IEC 60704-2-11:2025

IEC 60704-2-11 ®
Edition 2.0 2025-03
EXTENDED VERSION
INTERNATIONAL
STANDARD
This full version of IEC 60704-2-11:2025 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 2-11: Particular requirements for electrically-operated food preparation
appliances
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IEC 60704-2-11 ®
Edition 2.0 2025-03
EXTENDED VERSION
INTERNATIONAL
STANDARD
This full version of IEC 60704-2-11:2025 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 2-11: Particular requirements for electrically-operated food preparation
appliances
Appareils électrodomestiques et analogues – Code d’essai pour la
détermination du bruit aérien –
Partie 2-11: Exigences particulières pour les appareils électriques destinés à la
préparation des aliments
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.140.20, 97.040.50 ISBN 978-2-8327-0317-5

– 2 – IEC 60704-2-11:2025 EXV © IEC 2025
CONTENTS
FOREWORD . 4
INTRODUCTION to IEC 60704-1:2021 . 7
INTRODUCTION to IEC 60704-2-11:2025 . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Measurement methods and acoustical environments . 11
4.1 General . 11
4.2 Direct method . 12
4.3 Comparison method . 12
4.4 Acoustical environments . 13
4.5 Measurement uncertainties . 14
5 Instrumentation . 14
5.1 Instrumentation for measuring acoustical data . 14
5.2 Instrumentation for measuring climatic conditions . 15
5.3 Instrumentation for measuring operating conditions . 15
6 Operation and location of appliances under test . 15
6.1 Equipping and pre-conditioning of appliances . 15
6.2 Supply of electric energy and of water or gas . 16
6.3 Climatic conditions . 16
6.4 Loading and operating of appliances during tests . 16
6.5 Location and mounting of appliances . 20
7 Measurement of sound pressure levels . 22
7.1 Microphone array, measurement surface and RSS location for essentially
free field conditions over reflecting plane(s) . 22
7.2 Microphone array and RSS location in hard-walled test rooms . 25
7.3 Microphone array and RSS location in special reverberation test rooms . 25
7.4 Measurements . 25
8 Calculation of sound pressure and sound power levels . 26
8.1 General . 26
8.2 Corrections for background noise levels . 26
8.3 Corrections for the test environment . 27
8.4 Calculation of sound pressure level averaged over the microphone positions . 27
8.5 Calculation of sound power levels with the comparison method . 27
8.6 Calculation of sound power levels in free field conditions over a reflecting
plane . 28
8.7 Calculation of A-weighted sound power level with the direct method in
special reverberation test rooms . 28
9 Information to be recorded . 29
9.1 General data . 29
9.2 Description of appliance under test . 29
9.3 Measurement method . 29
9.4 Acoustical test environment . 29
9.5 Instrumentation . 30
9.6 Equipment and pre-conditioning of appliance under test . 30
9.7 Electric supply, water supply, etc. . 30

9.8 Climatic conditions . 30
9.9 Operation of the appliance under test . 30
9.10 Location and mounting of the appliance under test. 31
9.11 Microphone array . 31
9.12 Measurement data . 31
9.13 Calculated sound pressure and sound power levels . 31
9.14 Reporting . 31
10 Information to be reported . 32
10.1 General data . 32
10.2 Appliance under test . 32
10.3 Test conditions for the appliance . 32
10.4 Acoustical data . 33
Annex A (normative) Standard test table . 34
Annex B (normative) Test enclosure . 35
Annex C (informative) Guidelines for the design of simple test rooms with essentially
free field conditions. 36
Bibliography . 37

Figure 101 – Example of load for citrus juice extraction function . 19
Figure 102 – Examples of test fixtures for hand-held appliances . 22
Figure 4 – Measurement surface – hemisphere – with key microphone positions, for
hand-held, table type and floor-treatment appliances . 24

Table 1 – Standard deviations of sound power levels . 14
Table 2 – Standard deviations for declaration and verification . 14

– 4 – IEC 60704-2-11:2025 EXV © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
TEST CODE FOR THE DETERMINATION OF
AIRBORNE ACOUSTICAL NOISE –
Part 2-11: Particular requirements for electrically-operated
food preparation 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
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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https://patents.iec.ch. IEC shall not be held responsible for identifying any or all such patent rights.
This extended version (EXV) of the official IEC Standard provides the user with the full
content of the Standard.
made to IEC 60704-1:2021.
The specific content of IEC 60704-2-11:2025 is displayed on a blue background.

IEC 60704-2-11 has been prepared by subcommittee 59L: Small household appliances, of
IEC technical committee 59: Performance of household and similar electrical appliances. It is
an International Standard.
This second edition cancels and replaces the first edition published in 1998. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) definition of various kind of food preparation appliances added;
b) revision of the test conditions;
c) coffee mills and coffee grinders are removed from the scope.
The text of this International Standard is based on the following documents:
Draft Report on voting
59L/285/FDIS 59L/289/RVD
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.
This Part 2-11 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 publication establishes the test
code for electrically-operated food preparation appliances.
This Part 2-11 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 is applicable as far as reasonable. Where this standard states "addition",
"modification", "replacement" or "deletion", the relevant requirements, test specifications or
explanatory matter in IEC 60704-1:2021 should be adapted accordingly.
Subclauses and tables that are additional to those in IEC 60704-1:2021 are numbered starting
from 101.
Unless notes are in a new subclause or involve notes in IEC 60704-1:2021, they are
numbered starting from 101, including those in a replaced clause or subclause.
In this standard, the following print types are used:
• terms defined in Clause 3: bold type.
A list of all the parts in the IEC 60704 series, 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.
– 6 – IEC 60704-2-11:2025 EXV © IEC 2025
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 to IEC 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 IEC 60704-2-11:2025
The measuring conditions specified in this Part 2-11 provide for sufficient steadiness in the
noise emitted and reproducibility in different laboratories, whilst simulating as far as possible
the practical use of electrically-operated food preparation 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
electrically-operated food preparation appliances.
NOTE As stated in the introduction to IEC 60704-1:2021, this test code is concerned with airborne noise only.

– 8 – IEC 60704-2-11:2025 EXV © IEC 2025
HOUSEHOLD AND SIMILAR ELECTRICAL APPLIANCES –
TEST CODE FOR THE DETERMINATION OF
AIRBORNE ACOUSTICAL NOISE –
Part 2-11: Particular requirements for electrically-operated
food preparation appliances
1 Scope
This part of IEC 60704 applies to electric appliances (including their accessories or
components) for household and similar use, supplied from mains or from batteries.
By "similar use" is understood the use in conditions similar to those found in households, for
example in inns, coffee houses, tea rooms, hotels, barber or hairdresser shops, launderettes,
etc., if not otherwise specified in the IEC 60704-2 series.
This document does not apply to
– appliances, equipment, or machines designed exclusively for industrial or professional
purposes;
– appliances that are integrated parts of a building or its installations, such as equipment for
air conditioning, heating and ventilating (except household fans, cooker hoods, free-
standing heating appliances, dehumidifiers, air cleaners, and stand-alone water heaters),
oil burners for central heating, pumps for water supply and for sewage systems;
– separate motors or generators and
– appliances exclusively for outdoor use.
For determining and verifying noise emission values declared in product specifications, see
IEC 60704-3:2019.
This part of IEC 60704 applies to electrically-operated food preparation appliances, either in
the form of separate machines with a single function or in the form of multi-purpose machines
with appropriate tools or attachments for several functions. These machines are intended for
placing on counters, tables, work tops or sinks, for built-in, or for hand-held use, supplied
from mains or from batteries and able to ensure the functions described in IEC 60619:1993,
Clause 4 and IEC 60619:1993/AMD1:1995, Clause 4.
NOTE 1 A revised version of IEC 60619 is under preparation.
This document also applies to multifunctional cooking food processors.
This document does not apply to coffee mills and coffee grinders.
NOTE 2 Coffee mills and coffee grinders will be included in a separate standard, which is under preparation.
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 60619:1993, Electrically operated food preparation appliances – Methods for measuring
the performance
IEC 60619:1993/AMD1:1995
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

– 10 – IEC 60704-2-11:2025 EXV © IEC 2025
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.]
3.6
test enclosure
enclosure used for simulating the typical acoustic built-in or/and mounting conditions
3.101
hand-held appliances' standard container
container with sides of 500 mm ± 150 mm and a height of 300 mm ± 100 mm, the structure
being rigid enough to avoid structure-borne noise
3.102
hand-held appliance
portable appliance intended to be held in the hand during normal use
[SOURCE: IEC 60335-1:2020, 3.5.2]
3.103
kitchen machine
stand mixer
counter-top appliance for mixing or kneading food in a bowl, which is part of the appliance,
with the tool entering the bowl from the top
3.104
blender
appliance intended to pulverise solids, such as ice, vegetables or fruit, and to combine them
into a blend, or to merge liquids and solids into a blend (food blenders) or to combine liquids
only (liquid blenders)
Note 1 to entry: A blender can be with or without heating function.
Note 2 to entry: Smoothie-makers are considered to be blenders.
[SOURCE: IEC 60335-2-14:2016, 3.105, modified − Notes to entry have been added.]
3.105
food processor
counter-top appliance for mixing, cutting, dicing of food in a container, which is part of the
appliance, with the tool at the bottom of the container
3.106
multifunctional cooking food processor
counter-top appliance for cooking and at least one additional function (e.g. mixing, cutting or
dicing) in a container, which is part of the appliance
3.107
citrus juice extractor
counter-top appliance for juicing citrus fruits
3.108
other electrically-operated food preparation appliances
other electrically-operated appliances, that are not listed above, with at least one function
being mixing, cutting, dicing, kneading, juice extraction and blending
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).
– 12 – IEC 60704-2-11:2025 EXV © IEC 2025
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.
Electrically-operated food preparation appliances can produce pure tones. If pure tone
components are present in the noise emitted by the source, the estimated standard deviation
of the measured sound pressure levels in the special reverberation room can increase. In
such cases, additional microphone positions or source positions can be necessary, as
specified in ISO 3743-2:2018.
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.
Electrically-operated food preparation appliances can produce pure tones. If pure tone
components are present in the noise emitted by the source, the estimated standard deviation
of the measured sound pressure levels in the hard-walled test room or in the special
reverberation room can increase. In such cases, additional microphone positions or source
positions can be necessary, as specified in ISO 3743-1:2010 or ISO 3743-2:2018.
4.4 Acoustical environments
4.4.1 General requirements and criterion for adequacy of the test environment
They are given in the following clauses:
– Clause 4 of ISO 3743-1:2010 for hard-walled test rooms;
– Clause 5 of ISO 3743-2:2018 for special reverberation test rooms and
– Clause 4 of ISO 3744:2010 for free-field conditions over a reflecting plane.
A classification of different types of noise is given in ISO 12001:1996. The method specified
in ISO 3744:2010 is suitable for measurements of all types of noise emitted by household
appliances. The methods specified in ISO 3743-1:2010 and ISO 3743-2:2018 are suitable for
all types of noise, except for sources of impulsive noise consisting of short-duration noise
bursts. This will be taken into account in the preparation of parts of the IEC 60704-2 series.
The method specified in ISO 3744:2010 is applicable to noise sources of any size. Limitations
for the size of the source are given in 4.2 of ISO 3743-1:2010 and in Clause 5 of
ISO 3743-2:2018. This will be taken into account in the preparation of parts of the
IEC 60704-2 series.
NOTE For free-field conditions over a reflecting plane, the absolute comparison test for the qualification of the
environment, described in Clause A.2 of ISO 3744:2010, is preferred.
Guidelines for the design of simple test rooms with free-field conditions are given in Annex C.
Guidelines for the design of a suitable special reverberation test room are given in
ISO 3743-2:2018, Annex A.
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.
– 14 – IEC 60704-2-11:2025 EXV © IEC 2025
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
0,5 1,0
For the purpose of determining and verifying declared noise emission values according to
IEC 60704-3, the values in Table 2 apply:
Table 2 – Standard deviations for declaration and verification
Standard deviation
dB
σ (production) σ (total) σ (reference)
P t M
0,9 to 1,5 1,4 to 1,8 2,0
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.

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.
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 The appliance is equipped with attachments, accessories, etc. as delivered by the
manufacturer for the intended use or function.
For hand-held appliances with blending and pureeing function, the test load is contained in
the hand-held appliances' standard container defined in 3.101.
For other appliances, the bowl supplied by the manufacturer shall be used.
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 shall have been in operation for a total
period of at least 10 min or at least 5 cycles of typical application according to user instruction
for running-in, under the same conditions as the noise measurement. This total period of
running-in can be reduced if it is verified that this does not affect the noise emission of the
appliance under test.
If this procedure can damage the appliance, precautions shall be taken.
If the appliance under test is delivered with several accessories, each accessory used for
noise measurements shall be in operation for an equivalent period of running.
6.1.4 Immediately before each measurement, the appliance, equipped and loaded as for
the intended use, is operated during 20 s (or less, if specified by the manufacturer), for
stabilizing, at the same speed as defined for the measurement.

– 16 – IEC 60704-2-11:2025 EXV © IEC 2025
6.2 Supply of electric energy a
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