EN ISO 11201:1995
(Main)Acoustics - Noise emitted by machinery and equipment - Measurement of emission sound pressure levels at a work station and at other specified positions - Engineering method in an essentially free field over a reflecting plane (ISO 11201:1995)
Acoustics - Noise emitted by machinery and equipment - Measurement of emission sound pressure levels at a work station and at other specified positions - Engineering method in an essentially free field over a reflecting plane (ISO 11201:1995)
Specification of the conditions of measurement of noise at the operator's position(s) and at other specified locations in the vicinity of different types of machinery and equipment used indoors and outdoors. It also applies to operator positions which are partially or totally enclosed by the machine or are within a cab which may be an integral part of the machine or remote from the machine. The method is applicable to all sources, both moving and stationary, with the exception of transportation vehicles.
Akustik - Geräuschabstrahlung von Maschinen und Geräten - Messung von Emissions-Schalldruckpegeln am Arbeitsplatz und an anderen festgelegten Orten - Verfahren der Genauigkeitsklasse 2 für ein im wesentlichen freies Schallfeld über einer reflektierenden Ebene (ISO 11201:1995)
Diese Internationale Norm legt ein Verfahren zur Messung der Emissions-Schalldruckpegel an Arbeitsplätzen und anderen, sich in der Nähe befindenden, festgelegten Orten von Maschinen und Geräten in einem im wesentlichen freien Schallfeld über ein reflektierenden Ebene fest. Ein Arbeitsplatz wird von einer Bedienungsperson eingenommen; er kann sich frei in dem Raum befinden, in dem die Maschine betrieben wird, oder in einer Kabine, die fest mit der Maschine verbunden ist, oder in einem von der Quelle entfernt liegenden Bedienerstand.
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 d'expertise dans des conditions approchant celles du champ libre sur plan réfléchissant (ISO 11201:1995)
Akustika - Emisija hrupa naprav in opreme - Merjenje ravni zvočnega tlaka na mestu delovanja in na drugih opredeljenih mestih - Inženirska metoda v pretežno prostem zvočnem polju nad odbojno ravnino (ISO 11201:1995)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 11201:1997
01-april-1997
$NXVWLND(PLVLMDKUXSDQDSUDYLQRSUHPH0HUMHQMHUDYQL]YRþQHJDWODNDQD
PHVWXGHORYDQMDLQQDGUXJLKRSUHGHOMHQLKPHVWLK,QåHQLUVNDPHWRGDYSUHWHåQR
SURVWHP]YRþQHPSROMXQDGRGERMQRUDYQLQR ,62
Acoustics - Noise emitted by machinery and equipment - Measurement of emission
sound pressure levels at a work station and at other specified positions - Engineering
method in an essentially free field over a reflecting plane (ISO 11201:1995)
Akustik - Geräuschabstrahlung von Maschinen und Geräten - Messung von Emissions-
Schalldruckpegeln am Arbeitsplatz und an anderen festgelegten Orten - Verfahren der
Genauigkeitsklasse 2 für ein im wesentlichen freies Schallfeld über einer reflektierenden
Ebene (ISO 11201:1995)
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 d'expertise dans des conditions approchant celles du champ libre sur plan
réfléchissant (ISO 11201:1995)
Ta slovenski standard je istoveten z: EN ISO 11201:1995
ICS:
17.140.20 Emisija hrupa naprav in Noise emitted by machines
opreme and equipment
SIST EN ISO 11201:1997 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11201:1997
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SIST EN ISO 11201:1997
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SIST EN ISO 11201:1997
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SIST EN ISO 11201:1997
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SIST EN ISO 11201:1997
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SIST EN ISO 11201:1997
INTERNATIONAL
IS0
STANDARD
11201
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 -
Engineering method in an essentially free
field over a reflecting plane
Acoustique - Bruit 6mis par /es machines et 6quipements - Mew-age
des niveaux de pression acoustique d ’kmission au poste de travail et en
d ‘autres positions spkifikes - M&hode d/expertise dans des conditions
approchan t celles du champ libre sur plan rkflkchissant
Reference number
IS0 11201 :I 995(E)
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SIST EN ISO 11201:1997
IS0 11201:1995(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 11201 was prepared by Technical Committee
ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
Annexes A, B and C of this International Standard 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.
Intern ational Organization for Standardization
Case Postale 56 l CH-121 1 Geneve 20 l Switz erland
Printed in Switzerland
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SIST EN ISO 11201:1997
0 IS0
IS0 11201:1995(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, in an essen-
tially free field over a reflecting plane. In general, these sound pressure
levels will be equal to or lower than those that would occur when the
machinery or equipment is operating in its normal surroundings. This is
because the sound pressure levels are determined by excluding the ef-
fects 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.
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.
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SIST EN ISO 11201:1997
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SIST EN ISO 11201:1997
IS0 11201:1995(E)
INTERNATIONAL STANDARD 0 IS0
- Noise emitted by machinery and
Acoustics
equipment - Measurement of emission sound
pressure levels at a work station and at other specified
positions - Engineering method in an essentially free
field over a reflecting plane
formance of different units of a given family of ma-
1 Scope
chinery or equipment, under defined environmental
conditions and standardized mounting and operating
conditions. The data obtained may also be used for
1 .l General
the declaration and verification of emission sound
pressure levels as specified in IS0 4871.
This International Standard specifies a method for
measuring the emission sound pressure levels of
NOTE 2 At any given position in relation to a particular
machinery and equipment, at a work station and at
machine, and for given mounting and operating conditions,
other specified positions nearby, in an essentially free
the emission sound pressure levels determined by the
field over a reflecting plane. A work station is occu-
method of this International Standard will in general be
pied by an operator. It may be located in open space
lower than the directly measured sound pressure levels for
in the room where the source operates, or in a cab
the same machine in the typical workroom where it is used.
fixed to the source, or in an enclosure remote from This is due to reverberation and the contributions of other
machines. A method of calculating the sound pressure lev-
the source. One or more specified positions may be
els in the vicinity of a machine operating alone in a
located in the vicinity of a work station, or in the vi-
workroom is given in IS0 11690-3. Commonly observed
cinity of an unattended machine. As some of these
differences are 1 dB to 5 dB, but in extreme cases the dif-
positions may be occupied occasionally or regularly,
ference may be even greater.
they are sometimes referred to as bystander pos-
itions.
1.2 Types of noise and noise sources
Emission sound pressure levels are measured as A-
weighted and, if required, C-weighted peak, and in
The method specified in this lnternationa
Standard is
frequency bands.
applicable to all types of machinery, both
moving and
stationary, for indoor or outdoor use.
NOTE 1 The contents of this and related International
Standards are summarized in table 1 of IS0 11200:1995.
The method is applicable to machines of l
II sizes, and
to all types of noise as defined in IS0 2204 and
This International Standard specifies requirements for
IS0 12001.
the engineering grade of accuracy on the test en-
vironment and instrumentation. Corrections are ap-
plied for background noise, but not for the acoustic I .3 Test environment
environment. Instructions are given for the installation
and operation of the machine under test and for the The type of test environment influences the accuracy
choice of microphone positions for the work station of the determination of emission sound pressure lev-
and for other specified positions. The purpose of the els. An essentially free field over a reflecting plane
measurements is to permit comparison of the per- (indoors or outdoors) is required.
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SIST EN ISO 11201:1997
0 IS0
IS0 11201:1995(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-
ments may be made include the following: IS0 3744: 1994, Acoustics - Determination of sound
power levels of noise sources using sound pressure
work station located in the vicinity of the machine
a) - 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 3745:1977, Acoustics - Determination of sound
b) work station within a cab which is an integral part power levels of noise sources - Precision methods
of the machine under test; this is the case for
for anechoic and semi-anechoic rooms.
many industrial trucks and earth-moving ma-
chines; IS0 3746: 1995, Acoustics - Determination of sound
power levels of noise sources using sound pressure
c) work station within a partial or total enclosure (or - Survey method using an enveloping measurement
behind a screen) supplied by the manufacturer as surface over a reflecting plane.
an integral part of the machinery or equipment;
IS0 11200:1995, Acoustics - Noise emitted by ma-
d) work station partially or totally enclosed by the
chinery and equipment - Guidelines for the use of
machine under test; this situation may be en-
basic standards for the determination of emission
countered with some large industrial machines; sound pressure levels at a work station and at other
specified positions.
bystander positions occupied by individuals not
responsible for the operation of the machine
IS0 12001: -‘1, Acoustics - Noise emitted by ma-
under test, but who may be in its immediate vi-
chinery and equipment - Rules for the drafting and
cinity, either occasionally or continuously;
presentation of a noise test code.
other specified positions, not necessarily work IEC 651: 1979, Sound level meters,
stations or bystander positions.
I EC 804: 1985, Integrating-averaging sound level me-
The work station may also lie on a specified path
ters.
along which an operator moves (see 11.4).
I EC 942: 1988, Sound calibrators.
1.5 Measurement uncertainty
IEC 1260: -*I, Electroacoustics - Octave-band and
fractional-octave-band filters.
While it is not possible to give universal values for the
standard deviation of reproducibility of emission
sound pressure levels at work stations, guidance is
3 Definitions
given in clause 4.
For the purposes of this International Standard, the
following definitions apply. More detailed definitions
2 Normative references
may be found in noise test codes for specific types
of machinery and equipment.
The following standards contain provisions which,
through reference in this text, constitute provisions
3.1 emission: Airborne sound radiated by a well-
of this International Standard. At the time of publi-
defined noise source (e.g. the machine under test).
cation, the editions indicated were valid. All standards
are subject to revision, and parties to agreements
NOTE 3 Noise emission descriptors may be incorporated
based on this International Standard are encouraged
in a product label and/or product specification. The basic
to investigate the possibility of applying the most re-
noise emission descriptors are the sound power level of the
source itself and the emission sound pressure levels at a
cent editions of the standards indicated below.
1) To be published.
2) To be published. (Revision of IEC 225:1966)
2
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SIST EN ISO 11201:1997
0 IS0
IS0 11201:1995(E)
specified positions (if any) in the 6 Equation (I) is identical to that for the familiar IS0 en-
work statio na nd/or at
vicinity of t he source. vironmental noise descriptor “equivalent continuous sound
pressure level” defined in IS0 1996-I. However, the emis-
sion quantity defined above is used to characterize the noise
3.2 emission sound pressure, p: The sound press-
emitted by a machine under test and assumes that stan-
ure, at a specified position near a noise source, when
dardized measurement and operating conditions as well as
the source is in operation under specified operating
a controlled acoustical environment are used for the
and mounting conditions on a reflecting plane surface,
measurements.
excluding the effects of background noise as well as
the effects of reflections other than those from the
3.3.2 peak emission sound pressure level, L], peak:
I
plane or planes permitted for the purpose of the test.
Highest instantaneous value of the emission sound
It is expressed in pascals.
pressure level determined over an operational cycle.
It is expressed in decibels.
3.3 emission sound pressure level, Lp: Ten times
the logarithm to the base 10 of the ratio of the square
3.3.3 single-event emission sound pressure level,
of the emission sound pressure, p2 t), to the square
1
L p ,s: Time-integrated emission sound pressure level
of the reference sound pressure, po, measured with
of ’an isolated single sound event of specified duration
a particular time weighting and a particular frequency
T (or specified measurement time T) normalized to
weighting, selected from those defined in IEC 651. It
To=1 s.
is expressed in decibels. The reference sound press-
ure is 20 PPa.
It is expressed in decibels and is given by the follow-
ing equation:
NOTE 4 Examples include:
2
1 T P (0
- maximum A-weighted emission sound pressure level
L
10 Ig dt dB . . .
(2)
p,ls =
2
I
with time-weighting F: LpAFmax;
To 0
PO
- C-weighted peak emission sound pressure level:
L
= peqT+ 10 Ig T dB
L
/K,peak-
TO
The emission sound pressure level shall be deter-
NOTE 7 The above equation is identical to that for the
mined at a specified position in accordance with either
familiar IS0 environmental noise descriptor “sound expo-
sure level ”. However, the emission quantity defined above
a test code for a specific family of machines or, if no
is used to characterize a noise source and assumes that a
test code exists, a method that complies with the
controlled environment is used for the measurements.
IS0 11200 series.
3.4 impulsive noise index (impulsiveness): Quan-
3.3.1 time-averaged emission sound pressure
tity by means of which the noise emitted by a source
level, LpeqT: Emission sound pressure level of a con-
can be characterized as “impulsive ”. (See annex A.)
tinuous steady sound that, within a measurement
It is expressed in decibels.
time interval, T, has the same mean square sound
pressure as a sound under consideration which varies
3.5 free field over a reflecting plane: Sound field
with time.
in a homogeneous, isotropic medium in the half space
It is expressed in decibels and is given by the follow-
above an infinite, rigid plane surface on which the
ing equation:
machine under test is located.
2
P (4
3.6 work station; operator ’s position: Position in
L 7dt dB . . .
(1)
peqr= lo lg+/*
the vicinity of the machine under test which is in-
O PO
tended for the operator.
A-weighted time-averaged emission sound pressure
levels are denoted by LpAeqT, which is usually abbrevi-
3.7
operator: Individual whose work station is in the
shall be measured with an instru-
ated to LpA- LpAeqT vicinity of a machine and who is performing a work
ment which complies with the requirements of
task associated with that machine.
IEC 804.
3.8 specified position: Position defined in relation
NOTES
to a machine, including, but not limited to, an oper-
ator ’s position. The position can be a single, fixed
5 In general, the subscripts eq and T are omitted since
point, or a combination of points along a path or on a
time-averaged emission sound pressure levels are necess-
surface located at a specified distance from the ma-
arily determined over a certain measurement time interval.
3
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SIST EN ISO 11201:1997
0 IS0
IS0 11201:1995(E)
chine, as described in the relevant noise test code, if
4 Measurement uncertainty
any exists.
A single value of an emission sound pressure level of
NOTE 8 Positions located in the vicinity of a work station,
a noise source determined in accordance with the
or in the vicinity of an unattended machine, may be ident-
method specified in this International Standard is likely
if ied as ” bystander positions “.
to differ from the true value at a fixed position by an
amount within the range of the measurement uncer-
3.9 operational period: Interval of time during
tainty. The uncertainty in measurements of emission
which a specified process is accomplished by the
sound pressure levels arises from several factors
machine under test (e.g. for a dishwasher when
which affect the results, some associated with en-
washing or rinsing or drying).
vironmental conditions in the measurement room and
others with experimental techniques.
3.10 operational cycle: Specific sequence of oper-
The measurement uncertainty depends on the stan-
ational periods occurring while the machine under test
dard deviation of reproducibility and on the degree of
performs a complete work cycle. Each operational
confidence that is desired. Extensive measurement
period is associated with a specific process that may
data are necessary in order to establish standard de-
occur only once, or may be repeated, during the op-
viations of reproducibility of emission sound pressure
erational cycle (e.g. for a dishwasher when washing
levels at individual positions and, in any case, these
and rinsing and drying).
standard deviations are likely to vary considerably be-
tween the many different types of machinery and
3.11 measurement time interval: Portion or a
equipment to which this International Standard is ap-
multiple of an operational period or operational cycle
plicable. It is therefore not possible to provide infor-
for which the emission sound pressure level is deter-
mation which is universally applicable, and reference
mined or over which the maximum emission sound
can only be made to noise test codes for relevant data
pressure level is searched for.
on individual types of noise source.
3.12 time history: Continuous recording of the
The engineering method described in this lnter-
emission sound pressure level, as a function of time, national Standard yields a higher degree of accuracy
which is obtained during one or more operational than the survey method described in IS0 11202 be-
periods of an operational cycle. cause the measurements are carried out under
controlled environmental conditions.
3.13 background noise: The noise from all sources
For this engineering method, a value of the standard
other than the machine under test.
deviation of reproducibility equal to or less than
2,5 dB (excluding variations in operating and mounting
NOTE 9 Background noise may include contributions
conditions) is expected for the A-weighted emission
from airborne sound, structure-borne vibration, and elec-
sound pressure level of a source which emits noise
trical noise in instrumentation.
with a relatively “flat” spectrum in the frequency
range 100 Hz to 10 000 Hz.
3.14 background noise level: The sound pressure
level measured when the machine under test is not
The given value for the standard deviation of
operating. It is expressed in decibels.
reproducibility is a maximum value but, for a well-
defined family of machines, it may be smaller. For
3.15 background noise correction, K,: A correction
example, for one family of woodworking machines, it
term to account for the influence of background noise
has been shown that the standard deviation of
on the emission sound pressure level at the specified
reproducibility is equal to I,0 dB.
positions of the machine under test. K, is frequency
dependent and is expressed in decibels. The cor- NOTE 10 If the machine under test is highly directional
or its spectrum has tonal components, the measurement
rection in the case of A-weighting, &, is to be de-
uncertainty may be larger. The risk of this being the case
termined from A-weighted measured values.
can be reduced by keeping the environmental indicator (see
6.2) less than 0,5 dB.
3.16 environmental indicator, K2: A term to ac-
count for the influence of reflected or absorbed sound
on the surface sound pressure level. K2 is frequency 5 Instrumentation
dependent and is expressed in decibels. In the case
The instrumentation system, including the micro-
of A-weighting, it is denoted &A (see the IS0 3740
phone and cable, shall meet the requirements for a
series).
4
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SIST EN ISO 11201:1997
IS0 11201:1995(E)
0 IS0
condition. For this International Standard, the en-
class 1 instrument specified in IEC 651 or, in the case
vironmental indicator, &A, for a measurement surface
of integrating-averaging sound level meters, in
enveloping the measurement positions, shall not ex-
IEC 804.
ceed 2 dB.
For measurements in octave or one-third-octave
bands, the filters shall meet the requirements of NOTE 11 If it is necessary to make measurements in
spaces in which K2* exceeds 2 dB, then IS0 11202 or
IEC 1260.
IS0 11204 may be applicable.
Before and after each series of measurements, a
sound calibrator with an accuracy of + 0,3 dB (class
6.3 Enclosed work station positions
1 as specified in IEC 942) shall be applied to the
microphone to verify the calibration of the entire
When the operator is located in an enclosed cab or in
measuring system at one or more frequencies over
an enclosure remote from the machine under test, the
the frequency range of interest.
cab or enclosure is regarded as an integral part of the
machine under test and, consequently, sound re-
The compliance of the calibrator with the require-
flections inside the cab or enclosure are considered
ments of IEC 942 shall be verified once a year. The
contributions to the emission sound pressure level.
compliance of the instrumentation system with the
No environmental corrections are permitted.
in the case of
requirements of IEC 651 (or,
integrating-averaging systems, with the requirements
During noise emission measurements, doors and
of IEC 804) shall be verified at least every 2 years.
windows of the cabin or enclosure shall be open or
closed as defined in the noise test code for the ma-
The date of the last verification of the compliance with
chinery or equipment being measured.
the relevant IEC standards shall be recorded.
If the work station or bystander ’s position of the ma-
6 Test environment
chine is located inside a cab or a cabin, an additional
“conventional” work station or bystander ’s position
6.1 Specified positions in free space in the
outside the cab or cabin (e.g. for maintenance) in the
vicinity of the machine under test vicinity of machine under test shall be specified in the
noise test code.
Test environments that are suitable for measure-
ments in accordance with this International Standard
6.4 Criterion for background noise
are a flat outdoor area or an indoor space that pro-
vides an essentially free field over a reflecting plane.
At the microphone position(s), the background noise
(including wind noise at the microphone) measured
A laboratory hemi-anechoic room (see IS0 3745) or a
as a weighted sound pressure level or in each of the
flat outdoor area paved with sealed asphalt or con-
frequency bands of interest shall be at least 6 dB (and
crete that meets the requirements given in 6.4 and
preferably more than 15 dB) below the level due to
6.5 will be satisfactory for the purposes of measure-
the machine under test. Corrections for background
ments given in this International Standard. Other test
noise in decibels are given by the following equation:
environments meeting the requirements given in 6.2,
6.4 and 6.5 rnay also be used. No environmental cor-
Kl = - 10 Ig (1 - 10- “. ‘AL) dB . . .
(3)
rections are permitted.
where AL is the difference between the sound
6.2 Criterion for the adequacy of the test
pressure levels measured, at a specified position, with
environment
the machine under test in operation and turned off,
respectively.
Ideally, the test environment should be free of re-
flecting objects other than a reflecting plane so that
For the purposes of this International Standard, if
the machine under test radiates into a free field over
AL > 15 dB, assume KI = 0; if AL < 6 dB (i e
. .
a reflecting plane. Annex A of IS0 3744:1994 de-
&A > I,3 dB), the measurement is invalid according
scribes procedures for determining the magnitude of
to this International Standard.
the environmental indicator, K2, to account for the
deviations of the test environment from the ideal K, shall be determined for each microphone position.
5
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SIST EN ISO 11201:1997
0 IS0
IS0 11201:1995(E)
pressure level at the specified position (see 3.3.3) L,, ls,
6.5 Ambient conditions during
should be determined.
measurements
Ambient conditions may have an adverse effect on 9 Installation and operation of machine
the microphone used for the measurements. Such
under test
conditions (e.g. strong electric or magnetic fields,
wind, high or low temperatures, or impingement of
9.1 General
air discharge from the machine under test) shall be
avoided by proper selection or positioning of the
The manner in which the machine under test is in-
microphone.
stalled and operated may have a significant influence
on the emission sound pressure levels at the speci-
fied positions. This clause specifies conditions that are
7 Quantities to be measured
intended to minimize variations in the noise emission
due to the installation and operating conditions of the
The basic quantities to be measured at each specified
machine under test. Relevant instructions of a noise
position over the specified operational periods or op-
test code, if any exists for the family of machinery or
erational cycle of the machine under test are
equipment to which the machine under test belongs,
shall be followed. The same installation, mounting and
- the A-weighted sound pressure level, LtpA (the
operating conditions shall be used for the determi-
prime indicates measured values);
nation of emission sound pressure levels and sound
power levels. The noise test code for the machinery
pressure level,
- the C-weighted peak sound
concerned shall describe the installation, mounting
L
pC,peak-
and operating conditions in detail.
NOTES
NOTE 15 The noise test code may make an exception to
this requirement on identical installation, mounting and op-
12 Sound pressure levels using other frequency
erating conditions for equipment that is used on tables.
weightings or in octave or one-third-octave frequency
Such equipment may be mounted on the floor during sound
bands, as well as other entities relating to the time-history
power determinations.
of the noise emission (impulsiveness, sound pressure level
as a function of time, etc.) may also be measured, as re-
Particularly for large machines, it is necessary to make
quired for the design of low-noise machines.
a decision as to which components, sub-assemblies,
13 For some applications, it may not be necessary to
auxiliary equipment, power sources, etc., belong to
measure the value of the C-weighted peak sound pressure
the machine under test.
level. (See clause 5, note 4 of IS0 4871:-.)
9.2 Location of source
8 Quantities to be determined
The machine under test shall be installed with respect
to the reflecting plane in one or more locations as if
In order to obtain emission sound pressure levels at
it were being installed for normal usage. The machine
a specified position, only background noise cor-
under test shall be remote from any wall, ceiling or
rections K, shall be applied to measured sound
other reflecting object.
pressure levels, except peak sound pressure levels,
L for which no corrections are permitted.
pC,peakl
NOTE 16 Typical installation conditions for some ma-
chines involve two or more reflecting surfaces (e.g. an ap-
Corrections K, to be considered are those relevant to
pliance installed against a wall), or free space (e.g. a hoist),
the frequency weighting or frequency bands for which
or an opening in an otherwise reflecting plane (so that radi-
sound pressure levels have been measured. For fre-
ation may occur on both sides of the vertical plane). Detailed
quency bands and A-weighting, respectively:
information on installation conditions should be based on
the general r
...
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