EN ISO 11204:2009

SLOVENSKI STANDARD
01-november-2009
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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 - Method
requiring environmental corrections (ISO 11204:1995, including Cor 1:1997)
Akustik - Geräuschabstrahlung von Maschinen und Geräten - Messung von Emissions-
Schalldruckpegeln am Arbeitsplatz und an anderen festgelegten Orten - Verfahren mit
Umgebungskorrekturen (ISO 11204:1995, 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 nécessitant des corrections d'environnement (ISO 11204:1995, Cor 1:1997
inclus)
Ta slovenski standard je istoveten z: EN ISO 11204:2009
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 11204
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 17.140.20 Supersedes EN ISO 11204:1995
English Version
Acoustics - Noise emitted by machinery and equipment -
Measurement of emission sound pressure levels at a work
station and at other specified positions - Method requiring
environmental corrections (ISO 11204:1995, including Cor
1:1997)
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 nécessitant des corrections d'environnement (ISO mit Umgebungskorrekturen (ISO 11204:1995,
11204:1995, Cor 1:1997 inclus) einschließlich Cor 1:1997)
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 11204:2009: 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 11204:1995, including Cor 1:1997 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
11204:2009 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 11204:1995.
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 EU Directives.
For relationship with EU 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 11204:1995, including Cor 1:1997 has been approved by CEN as a EN ISO 11204:2009
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 11204
First edition
1995-I 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 -
Method requiring environmental
corrections
Acoustique - Bruit 6mis par /es machines et gquipements - Mesurage
des niveaux de pression acoustique d ’kmission au poste de travail et en
d ’autres positions spGcifi6es - Mgthode nbessitant des corrections
d ‘environnemen t
Reference number
IS0 11204:1995(E)
IS0 11204:1995(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
(IEC) 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 11204 was prepared by Technical Committee
lSO/TC 43, Acoustics, Subcommittee SC 1, Noise.
Annex A forms an integral part of this International Standard. 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 1 Geneve 20 l Switzer 4and
Printed in Switzerland
ii
0 IS0 IS0 11204:1995(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 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. If this
correction is less than the specified value, the results meet the engi-
neering grade of accuracy, but otherwise they meet the survey grade.
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 Inter-
national Standards giving methods for the determination of sound power
levels.
III
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IS0 11204:1995(E)
INTERNATIONAL STANDARD 0 IS0
Acoustics - Noise emitted by machinery and
Measurement of emission sound
equipment -
pressure levels at a work station and at other specified
- Method requiring environmental
positions
corrections
fied positions may be located in the vicinity of an
1 Scope
attended or unattended machine. Such positions are
sometimes referred to as bystander positions.
1.1 General
This International Standard specifies requirements on
the test environment. Instructions are given for the
This International Standard specifies a method for
installation and operation of the machine under test
measuring the emission sound pressure levels of
and for the choice of microphone positions for the
machinery and equipment, at a work station and at
work station and for other specified positions. The
other specified positions nearby, in any environment
purpose of the measurements is to permit compar-
which meets certain qualification requirements.
ison of the performance of different units of a given
family of machinery or equipment, under defined en-
Emission sound pressure levels are measured as A-
vironmental conditions and standardized mounting
weighted and, if required, C-weighted peak, and in
and operating conditions. The data obtained may also
frequency bands.
be used for the declaration and verification of emis-
sion sound pressure levels as specified in IS0 4871.
NOTE 1 The contents of this and related International
Standards are summarized in table 1 of IS0 11 ZOO:1 995.
NOTE 2 At any given position in relation to a particular
machine, and for given mounting and operating conditions,
A method is given for determining a local environ-
the emission sound pressure levels determined by the
mental correction (the acceptable maximum value of
method of this International Standard will in general be
which is specified) to be applied to the measured
lower than the directly measured sound pressure levels for
sound pressure levels to exclude the effects of re-
the same machine in the typical workroom where it is used.
flections from reflecting surfaces other than the plane
This is due to reverberation and the contributions of other
on which the machinery or equipment is placed. This
machines. A method of calculating the sound pressure lev-
correction is based upon the mean sound pressure els in the vicinity of a machine operating alone in a
workroom is given in IS0 11690-3. Commonly observed
level on a measurement surface, the sound pressure
differences are 1 dB to 5 dB, but in extreme cases the dif-
level measured at a specified position, and either an
ference may be even greater.
environmental indicator or the equivalent absorption
area of the test room. The grade of accuracy of the
measurements (engineering or survey) depends upon
the vaule of the local environmental correction.
1.2 Types of noise and noise sources
A work station is occupied by an operator. It may be
located in open space in the room where the source The method specified in this International Standard is
operates, or in a cab fixed to the source, or in an en- applicable to all types of machinery, both moving and
closure remote from the source. One or more speci- stationary, for indoor or outdoor use.

0 IS0
IS0 11204:1995(E)
The method is applicable to machines of all sizes, and
2 Normative references
to all types of noise as defined in IS0 2204 and
IS0 12001. The following standards contain provisions which,
through reference in this text, constitute provisions
of this International Standard. At the time of publi-
1.3 Test environment
cation, the editions indicated were valid. All standards
are subject to revision, and parties to agreements
The method is applicable to an indoor or outdoor en-
based on this International Standard are encouraged
vironment with one or more reflecting planes present,
to investigate the possibility of applying the most re-
meeting specified requirements.
cent editions of the standards indicated below.
Members of IEC and IS0 maintain registers of cur-
rently valid International Standards.
1.4 Specified positions
IS0 2204: 1979, Acoustics - Guide to Inter-national
This International Standard is applicable to work
Standards on the measurement of airborne acoustical
stations and other specified positions where emission
noise and evaluation of its effects on human beings.
sound pressure levels are to be measured.
IS0 3744:1994, Acoustics - Determination of sound
Examples of appropriate positions where measure-
power- levels of noise sources using sound pressure
ments may be made include the following:
- Engineering method in an essentially free field over-
a) work station located in the vicinity of the machine a reflecting plane.
under test; this is the case for many industrial
IS0 3746: 1995, Acoustics - Determination of sound
machines and domestic appliances;
power levels of noise sources using sound pressure
b) work station within a cab which is an integral part - Survey method using an enveloping measurement
of the machine under test; this is the case for surface over a reflecting plane.
many industrial trucks and earth-moving ma-
IS0 11200: 1995, Acoustics - Noise emitted by ma-
chines;
chinery and equipment - Guidelines for the use of
c) work station within a partial or total enclosure (or basic standards for the determina Con of emission
behind a screen) supplied by the manufacturer as sound pressure levels at a work station and at other
specified positions.
an integral part of the machinery or equipment;
d) work station partially or totally enclosed by the IS0 12001: -‘1, Acoustics - Noise emitted by ma-
machine under test; this situation may be en- chinery and equipment - Rules for the drafting and
countered with some large industrial machines; presentation of a noise test code.
e) bystander positions occupied by individuals not EC 651 :I 979, Sound level meter-s.
responsible for the operation of the machine
EC 804: 1985, Integrating-averaging sound level
under test, but who may be in its immediate vi-
ne tefs.
cinity, either occasionally or continuously;
EC 942: 1988, Sound calibrator-s.
f) other specified positions, not necessarily work
stations or bystander positions.
IEC 1260: -2), Electroacoustl ’cs - Octave-band and
The work station may also lie on a specified path fractional-octave-band filters.
along which an operator moves (see 11.4).
3 Definitions
15 . Measurement uncertainty
For the purposes of this International Standard, the
While it is not possible to give universal values for the
following definitions apply. More detailed definitions
standard deviation of reproducibility of emission
may be found in noise test codes for specific types
sound pressure levels at work stations, guidance is
of machinery and equipment.
given in clause 4.
1) To be published.
2) To be published. (Revision of IEC 225:1966)
IS0 11204:1995(E)
0 IS0
3.1 emission: Airborne sound radiated by a well- ated to LpA. LpAeqT shall be measured with an instru-
ment which complies with the requirements of
defined noise source (e.g. the machine under test).
IEC 804.
Noise emission descriptors may be incorporated
NOTE 3
in a product label and/or product specification. The basic NOTES
noise emission descriptors are the sound power level of the
source itself and the emission sound pressure levels at a 5 In general, the subscripts eq and T are omitted since
time-averaged emission sound pressure levels are necess-
work station and/or at other specified positions (if any) in the
arily determined over a certain measurement time interval.
vicinity of the source.
6 Equation (1) is identical to that for the familiar IS0 en-
3.2 emission sound pressure, p: The sound press-
vironmental noise descriptor “equivalent continuous sound
ure, at a specified position near a noise source, when pressure level” defined in IS0 1996-1. However, the emis-
sion quantity defined above is used to characterize the noise
the source is in operation under specified operating
emitted by a machine under test and assumes that stan-
and mounting conditions on a reflecting plane surface,
dardized measurement and operating conditions as well as
excluding the effects of background noise as well as
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, L!, peak:
I
The highest instantaneous value of the emission
3.3 emission sound pressure level, Lp: Ten times
sound pressure level determined over an operational
the logarithm to the base IO of the ratio of the square
cycle. It is expressed in decibels.
of the emission sound pressure, p* t), to the square
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 ,s: 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 T) normalized to
ure is 20 PPa.
To=1 s.
NOTE 4 Examples include:
It is expressed in decibels and is given by the follow-
- maximum A-weighted emission sound pressure level ing equation:
with time-weighting F: LpAFmax;
P (4
L pls= IO Ig +lT ,dt dB . . .
(2)
emission sound pressure level: I
- C-weighted peak
O O PO
L
pC,peak-
+lOlg 2 dB
= LpeqT
The emission sound pressure level shall be deter-
TO
mined at a specified position in accordance with either
a test code for a specific family of machines or, if no
NOTE 7 The above equation is identical to that for the
test code exists, a method that complies with the
familiar IS0 environmental noise descriptor “sound expo-
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
level, LpeqT: Emission sound pressure level of a con-
3.4 impulsive noise index (impulsiveness): Quan-
tinuous steady sound that, within a measurement
tity by means of which the noise emitted by a source
time interval, T, has the same mean square sound
can be characterized as “impulsive ”. (See annex C.)
pressure as a sound under consideration which varies
It is expressed in decibels.
with time.
It is expressed in decibels and is given by the follow-
3.5 free field over a reflecting plane: Sound field
ing equation: in a homogeneous, isotropic medium in the half space
above an infinite, rigid plane surface on which the
machine under test is located.
P (4
ldt dB . . .
L
(1)
peqT= lo lgGIT
O PO
3.6 work station; operator ’s position: Position in
A-weighted time-averaged emission sound pressure
the vicinity of the machine under test which is in-
levels are denoted by L,,AeqT, which is usually abbrevi- tended for the operator.
0 IS0
IS0 11204:1995(E)
3.16 environmental indicator, K2: A term to ac-
3.7 operator: Individual whose work station is in the
count for the influence of reflected or absorbed sound
vicinity of a machine and who is performing a work
task associated with that machine. on the surface sound pressure level: K2 is frequency
dependent and is expressed in decibels. In the case
of A-weighting, it is denoted KzA (see the IS0 3740
3.8 specified position: Position defined in relation
series).
to a machine, including, but not limited to, an operat-
or’s position. The position can be a single, fixed point,
3.17 local environmental correction, KS: A cor-
or a combination of points along a path or on a surface
rection term to account for the influence of reflected
located at a specified distance from the machine, as
sound on the emission sound pressure level at a
described in the relevant noise test code, if any exists.
specified position (e.g. a work station) for the machine
NOTE 8 Positions located in the vicinity of a work station, under test. K3 is dependent upon both frequency and
or in the vicinity of an unattended machine, may be ident-
position and is expressed in decibels. In the case of
ified as “bystander positions ”.
A-weighting, it is denoted I&.
3.9 operational period: Interval of time during
which a specified process is accomplished by the 4 Measurement uncertainty
machine under test (e.g. for a dishwasher when
washing or rinsing or drying). A single value of an emission sound pressure level of
a noise source determined in accordance with the
method specified in this International Standard is likely
3.10 operational cycle: Specific sequence of oper-
to differ from the true value at a fixed position by an
ational periods occurring while the machine under test
amount within the range of the measurement uncer-
performs a complete work cycle. Each operational
tainty. The uncertainty in measurements of emission
period is associated with a specific process that may
sound pressure levels arises from several factors
occur only once, or may be repeated, during the
which affect the results, some associated with en-
operational cycle (e.g. for a dishwasher when washing
vironmental conditions in the measurement room and
and rinsing and drying).
others with experimental techniques.
3.11 measurement time interval: Portion or a
The measurement uncertainty depends on the stan-
multiple of an operational period or operational cycle
dard deviation of reproducibility and on the degree of
for which the emission sound pressure level is deter-
confidence that is desired. Extensive measurement
mined or over which the maximum emission sound
data are necessary in order to establish standard de-
pressure level is searched for.
viations of reproducibility of emission sound pressure
levels at individual positions and, in any case, these
3.12 time history: Continuous recording of the
standard deviations are likely to vary considerably be-
emission sound pressure level, as a function of time,
tween the many different types of machinery and
which is obtained during one or more operational pe-
equipment to which this International Standard is ap-
riods of an operational cycle.
plicable. It is therefore not possible to provide infor-
mation which is universally applicable, and reference
3.13 background noise: The noise from all sources
can only be made to noise test codes for relevant data
other than the machine under test.
on individual types of noise source.
NOTE 9 Background noise may include contributions
The method described in this International Standard
from airborne sound, structure-borne vibration, and elec-
yields different degrees of accuracy depending upon
trical noise in instrumentation.
the specified position and the related local environ-
mental correction. If I&A is less than or equal to
3.14 background noise level: The sound pressure
2 dB, the degree of accuracy is that of an engineering
level measured when the machine under test is not
method. If KS* is greater than 2 dB, but less than or
operating. It is expressed in decibels.
equal to 7 dB, the degree of accuracy is that of a
survey method. The accuracy is position dependent.
3.15 background noise correction, K,: A correction
term to account for the influence of background noise A value of the standard deviation of reproducibility
on the emission sound pressure level at the specified equal to or less than 2,5 dB (excluding variations in
operating and mounting conditions) for engineering
positions of the machine under test. K, is frequency
dependent and is expressed in decibels. The cor- grade measurements, and equal to or less than 5 dB
rection in the case of A-weighting, I&, is to be de- for survey grade measurements can be expected for
termined from A-weighted measured values. the A-weighted emission sound pressure level of a
IS0 11204:1995(E)
0 IS0
source which emits noise with a relatively “flat” 6.3 Enclosed work station positions
spectrum in the frequency range 100 Hz to
When the operator is located in an enclosed cab or in
IO 000 Hz. The given value for the standard deviation
an enclosure remote from the machine under test, the
of reproducibility is a maximum value, but for a well-
cab or enclosure is regarded as an integral part of the
defined family of machines, it may be smaller. For
machine under test and, consequently, sound re-
example, for one family of woodworking machines, it
flections inside the cab or enclosure are considered
has been shown that the standard deviation of
contributions to the emission sound pressure level.
reproducibility is equal to I,0 dB.
No environmental corrections are permitted.
5 Instrumentation
During noise emission measurements, doors and
windows of the cabin or enclosure shall be open or
The instrumentation system, including the micro-
closed as defined in the noise test code for the ma-
phone and cable, shall meet the requirements for a
chinery or equipment being measured.
class 1 instrument specified in IEC 651 or, in the case
of integrating-averaging sound level meters, in
NOTE 10 Because of the instrumentation and back-
IEC 804.
ground noise level requirements of this International Stan-
dard, the measurements will comply with engineering grade
For measurements in octave or one-third-octave
requirements and accuracy (see IS0 11201).
bands, the filters shall meet the requirements of
IEC 1260.
If the work station or bystander ’s position of the ma-
chine is located inside a cab or a cabin, an additional
Before and after each series of measurements, a
“conventional” work station or bystander ’s position
sound calibrator with an accuracy of + 0,3 dB (class
outside the cab or cabin (e.g. for maintenance) in the
1 as specified in IEC 942) shall be applied to the
vicinity of machine under test shall be specified in the
microphone to verify the calibration of the entire
noise test code.
measuring system at one or more frequencies over
the frequency range of interest.
6.4 Criterion for background noise
The compliance of the calibrator with the require-
ments of IEC 942 shall be verified once a year. The
At the microphone position(s), the background noise
compliance of the instrumentation system with the
(including wind noise at the microphone) measured
of IEC 651 (or, in the case of
requirements
as a weighted sound pressure level or in each of the
integrating-averaging systems, with the requirements
frequency bands of interest shall be at least 6 dB (and
of IEC 804) shall be verified at least every 2 years.
preferably more than 15 dB) below the level due to
the machine under test. Corrections for background
The date of the last verification of the compliance with
noise in decibels are given by the following equation:
the relevant IEC standards shall be recorded.
K, = - IO Ig (1 - 10- “. ‘hL) dB . . .
(3)
6 Test environment
where AL is the difference between the sound
pressure levels measured, at a specified position, with
6.1 General
the machine under test in operation and turned off,
respectively.
Any environment which meets the qualification re-
quirements of 6.2 and which is adequately isolated
For the purposes of this International Standard, if
from background noise in accordance with the re-
AL > 15 dB, assume K, = 0; if AL < 6 dB (i.e.
quirements of 6.4 is suitable for measurements in
K,A > I,3 dB), the measurement is invalid according
accordance with this International Standard.
to this International Standard.
6.2 Criterion for the adequacy of the test
K, shall be determined for each microphone position.
environment
6.5 Ambient conditions during
IS0 3744:1994, annex A, and IS0 3746:1995, annex
A, describe procedures for determining the magnitude measurements
of the environmental indicator KzA, to account for de-
Ambient conditions may have an adverse effect on
viations of the test environment from ideal, free-field
the microphone used for the measurements. Such
conditions. For this International Standard, the en-
vironmental indicator, KzA, shall not exceed 7 dB. conditions (e.g. strong electric or magnetic fields,
@I3 IS0
IS0 11204:1995(E)
Corrections K, and K3 to be considered are those rel-
wind, high or low temperatures, or impingement of
evant to the frequency weighting for which emission
air discharge from the machine under test) shall be
sound pressure levels have been measured. For A-
avoided by proper selection or positioning of the
weighting:
microphone.
L = L ’,, - K,A - &A . . .
(4)
PA
66 l Local environmental correction
where the prime indicates measured values; no prime
Annex A describes a procedure for determining the indicates emission values.
magnitude of the local environmental correction K3, to
For a specified position inside an enclosure, as de-
account for the influence of reflected sound on the
fined in 6.3, no environmental corrections are permit-
emission sound pressure level at the specified
ted.
position(s).
NOTE 13 If the machine under test produces isolated
The method given in annex A requires data for a
single-event sounds,
the single-event emission sound
number of measurement positions around the ma-
pressure level at the specified position (see 3.3.3) L,, ls,
chine under test, as well as information about the
should be determined.
acoustical properties of the test room. Measurements
made in accordance with this International Standard
9 Installation and operation of machine
are valid if &A does not exceed 7 dB. lf &A is less
than or equal to 2 dB, the degree of accuracy is that
under test
of an engineering method. If &A is greater than
2 dB, but less than or equal to 7 dB, the degree of
9.1 General
accuracy is that of a survey method.
The manner in which the machine under test is in-
stalled and operated may have a significant influence
7 Quantities to be measured
on the emission sound pressure levels at the speci-
fied positions. This clause specifies conditions that are
The basic quantities to be measured at each specified
intended to minimize variations in the noise emission
position over the specified operational periods or
due to the installation and operating conditions of the
operational cycle of the machine under test are
machine under test. Relevant instructions of a noise
test code, if any exists for the family of machinery or
- the A-weighted sound pressure level, LtpA (the
equipment to which the machine under test belongs,
prime indicates measured values);
shall be followed. The same installation and operating
conditions of the machine under test shall be used for
- the C-weighted peak sound pressure level,
the determination of emission sound pressure levels
L
pC,peak-
and sound power levels. The noise test code for the
NOTES
machinery concerned shall describe the installation,
mounting and operating conditions in detail.
11 Sound pressure levels using other frequency
weightings or in octave or one-third-octave frequency
NOTE 14 The noise test code may make an exception to
bands, as well as other entities relating to the time-history
this requirement on identical installation, mounting and op-
of the noise emission (impulsiveness, sound pressure level
erating conditions for equipment that is used on tables.
as a function of time, etc.) may also be measured, as re-
Such equipment may be mounted on the floor during sound
quired for the design of low-noise machines.
power determinations.
12 For some. applications, it may not be necessary to
Particularly for large machines, it is necessary to make
measure the value of the C-weighted peak sound pressure
a decision as to which components, sub-assemblies,
level. (See clause 5, note 4 of IS0 4871:-J
auxiliary equipment, power sources, etc., belong to
the machine under test.
8 Quantities to be determined
9.2 Location of source
In order to obtain emission sound pressure levels at
a specified position, both background noise cor- The machine under test shall be installed with respect
to the reflecting plane in one or more locations as if
rections K, and local environmental corrections K3
it were being installed for normal usage. The machine
shall be applied to measured sound pressure levels,
under test shall be remote from any wall, ceiling or
except peak sound pressure levels, Lpc peak, for which
I
no corrections are permitted. other reflecting object.
0 IS0 IS0 11204:1995(E)
NOTE 15 Typical installation conditions for some ma- 9.3.2 Base-mounted and wall-mounted
chines involve two or more reflecting surfaces (e.g. an ap-
machinery and equipment
pliance installed against a wall), or free space (e.g. a hoist),
or an opening in an otherwise reflecting plane (so that radi-
Such machinery and equipment shall be placed on a
ation may occur on both sides of the vertical plane). Detailed
reflecting (acoustically hard) plane (floor or wall).
information on installation conditions should be based on
Base-mounted machinery or equipment intended ex-
the general requirements of this International Standard and
clusively for mounting in front of a wall shall be in-
on the relevant noise test code, if one exists.
stalled on an acoustically hard surface in front of an
acoustically hard wall. Table-top machinery or equip-
ment shall be placed on a table or stand as required
for operation according to the noise test code specific
9.3 Mounting of source
to the family of machinery or equipment to which the
machine under test belongs. The table or stand shall
In many cases, the noise emission at the specified
be at least I,5 m from any absorptive surface of the
positions of the machine under test will depend upon
test room. Such machinery or equipment shall be
the support or mounting conditions of the machine.
placed at the centre of the top of the standard test
Whenever a typical mounting condition exists for a
table. A suitable design for a test table is shown in
machine, that condition shall be used or simulated, if
annex B.
practicable.
If a typical mounting condition does not exist or can-
94 . Auxiliary equipment
not be utilized for the test, care shall be taken to avoid
changes in the sound emission of the machine caused
Care shall be taken to ensure that any electrical
by the mounting system used for the test. Steps shall
conduits, piping or air ducts connected to the machine
be taken to reduce any sound radiation from the
under test do not radiate significant amounts of sound
structure on which the machine is mounted.
energy into the test environment.
Many small machines, although themselves poor
If practicable, all auxiliary equipment necessary for the
radiators of low-frequency sound, may, as a result of
operation of the machine under test that is not a part
the method of mounting, radiate more low-frequency
of it (see 9.1) shall be located outside the test en-
sound when their vibrational energy is transmitted to
vironment. If this is impracticable, the auxiliary equip-
surfaces large enough to be efficient radiators. Resil-
ment shall be included in the test configuration and its
ient mounting shall be interposed, if possible, be-
operating conditions described in the test report.
tween the machine to be tested and the supporting
surfaces so that the transmission of vibration to the
support and the reaction of the source are both mini-
9.5 Operation of the machine during test
mized. In this case, the mounting base should be rigid
(i.e. have a sufficiently high mechanical impedance) to
During the noise measurements, the operating condi-
prevent it from vibrating excessively and radiating
tions specified in the relevant noise test code shall be
sound. However, resilient mounts shall be used only
used, if any exists for the particular family of machin-
if the machine under test is resiliently mounted in
ery or equipment to which the machine under test
typical field installations.
belongs. If there is no test code, the machine under
test shall, if possible, be operated in a manner which
is typical of normal use. In such a case, one or more
of the following operating conditions shall be se-
lected:
a) machine under specified load and operating
9.3.1 Hand-held machinery and equipment
conditions;
Such machinery and equipment shall be suspended
b) machine under full load (if different from the first
or guided by hand, so that no structure-borne sound
condition above);
is transmitted via any attachment that does not be-
long to the machine under test. If the machine under
machine under no load (idling);
d
test requires a support for its operation, the support
structure shall be small, considered to be a part of the d) machine under operating conditions correspond-
machine under test, and as described in the relevant ing to maximum sound generation representative
of normal use;
noise test code, if any exists.

0 IS0
IS0 11204:1995(E)
machine with simulated load operating under emission at specified positio ns can be determined for
d
carefully defined conditions; the speci fied operatin g cond itions.
For a given source under test, the measurement time
machine under operating conditions with charac-
f 1
interval, T, may be composed of a number of sub-
teristic operational cycle.
measurement time intervals, Tj, each of which corre-
Emission sound pressure levels at specified positions
sponds to a specified operational period of the source.
shall be determined for any desired set of operating
In this case, a single emission sound pressure level is
conditions (i.e. temperature, humidity, device speed,
usually desired. It is obtained by averaging the indi-
etc.).
vidual A-weighted emission sound pressure levels
according to the following equation:
These test conditions shall be selected beforehand
N
and shall be held constant during the test. The ma-
+ )-$-I oO- ‘A~T~i) . . . (5)
chine under test shall be in the desired operating
i=l
condition before any noise measurements are made.
If the noise emission also depends on other operating
parameters (e.g. type of material being processed or
T is the total measurement time interval
type of tool) then, out of the aggregate of possibilities,
the ones to be defined shall be those which narrow N
down the variation possibilities as far as is practicable
T= Ti
c
and which can be regarded as typical with regard to
the noise emission.
are the sub-measurement time intervals;
Ti
For special purposes, it is appropriate to define one
N is the total number of sub-measurement
or more operating conditions in such a way that both
time intervals or operational periods;
a high reproducibility of noise emission of machinery
or equipment of the same family is ensured and that
is the A-weighted emission sound
L./AT(i)
the operating conditions which are most common and
pressure level over a sub-measurement
typical for the family of machinery or equipment are
time interval I-;:.
covered. These operating conditions shall be defined
in specific noise test codes.
For machinery and equipment with a specified oper-
ational cycle, it is usually necessary to extend the
If simulated operating conditions are used, they shall
measurement time interval to an integral number of
be chosen to give emission sound pressure levels at
consecutive operational cycles.
specified positions which are representative of normal
usage of the machine under test.
The measurement time interval shall correspond only
to the operational periods for which the emission
In special cases, the resul
...