EN ISO 11201:2010

SLOVENSKI STANDARD
01-september-2010
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Acoustics - Noise emitted by machinery and equipment - Determination of emission
sound pressure levels at a work station and at other specified positions in an essentially
free field over a reflecting plane with negligible environmental corrections (ISO
11201:2010)
Akustik - Geräuschabstrahlung von Maschinen und Geräten - Messung von Emissions-
Schalldruckpegeln am Arbeitsplatz und an anderen festgelegten Orten in einem im
Wesentlichen freien Schallfeld über einer reflektierenden Ebene mit vernachlässigbaren
Umgebungskorrekturen (ISO 11201:2010)
Acoustique - Bruit émis par les machines et équipements - Mesurage des niveaux de
pression acoustique d'émission au poste de travail et en d'autres positions spécifiées
dans des conditions approchant celles du champ libre sur plan réfléchissant avec des
corrections d'environnement négligeables (ISO 11201:2010)
Ta slovenski standard je istoveten z: EN ISO 11201:2010
ICS:
17.140.20 Emisija hrupa naprav in Noise emitted by machines
opreme and equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 11201
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2010
ICS 17.140.20 Supersedes EN ISO 11201:2009
English Version
Acoustics - Noise emitted by machinery and equipment -
Determination of emission sound pressure levels at a work
station and at other specified positions in an essentially free field
over a reflecting plane with negligible environmental corrections
(ISO 11201:2010)
Acoustique - Bruit émis par les machines et équipements - Akustik - Geräuschabstrahlung von Maschinen und
Détermination des niveaux de pression acoustique
Geräten - Bestimmung von Emissions-Schalldruckpegeln
d'émission au poste de travail et en d'autres positions am Arbeitsplatz und an anderen festgelegten Orten in
spécifiées dans des conditions approchant celles du champ einem im Wesentlichen freien Schallfeld über einer
libre sur plan réfléchissant avec des corrections reflektierenden Ebene mit vernachlässigbaren
d'environnement négligeables (ISO 11201:2010) Umgebungskorrekturen (ISO 11201:2010)
This European Standard was approved by CEN on 22 April 2010.

CEN 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 Management Centre or to any CEN 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 CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11201:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC .4

Foreword
This document (EN ISO 11201:2010) has been prepared by Technical Committee ISO/TC 43 “Acoustics” in
collaboration with Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by DS.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by November 2010, and conflicting national standards shall be withdrawn
at the latest by November 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 11201:2009.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive.
For relationship with EU Directive, see informative Annex ZA, which is an integral part of this document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 11201:2010 has been approved by CEN as a EN ISO 11201:2010 without any modification.
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide a means of conforming to Essential Requirements of the
New Approach Directive 2006/42/EC on machinery.
Once this standard is cited in the Official Journal of the European Union under that Directive and has been
implemented as a national standard in at least one Member State, compliance with the normative clauses of
this standard confers, within the limits of the scope of this standard, a presumption of conformity with the
corresponding Essential Requirements of that Directive and associated EFTA regulations.
WARNING — Other requirements and other EU Directives may be applicable to the product(s) falling within
the scope of this standard.
INTERNATIONAL ISO
STANDARD 11201
Second edition
2010-05-15
Acoustics — Noise emitted by machinery
and equipment — Determination of
emission sound pressure levels at a work
station and at other specified positions in
an essentially free field over a reflecting
plane with negligible environmental
corrections
Acoustique — Bruit émis par les machines et équipements —
Détermination des niveaux de pression acoustique d'émission au poste
de travail et en d'autres positions spécifiées dans des conditions
approchant celles du champ libre sur plan réfléchissant avec des
corrections
Reference number
ISO 11201:2010(E)
©
ISO 2010
ISO 11201:2010(E)
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ii © ISO 2010 – All rights reserved

ISO 11201:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.2
3 Terms and definitions .3
4 Instrumentation .7
5 Test environment.7
6 Measured quantities.11
7 Quantities to be determined.12
8 Mounting and operation of source under test.12
9 Microphone positions .14
10 Measurements .16
11 Measurement uncertainty.18
12 Information to be recorded.21
13 Test report.22
Annex A (normative) Allocation of the accuracy grade (1 or 2).23
Annex B (normative) Criteria for background noise for measurements in frequency bands .24
Annex C (informative) Guidance on the development of information on measurement uncertainty .26
Annex D (informative) Principles of the methodology .32
Annex E (informative) Example of a test table.33
Bibliography.34

ISO 11201:2010(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 11201 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This second edition cancels and replaces the first edition (ISO 11201:1995), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 11201:1995/Cor.1:1997.
iv © ISO 2010 – All rights reserved

ISO 11201:2010(E)
Introduction
This International Standard specifies a method for determining the emission sound pressure levels at a work
station and at other well defined positions, in the vicinity of a machine or piece of equipment, in an essentially
[15] [19]
free field over a reflecting plane. It is one of a series (ISO 11200 to ISO 11205 ) which specifies various
methods for determining the emission sound pressure level at a work station and at other specified positions
[15]
of a machine or equipment. ISO 11200 gives guidance on the choice of the method to be used to
determine the emission sound pressure levels of machinery and equipment.
The method specified in this International Standard differs from those in other International Standards in the
[15] [19]
ISO 11200 to ISO 11205 series in not applying any environmental correction. Requirements to be
fulfilled by the environment are specified for accuracy grade 1 (precision) and grade 2 (engineering)
measurements indoors and outdoors.
Precision measurements with accuracy grade 1 can generally be carried out in hemi-anechoic test rooms or
outdoors provided that requirements on environmental conditions are met. With the specifications defined in
the following it should be possible in some cases to provide such conditions in industrial ambience on larger
plane areas outdoors free from reflecting objects.
ISO 11201:1995 provided results of accuracy grade 2 only. This edition of this International Standard provides
a method of accuracy grade 2 that is essentially identical to that given in ISO 11201:1995. It also provides a
more precise method of accuracy grade 1. Users and drafters of noise test codes referring to this International
Standard should indicate clearly which method (accuracy grade 1 or accuracy grade 2) is used.
In general, the emission sound pressure levels are less than or equal to those that occur when the machinery
or equipment is operating in its normal surroundings. This is because the sound pressure levels are
determined by excluding the effects of background noise, as well as the effects of reflections other than those
from the reflecting plane on which the machine under test is placed. For determination or calculation of the
sound pressure level at the operator's position with the machine operating in a room, both sound power level
and sound pressure level are required (as well as information on the room properties or reflections and noise
from other sound sources or machines). A method of calculating the sound pressure levels in the vicinity of a
[20]
machine operating alone in a workroom is given in ISO/TR 11690-3 . Commonly observed differences are
1 dB to 5 dB, but in extreme cases the difference may be even greater.

INTERNATIONAL STANDARD ISO 11201:2010(E)

Acoustics — Noise emitted by machinery and equipment —
Determination of emission sound pressure levels at a work
station and at other specified positions in an essentially free
field over a reflecting plane with negligible environmental
corrections
1 Scope
1.1 General
This International Standard specifies a method for determining the emission sound pressure levels of
machinery or equipment, at a work station and at other specified positions nearby, in an essentially free field
over a reflecting plane. A work station is occupied by an operator and may be located in open space, in the
room where the source under test operates, in a cab fixed to the source under test, or in an enclosure remote
from the source under test. One or more specified positions may be located in the vicinity of a work station, or
in the vicinity of an attended or unattended machine. Such positions are sometimes referred to as bystander
positions.
Emission sound pressure levels are determined as A-weighted levels. Additionally, levels in frequency bands
and C-weighted peak emission sound pressure levels can be determined in accordance with this International
Standard, if required.
[15] [19] [15]
NOTE 1 The contents of the series ISO 11200 to ISO 11205 are summarized in ISO 11200 .
With the method specified in this International Standard, results of accuracy grade 1 (precision grade) or
accuracy grade 2 (engineering grade) are obtained. Corrections are applied for background noise, but not for
the acoustic environment. Instructions are given for the mounting and operation of the source under test and
for the choice of microphone positions for the work station and for other specified positions. One purpose of
the measurements is to permit comparison of the performance of different units of a given family of machines,
under defined environmental conditions and standardized mounting and operating conditions.
NOTE 2 The data obtained can also be used for the declaration and verification of emission sound pressure levels as
[8]
specified in ISO 4871 .
1.2 Types of noise and noise sources
The method specified in this International Standard is suitable for all types of noise (steady, non-steady,
fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001.
The method specified in this International Standard is applicable to all types and sizes of noise sources.
NOTE Throughout this International Standard the words “machine” and “source under test” are used to represent
either a machine or a piece of equipment.
ISO 11201:2010(E)
1.3 Test environment
The type of test environment influences the accuracy of the determination of emission sound pressure levels.
For the application of this International Standard, an essentially free field over a reflecting plane (indoors or
outdoors) is required.
1.4 Work station and other specified positions
This International Standard is applicable to work stations and other specified positions where emission sound
pressure levels are to be determined.
Appropriate positions where measurements may be made include the following:
a) work station located in the vicinity of the source under test; this is the case for many industrial machines
and domestic appliances;
b) work station within a cab which is an integral part of the source under test; this is the case for many
industrial trucks and earth-moving machines;
c) work station within a partial or total enclosure (or behind a screen) supplied by the manufacturer as an
integral part of the source under test;
d) work station partially or totally enclosed by the source under test — this situation may be encountered
with some large industrial machines;
e) bystander positions occupied by individuals not responsible for the operation of the source under test, but
who may be in its immediate vicinity, either occasionally or continuously;
f) other specified positions, not necessarily work stations or bystander positions.
The work station may also lie on a specified path along which an operator moves (see 9.4).
2 Normative references
The following referenced documents are indispensable for the application 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.
ISO 3744, Acoustics — Determination of sound power levels of noise sources using sound pressure —
Engineering method in an essentially free field over a reflecting plane
ISO 3745, Acoustics — Determination of sound power levels of noise sources using sound pressure —
Precision methods for anechoic and hemi-anechoic rooms
ISO 3746, Acoustics — Determination of sound power levels of noise sources using sound pressure —
Survey method using an enveloping measurement surface over a reflecting plane
ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results
ISO 12001, Acoustics — Noise emitted by machinery and equipment — Rules for the drafting and
presentation of a noise test code
IEC 60942:2003, Electroacoustics — Sound calibrators
IEC 61260:1995, Electroacoustics — Octave-band and fractional-octave-band filters (amended by
IEC 61260/Amd.1:2001)
2 © ISO 2010 – All rights reserved

ISO 11201:2010(E)
IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications
ISO/IEC Guide 98-3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply. More detailed definitions can be
found in noise test codes for specific types of machines.
3.1
emission
〈acoustics〉 airborne sound radiated by a well-defined noise source (e.g. the machine under test)
NOTE Noise emission descriptors can be incorporated into a product label and/or product specification. The basic
noise emission descriptors are the sound power level of the source itself and the emission sound pressure levels at a work
station and/or at other specified positions (if any) in the vicinity of the source.
3.2
emission sound pressure
p
sound pressure, at a work station or another specified position near a noise source, when the source is in
operation under specified operating and mounting conditions on a reflecting plane surface, excluding the
effects of background noise as well as the effects of reflections other than those from the plane or planes
permitted for the purpose of the test
NOTE Emission sound pressure is expressed in pascals.
3.3
emission sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the square of the emission sound pressure, p, to the
square of a reference value, p , expressed in decibels
p
L = 10lg dB (1)
p
p
where the reference value, p , is 20 µPa
NOTE The emission sound pressure level is determined at a work station or another specified position in accordance
with either a noise test code for a specific family of machines or, if no noise test code exists, one of the standards of the
[15] [19]
ISO 11200 to ISO 11205 series.
3.4
time-averaged emission sound pressure level
L
p,T
ten times the logarithm to the base 10 of the ratio of the time average of the square of the emission sound
pressure, p, during a stated time interval of duration, T (starting at t and ending at t ), to the square of a
1 2
reference value, p , expressed in decibels
t
⎡⎤2
⎢⎥
pt()dt
∫
⎢⎥
T
t
⎢⎥
L = 10lg dB (2)
pT,
⎢⎥2
p
⎢⎥
⎢⎥
⎢⎥
⎣⎦
where the reference value, p , is 20 µPa
ISO 11201:2010(E)
[21]
NOTE 1 Adapted from ISO/TR 25417:2007 , 2.3, “time-averaged sound pressure level”.
NOTE 2 For simplicity of notation, the subscript T is omitted throughout the following text.
NOTE 3 If specific frequency and time weightings as specified in IEC 61672-1 and/or specific frequency bands are
applied, this is indicated by appropriate subscripts; e.g. L denotes the A-weighted emission sound pressure level.
pA
NOTE 4 Equation (2) is equivalent to that for the environmental noise descriptor “equivalent continuous sound pressure
[1]
level” (ISO 1996-1 ). However, the emission quantity defined above is used to characterize the noise emitted by a source
under test and assumes that standardized measurement and operating conditions as well as a controlled acoustical
environment are used for the measurements.
3.5
peak emission sound pressure
p
peak
greatest absolute emission sound pressure during a stated time interval
NOTE 1 Peak emission sound pressure is expressed in pascals.
NOTE 2 A peak emission sound pressure may arise from a positive or negative sound pressure.
3.6
peak emission sound pressure level
L
p,peak
ten times the logarithm to the base 10 of the ratio of the square of the peak emission sound pressure, p , to
peak
the square of a reference value, p , expressed in decibels
p
peak
L = 10lg dB (3)
p,peak
p
where the reference value, p , is 20 µPa
NOTE The peak emission sound pressure level is usually C-weighted and denoted by L .
pC,peak
3.7
single event emission sound pressure level
L
E
ten times the logarithm to the base 10 of the ratio of the integral of the square of the emission sound pressure,
p, of an isolated single sound event (burst of sound or transient sound) of specified duration, T (or specified
measurement time interval T = t – t covering the single event), to the square of a reference value, p ,
2 1 0
normalized to reference time interval T = 1 s, expressed in decibels
t
⎡⎤
1(pt)
⎢⎥
Lt= 10lg d dB
E
∫
⎢⎥
T
p
t
⎢⎥ (4)
⎣⎦1
T
=+L 10lg dB
pT,
T
NOTE Equation (4) is equivalent to that for the environmental noise descriptor “sound exposure level”
[21]
(ISO/TR 25417:2007 , 2.7). However, the emission quantity defined above is used to characterize the noise emitted by a
source under test and assumes that standardized measurement, mounting, and operating conditions as well as a
controlled acoustical environment are used for the measurements.
4 © ISO 2010 – All rights reserved

ISO 11201:2010(E)
3.8
acoustic free field over a reflecting plane
sound field in a homogeneous, isotropic medium in the half space above an infinite reflecting plane, in the
absence of any other obstacles
3.9
essentially free field over a reflecting plane
environment approximating an acoustic free field over a reflecting plane on which the noise source under test
is located
NOTE The requirements on the environment are specified in 5.2.
3.10
frequency range of interest
for general purposes, the frequency range of octave bands with nominal mid-band frequencies from 125 Hz to
8 000 Hz or the one-third octave bands with nominal mid-band frequencies from 100 Hz to 10 000 Hz
[9]
NOTE 1 Adapted from ISO 6926:1999 , 3.10.
NOTE 2 For special purposes, the frequency range may be extended or reduced, provided that the test environment
and instrument specifications are satisfactory for use over the modified frequency range. Changes to the frequency range
of interest should be made clear in the test report. For sources which emit sound at predominantly high or low frequencies,
the frequency range of interest should be extended to include these frequencies.
3.11
work station
operator's position
position in the vicinity of the machine under test which is intended for the operator
3.12
operator
individual whose work station is in the vicinity of a machine and who is performing a work task associated with
that machine
3.13
specified position
position defined in relation to a machine, including, but not limited to, an operator's position
NOTE 1 The position can be a single, fixed point, or a combination of points along a path or on a surface located at a
specified distance from the machine, as described in the relevant noise test code, if one exists.
NOTE 2 Positions located in the vicinity of a work station, or in the vicinity of an unattended machine, are identified as
“bystander positions”.
NOTE 3 Throughout the text of this International Standard, the term “work station” applies to any possible specified
position listed in 1.4.
3.14
operational period
interval of time during which a specified process is accomplished by the source under test
EXAMPLE For a dishwasher, when washing or rinsing or drying.
3.15
operational cycle
specific sequence of operational periods occurring while the source under test performs a complete work
cycle, where each operational period is associated with a specific process that may occur only once, or may
be repeated, during the operational cycle
EXAMPLE For a dishwasher, when washing and rinsing and drying.
ISO 11201:2010(E)
3.16
measurement time interval
portion or a multiple of an operational period or operational cycle of the source under test, for which the time-
averaged emission sound pressure level is determined or over which the maximum emission sound pressure
level is sought
3.17
time history
continuous recording of the emission sound pressure level, as a function of time, which is obtained during one
or more operational periods of an operational cycle
3.18
background noise
noise from all sources other than the source under test
NOTE Background noise can include contributions from airborne sound, noise from structure-borne vibration, and
electrical noise in instrumentation.
3.19
background noise correction
K
correction applied to the measured sound pressure levels to account for the influence of background noise
NOTE 1 Background noise correction is expressed in decibels.
NOTE 2 Background noise correction is frequency dependent. In the case of A-weighting, the correction, K , is
1A
determined from A-weighted measured values.
3.20
reference box
hypothetical rectangular 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 may be mounted
3.21
reference measurement surface
S
M
hypothetical surface defined by a rectangular parallelepiped enveloping the noise source under test,
terminating on the reflecting plane(s) on which the source is located, and having sides parallel to those of the
reference box with each side spaced at equal distance from the corresponding side of the reference box
3.22
environmental correction
K
term to account for the influence of reflected sound on the mean sound pressure level on the reference
measurement surface, expressed in decibels
NOTE 1 K is frequency dependent and can be determined in accordance with ISO 3744 or ISO 3746. In the case of
A-weighting, it is denoted K .
2A
NOTE 2 For the purposes of this International Standard, the environmental correction, K , is only used as an indicator
to qualify the environment and is determined for the reference measurement surface.
3.23
local environmental correction
K
correction applied to the measured sound pressure levels at the work station to account for the influence of
reflected sound, expressed in decibels
6 © ISO 2010 – All rights reserved

ISO 11201:2010(E)
NOTE 1 In the case of A-weighting, it is denoted K .
3A
NOTE 2 The local environmental correction is not applied in this International Standard, but appears in other standards
[16] [18]
of this series (ISO 11202 , ISO 11204 ).
4 Instrumentation
4.1 General
The instrumentation system, including the microphones, cables, and windscreen if used, shall meet the
requirements of IEC 61672-1:2002, class 1, and the filters shall meet the requirements of IEC 61260:1995,
class 1.
4.2 Calibration
Before and after each series of measurements, a sound calibrator meeting the requirements of
IEC 60942:2003, class 1, shall be applied to each microphone to verify the calibration of the entire measuring
system at one or more frequencies within the frequency range of interest. Without any further adjustment, the
difference between the readings at each end of the series of measurements shall be less than or equal to
0,5 dB. If the difference exceeds 0,5 dB, the results of the series of measurements shall be discarded.
The sound calibrator shall be calibrated, and the compliance of the instrumentation system with the
requirements of IEC 61672-1 shall be verified at intervals in a laboratory making calibrations traceable to
appropriate standards.
Unless national regulations dictate otherwise, the sound calibrator should be calibrated annually, and the
compliance of the instrumentation system with the requirements of IEC 61672-1 should be verified at intervals
not exceeding 2 years.
5 Test environment
5.1 General
This International Standard allows the determination of the emission sound pressure level with accuracy
grade 1 (precision) and grade 2 (engineering) in a test environment under essentially free-field conditions over
a reflecting plane, where no correction for environmental influence is necessary and permitted.
The user of this International Standard shall choose between these two grades of accuracy. The accuracy
grade used shall be recorded and reported.
The test environment, therefore, has to meet strict requirements which are often impossible to comply with for
installations in situ.
Determinations of the emission sound pressure level with accuracy grade 1 (precision) or accuracy grade 2
(engineering) is possible in a hemi-anechoic room as well as outdoors on a reflecting plane, with no reflecting
objects influencing the result of the measurement.
Determinations of accuracy grade 2 in accordance with this International Standard are possible indoors and
outdoors if background noise and influence from reflected sound do not exceed certain limits.
ISO 11201:2010(E)
5.2 Criteria for the adequacy of the test environment
5.2.1 Accuracy grade 1 (precision)
5.2.1.1 Indoors
A suitable test environment is a hemi-anechoic room as specified in ISO 3745.
5.2.1.2 Outdoors
A suitable test environment is a plane area outdoors with hard ground (concrete, asphalt or similar surfaces)
and no reflecting objects in the near vicinity.
For the purposes of this International Standard, an object is considered as sound-reflecting if three conditions
are fulfilled:
a) its width (e.g. diameter of a pole or supporting member) exceeds one-tenth its distance from the
reference box;
b) it is not covered with absorbing material;
c) either, having an acoustically smooth surface, the object is arranged in such a way as to reflect sound like
a mirror towards the microphone position or its surface texture gives rise to diffuse reflection (reflection of
sound in many directions).
Assessment of item c) requires advanced expertise.
The distance between a reflecting object and the closest point of the sound source under test or the distance
between a reflecting object and the microphone position shall be:
a) at least twice the distance between the microphone position and the most remote point of the source
under test;
b) not smaller than 10 m.
With more complex conditions for sound propagation, e.g. more reflecting surfaces or with microphone
positions screened from the sound radiating part of the source under test and reflecting objects in the vicinity,
accuracy grade 1 can only be claimed if it is proven by simulation techniques or with a reference sound source
that the influence of all reflecting objects does not exceed 0,3 dB at any microphone position.
[11]
NOTE The contributions of reflections can be calculated, e.g. by using the methods of ISO 9613-2 .
The influence of meteorological conditions like temperature, ambient pressure and humidity on sound
propagation is negligible with a measuring distance of 1 m. Measurements shall not be made during periods of
precipitation (e.g. rain, hail) or when wind speeds exceed 3 m/s.
5.2.2 Accuracy grade 2 (engineering)
5.2.2.1 Indoors
Measurements with accuracy grade 2 may be made indoors in conformity with this International Standard
provided that the environmental influence is negligible. This condition is met if both the following statements
are true.
⎯ The environmental correction, K , does not exceed 2 dB for the reference measurement surface on
2A
which the microphone positions are located.
⎯ The radiation of the source is not directed mainly upwards or to opposite directions of the work station.
8 © ISO 2010 – All rights reserved

ISO 11201:2010(E)
Alternatively, there is negligible environmental influence if all three of the following statements are true.
⎯ The ratio A/S , where A is the equivalent absorption area determinable, for example, in accordance with
M
methods given in ISO 3744; S is the area of the reference measurement surface including the work
M
station of the source under test, exceeds 30. In hard-walled rooms without absorption, this is the case if
the ratio S /S , where S is the area of the room surfaces, exceeds 250.
R M R
NOTE 1 The parameter S defined here is different from that used in ISO 3744 since the reference measurement
M
surface is passing through the work station.
NOTE 2 A ratio A/S exceeding 30 is only valid for rooms that are normally considered to provide a free field over a
M
reflecting plane.
⎯ The height of the room exceeds 5 times the height of the source under test if the ceiling is not highly
absorbent.
⎯ The distance between a reflecting object and the sound source under test or the microphone position is
not smaller than the distance between the microphone position and the most remote point of the source
under test.
This International Standard cannot be used if the sound level at the work station is dominated by radiating
parts of the machine that are not in direct line of sight to the microphone position.
Alternatively, a hemi-anechoic room as specified in ISO 3745 can be used.
The environmental correction, K , describing the deviations of the test environment from ideal conditions
2A
shall be determined in accordance with one of the methods given in ISO 3744 or ISO 3746.
If it is necessary to make measurements in spaces not in accordance with these requirements, then
[16] [18] [19]
ISO 11202 , ISO 11204 or ISO 11205 may be applicable.
5.2.2.2 Outdoors
Measurements with accuracy grade 2 may be made outdoors in conformity with this International Standard
provided that the environmental influence is negligible. This condition is met if the following two statements
are true.
⎯ The source under test is located on a reflecting plane ground.
⎯ The distance between a reflecting object and the sound source under test or the microphone position is
not smaller than the distance between the microphone position and the most remote point of the source
under test.
If approximately parallel reflecting surfaces produce higher order reflections, one of each pair shall be
removed or covered with absorbing material.
Measurements shall not be made during periods of precipitation (e.g. rain, hail) or when wind speeds exceed
3 m/s.
5.3 Enclosed work station positions
When the operator is located in an enclosed cab or in an enclosure separate from the source under test, the
cab or enclosure is regarded as an integral part of the source under test and, consequently, sound reflections
inside the cab or enclosure are considered contributions to the emission sound pressure level.
During noise emission measurements, doors and windows of the cabin or enclosure shall be open or closed
as defined in the relevant noise test code, if one exists.
The emission sound pressure level at an enclosed work station position can be determined with accuracy
grade 1 or 2. The criteria referenced in Annex A for both grades of accuracy are determined using an
additional work station position outside the cab or cabin, but at a comparable distance (distance from the
ISO 11201:2010(E)
source under test to the centre of the cabin) from the source under test. This is necessary in all cases when
the noise inside the cabin is due to airborne sound transmission into the cabin enclosure, i.e. the noise level at
the ears of the operator in the cabin is due to the sound field outside the cabin. If levels inside the cabin are
strongly dependent on the microphone position, at least four measurement points shall be used to sample the
sound field in the relevant part of the cabin. These positions shall be reported in accordance with 12.6.
5.4 Criteria for background noise
5.4.1 General
At the microphone position(s), the background noise (including wind noise at the microphone) measured as
A-weighted sound pressure level or (if results in frequency bands are required) in each of the frequency bands
of interest shall be at least 10 dB for accuracy grade 1 (precision) or 6 dB for accuracy grade 2 (engineering)
below the uncorrected level of the source under test measured in the presence of this background noise.
If the 10 dB criterion or 6 dB criterion in the previous paragraph is not satisfied, data may still be taken and
reported, but the accuracy of the results may be reduced. In this case, the report shall clearly state that the
background noise requirements of this International Standard have not been met, and (if frequency band data
are reported) shall identify the particular frequency bands that do not meet the criteria. Furthermore the report
shall not state or imply that the measurements have been made in “full conformity” with this International
Standard.
For measurements in frequency bands, further criteria for background noise are given in Annex B.
5.4.2 Corrections for background noise
The measured sound pressure levels (A-weighted or in frequency bands) shall be subject to a correction for
the presence of background noise, K , calculated according to Equation (5):
−∆0,1 L
K =−10 lg(1−10 ) dB (5)
where ∆L is the difference between the sound pressure levels measured (A-weighted or in frequency bands),
at the work station, with the source under test in operation and turned off, respectively.
For the purposes of this International Standard, if ∆L > 15 dB, assume K = 0.
For accuracy grade 1, if ∆L < 10 dB for one or more octave or one-third-octave fr
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