household and similar electrical appliances – Test code for the
determination of airborne acoustical noise
IEC 60704-3:2019, Household and similar electrical appliances – Test code for the
determination of airborne acoustical noise – Part 3: Procedure for determining and verifying
declared noise emission values
IEC 61260-1:2014, Electroacoustics – Octave-band and fractional-octave-band filters – Part 1:
Specifications
IEC 61672-1:2013, Electroacoustics – Sound level meters – Part 1: Specifications
ISO 3743-1:2010, Acoustics – Determination of sound power levels of noise sources –
Engineering methods for small, movable sources in reverberant fields – Part 1: Comparison
method for hard-walled test rooms
ISO 3743-2:2018, Acoustics – Determination of sound power levels of noise sources using
sound pressure – Engineering methods for small, movable sources in reverberant fields –
Part 2: Methods for special reverberation test rooms
ISO 3744:2010, Acoustics – Determination of sound power levels of noise sources using
sound pressure – Engineering method in an essentially free field over a reflecting plane

ISO 9614-1:1993, Acoustics – Determination of sound power levels of noise sources using
sound intensity – Part 1: Measurement at discrete points
ISO 9614-2:1996, Acoustics – Determination of sound power levels of noise sources using
sound intensity – Part 2: Measurement by scanning
ISO 9614-3:2002, Acoustics – Determination of sound power levels of noise sources using
sound intensity – Part 3: Precision method for measurement by scanning
ISO 6926:2016, Acoustics – Requirements for the performance and calibration of reference
sound sources used for the determination of sound power levels
ISO 12001:1996, Acoustics – Noise emitted by machinery and equipment – Rules for the
drafting and presentation of a noise test code
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. Terms and
definitions pertinent to the determination of sound power levels can be found in ISO 3743-
1:2010, ISO 3743-2:2018 and ISO 3744:2010.
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
measurement time interval
portion or a multiple of an operational period or operational cycle for which the sound power
levels are determined
3.2
operational period
interval of time during which a specified process is accomplished by the appliance under test
(for example, washing or rinsing or drying for a dishwasher)
3.3
operational cycle
specific sequence of operational periods occurring while the appliance under test performs a
complete work cycle
Note 1 to entry: During the operational cycle, each operational period is associated with a specific process that
can occur only once, or can be repeated (for example, washing and rinsing and drying for a dishwasher).
3.4
time history
continuous recording of the sound pressure level (for a distinct microphone position) as a
function of time, which is obtained during one or more operational periods of an operational
cycle
3.5
reference box
hypothetical right parallelepiped terminating on the reflecting plane(s) on which the noise
source under test is located, that just encloses the source including all the significant sound
radiating components and any test table on which the source is mounted
[SOURCE: ISO 3744:2010, 3.10, modified – The note has been omitted.]

– 10 – IEC 60704-2-9:2024 EXV © IEC 2024
3.6
test enclosure
enclosure used for simulating the typical acoustic built-in or/and mounting conditions
3.101
hand-held hairdryer
hairdryer which is held by hand during normal permanent use
3.102
hairstyling appliance
appliance for styling and/or curling hairs
Note 1 to entry: Hair styling appliances can comprise brushes and combs.
3.103
helmet-type hairdryer
hairdryer, in which the drying is performed under a rigid or flexible hood
4 Measurement methods and acoustical environments
4.1 General
This document is concerned with objective methods of engineering accuracy grade 2 in
accordance with ISO 12001:1996 for determining sound power levels L , expressed in
W
decibels (dB), with reference to a sound power of one picowatt (1 pW), of airborne acoustical
noise within the specified frequency range of interest (generally including the octave-bands
with centre frequencies from 125 Hz to 8 000 Hz), and for prescribed operating conditions of
the appliance to be measured.
Methods for determining sound power levels with precision accuracy grade 1 in accordance
with ISO 12001:1996, as specified for example in ISO 3741 and ISO 3745, are not included in
this document. They may, however, be applied if the appropriate test environment and
instrumentation are available.
NOTE 1 The noise values obtained under the described conditions of this document will not necessarily
correspond to the noise experienced under the operational conditions of practical use.
NOTE 2 For quality control during production etc., simplified methods can be appropriate. For noise reduction
purposes, other measurement methods employing, for example, narrow-band analysis or intensity techniques
usually have to be applied. These methods are not covered by this document.
The total noise emitted by machinery or equipment and radiated in all directions to the space
surrounding the machine can be characterized by the sound power of the machine. Within the
accuracy range of this document, the sound power of a machine is basically independent of
the environment in which the machine is installed
Therefore, the concept of sound power level has been chosen for expressing the noise
emission of appliances for household and similar purposes.
The preferred noise emission quantity is the A-weighted sound power level, L , in dB
WA
(re 1 pW).
According to this document, two principal methods exist, the direct method and the
comparison method, as described in 4.2 and 4.3. These two methods can be used
alternatively.
Different types of environments, as described in 4.4, may be used. A part of the IEC 60704-2
series may, if necessary, exclude one or several combinations among those available.

4.2 Direct method
The direct method can be used only for measurements in qualified test environments in
accordance with ISO 3744:2010 for free field conditions over reflecting plane(s), and in
accordance with ISO 3743-2:2018 for special reverberation test rooms.
With this method, the sound power level is determined
– in free field conditions over reflecting plane(s), from time-averaged sound pressure levels
(on a mean-square basis) over the measurement surface and from the area of the
measurement surface, S, or
– in reverberation and special reverberation test rooms, from averaged sound pressure
levels, and from the reverberation time and the volume of the test room.
If for a measurement in a free field, reverberation or special reverberation room is not
possible because the appliance cannot be placed or operated in such an environment, the
intensity method in accordance with ISO 9614-1:1993, ISO 9614-2:1996, and ISO 9614-
3:2002 shall be applied. For the intensity method, the standard deviations given in the parts of
the IEC 60704-2 series and IEC 60704-3:2019 are not applicable unless stated explicitly.
These methods yield results expressed in A-weighted sound power levels (and in octave- or
1/3 octave-band sound power levels, if required) that are calculated directly from measured
sound pressure levels.
NOTE This method can also be used in conjunction with more precise methods, such as those given in ISO 3741
and ISO 3745.
If pure tone components are present in the noise emitted, proper precautions shall be taken
as specified in ISO 3743-2.
4.3 Comparison method
The comparison method for measurement is explicitly described in ISO 3743-1:2010 and in
ISO 3743-2:2018.
NOTE The term "comparison method" is not explicitly given in ISO 3744:2010, but when applying the "absolute
comparison test" for the determination of the environmental correction given in A.3 of ISO 3744:2010, by using a
reference sound source, the procedure is, in fact, a comparison method.
With this method, the sound power level is determined by comparing the averaged values (on
a mean-square basis) of the sound pressure levels produced by the source in the test room to
the averaged values of the sound pressure levels produced in the same room by a calibrated
reference sound source (RSS) of known sound power output, complying with the requirements
of ISO 6926:2016. The difference in sound pressure levels is equal to the difference in sound
power levels when conditions are the same for both sets of measurements.
This method yields results expressed in octave- or 1/3 octave-band sound power levels, and
the A-weighted sound power level is calculated from the octave- or 1/3 octave-band sound
power levels.
To check whether there is a systematic difference between results obtained in different
environments, the use of the comparison method is recommended.
If pure tone components are present in the noise emitted, proper precautions shall be taken
as specified in ISO 3743-1 and ISO 3743-2.

– 12 – IEC 60704-2-9:2024 EXV © IEC 2024
4.4 Acoustical environments
4.4.1 General requirements and criterion for adequacy of the test environment
ISO 3743-1, ISO 3743-2 and ISO 3744 can be used for measuring noise emitted by electric
hairdryers.
The method specified in ISO 3744 is applicable to noise sources of any size (limited only by
the available test environment). When applying ISO 3743-1 and ISO 3743-2, the maximum
size of the electric hair care appliance under test shall fulfil the requirements specified in
ISO 3743-1:2010, 4.2 and in ISO 3743-2:2018, Clause 5.
4.4.2 Criterion for background noise level
Requirements for the background noise level are given in 4.5 of ISO 3743-1:2010, in 6.5 of
ISO 3743-2:2018 and in 4.2 of ISO 3744:2010. Averaged over the microphone positions, the
background noise level shall be at least 6 dB below, and preferably more than 15 dB below,
the sound pressure level to be measured.
NOTE If the difference between the sound pressure levels of the background noise and the appliance noise is
less than 6 dB, see 8.2.
4.4.3 Environmental conditions
Environmental conditions having an adverse effect on the microphone used for the
measurements (for example, strong electric or magnetic fields, wind, impingement of air
discharge from the equipment being tested, high or low temperatures) shall be avoided by
proper selection or positioning of the microphone.
The instructions of the manufacturers of the measurement instruments regarding adverse
environmental conditions shall be followed. The microphone shall always be oriented in such
a way that the angle of incidence of the sound waves is that for which the microphone is
calibrated.
4.5 Measurement uncertainties
4.5.1 General
The estimated values of the standard deviations of reproducibility of sound power levels
determined in accordance with this document are given in 9.1 of ISO 3743-1:2010, in 11.1 of
ISO 3743‑2:2018 and in 9.1 of ISO 3744:2010. But for a particular family of appliances of
similar size with similar operating conditions, the standard deviations of reproducibility can be
smaller than these values. Hence, in the IEC 60704-2 series, standard deviations smaller than
those listed in ISO standards can be stated if substantiation is available from the results of
suitable interlaboratory tests.
In the case of discrepancies between the measurements where the results normally remain
inside the foreseen standard deviation, it can be helpful to perform measurements according
to the upper grade of accuracy: grade 1, laboratory or precision, as described in ISO 3741 or
ISO 3745.
4.5.2 Standard deviations on repeatability and reproducibility and standard
deviations related to declaration and verification
The estimated values of standard deviations of sound power levels, determined according to
this document, are given in Table 1:
Table 1 – Standard deviations of sound power levels
Standard deviation
dB
σ (repeatability) σ (reproducibility)
r R
0,4 0,8
For the purpose of determining and verifying declared noise emission values according to
IEC 60704-3, the following values given in Table 2 apply:
Table 2 – Standard deviations for declaration and verification
Standard deviation
dB
σ (production) σ (total) σ (reference)
P t M
0,5 to1,3 0,9 to1,5 1,5
5 Instrumentation
5.1 Instrumentation for measuring acoustical data
Requirements for the instrumentation system and for its calibration are given in Clause 5 of
ISO 3743-1:2010, in Clause 7 of ISO 3743-2:2018 and in Clause 5 of ISO 3744:2010.
The instrumentation system shall meet the requirements for a type 1 instrument laid down in
IEC 61672-1:2013, in accordance with the basic standard used. For measurements in octave-
and 1/3 octave-bands, the instrumentation system shall meet the requirements of
IEC 61260‑1:2014.
RSS shall meet the requirements of ISO 6926:2016, and shall be calibrated annually.
Windscreens shall be used if necessary and then corrections for change in the microphones
sensitivity shall be added to the observed sound pressure levels.
5.2 Instrumentation for measuring climatic conditions
5.2.1 The temperature is determined with instruments having an accuracy of ±1 °C.
5.2.2 The relative humidity is determined with instruments having an absolute accuracy of
±2 % within the measuring range.
5.2.3 The absolute air pressure is determined with instruments having an accuracy of
±0,5 kPa.
5.3 Instrumentation for measuring operating conditions
5.3.1 The voltage at the plug of the cable or cord of mains-powered appliances is
measured with voltmeters having an accuracy of class 0,5 instruments.

– 14 – IEC 60704-2-9:2024 EXV © IEC 2024
5.3.2 The voltage at the battery terminals of battery-powered appliances is measured with
voltmeters having an accuracy of class 0,5 instruments.
5.3.3 The rotational speed of motors, attachments, etc. is measured, if necessary, with
speed indicators having an accuracy of ±1 % of full scale.
6 Operation and location of appliances under test
6.1 Equipping and pre-conditioning of appliances
6.1.1 Appliances shall be equipped as for normal use. They shall not be equipped with
attachments such as nozzles, concentrators, diffusers, brushes, combs, etc. The air intake
and especially the inlet filter shall be clean and free of fluff and hairs.
6.1.2 Care shall be taken to ensure that any auxiliary equipment (such as electrical
conduits or cables, piping for water supply or drainage, air ducts, etc.) necessary for the
operation of the appliance, does not radiate a significant amount of sound into the test
environment or change the sound output of the appliance. Guidelines are given in 6.2 of
ISO 3743-1:2010, in 8.4 of ISO 3743-2:2018 and in 6.2 ISO 3744:2010.
6.1.3 Prior to noise measurements, the appliance equipped in accordance with 6.1.1 shall
have been run in for a total period of at least 5 min at the highest speed and temperature
setting for normal permanent use. A boost position, if any, shall not be used.
NOTE 101 A boost position is a setting of a control for occasional use, which results in a higher temporary fan
speed.
6.1.4 Immediately before each series of noise measurements, the appliance equipped in
accordance with 6.1.1 is operated for stabilizing at the highest speed and temperature setting
for normal permanent use for at least 2 min. A boost position, if any, shall not be used.
6.2 Supply of electric energy and of water or gas
6.2.1 Appliances with mains powered electric motor(s) are supplied at rated voltage and at
rated frequency. Appliances designed for DC only are supplied with DC. If a voltage range
and/or a frequency range are indicated, then the supply voltage and/or frequency shall be the
nominal system voltage and/or system frequency of the country in which the appliance is
intended to be used. Tolerances shall not exceed ±2 % for voltage and ±1 % for frequency
throughout the test.
Modification:
The voltage tolerance shall be ±0,5 %.
The nominal system voltage and its values are defined in IEC 60038:2009.
If the rated voltage of a mains supplied appliance differs from the nominal system voltage as
common in the country of use, measurements should be carried out at the nominal voltage as
common in the country of use.
The supply voltage is measured at the plug of a non-detachable cable or cord, or at the
appliance inlet if a detachable cable is provided, but in no case at the entrance of extension
cables or cords.
6.2.2 Not applicable.
6.2.3 Not applicable.
6.2.4 Not applicable.
6.3 Climatic conditions
In general, household appliances (unless otherwise specified for a special family) are
operated under the following climatic conditions:
ambient temperature 18 °C to 28 °C
relative humidity 25 % to 70 %
atmospheric pressure 86 kPa to 106 kPa
6.4 Loading and operating of appliances during tests
6.4.1 General requirements are given in 6.5 of ISO 3743-1:2010, in 8.5 of ISO 3743-
2:2018 and in 6.6 of ISO 3744:2010. For the purpose of establishing a noise test code, the
following guidelines are given, unless otherwise specified in the relevant part of the
IEC 60704-2 series.
In general, the loading and operating conditions should, as far as practicable, simulate normal
use but, in every case, preference has to be given to simple conditions providing satisfactory
repeatability and reproducibility.
The presence of an operator should be avoided. An operator shall be present only if the
application of the load is not practicable without an operator. This operator shall not wear
abnormally sound absorptive clothing that might influence the sound measurements.
6.4.2 The appliance shall be equipped according to 6.1.1.
The noise emission values shall be determined at the highest speed setting of the fan and the
highest power setting of the heater for normal permanent use. Attachments shall be removed.
NOTE 101 Other possible speed and power settings (e.g. boost position, cold position, etc.) can be measured in
addition. Additional measurements with accessories can also be done.
The actual settings and configuration during the measurement shall be carefully recorded.
6.4.3 Not applicable.
6.4.4 Not applicable.
6.5 Location and mounting of appliances
6.5.1 The basic requirements in 6.3 and 6.4 of ISO 3743-1:2010, in 8.2 and 8.3 of
ISO 3743-2:2018 and in 6.3 and 6.4 of ISO 3744:2010 shall be followed. The following
guidelines are given, unless otherwise specified in the relevant part of the IEC 60704-2
series.
The outlet of the appliance shall be placed in a position which is appropriate for the practical
use. Restriction of the airflow of the hairdryer shall be avoided. This shall be considered at
the inlet, the outlet and through the appliance.
The appliance shall be placed so as to prevent additional structure-borne noise. No other
pieces than those delivered by the manufacturer shall be used.

– 16 – IEC 60704-2-9:2024 EXV © IEC 2024
6.5.2 Floor-standing appliances, counter-top or table-type appliances, are placed in their
normal position directly, without any resilient means other than those incorporated in the
appliance:
– either on the floor of the hard-walled test room or of the special reverberation test room
with a minimum distance of 1 m between any surface (including protruding parts)
of the appliance and the nearest wall;
– or on the reflecting plane of the free field e
...

IEC 60704-2-9 ®
Edition 2.0 2024-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Test code for the determination of
airborne acoustical noise –
Part 2-9: Particular requirements for electric hair care appliances

Appareils électrodomestiques et analogues – Code d'essai pour la détermination
du bruit aérien –
Partie 2-9: Exigences particulières pour les appareils électriques destinés aux
soins des cheveux
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IEC 60704-2-9 ®
Edition 2.0 2024-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Household and similar electrical appliances – Test code for the determination of

airborne acoustical noise –
Part 2-9: Particular requirements for electric hair care appliances

Appareils électrodomestiques et analogues – Code d'essai pour la

détermination du bruit aérien –

Partie 2-9: Exigences particulières pour les appareils électriques destinés aux

soins des cheveux
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 97.170, 17.140.20 ISBN 978-2-8322-9000-2

– 2 – IEC 60704-2-9:2024 © IEC 2024
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
3 Terms and definitions . 6
4 Measurement methods and acoustical environments . 6
5 Instrumentation . 8
6 Operation and location of appliances under test . 8
7 Measurement of sound pressure levels . 9
9 Information to be recorded . 10
10 Information to be reported . 10
Annexes . 11
Annex A (normative) Standard test table . 11
Bibliography . 12

Table 1 – Standard deviations of sound power levels . 7
Table 2 – Standard deviations for declaration and verification . 7

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
TEST CODE FOR THE DETERMINATION OF
AIRBORNE ACOUSTICAL NOISE –
Part 2-9: Particular requirements for electric hair care appliances

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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
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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
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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 60704-2-9 has been prepared by subcommittee 59L: Small household appliances, of IEC
technical committee 59: Performance of household electrical appliances. It is an International
Standard.
This second edition cancels and replaces the first edition published in 2003. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Alignment with IEC 60704-1:2021.

– 4 – IEC 60704-2-9:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
59L/239/CDV 59L/253/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 60704 series, published under the general title Household and
similar electrical appliances – Test code for the determination of airborne acoustical noise, can
be found on the IEC website.
This part 2-9 is intended to be used in conjunction with the fourth edition of IEC 60704-1:2021:
Household and similar electrical appliances – Test code for the determination of airborne
acoustical noise – Part 1: General requirements.
The relevant text of IEC 60704-1:2021 as amended by this standard establishes the test code
for electric hair care appliances.
This document supplements or modifies the corresponding clauses in IEC 60704-1:2021. When
a particular subclause of IEC 60704-1:2021 is not mentioned in this document, that subclause
applies as far as reasonable. Where this standard states "addition", "modification" or
"replacement", the relevant requirements, test specification or explanatory matter in
IEC 60704-1:2021 is adapted accordingly.
Subclauses or figures which are additional to those in IEC 60704-1:2021 are numbered starting
from 101. Additional annexes are lettered AA, BB, etc.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
INTRODUCTION
The measuring conditions specified in this document provide for sufficient accuracy in
determining the noise emitted and comparing the results of measurements taken by different
laboratories, whilst simulating as far as possible the practical use of hair care appliances.
It is recommended to consider the determination of noise levels as part of a comprehensive
testing procedure covering many aspects of the properties and performance of electric hair care
appliances.
NOTE As stated in the introduction to IEC 60704-1, this test code is concerned with airborne noise only.

– 6 – IEC 60704-2-9:2024 © IEC 2024
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
TEST CODE FOR THE DETERMINATION OF
AIRBORNE ACOUSTICAL NOISE –
Part 2-9: Particular requirements for electric hair care appliances

1 Scope
Replacement:
This part of IEC 60704 applies to electric hand-held hairdryers for household and similar use
supplied from mains, which operate with a flow of air.
These particular requirements can also be applied to analogous electrically operated devices
such as hairstyling appliances, which produce the airflow by a fan.
Helmet-type hairdryers are excluded from this document.
This document does not apply to hair care appliances with radiant heating.
For determining and verifying noise emission values declared in product specifications, see
IEC 60704-3.
3 Terms and definitions
Addition:
3.101
hand-held hairdryer
hairdryer which is held by hand during normal permanent use
3.102
hairstyling appliance
appliance for styling and/or curling hairs
Note 1 to entry: Hair styling appliances can comprise brushes and combs.
3.103
helmet-type hairdryer
hairdryer, in which the drying is performed under a rigid or flexible hood
4 Measurement methods and acoustical environments
4.2 Direct method
Addition:
If pure tone components are present in the noise emitted, proper precautions shall be taken as
specified in ISO 3743-2.
4.3 Comparison method
Addition:
If pure tone components are present in the noise emitted, proper precautions shall be taken as
specified in ISO 3743-1 and ISO 3743-2.
4.4 Acoustical environments
4.4.1 General requirements and criterion for adequacy of the test environment
Replacement:
ISO 3743-1, ISO 3743-2 and ISO 3744 can be used for measuring noise emitted by electric
hairdryers.
The method specified in ISO 3744 is applicable to noise sources of any size (limited only by the
available test environment). When applying ISO 3743-1 and ISO 3743-2, the maximum size of
the electric hair care appliance under test shall fulfil the requirements specified in ISO 3743-
1:2010, 4.2 and in ISO 3743-2:2018, Clause 5.
4.5 Measurement uncertainties
4.5.2 Standard deviations on repeatability and reproducibility and standard deviations
related to declaration and verification
Replacement:
The estimated values of standard deviations of sound power levels, determined according to
this document, are given in Table 1:
Table 1 – Standard deviations of sound power levels
Standard deviation
dB
σ (repeatability) σ (reproducibility)
r R
0,4 0,8
For the purpose of determining and verifying declared noise emission values according to
IEC 60704-3, the following values given in Table 2 apply:
Table 2 – Standard deviations for declaration and verification
Standard deviation
dB
σ (production) σ (total) σ (reference)
P t M
0,5 to1,3 0,9 to1,5 1,5
– 8 – IEC 60704-2-9:2024 © IEC 2024
5 Instrumentation
5.1 Instrumentation for measuring acoustical data
Addition:
Windscreens shall be used if necessary and then corrections for change in the microphones
sensitivity shall be added to the observed sound pressure levels.
6 Operation and location of appliances under test
6.1 Equipping and pre-conditioning of appliances
6.1.1
Replacement:
Appliances shall be equipped as for normal use. They shall not be equipped with attachments
such as nozzles, concentrators, diffusers, brushes, combs, etc. The air intake and especially
the inlet filter shall be clean and free of fluff and hairs.
6.1.3
Replacement:
Prior to noise measurements, the appliance equipped in accordance with 6.1.1 shall have been
run in for a total period of at least 5 min at the highest speed and temperature setting for normal
permanent use. A boost position, if any, shall not be used.
NOTE 101 A boost position is a setting of a control for occasional use, which results in a higher temporary fan
speed.
6.1.4
Replacement:
Immediately before each series of noise measurements, the appliance equipped in accordance
with 6.1.1 is operated for stabilizing at the highest speed and temperature setting for normal
permanent use for at least 2 min. A boost position, if any, shall not be used.
6.2 Supply of electric energy and of water or gas
6.2.1
Modification:
The voltage tolerance shall be ±0,5 %.
6.2.2 to 6.2.4 Not applicable.

6.4 Loading and operating of appliances during tests
6.4.2
Replacement:
The appliance shall be equipped according to 6.1.1.
The noise emission values shall be determined at the highest speed setting of the fan and the
highest power setting of the heater for normal permanent use. Attachments shall be removed.
NOTE 101 Other possible speed and power settings (e.g. boost position, cold position, etc.) can be measured in
addition. Additional measurements with accessories can also be done.
The actual settings and configuration during the measurement shall be carefully recorded.
6.4.3 and 6.4.4 Not applicable.
6.5 Location and mounting of appliances
6.5.1
Addition:
The outlet of the appliance shall be placed in a position which is appropriate for the practical
use. Restriction of the airflow of the hairdr
...