EN ISO 11202:2009

SLOVENSKI STANDARD
01-november-2009
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SIST EN ISO 11202:1995/AC:2004
SIST EN ISO 11202:1997
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Acoustics - Noise emitted by machinery and equipment - Measurement of emission
sound pressure levels at a work station and at other specified positions - Survey method
in situ (ISO 11202:1995)
Akustik - Geräuschabstrahlung von Maschinen und Geräten - Messung von Emissions-
Schalldruckpegeln am Arbeitsplatz und an anderen festgelegten Orten - Verfahren der
Genauigkeitsklasse 3 für Messungen unter Einsatzbedingungen (ISO 11202:1995,
einschließlich Cor 1:1997)
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 -
Méthode de contrôle in situ (ISO 11202:1995, Cor 1:1997 inclus)
Ta slovenski standard je istoveten z: EN ISO 11202:2009
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 11202
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 17.140.20 Supersedes EN ISO 11202:1995
English Version
Acoustics - Noise emitted by machinery and equipment -
Measurement of emission sound pressure levels at a work
station and at other specified positions - Survey method in situ
(ISO 11202:1995)
Acoustique - Bruit émis par les machines et équipements - Akustik - Geräuschabstrahlung von Maschinen und
Mesurage des niveaux de pression acoustique d'émission Geräten - Messung von Emissions-Schalldruckpegeln am
au poste de travail et en d'autres positions spécifiées - Arbeitsplatz und an anderen festgelegten Orten - Verfahren
Méthode de contrôle in situ (ISO 11202:1995, Cor 1:1997 der Genauigkeitsklasse 3 für Messungen unter
inclus) Einsatzbedingungen (ISO 11202:1995)
This European Standard was approved by CEN on 27 July 2009.
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, 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
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11202:2009: 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 98/37/EC .4
Annex ZB (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC .5

Foreword
The text of ISO 11202:1995 has been prepared by Technical Committee ISO/TC 43 “Acoustics” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 11202:2009 by
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 February 2010, and conflicting national standards shall be withdrawn
at the latest by February 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 11202:1995.
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 EC Directives.
For relationship with EC Directives, see informative Annexes ZA and ZB, which are integral parts 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, 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 11202:1995 has been approved by CEN as a EN ISO 11202:2009 without any modification.
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 98/37/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 98/37/EC, amended by 98/79/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
relevant 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.
Annex ZB
(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
relevant 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 Is0
STANDARD 11202
First edition
1995-l 2-l 5
Acoustics - Noise emitted by machinery
and equipment - Measurement of
emission sound pressure levels at a work
station and at other specified positions -
Survey method in situ
Acoustique - Bruit 6mis par /es machines et gquipements - Mesurage
des niveaux de pression acoustique d ’bmission au poste de travail et en
d ‘autres positions spkifikes - M&hode de con tr6le in situ
Reference number
IS0 11202:1995(E)
IS0 11202:1995(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
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. IS0
collaborates closely with the International Electrotechnical Commission
(I EC) on all matters of electrotechnical standardization.
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.
International Standard IS0 11202 was prepared by Technica I Committee
ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
Annex A forms an integral part of this International Standard0 I Annexes B,
C and D are for information only.
0 IS0 1995
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-121 I Geneve 20 l Switzerland
Printed in Switzerland
II
0 IS0 IS0 11202:1995(E)
Introduction
0.1 This International Standard specifies a method for measuring the
emission sound pressure levels at a work station and at other specified
positions in the vicinity of a machine or piece of equipment. The method
specified in this International Standard follows the method specified in
IS0 11201 (engineering method), except for the following:
measurements are permitted in situ; and
a)
b) a simplified method is specified for determining a local environmental
correction which yields results approximating those obtained in a free
field over a reflecting plane. This correction is used to derive the
emission sound pressure levels at specified positions, including work
stations. The results are limited to the survey grade of accuracy.
0.2 This International Standard is one of a series (IS0 11200 to
IS0 11204) which specifies various methods for determining the noise
emissions of a piece of machinery or equipment, or a sub-assembly of
such equipment (machine under test). IS0 11200 gives guidance on the
choice of the method to be used to determine the emission sound
pressure levels of machinery and equipment. It also gives details of lnter-
national Standards giving methods for the determination of sound power
levels.
. . .
III
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IS0 11202:1995(E)
INTERNATIONAL STANDARD 0 ISO
- Noise emitted by machinery and
Acoustics
Measurement of emission sound
equipment -
pressure levels at a work station and at other specified
positions - Survey method in sifu
station and for other specified positions. The purpose
1 Scope
of the measurements is to permit comparison of the
performance of different units of a given family of
machinery or equipment, under defined environ-
mental conditions and standardized mounting and op-
1 .l General
erating conditions. The data obtained may also be
used for the declaration and verification of emission
This International Standard specifies a method for
sound pressure levels as specified in IS0 4871.
measuring the emission sound pressure levels of
machinery and equipment, at a work station and at
NOTE 2 At any given position in relation to a particular
other specified positions nearby, in a semi-reverberant
machine, and for given mounting and operating conditions,
field. Emission sound pressure level are measured as
the emission sound pressure levels determined by the
A-weighted and, if required, C-weighted peak.
method of this International Standard will in general be
lower than the directly measured sound pressure levels for
NOTE 1 The contents of this and related International
the same machine in the typical workroom where it is used.
Standards are summarized in table 1 of IS0 11200:1995.
This is due to reverberation and the contributions of other
machines. A method of calculating the sound pressure lev-
A method is given for determining a local environment
els in the vicinity of a machine operating alone in a
correction (subject to a specified limiting maximum
workroom is given in IS0 11690-3. Commonly observed
value) to be applied to the measured sound pressure differences are 1 dB to 5 dB, but in extreme cases the dif-
ference may be even greater.
levels in order to exclude at least part of the effects
of reflections from reflecting surfaces other than the
plane on which the machinery or equipment is placed.
1.2 Types of noise and noise sources
This correction is based on the equivalent sound ab-
sorption area of the test room.
The method specified in this International Standard is
A work station is occupied by an operator. It may be applicable to all types of machinery, both moving and
located in open space in the room where the source stationary, for indoor or outdoor use.
operates, or in a cab fixed to the source, or in an en-
The method is applicable to machines of all sizes, and
closure remote from the source. One or more speci-
to all types of noise as defined in IS0 2204 and
fied positions may be located in the vicinity of an
IS0 12001.
attended or unattended machine. Such positions are
sometimes referred to as bystander positions.
This International Standard specifies requirements for
1.3 Test environment
the survey grade of accuracy on the test environment
and instrumentation. Instructions are given for the in- The method is applicable to an indoor or outdoor en-
stallation and operation of the machine under test and vironment with one or more reflecting planes present,
meeting specified requirements.
for the choice of microphone positions for the work

0 IS0
IS0 11202:1995(E)
Members of IEC and IS0 maintain registers of cur-
1.4 Specified positions
rently valid International Standards.
This International Standard is applicable to work
IS0 2204: 1979, Acoustics - Guide to International
stations and other specified positions where emission
Standards on the measurement of airborne acoustical
sound pressure levels are to be measured.
noise and evaluation of its effects on human beings.
Examples of appropriate positions where measure-
IS0 3744:1994, Acoustics - Determination of sound
ments may be made include the following:
power levels of noise sources using sound pressure
a) work station located in the vicinity of the machine - Engineering method in an essentially free field over
under test; this is the case for many industrial a reflecting plane.
machines and domestic appliances;
IS0 3746:1995, Acoustics - Determination of sound
work station within a cab which is an integral part power levels of noise sources using sound pressure
b)
of the machine under test; this is the case for - Survey method using an enveloping measurement
many industrial trucks and earth-moving ma-
surface over a reflecting plane.
chines;
IS0 11200:1995, Acoustics - Noise emitted by ma-
work station within a partial or total enclosure (or
cl chinery and equipment - Guidelines for the use of
behind a screen) supplied by the manufacturer as
basic standards for the determination I of emission
an integral part of the machinery or equipment; sound pressure levels at a work station and at other
specified positions.
work station partially or totally enclosed by the
d)
machine under test; this situation may be en- - Noise emitted by ma-
IS0 12001: -‘I, Acoustics
countered with some large industrial machines;
chinery and equipment - Rules for the drafting and
presentation of a noise test code.
d bystander positions occupied by individuals not
responsible for the operation of the machine un- IEC 651 :I 979, Sound level meters.
der test, but who may be in its immediate vicinity,
either occasionally or continuously; I EC 804: 1985, Integrating-averaging sound level me-
ters.
other specified positions, not necessarily work
f 1
I EC 942: 1988, Sound calibrators.
stations or bystander positions.
l-l
I ne work station may also lie on a specified path
3 Definitions
along which an operator moves (see 11.4).
For the purposes of this International Standard, the
following definitions apply. More detailed definitions
1.5 Measurement uncertainty
may be found in noise test codes for specific types
While it is not possible to give universal values for the of machinery and equipment.
standard deviation of reproducibility of emission
emission: Airborne
31 . sound radiated by a well-
sound pressure levels at work stations, guidance is
defined noise source (e.g. the machine under test).
given in clause 4.
NOTE 3 Noise emission descriptors may be incorporated
in a product label and/or product specification. The basic
2 Normative references
noise emission descriptors are the sound power level of the
source itself and the emission sound pressure levels at a
The following standards contain provisions which,
work station and/or at other specified positions (if any) in the
through reference in this text, constitute provisions vicinity of the source.
of this International Standard. At the time of publi-
cation, the editions indicated were valid. All standards 3.2 emission sound pressure, p: The sound press-
ure, at a specified position near a noise source, when
are subject to revision, and parties to agreements
based on this International Standard are encouraged the source is in operation under specified operating
to investigate the possibility of applying the most re- and mounting conditions on a reflecting plane surface,
cent editions of the standards indicated below. excluding the effects of background noise as well as
1) To be published.
0 IS0 IS0 11202:1995(E)
a controlled acoustical environment are used for the
the effects of reflections other than those from the
measurements.
plane or planes permitted for the purpose of the test.
It is expressed in pascals.
3.3.2 peak emission sound pressure level, Lppeak:
,
Highest instantaneous value of the emission sound
3.3 emission sound pressure level, Lp: Ten times
pressure level determined over an operational cycle.
the logarithm to the base 10 of the ratio of the square
It is expressed in decibels.
to the square
of the emission sound pressure, p* t),
of the reference sound pressure, po, measured with
3.3.3 single-event emission sound pressure level,
a particular time weighting and a particular frequency
L p Is: Time-integrated emission sound pressure level
weighting, selected from those defined in IEC 651. It
of ’an isolated single sound event of specified duration
is expressed in decibels. The reference sound press-
T (or specified measurement time 7 ’) normalized to
ure is 20 PPa.
To=1 s.
NOTE 4 Examples include:
It is expressed in decibels and is given by the follow-
ing equation:
- maximum A-weighted emission sound pressure level
with time-weighting F: $rmax;
P (4
L = 10 Ig -J-IT ldt dB . . .
(2)
pJs
- C-weighted peak emission sound pressure level:
To O PO
L
pC,peak-
+lOlg L dB
= LpeqT
TO
The emission sound pressure level shall be deter-
mined at a specified position in accordance with either
NOTE 7 The above equation is identical to that for the
a test code for a specific family of machines or, if no
familiar IS0 environmental noise descriptor “sound expo-
test code exists, a method that complies with the
sure level ”. However, the emission quantity defined above
IS0 11200 series.
is used to characterize a noise source and assumes that a
controlled environment is used for the measurements.
3.3.1 time-averaged emission sound pressure
3.4 impulsive noise index (impulsiveness): Quan-
Emission sound pressure level of a con-
level, LpeqT:
tity by means of which the noise emitted by a source
tinuous steady sound that, within a measurement
can be characterized as “impulsive ”. (See annex C.)
time interval, T, has the same mean square sound
It is expressed in decibels.
pressure as a sound under consideration which varies
with time.
3.5 free field over a reflecting plane: Sound field
It is expressed in decibels and is given by the follow- in a homogeneous, isotropic medium in the half space
ing equation: above an infinite, rigid plane surface on which the
machine under test is located.
. . .
(1)
3.6 work station; operator ’s position: Position in
the vicinity of the machine under test which is in-
tended for the operator.
A-weighted time-averaged emission sound pressure
levels are denoted by LpAeqr, which is usually abbrevi-
3.7 operator: Individual whose work station is in the
ated to LpA. LpAeqr shall be measured with an instru-
vicinity of a machine and who is performing a work
ment which complies with the requirements of
task associated with that machine.
IEC 804.
NOTES
3.8 specified position: Position defined in relation
to a machine, including, but not limited to, an oper-
5 In general, the subscripts eq and T are omitted since
ator ’s position. The position can be a single, fixed
time-averaged emission sound pressure levels are neces-
point, or a combination of points along a path or on a
sarily determined over a certain measurement time interval.
surface located at a specified distance from the ma-
chine, as described in the relevant noise test code, if
6 Equation (I) is identical to that for the familiar IS0 en-
vironmental noise descriptor “equivalent continuous sound any exists.
pressure level” defined in IS0 1996-l. However, the emis-
sion quantity defined above is used to characterize the noise NOTE 8 Positions located in the vicinity of a work station,
emitted by a machine under test and assumes that stan- or in the vicinity of an unattended machine, may be ident-
dardized measurement and operating conditions as well as ified as “bystander positions ”.
0 IS0
IS0 11202:1995(E)
3.18 typical distance, a: Distance from the speci-
3.9 operational period: Interval of time during
fied position to the. closest major sound source of the
which a specified process is accomplished by the
machine under test. If the major sound sources of the
machine under test (e.g. for a dishwasher when
machine are ill-defined, then a is chosen as the dis-
washing or rinsing or drying).
tance from the specified position to the nearest part
of the machine under test.
3.10 operational cycle: Specific sequence of oper-
ational periods occurring while the machine under test
performs a complete work cycle. Each operational
4 Measurement uncertainty
period is associated with a specific process that may
occur only once, or may be repeated, during the op-
A single value of an emission sound pressure level of
erational cycle (e.g. for a dishwasher when washing
a noise source determined in accordance with the
and rinsing and drying).
method specified in this International Standard is likely
to differ from the true value at a fixed position by an
3.11 measurement time interval: Portion or a
amount within the range of the measurement uncer-
multiple of an operational period or operational cycle
tainty. The uncertainty in measurements of emission
for which the emission sound pressure level is deter-
sound pressure levels arises from several factors
mined or over which the maximum emission sound
which affect the results, some associated with en-
pressure level is searched for.
vironmental conditions in the measurement room and
others with experimental techniques.
3.12 time history: Continuous recording of the
emission sound pressure level, as a function of time,
The measurement uncertainty depends on the stan-
which is obtained during one or more operational dard deviation of reproducibility and on the degree of
periods of an operational cycle. confidence that is desired. Extensive measurement
data are necessary in order to establish standard de-
3.13 background noise: The noise from all sources viations of reproducibility of emission sound pressure
other than the machine under test. levels at individual positions and, in any case, these
standard deviations are likely to vary considerably be-
NOTE 9 Background noise may include contributions
tween the many different types of machinery and
from airborne sound, structure-borne vibration, and elec- .
equipment to which this International Standard is ap-
trical noise in instrumentation.
plicable. It is therefore not possible to provide infor-
mation which is universally applicable, and reference
3.14 background noise level: The sound pressure
can only be made to noise test codes for relevant data
level measured when the machine under test is not
on individual types of noise source.
operating. It is expressed in decibels.
The survey method described in this International
3.15 background noise correction, K,: A correction Standard yields a lower degree of accuracy than the
term to account for the influence of background noise engineering method described in IS0 11201 because
on the emission sound pressure level at the specified the measurements are carried out under environ-
positions of the machine under test. K, is frequency mental conditions that are less well controlled.
dependent and is expressed in decibels. The cor-
NOTE 10 The method for determination of the local en-
rection in the case of A-weighting, I&, is to be de-
vironmental correction, K3, which is described in this Inter-
termined from A-weighted measured values.
national Standard, nominally underestimates the magnitude
of K3 and the value of K3 to be applied is limited to 2,5 dB.
3.16 environmental indicator, K2: A term to ac-
Therefore, the emission sound pressure levels obtained by
count for the influence of reflected or absorbed sound
this method will often be higher than the emission sound
on the surface sound pressure level. K2 is frequency
pressure levels obtained in accordance with IS0 11201.
dependent and is expressed in decibels. In the case
of A-weighting, it is denoted K2* (see the IS0 3740
Detailed information on the precision of this method
series). cannot be given as the magnitude of the local en-
vironmental correction is limited to 2,5 dB. However,
3.17 local environmental correction, KS: A cor- a value of the standard deviation of reproducibility
rection term to account for the influence of reflected equal to or less than 5 dB (excluding variations in op-
sound on the emission sound pressure level at a erating and mounting conditions) is expected for a
specified position (e.g. a work station) for the machine source which emits noise with a relatively “flat”
under test. K3 is dependent upon both frequency and spectrum in the frequency range 100 Hz to
position and is expressed in decibels. In the case of 10 000 Hz, provided the tests are performed in similar
A-weighting, it is denoted K3*. acoustic environments. The given value for the stan-

IS0 11202:1995(E)
0 IS0
cab or enclosure is regarded as an integral part of the
dard deviation of reproducibility is a maximum value,
machine under test and, consequently, sound re-
but for a well-defined family of machines, it may be
flections inside the cab or enclosure are considered
smaller.
contributions to the emission sound pressure level.
IS0 11204 gives another more accurate
NOTE 11
No environmental corrections are permitted.
method to determine &. Requirements on &, depend on
the method used to determine LpA. During noise emission measurements, doors and
windows of the cabin or enclosure shall be open or
closed as defined in the noise test code for the ma-
5 Instrumentation
chinery or equipment being measured.
The instrumentation system, including the micro-
NOTE 12 If the instrumentation system meets the re-
phone and cable, shall meet the requirements for a
quirements for a class 1 instrument as specified in IEC 651
class 1 or class 2 instrument specified in IEC 651 or,
and IEC 804, the measurements will comply with the re-
in the case of integrating-averaging sound level me-
quirements of IS0 11201, provided that the background
ters, in IEC 804.
noise requirements of that standard are met.
Before and after each series of measurements, a
If the work station or bystander ’s position of the ma-
sound calibrator with an accuracy of + 0,3 dB (class
chine is located inside a cab or a cabin, an additional
1 as specified in IEC 942) shall be applied to the
“conventional” work station or bystander ’s position
microphone to verify the calibration of the entire
outside the cab or cabin (e.g. for maintenance) in the
measuring system at one or more frequencies over
vicinity of the machine under test shall be specified in
the frequency range of interest.
the noise test code.
The compliance of the calibrator with the require-
ments of IEC 942 shall be verified once a year. The 6.4 Criterion for background noise
compliance of the instrumentation system with the
At the microphone position(s), the background noise
requirements of IEC 651 (or, in the case of
(including wind noise at the microphone) measured
integrating-averaging systems, with the requirements
as a weighted sound pressure level or in each of the
of IEC 804) shall be verified at least every 2 years.
frequency bands of interest shall be at least 3 dB (and
The date of the last verification of the compliance with
preferably more than 10 dB) below the level due to
the relevant IEC standards shall be recorded.
the machine under test. Corrections for background
noise in decibels are given by the following equation:
6 Test environment
K, = - 10 Ig (1 - 10- “# ‘AL) dB . . .
(3)
6.1 General
where AL is the difference between the sound
pressure levels measured, at a specified position, with
Any environment which meets the qualification re-
the machine under test in operation and turned off,
quirements of 6.2 and which is adequately isolated
respectively.
from background noise in accordance with the re-
quirements of 6.4 is suitable for measurements in
For the purposes of this International Standard, if
accordance with this International Standard.
hL > 10 dB, assume K, = 0; if AL < 3 dB (i.e.
K,A > 3 dB), the measurement is invalid according to
this International Standard.
6.2 Criterion for the adequacy of the test
environment
K, shall be determined for each microphone position.
Annex A of IS0 3746:1995 describes procedures for
determining the magnitude of the environmental indi-
6.5 Ambient conditions during
cator K2*, to account for deviations of the test en-
measurements
vironment from ideal, free-field conditions. For this
International Standard, the environmental indicator,
Ambient conditions may have an adverse effect on
K2*, shall not exceed 7 dB.
the microphone used for the measurements. Such
conditions (e.g. strong electric or magnetic fields,
wind, high or low temperatures, or impingement of
6.3 Enclosed work station positions
air discharge from the machine under test) shall be
in an enc losed cab or in avoided by proper selection or posit
...