SIST EN ISO 3745:2012
(Main)Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Precision methods for anechoic rooms and hemi-anechoic rooms (ISO 3745:2012)
Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Precision methods for anechoic rooms and hemi-anechoic rooms (ISO 3745:2012)
2011-06-08 EMA: draft for // vote received in ISO/CS (see notification of 2011-06-07 in dataservice).
Akustik - Bestimmung der Schallleistungs- und Schallenergiepegel von Geräuschquellen aus Schalldruckmessungen - Verfahren der Genauigkeitsklasse 1 für reflexionsarme Räume und Halbräume (ISO 3745:2012)
1.1 Allgemeines
Diese Internationale Norm legt Verfahren zur Messung der Schalldruckpegel auf einer Messfläche fest, die die
Geräuschquelle (Maschine oder Gerät) in einem Freifeld-Prüfraum oder einem Freifeld-Halbraum einhüllt. Der
von der Geräuschquelle erzeugte Schallleistungspegel (oder Schallenergiepegel bei Impulsen oder anderen
Geräuschen von kurzer Dauer) in Terzbändern oder mit A-Bewertung wird aus diesen Messungen unter
Einbeziehung von Korrekturen berechnet, die die Unterschiede berücksichtigen, die zwischen den meteorologischen
Bedingungen zur Zeit und am Ort der Messungen und den Bedingungen auftreten können, die dem
Bezugswert der Schallkennimpedanz entsprechen.
Im Allgemeinen umfasst der interessierende Frequenzbereich die Terzbänder mit Mittenfrequenzen von
100 Hz bis 10 000 Hz. In der Praxis wird der Bereich auf solche Frequenzen jenseits oder innerhalb der
genannten Grenzen erweitert oder eingeschränkt, innerhalb derer der Prüfraum für die Zwecke dieser
Messungen geeignet ist.
1.2 Geräuscharten und Geräuschquellen
Die in dieser Internationalen Norm festgelegten Verfahren sind für alle in ISO 12001 definierten Geräuscharten
(gleichförmig, ungleichförmig, schwankend) geeignet.
Die Geräuschquelle kann ein Gerät, eine Maschine, ein Bauteil oder eine Baugruppe sein. Die maximale
Größe der Geräuschquelle wird durch die Anforderungen des Abschnitts 8 an den Radius der gedachten
Kugel oder Halbkugel bestimmt, die als einhüllende Messfläche verwendet wird.
1.3 Prüfraum
Prüfräume, die sich für Messungen nach dieser Internationalen Norm eignen, sind reflexionsarme Prüfräume
oder reflexionsarme Halbräume, die auch als Freifeld-Prüfräume oder Freifeld-Halbräume bezeichnet werden.
1.4 Messunsicherheit
Es werden Angaben zur Unsicherheit der nach dieser Internationalen Norm ermittelten Schallleistungspegel
und Schallenergiepegel für Messungen in begrenzten Frequenzbändern und unter Anwendung der
Frequenzbewertung A bereitgestellt. (...)
Acoustique - Détermination des niveaux de puissance acoustique et des niveaux d'énergie acoustique émis par les sources de bruit à partir de la pression acoustique - Méthodes de laboratoire pour les salles anéchoïques et les salles semi-anéchoïques (ISO 3745:2012)
L'ISO 3745:2012 spécifie des méthodes de mesure des niveaux de pression acoustique sur une surface de mesurage entourant la source de bruit (machine ou équipement) dans une salle anéchoïque ou dans une salle semi-anéchoïque. Le niveau de puissance acoustique (ou, dans le cas d'impulsions sonores ou d'émissions sonores transitoires, le niveau d'énergie acoustique) produit par la source de bruit, par bandes de fréquences de tiers d'octave de largeur ou avec la pondération fréquentielle A appliquée, est calculé en utilisant ces mesures, comprenant des corrections pour prendre en compte les différences entre les conditions météorologiques au moment et sur le lieu de l'essai et celles correspondant à une impédance acoustique caractéristique de référence.
En général, le domaine de fréquences représentatif inclut des bandes de tiers d'octave avec des fréquences centrales de 100 Hz à 10 000 Hz. En pratique, le domaine est étendu ou restreint à des fréquences au-delà ou dans ces limites, pour correspondre à celles entre lesquelles la salle d'essai est qualifiée aux fins des mesures.
Les méthodes spécifiées dans l'ISO 3745:2012 sont applicables à tous les types de bruit (stable, non stable, fluctuant, impulsions acoustiques isolées, etc.) définis dans l'ISO 12001.
La source de bruit soumise à essai peut être un dispositif, une machine, un composant ou un sous-ensemble. La taille maximale de la source de bruit dépend des exigences spécifiées concernant le rayon de la sphère fictive ou de l'hémisphère fictif utilisé(e) comme surface de mesurage enveloppant la source.
Les salles d'essai applicables aux mesures prises conformément à l'ISO 3745:2012 sont une salle anéchoïque ou une salle semi-anéchoïque, également appelées, respectivement, salle d'essai en champ libre ou salle d'essai en champ semi-libre.
Des informations sont données sur l'incertitude associée aux niveaux de puissance acoustique et aux niveaux d'énergie acoustique déterminés conformément à l'ISO 3745:2012 pour des mesurages effectués dans des bandes de fréquences limitées et avec la pondération fréquentielle A. L'incertitude est conforme à celle de la classe de précision 1 (méthode de précision) définie dans l'ISO 12001:1996.
Akustika - Ugotavljanje ravni zvočnih moči in ravni zvočne energije virov hrupa z zvočnim tlakom - Precizijska metoda za gluhe in polgluhe prostore (ISO 3745:2012)
Ta mednarodni standard opisuje metode za merjenje ravni zvočnega tlaka na merilni površini, oviti okrog vira hrupa (stroja ali opreme) v gluhem ali polgluhem prostoru. S temi meritvami se računa raven zvočne moči (ali v primeru impulznih ali prehodnih emisij hrupa raven zvočne energije) ki jo proizvede vir hrupa, v frekvenčnih pasovih s širino tretjine oktave ali z A-frekvenčnim vrednotenjem, ob upoštevanju popravkov, ki dopuščajo morebitne razlike med vremenskimi razmerami ob času in v kraju preskusa in razmerami, ki ustrezajo referenčni karakteristični akustični impedanci. Aktualno frekvenčno območje na splošno vključuje terčne pasove s srednjimi frekvencami od 100 Hz do 10.000 Hz. V praksi se območje razširi ali omeji na frekvence, ki te meje presegajo ali ne, in za katere je primeren preskusni prostor za meritve.
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 3745:2012
01-julij-2012
1DGRPHãþD
SIST EN ISO 3745:2009
$NXVWLND8JRWDYOMDQMHUDYQL]YRþQLKPRþLLQUDYQL]YRþQHHQHUJLMHYLURYKUXSD]
]YRþQLPWODNRP3UHFL]LMVNDPHWRGD]DJOXKHLQSROJOXKHSURVWRUH ,62
Acoustics - Determination of sound power levels and sound energy levels of noise
sources using sound pressure - Precision methods for anechoic rooms and hemi-
anechoic rooms (ISO 3745:2012)
Akustik - Bestimmung der Schallleistungs- und Schallenergiepegel von Geräuschquellen
aus Schalldruckmessungen - Verfahren der Genauigkeitsklasse 1 für reflexionsarme
Räume und Halbräume (ISO 3745:2012)
Acoustique - Détermination des niveaux de puissance acoustique et des niveaux
d'énergie acoustique émis par les sources de bruit à partir de la pression acoustique -
Méthodes de laboratoire pour les salles anéchoïques et les salles semi-anéchoïques
(ISO 3745:2012)
Ta slovenski standard je istoveten z: EN ISO 3745:2012
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
91.120.20 $NXVWLNDYVWDYEDK=YRþQD Acoustics in building. Sound
L]RODFLMD insulation
SIST EN ISO 3745:2012 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 3745:2012
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SIST EN ISO 3745:2012
EUROPEAN STANDARD
EN ISO 3745
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2012
ICS 17.140.01 Supersedes EN ISO 3745:2009
English Version
Acoustics - Determination of sound power levels and sound
energy levels of noise sources using sound pressure - Precision
methods for anechoic rooms and hemi-anechoic rooms (ISO
3745:2012)
Acoustique - Détermination des niveaux de puissance Akustik - Bestimmung der Schallleistungs- und
acoustique et des niveaux d'énergie acoustique émis par Schallenergiepegel von Geräuschquellen aus
les sources de bruit à partir de la pression acoustique - Schalldruckmessungen - Verfahren der Genauigkeitsklasse
Méthodes de laboratoire pour les salles anéchoïques et les 1 für reflexionsarme Räume und Halbräume (ISO
salles semi-anéchoïques (ISO 3745:2012) 3745:2012)
This European Standard was approved by CEN on 14 March 2012.
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-CENELEC 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-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3745:2012: E
worldwide for CEN national Members.
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SIST EN ISO 3745:2012
EN ISO 3745:2012 (E)
Contents Page
Foreword .3
Annex ZA (informative) Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC .4
2
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SIST EN ISO 3745:2012
EN ISO 3745:2012 (E)
Foreword
This document (EN ISO 3745:2012) has been prepared by Technical Committee ISO/TC 43 "Acoustics" in
collaboration with Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by DS.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by September 2012, and conflicting national standards shall be
withdrawn at the latest by September 2012.
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 3745:2009.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive.
For relationship with EU Directive, see informative Annex ZA, which is an integral part of this document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland, Turkey and the United Kingdom.
Endorsement notice
The text of ISO 3745:2012 has been approved by CEN as a EN ISO 3745:2012 without any modification.
3
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SIST EN ISO 3745:2012
EN ISO 3745:2012 (E)
Annex ZA
(informative)
Relationship between this European Standard and the Essential
Requirements of EU Directive 2006/42/EC
This European Standard has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association to provide one means of conforming to Essential Requirements of
the New Approach Directive 2006/42/EC, Machinery directive.
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 products falling
within the scope of this standard.
4
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SIST EN ISO 3745:2012
INTERNATIONAL ISO
STANDARD 3745
Third edition
2012-03-15
Acoustics — Determination of sound
power levels and sound energy levels of
noise sources using sound pressure —
Precision methods for anechoic rooms
and hemi-anechoic rooms
Acoustique — Détermination des niveaux de puissance acoustique et
des niveaux d’énergie acoustique émis par les sources de bruit à partir
de la pression acoustique — Méthodes de laboratoire pour les salles
anéchoïques et les salles semi-anéchoïques
Reference number
ISO 3745:2012(E)
©
ISO 2012
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012
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 either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
Contents Page
Foreword . v
Introduction .vi
1 Scope . 1
1.1 General . 1
1.2 Types of noise and noise sources . 1
1.3 Test room . 1
1.4 Measurement uncertainty . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Reference meteorological conditions . 7
5 Test rooms . 8
5.1 Acoustic criterion for adequacy of the test room . 8
5.2 Criteria for background noise . 8
5.3 Criterion for air temperature . 9
6 Instrumentation . 9
6.1 Instruments for acoustical measurements . 9
6.2 Instruments for meteorological measurements . 11
7 Definition, location, installation and operation of noise source under test . 11
7.1 General . 11
7.2 Auxiliary equipment . 11
7.3 Noise source location . 11
7.4 Mounting of the noise source .12
7.5 Operation of source during test .12
8 Measurement surface .13
8.1 Spherical measurement surface for use in an anechoic room .13
8.2 Hemispherical measurement surface for use in a hemi-anechoic room .13
9 Determination of sound power levels and sound energy levels .14
9.1 Measurements in the test room .14
9.2 Measurement of meteorological conditions .14
9.3 Microphone positions .14
9.4 Determination of sound power levels of a noise source which emits steady or
non-steady noise .16
9.5 Determination of sound energy levels for a noise source which emits impulsive noise .20
9.6 Calculation of directivity indices .22
9.7 Calculation of surface sound pressure level non-uniformity index .23
9.8 Frequency-weighted sound power level and sound energy level .23
10 Measurement uncertainty .23
10.1 Methodology .23
10.2 Determination of σ .24
omc
10.3 Determination of σ .24
R0
10.4 Typical upper bound values of σ .25
R0
10.5 Total standard deviation, σ , and expanded measurement uncertainty, U .26
tot
11 Information to be recorded .27
11.1 General .27
11.2 Noise source under test .27
11.3 Test room .27
11.4 Instrumentation .27
11.5 Acoustical data .27
12 Test report .28
© ISO 2012 – All rights reserved iii
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
Annex A (normative) General procedures for qualification of anechoic and hemi-anechoic rooms .29
Annex B (normative) Qualification procedure for spaces within test rooms used in the determination of
sound power levels and sound energy levels of specific noise sources .36
Annex C (normative) Calculation of A-weighted sound power levels and A-weighted sound energy
levels from one-third-octave band levels .38
Annex D (normative) Array of microphone positions on a spherical measurement surface in a
free field .40
Annex E (normative) Arrays of microphone positions on a hemispherical measurement surface in a
hemi-free field .43
Annex F (normative) Coaxial circular paths of microphones on a hemispherical measurement surface
in a hemi-free field .48
Annex G (normative) Meridional paths of microphones on a hemispherical measurement surface in a
hemi-free field .49
Annex H (normative) Spiral paths of microphones on a hemispherical measurement surface in a hemi-
free field .51
Annex I (informative) Guidance on the development of information on measurement uncertainty .52
Bibliography .62
iv © ISO 2012 – All rights reserved
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 3745 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This third edition cancels and replaces the second edition (ISO 3745:2003), which has been technically revised.
© ISO 2012 – All rights reserved v
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
Introduction
[3] [8]
This International Standard is one of the series ISO 3741 to ISO 3747 , which specify various methods for
determining the sound power levels and sound energy levels of noise sources including machinery, equipment
and their sub-assemblies. The selection of one of the methods from the series for use in a particular application
depends on the purpose of the test to determine the sound power level or sound energy level and on the
[2] [3]
facilities available. General guidelines to assist in the selection are provided in ISO 3740 . ISO 3741 to
[8]
ISO 3747 give only general principles regarding the operating and mounting conditions of the machinery
or equipment for the purposes of the test. It is important that test codes be established for individual kinds of
noise source, in order to give detailed requirements on mounting, loading and operating conditions under which
the sound power levels or sound energy levels are to be obtained and to select the appropriate measurement
surface and microphone array from among those specified in this International Standard.
The methods given in this International Standard require the source to be mounted in either an anechoic
room or a hemi-anechoic room having specified acoustical characteristics. The methods are then based on
the premise that the sound power or sound energy of the source is directly proportional to the mean-square
sound pressure over a hypothetical measurement surface enclosing the source and otherwise depends on the
physical constants of air.
The methods specified in this International Standard permit the determination of the sound power level and the
sound energy level in frequency bands and/or with frequency A-weighting applied.
The methods give a precision grade of accuracy (grade 1) as defined in ISO 12001. The resulting sound power
levels and sound energy levels include corrections to allow for any differences that might exist between the
meteorological conditions under which the tests are conducted and reference meteorological conditions. For
applications where there are large uncertainties due to operating conditions or where reduced accuracy is
[6] [7]
acceptable, reference can be made to the more practical methods of ISO 3744 or ISO 3746 . Guidance on
evaluation of measurement uncertainty is given in Annex I.
vi © ISO 2012 – All rights reserved
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SIST EN ISO 3745:2012
INTERNATIONAL STANDARD ISO 3745:2012(E)
Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure — Precision
methods for anechoic rooms and hemi-anechoic rooms
1 Scope
1.1 General
This International Standard specifies methods for measuring the sound pressure levels on a measurement
surface enveloping a noise source (machinery or equipment) in an anechoic room or a hemi-anechoic room.
The sound power level (or, in the case of impulsive or transient noise emission, the sound energy level)
produced by the noise source, in frequency bands of width one-third octave or with frequency weighting A
applied, is calculated using those measurements, including corrections to allow for any differences between
the meteorological conditions at the time and place of the test and those corresponding to a reference
characteristic acoustic impedance.
In general, the frequency range of interest includes the one-third-octave bands with mid-band frequencies from
100 Hz to 10 000 Hz. In practice, the range is extended or restricted to frequencies beyond or within these
limits, to those between which the test room is qualified for the purposes of the measurements.
1.2 Types of noise and noise sources
The methods specified in this International Standard are suitable for all types of noise (steady, non-steady,
fluctuating, isolated bursts of sound energy, etc.) defined in ISO 12001.
The noise source under test can be a device, machine, component or sub-assembly. The maximum size of the
noise source depends on specified requirements regarding the radius of the hypothetical sphere or hemisphere
used as the enveloping measurement surface.
1.3 Test room
The test rooms that are applicable for measurements made in accordance with this International Standard are an
anechoic room or hemi-anechoic room, also called, respectively, a free-field test room or hemi-free-field test room.
1.4 Measurement uncertainty
Information is given on the uncertainty of the sound power levels and sound energy levels determined in
accordance with this International Standard, for measurements made in limited bands of frequency and with
frequency weighting A applied. The uncertainty conforms to ISO 12001:1996, accuracy grade 1 (precision grade).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results
ISO 9613-1:1993, Acoustics — Attenuation of sound during propagation outdoors — Part 1: Calculation of the
absorption of sound by the atmosphere
ISO 12001:1996, Acoustics — Noise emitted by machinery and equipment — Rules for the drafting and
presentation of a noise test code
© ISO 2012 – All rights reserved 1
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
ISO/IEC Guide 98-3, Uncertainty in measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
IEC 60942:2003, Electroacoustics — Sound calibrators
IEC 61183, Electroacoustics — Random-incidence and diffuse-field calibration of sound level meters
IEC 61260:1995 + AM1:2001, Electroacoustics — Octave-band and fractional-octave-band filters
IEC 61672-1:2002, Electroacoustics — Sound level meters — Part 1: Specifications
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
sound pressure
p
difference between instantaneous pressure and static pressure
[22]
NOTE 1 Adapted from ISO 80000-8:2007 , 8-9.2.
NOTE 2 Sound pressure is expressed in pascals.
3.2
sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to the square of a
reference value, p , expressed in decibels
0
2
p
L =10lg dB (1)
p
2
p
0
where the reference value, p , is 20 µPa
0
[20]
[ISO/TR 25417:2007 , 2.2]
NOTE 1 If specific frequency and time weightings as specified in IEC 61672-1 and/or specific frequency bands are
applied, this should be indicated by appropriate subscripts; e.g. L denotes the A-weighted sound pressure level.
pA
[22]
NOTE 2 This definition is technically in accordance with ISO 80000-8:2007 , 8-22.
3.3
time-averaged sound pressure level
L
p,T
ten times the logarithm to the base 10 of the ratio of the time average of the square of the sound pressure, p,
during a stated time interval of duration, T (starting at t and ending at t ), to the square of a reference value,
1 2
p , expressed in decibels
0
t
2
1
2
pt()dt
∫
T
t
1
L =10lg dB (2)
pT,
2
p
0
where the reference value, p , is 20 µPa
0
NOTE 1 In general, the subscript “T” is omitted since time-averaged sound pressure levels are necessarily determined
over a certain measurement time interval.
2 © ISO 2012 – All rights reserved
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
NOTE 2 Time-averaged sound pressure levels are often A-weighted, in which case they are denoted by L , which is
pA,T
usually abbreviated to L .
pA
[20]
NOTE 3 Adapted from ISO/TR 25417:2007 , 2.3.
3.4
single event time-integrated sound pressure level
L
E
ten times the logarithm to the base 10 of the ratio of the integral of the square of the sound pressure, p, of an
isolated single sound event (burst of sound or transient sound) over a stated time interval T (starting at t and
1
ending at t ) to a reference value, E , expressed in decibels
2 0
t
2
2
pt()dt
∫
t
1
L =10lg dB (3)
E
E
0
2 −10 2
where the reference value, E , is (20 µPa) s = 4 × 10 Pa s
0
[3]
[ISO 3741:2010 , 3.4]
NOTE 1 This quantity can be obtained by L + 10lg(T/T ) dB, where T = 1 s.
p,T 0 0
[19]
NOTE 2 When used to measure sound immission (see ISO 11690-1 ), this quantity is usually called “sound exposure
[20]
level” (see ISO/TR 25417:2007 , 2.7).
3.5
measurement time interval
T
portion or a multiple of an operational period or operational cycle of the noise source under test for which the
time-averaged sound pressure level is determined
NOTE Measurement time interval is expressed in seconds.
[3]
[ISO 3741:2010 , 3.5]
3.6
free sound field
sound field in a homogeneous, isotropic medium free of boundaries
NOTE In practice, a free sound field is a field in which the influence of reflections at the boundaries or other disturbing
objects is negligible over the frequency range of interest.
[20]
[ISO/TR 25417:2007 , 2.17]
3.7
anechoic room
anechoic test room
free-field test room
test room in which a free sound field is obtained
3.8
free sound field over a reflecting plane
free sound field in the half-space above an infinite reflecting plane in the absence of any other obstacles
3.9
reflecting plane
sound reflecting planar surface on which the noise source under test is located
© ISO 2012 – All rights reserved 3
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SIST EN ISO 3745:2012
ISO 3745:2012(E)
3.10
hemi-anechoic room
hemi-anechoic test room
hemi-free-field test room
test room in which a free sound field over a reflecting plane is obtained
3.11
frequency range of interest
for general purposes, the frequency range of one-third-octave bands with nominal mid-band frequencies from
100 Hz to 10 000 Hz
NOTE For special pur
...
SLOVENSKI SIST EN ISO 3745
STANDARD
julij 2012
Akustika – Določanje ravni zvočne moči in ravni zvočne energije virov
hrupa z zvočnim tlakom – Precizijska metoda za gluhe in polgluhe
prostore (ISO 3745:2012)
Acoustics – Determination of sound power levels and sound energy levels of
noise sources using sound pressure – Precision methods for anechoic rooms
and hemi-anechoic rooms (ISO 3745:2012)
Acoustique – Détermination des niveaux de puissance acoustique et des
niveaux d'énergie acoustique émis par les sources de bruit à partir de la
pression acoustique – Méthodes de laboratoire pour les salles anéchoïques et
les salles semi-anéchoïques (ISO 3745:2012)
Akustik – Bestimmung der Schallleistungs- und Schallenergiepegel von Geräusch-
quellen aus Schalldruckmessungen – Verfahren der Genauigkeitsklasse 1 für
reflexionsarme Räume und Halbräume (ISO 3745:2012)
Referenčna oznaka
ICS 17.140.01, 91.120.20 SIST EN ISO 3745:2012 (sl)
Nadaljevanje na straneh II in III ter od 1 do 67
© 2012-11. Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST EN ISO 3745 : 2012
NACIONALNI UVOD
Standard SIST EN ISO 3745 (sl), Akustika – Določanje ravni zvočne moči in ravni zvočne energije
virov hrupa z zvočnim tlakom – Precizijska metoda za gluhe in polgluhe prostore (ISO 3745:2012),
2012, ima status slovenskega standarda in je enakovreden evropskemu standardu EN ISO 3745 (en,
de, fr), Acoustics – Determination of sound power levels and sound energy levels of noise sources
using sound pressure – Precision methods for anechoic rooms and hemi-anechoic rooms
(ISO 3745:2012), 2012.
NACIONALNI PREDGOVOR
Evropski standard EN ISO 3745:2012 je pripravil tehnični odbor Evropskega komiteje za
standardizacijo CEN/TC 211 Akustika. Slovenski standard SIST EN ISO 3745:2012 je prevod
evropskega standarda EN ISO 3745:2012. V primeru spora glede besedila slovenskega prevoda v
tem standardu je odločilen izvirni evropski standard v enem izmed treh uradnih jezikov CEN.
Slovensko izdajo standarda je pripravil tehnični odbor SIST/TC AKU Akustika.
Ta dokument nadomešča SIST EN ISO 3745:2009.
Odločitev za izdajo tega standarda je dne 30. julija 2012 sprejel SIST/TC AKU Akustika.
ZVEZA Z NACIONALNIMI STANDARDI
S privzemom tega evropskega standarda veljajo za omejeni namen referenčnih standardov vsi
standardi, navedeni v izvirniku, razen tistih, ki so že sprejeti v nacionalno standardizacijo:
SIST ISO 5725 (vsi deli) Točnost (pravilnost in natančnost) merilnih metod in rezultatov
SIST ISO 9613-1:1998 Akustika – Slabljenje zvoka pri širjenju na prostem – 1. del:
Metoda za računanje slabljenja zvoka zaradi atmosferske
absorpcije
SIST EN ISO 12001:2009 Akustika – Emisija hrupa naprav in opreme – Pravila za
oblikovanje in pripravo pravil za merjenje hrupa
(ISO 12001:1996)
SIST EN 60942:2004 Elektroakustika – Kalibratorji za zvokomere
SIST EN 61183 Elektroakustika – Kalibracija merilnikov ravni zvočnega tlaka
za naključno vpadno smer zvoka in za difuzno zvočno polje
SIST EN 61260:1998 in A1:2006 Elektroakustika – Oktavni, poloktavni in terčni filtri
SIST EN 61672-1:2004 Elektroakustika – Merilniki zvočne jakosti – 1. del:
Specifikacije
OSNOVA ZA IZDAJO STANDARDA
– Privzem standarda EN ISO 3745:2012
PREDHODNA IZDAJA
– SIST EN ISO 3745:2009, Akustika – Ugotavljanje ravni zvočnih moči virov hrupa – Precizijska
metoda za gluhe in polgluhe prostore
II
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SIST EN ISO 3745 : 2012
OPOMBE
– Povsod, kjer se v besedilu standarda uporablja izraz ''evropski standard'', v
SIST EN ISO 3745:2012 to pomeni ''slovenski standard''.
– Nacionalni uvod in nacionalni predgovor nista sestavni del standarda SIST EN ISO 3745:2012.
– Ta nacionalni dokument je enakovreden EN ISO 3745:2012 in je objavljen z dovoljenjem
CEN
Upravni center
Avenue Marnix 17
B-1000 Bruselj
– This national document is identical with EN ISO 3745:2012 and is published with the permission of
CEN
Management Centre
Avenue Marnix 17
B-1000 Brussels
III
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SIST EN ISO 3745 : 2012
(Prazna stran)
IV
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EVROPSKI STANDARD EN ISO 3745
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM julij 2012
ICS 17.140.01 Nadomešča EN ISO 3745:2009
Slovenska izdaja
Akustika – Določanje ravni zvočne moči in ravni zvočne energije virov hrupa z
zvočnim tlakom – Precizijska metoda za gluhe in polgluhe prostore
(ISO 3745:2012)
Acoustics – Determination of Acoustique – Détermination des Akustik – Bestimmung der
sound power levels and sound niveaux de puissance acoustique et Schallleistungs- und Schallenergiepegel
energy levels of noise sources des niveaux d'énergie acoustique von Geräusch-quellen aus
using sound pressure – émis par les sources de bruit à partir Schalldruckmessungen – Verfahren der
Precision methods for anechoic de la pression acoustique – Genauigkeitsklasse 1 für reflexionsarme
rooms and hemi-anechoic Méthodes de laboratoire pour les Räume und Halbräume (ISO 3745:2012)
rooms (ISO 3745:2012) salles anéchoïques et les salles
semi-anéchoïques (ISO 3745:2012)
Ta evropski standard je CEN sprejel 14. marca 2012.
Člani CEN morajo izpolnjevati notranje predpise CEN/CENELEC, s katerimi je predpisano, da mora
biti ta standard brez kakršnih koli sprememb sprejet kot nacionalni standard. Seznami najnovejših
izdaj teh nacionalnih standardov in njihovi bibliografski podatki so na voljo pri Upravnem centru CEN
ali članicah CEN.
Ta evropski standard obstaja v treh izvirnih izdajah (angleški, francoski, nemški). Izdaje v drugih
jezikih, ki jih članice CEN na lastno odgovornost prevedejo in izdajo ter prijavijo pri Upravnem centru
CEN, veljajo kot uradne izdaje.
Člani CEN so nacionalni organi za standardizacijo Avstrije, Belgije, Bolgarije, Cipra, Češke republike,
Danske, Estonije, Finske, Francije, Grčije, Hrvaške, Islandije, Irske, Italije, Latvije, Litve, Luksemburga,
Madžarske, Malte, Nemčije, Nizozemske, Norveške, Poljske, Portugalske, Romunije, Slovaške,
Slovenije, Španije, Švedske, Švice, Turčije in Združenega kraljestva.
CEN
Evropski komite za standardizacijo
European Committee for Standardisation
Europäisches Komitee für Normung
Comité Européen de Normalisation
Upravni center: Avenue Marnix 17, B-1000 Bruselj
© 2012 CEN Lastnice avtorskih pravic so vse države članice CEN Ref. št. EN ISO 3745:2012: E
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SIST EN ISO 3745 : 2012
VSEBINA Stran
Predgovor k evropskemu standardu .4
Dodatek ZA.5
Predgovor k mednarodnemu standardu.6
Uvod .7
1 Področje uporabe .8
1.1 Splošno.8
1.2 Vrste in viri hrupa.8
1.3 Preskusni prostor.8
1.4 Merilna negotovost .8
2 Zveze s standardi .8
3 Izrazi in definicije .9
4 Referenčni meteorološki pogoji .14
5 Preskusni prostori.14
5.1 Merilo akustične ustreznosti preskusnega prostora .14
5.2 Merila za hrup ozadja .15
5.3 Merilo za temperaturo zraka.16
6 Merilna oprema.16
6.1 Instrumenti za akustične meritve.16
6.2 Instrumenti za meteorološke meritve .17
7 Definicija, lokacija, namestitev in delovanje merjenega vira hrupa.18
7.1 Splošno.18
7.2 Dodatna oprema.18
7.3 Lokacija vira hrupa .18
7.4 Nameščanje vira hrupa .18
7.5 Delovanje merjenega vira hrupa .19
8 Merilna površina .20
8.1 Krogelna merilna površina za meritve v gluhi sobi.20
8.2 Polkrogelna merilna površina za meritve v polgluhi sobi .20
9 Določanje ravni zvočne moči in ravni zvočne energije.21
9.1 Meritve v preskusnem prostoru .21
9.2 Meteorološke meritve .21
9.3 Postavitev mikrofonov .22
9.4 Določitev ravni zvočne moči vira hrupa, ki oddaja enakomeren ali neenakomeren hrup .23
9.5 Določitev ravni zvočne energije vira hrupa, ki oddaja impulzni hrup .27
9.6 Izračun koeficientov usmerjenosti .29
9.7 Izračun neuniformnega koeficienta ravni površinskega zvočnega tlaka.29
9.8 Frekvenčno vrednotenje ravni zvočne moči in ravni zvočne energije.29
10 Merilna negotovost .29
10.1 Metodologija .29
2
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SIST EN ISO 3745 : 2012
10.2 Določitev σ .30
omc
10.3 Določitev σ .30
R0
10.4 Značilne zgornje mejne vrednosti σ .31
R0
10.5 Skupni standardni odklon σ in razširjena merilna negotovost U .32
tot
11 Informacije, ki jih je treba zabeležiti.33
11.1 Splošno.33
11.2 Preskusni vir hrupa.33
11.3 Preskusni prostor.33
11.4 Merilna oprema.33
11.5 Akustični podatki.33
12 Poročilo o preskusu.34
Dodatek A (normativni): Splošni postopki za kvalifikacijo zvočnega polja v gluhem
in polgluhem prostoru.35
Dodatek B (normativni): Postopek kvalifikacije za področja znotraj preskusnih prostorov
za določanje ravni zvočne moči in ravni zvočne energije specifičnih virov hrupa .42
Dodatek C (normativni): Izračun A-vrednotenih ravni zvočne moči in A-vrednotenih
ravni zvočne energije s podatki terčnega pasu.44
Dodatek D (normativni): Polje položajev mikrofonov na krogelni merilni površini v
prostem zvočnem polju .46
Dodatek E (normativni): Polja položajev mikrofonov na polkrogelni merilni površini
v polprostem zvočnem polju.48
Dodatek F (normativni): Koaksialne poti mikrofonov na polkrogelni merilni površini
v polprostem zvočnem polju.52
Dodatek G (normativni): Meridianske poti mikrofonov na polkrogelni merilni površini
v polprostem zvočnem polju.53
Dodatek H (normativni): Spiralne poti mikrofonov na polkrogelni merilni površini
v polprostem zvočnem polju.55
Dodatek I (informativni): Navodila za razvoj informacij o merilni negotovosti.56
Literatura.66
3
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SIST EN ISO 3745 : 2012
Predgovor k evropskemu standardu
Ta dokument (EN ISO 3745:2012) je pripravil tehnični odbor ISO/TC 43 Akustika v sodelovanju s
tehničnim odborom CEN/TC 211 Akustika, katerega sekretariat vodi DS (Danish Standards).
Ta evropski standard mora dobiti status nacionalnega standarda bodisi z objavo istovetnega besedila
ali z razglasitvijo najpozneje do septembra 2012, nacionalne standarde, ki so z njim v nasprotju, pa je
treba razveljaviti najpozneje do septembra 2012.
Opozoriti je treba na možnost, da so nekateri elementi tega dokumenta lahko predmet patentnih
pravic. CEN (in/ali CENELEC) ne prevzema odgovornosti za identifikacijo katerihkoli ali vseh takih
patentnih pravic.
Ta dokument nadomešča EN ISO 3745:2009.
Ta dokument je bil pripravljen v okviru mandata, ki sta ga Evropska komisija in Evropsko združenje za
prosto trgovino (EFTA) dala CEN, in podpira bistvene zahteve direktive (direktiv) Evropske unije.
Za povezavo z direktivo(-ami) EU glejte informativni dodatek ZA, ki je sestavni del tega dokumenta.
V skladu z notranjimi predpisi CEN/CENELEC so ta evropski standard dolžne privzeti nacionalne
organizacije za standardizacijo naslednjih držav: Avstrije, Belgije, Bolgarije, Cipra, Češke republike,
Danske, Estonije, Finske, Francije, Grčije, Hrvaške, Islandije, Irske, Italije, Latvije, Litve, Luksemburga,
Madžarske, Malte, Nemčije, Nizozemske, Norveške, Poljske, Portugalske, Romunije, Slovaške,
Slovenije, Španije, Švedske, Švice, Turčije in Združenega kraljestva.
Razglasitvena objava
Besedilo ISO 3745:2012 je CEN odobril kot EN ISO 3745:2012 brez kakršnihkoli sprememb.
4
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SIST EN ISO 3745 : 2012
Dodatek ZA
(informativni)
Povezava med tem evropskim standardom in bistvenimi zahtevami Direktive
EU 2006/42/EC
Ta evropski standard je bil pripravljen v okviru mandata, ki sta ga Evropska komisija in Evropsko
združenje za prosto trgovino dala CEN, da bi zagotovila skladnost z bistvenimi zahtevami Direktive
novega pristopa 2006/42/EC o strojih.
Ko bo ta standard objavljen v Uradnem listu Evropskih skupnosti v okviru navedene direktive in bo kot
nacionalni standard privzet v vsaj eni državi članici, bo skladnost s točkami tega standarda, v okviru
področja uporabe tega standarda, ustvarila domnevo o skladnosti z ustreznimi bistvenimi zahtevami
ustrezne direktive in pridruženimi predpisi EFTA.
OPOZORILO: Za proizvode, ki spadajo v področje uporabe tega standarda, se lahko uporabljajo tudi
druge zahteve in druge direktive EU.
5
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SIST EN ISO 3745 : 2012
Predgovor k mednarodnemu standardu
ISO (Mednarodna organizacija za standardizacijo) je svetovna zveza nacionalnih organov za
standarde (članov ISO). Mednarodne standarde ponavadi pripravljajo tehnični odbori ISO. Vsak član,
ki želi delovati na določenem področju, za katero je bil ustanovljen tehnični odbor, ima pravico biti
zastopan v tem odboru. Pri delu sodelujejo tudi mednarodne vladne in nevladne organizacije,
povezane z ISO. V vseh zadevah, ki so povezane s standardizacijo na področju elektrotehnike, ISO
tesno sodeluje z Mednarodno elektrotehniško komisijo (IEC).
Mednarodni standardi so pripravljeni v skladu s pravili, podanimi v 2. delu Direktiv ISO/IEC.
Glavna naloga tehničnih odborov je priprava mednarodnih standardov. Osnutki mednarodnih
standardov, ki jih sprejmejo tehnični odbori, se pošljejo vsem članom v glasovanje. Za objavo
mednarodnega standarda je treba pridobiti soglasje najmanj 75 odstotkov članov, ki se udeležijo
glasovanja.
Opozoriti je treba na možnost, da je lahko nekaj elementov tega dokumenta predmet patentnih pravic.
ISO ne prevzema odgovornosti za identifikacijo katerihkoli ali vseh takih patentnih pravic.
ISO 3745 je pripravil tehnični odbor ISO/TC 43, Akustika, pododbor SC1, Hrup.
Ta tretja izdaja razveljavlja in nadomešča drugo izdajo (ISO 3745:2003), ki je bila tehnično
spremenjena.
6
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SIST EN ISO 3745 : 2012
Uvod
[3] [8]
Ta mednarodni standard je eden v seriji ISO 3741 do ISO 3747 , ki opisuje različne metode za
določanje zvočne moči in zvočne energije virov hrupa, vključno s stroji, opremo in njihovimi
podsestavi. Izbira ene izmed metod iz serije za uporabo v določen namen je odvisna od namena
preskusa za določanje zvočne moči in zvočne energije ter od razpoložljivih sredstev oziroma pogojev.
[2]
Splošne smernice za pomoč pri izbiri metode so na voljo v standardu ISO 3740 . Serija standardov
[3] [8]
ISO 3741 do ISO 3747 daje le splošne napotke v zvezi z obratovalnimi in montažnimi pogoji strojev
ali opreme za namene preskusa. Pomembno je, da se osnujejo preskusne zahteve za posamezne vire
hrupa, ki so postavljene kot natančno navodilo za montažne in obratovalne pogoje ter pogoje
obremenitve, v katerih je vir, ko se določata zvočna moč in zvočna energija. Zahteve se uporabljajo
tudi pri izbiri primerne merilne površine in polja mikrofona, določeni v tem mednarodnem standardu.
Metode, dane v tem mednarodnem standardu, zahtevajo, da je vir nameščen v gluhem ali polgluhem
prostoru z določenimi akustičnimi lastnostmi. Osnovane so na predpostavki, da je zvočna moč ali
zvočna energija vira neposredno proporcionalna srednjemu kvadratu zvočnega tlaka ter hipotetične
merilne površine z virom, sicer pa je odvisna od fizičnih konstant zraka.
Metode, opisane v tem mednarodnem standardu, dovoljujejo določanje ravni zvočne moči in ravni
zvočne energije v frekvenčnih pasovih in/ali s frekvenčnim A-vrednotenjem.
Metode dajejo prvi razred natančnosti, kot je določeno v ISO 12001. Ravni zvočne moči in ravni
zvočne energije vključujejo popravke, ki upoštevajo kakršnekoli morebitne spremembe med
meteorološkimi pogoji, v katerih potekajo preskusi, in referenčnimi meteorološkimi pogoji. Za primere,
ko je prisotna velika negotovost zaradi pogojev obratovanja ali kjer je zmanjšana natančnost
[6] [7]
sprejemljiva, se je mogoče sklicevati na bolj praktične metode standarda 3744 ali ISO 3746 .
Navodilo za oceno merilne negotovosti je dano v dodatku I.
7
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SIST EN ISO 3745 : 2012
Akustika – Določanje zvočne moči in zvočne energije virov
hrupa z uporabo zvočnega tlaka – Precizijska metoda za
gluhe in polgluhe prostore
1 Področje uporabe
1.1 Splošno
Ta mednarodni standard opisuje metode za določanje ravni zvočnega tlaka na merilni površini, ki
obdaja vir hrupa (stroje ali opremo) v gluhem ali polgluhem prostoru. Raven zvočne moči (ali raven
zvočne energije v primeru impulzne ali prehodne emisije hrupa), ustvarjena z virom hrupa v
frekvenčnih pasovih s širino ene tretjine oktavne frekvence ali z uporabo frekvenčnega A-vrednotenja,
je izračunana z uporabo teh meritev. Vključeni so popravki, ki upoštevajo kakršnekoli spremembe med
meteorološkimi pogoji v času in na mestu preskusa in tistimi, ki ustrezajo referenčni karakteristični
akustični impedanci.
V splošnem obravnavano frekvenčno območje zajema terčne pasove z vmesnimi frekvencami od 100
do 10 000 Hz. V praksi je območje razširjeno ali omejeno na frekvence zunaj ali znotraj teh meja
oziroma do meja, do katerih je preskusni prostor kvalificiran za namen meritev.
1.2 Vrste in viri hrupa
Metode, določene v tem mednarodnem standardu, so ustrezne za vse vrste hrupa (nespremenljivega,
spremenljivega, nihajočega, izoliran izbruh zvočne energije itd.), ki so opredeljene v standardu
ISO 12001.
Preskusni vir hrupa je lahko naprava, stroj, sestavni del ali podsestav. Največja velikost vira hrupa je
odvisna od zahtev, ki se nanašajo na polmer namišljene krogle ali polkrogle, ki predstavlja merilno
površino.
1.3 Preskusni prostor
Preskusni prostori, ki se uporabljajo za meritve, izvedene v skladu s tem mednarodnim standardom,
so gluhe ali polgluhe sobe, ki se imenujejo tudi sobe s prostim poljem ali sobe s polprostim poljem.
1.4 Merilna negotovost
Merilna negotovost se določa glede na negotovost ravni zvočne moči in ravni zvočne energije v skladu
s tem mednarodnim standardom za meritve, izvedene v omejenih frekvenčnih pasovih in z uporabo
frekvenčnega A-vrednotenja.
2 Zveze s standardi
Za uporabo tega dokumenta so nujno potrebni naslednji referenčni dokumenti. Za datirana sklicevanja
se uporablja samo navedena izdaja. Za nedatirana sklicevanja se uporablja zadnja izdaja
referenčnega dokumenta (vključno z vsemi dopolnili).
ISO 5725 (vsi deli) Točnost (pravilnost in natančnost) merilnih metod in rezultatov
ISO 9613-1:1993 Akustika – Slabljenje zvoka pri širjenju na prostem – 1. del: Metoda za
računanje slabljenja zvoka zaradi atmosferske absorpcije
ISO 12001:1996 Akustika – Emisija hrupa naprav in opreme – Pravila za oblikovanje in
pripravo pravil za merjenje hrupa (ISO 12001:1996)
8
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SIST EN ISO 3745 : 2012
ISO/IEC Vodilo 98-3 Merilna negotovost – 3. del: Vodilo za izražanje merilne negotovosti
(GUM:1995)
IEC 60942:2003 Elektroakustika – Kalibratorji za zvokomere
IEC 61183 Elektroakustika – Kalibracija merilnikov ravni zvočnega tlaka za
naključno vpadno smer zvoka in za difuzno zvočno polje
IEC 61260:1995 in AM1:2001 Elektroakustika – Oktavni, poloktavni in terčni filtri
IEC 61672-1:2002 Elektroakustika – Merilniki zvočne jakosti – 1. del: Specifikacije
3 Izrazi in definicije
V tem dokumentu se uporabljajo naslednji izrazi in definicije.
3.1
zvočni tlak
p
razlika med trenutnim tlakom in statičnim tlakom
[22]
OPOMBA 1: Povzeto po ISO 80000-8:2007 , 8-9.2.
OPOMBA 2: Zvočni tlak se izraža v paskalih.
3.2
raven zvočnega tlaka
L
p
desetkratni logaritem z osnovo 10 razmerja kvadrata zvočnega tlaka p s kvadratom referenčne
vrednosti tlaka p , izražena v decibelih
0
(1)
kjer je referenčna vrednost p 20 µPa
0
[20]
[ISO/TR 25417:2007 , 2.2]
OPOMBA 1: Če so uporabljeni specifična frekvenca in časovni dodatki, kot je določeno v IEC 61672-1, in/ali specifični
frekvenčni pasovi, naj se to označi z ustreznim podpisom, kot na primer L označuje A-vrednoteno raven
A
p
zvočnega tlaka.
[22]
OPOMBA 2: Ta definicija je tehnično skladna z ISO 80000-8:2007 , 8-22.
3.3
časovno povprečena raven zvočnega tlaka
L
p,T
desetkratni logaritem z osnovo 10 razmerja časovnega povprečja med kvadratom zvočnega tlaka p v
navedenem časovnem intervalu (začetek pri t in konec pri t ) s kvadratom referenčne vrednosti p ,
1 2 0
izražena v decibelih
(2)
kjer je referenčna vrednost p 20 µPa
0
9
---------------------- Page: 13 ----------------------
SIST EN ISO 3745 : 2012
OPOMBA 1: V splošnem je indeks "T" izpuščen, saj se časovno povprečene ravni zvočnega tlaka nujno določijo v
določenem časovnem intervalu.
OPOMBA 2: Časovno povprečene ravni zvočnega tlaka so pogosto A-vrednotene in zato označene z L , kar se običajno
pA,T
poenostavi v L .
pA
[20]
OPOMBA 3: Povzeto po ISO/TR 25417:2007 , 2.3.
3.4
časovno integrirana raven zvočnega tlaka posameznega zvočnega dogodka
L
E
desetkratni logaritem z osnovo 10 razmerja integrala kvadrata zvočnega tlaka p posameznega
zvočnega dogodka (izbruh zvoka ali prehoden zvok) v časovnem intervalu T (začetek pri t in konec
1
pri t ) z referenčno vrednostjo E , izraženo v decibelih
2 0
(3)
2 10 2
−
kjer je referenčna vrednost E (20 µPa) s = 4 × 10 Pa s
0
[3]
[ISO 3741:2010 , 3.4]
OPOMBA 1: Ta vrednost se lahko pridobi z L + 10lg(T/T ) dB, kjer je T = 1 s.
p,T 0 0
[19]
OPOMBA 2: Za merjenje zvočne imisije (glej ISO 11890-1 ) se ta vrednost običajno imenuje »ekspozicijska zvočna raven«
[20]
(glej ISO/TR 25417:2007 , 2.7).
3.5
časovni interval merjenja
T
del ali več delov operativnega obdobja ali operativnega cikla preskusnega vira hrupa, za katerega je
določeno časovno povprečenje ravni zvočnega tlaka
OPOMBA: Časovni interval merjenja je izražen v sekundah.
[3]
[ISO 3741:2010 , 3.5]
3.6
prosto zvočno polje
prosto zvočno polje v homogenem, izotropnem mediju v neskončnem prostoru
OPOMBA: V praksi je prosto zvočno polje tisto polje, v katerem je vpliv odboja na mejah ali drugih motečih objektih
zanemarljiv v izbranem frekvenčnem območju.
[20]
[ISO/TR 25417:2007 , 2.17]
3.7
gluha soba
gluha preskusna soba
preskusna soba s prostim zvočnim poljem
preskusni prostor, v katerem obstaja prosto zvočno polje
3.8
prosto zvočno polje nad odbojno površino
prosto zvočno polje v polprostoru nad neskončno veliko odbojno površino brez kakršnihkoli drugih ovir
10
---------------------- Page: 14 ----------------------
SIST EN ISO 3745 : 2012
3.9
odbojna površina
ravna površina, ki odbija zvok in na kateri je nameščen vir hrupa med preskusom
3.10
polgluha soba
polgluha preskusna soba
preskusna soba s polprostim zvočnim poljem
preskusni prostor, v katerem obstaja prosto zvočno polje nad odbojno površino
3.11
izbrano frekvenčno območje
v splošnem frekvenčno območje terčnih pasov z nazivnimi vmesnimi frekvencami od 100 Hz do
10 000 Hz
OPOMBA: Za posebne namene se območje lahko razširi ali zoži na katerikoli strani frekvenčnega območja. Pri tem se
zagotovi ustrezna točnost merilne opreme in preskusnega prostora v tem razširjenem območju. Spremembe na
frekvenčnem območju morajo biti jasno izražene v poročilu o preskusu. Za vire, v katerih so določene
A-vrednotene ravni zvočne moči z zvokom pri pretežno visokih ali nizkih frekvencah, naj se izbrano frekvenčn
...
SLOVENSKI STANDARD
oSIST prEN ISO 3745:2010
01-september-2010
$NXVWLND8JRWDYOMDQMHUDYQL]YRþQLKPRþLLQUDYQL]YRþQHHQHUJLMHYLURYKUXSD]
]YRþQLPWODNRP3UHFL]LMVNDPHWRGD]DJOXKHLQSROJOXKHSURVWRUH ,62',6
Acoustics - Determination of sound power levels and sound energy levels of noise
sources using sound pressure - Precision methods for anechoic test rooms and hemi-
anechoic test rooms (ISO/DIS 3745:2010)
Akustik - Bestimmung der Schallleistungs- und Schallenergiepegel von Geräuschquellen
aus Schalldruckmessungen - Verfahren der Genauigkeitsklasse 1 für reflexionsarme
Räume und Halbräume (ISO/DIS 3745:2010)
Acoustique - Détermination des niveaux de puissance acoustique et des niveaux
d'énergie acoustique émis par les sources de bruit à partir de la pression acoustique -
Méthodes de laboratoire pour les salles d'essai anéchoïques et semi-anéchoïques
(ISO/DIS 3745:2010)
Ta slovenski standard je istoveten z: prEN ISO 3745
ICS:
17.140.01 $NXVWLþQDPHUMHQMDLQ Acoustic measurements and
EODåHQMHKUXSDQDVSORãQR noise abatement in general
91.120.20 $NXVWLNDYVWDYEDK=YRþQD Acoustics in building. Sound
L]RODFLMD insulation
oSIST prEN ISO 3745:2010 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 3745:2010
EUROPEAN STANDARD
DRAFT
prEN ISO 3745
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2010
ICS 17.140.01 Will supersede EN ISO 3745:2009
English Version
Acoustics - Determination of sound power levels and sound
energy levels of noise sources using sound pressure - Precision
methods for anechoic test rooms and hemi-anechoic test rooms
(ISO/DIS 3745:2010)
Acoustique - Détermination des niveaux de puissance Akustik - Bestimmung der Schallleistungs- und
acoustique et des niveaux d'énergie acoustique émis par Schallenergiepegel von Geräuschquellen aus
les sources de bruit à partir de la pression acoustique - Schalldruckmessungen - Verfahren der Genauigkeitsklasse
Méthodes de laboratoire pour les salles d'essai 1 für reflexionsarme Räume und Halbräume (ISO/DIS
anéchoïques et semi-anéchoïques (ISO/DIS 3745:2010) 3745:2010)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 211.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 3745:2010: E
worldwide for CEN national Members.
---------------------- Page: 2 ----------------------
oSIST prEN ISO 3745:2010
prEN ISO 3745:2010 (E)
Contents Page
Foreword .3
2
---------------------- Page: 3 ----------------------
oSIST prEN ISO 3745:2010
prEN ISO 3745:2010 (E)
Foreword
This document (prEN ISO 3745:2010) has been prepared by Technical Committee ISO/TC 43 "Acoustics" in
collaboration with Technical Committee CEN/TC 211 “Acoustics” the secretariat of which is held by DS.
This document is currently submitted to the parallel Enquiry.
This document will supersede EN ISO 3745:2009.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive(s).
Endorsement notice
The text of ISO/DIS 3745:2010 has been approved by CEN as a prEN ISO 3745:2010 without any
modification.
3
---------------------- Page: 4 ----------------------
oSIST prEN ISO 3745:2010
---------------------- Page: 5 ----------------------
oSIST prEN ISO 3745:2010
DRAFT INTERNATIONAL STANDARD ISO/DIS 3745
ISO/TC 43/SC 1 Secretariat: DS
Voting begins on: Voting terminates on:
2010-05-06 2010-10-06
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure —
Precision methods for anechoic test rooms and hemi-anechoic
test rooms
Acoustique — Détermination des niveaux de puissance acoustique et des niveaux d'énergie acoustique émis
par les sources de bruit à partir de la pression acoustique — Méthodes de laboratoire pour les salles d'essai
anéchoïques et semi-anéchoïques
[Revision of second edition (ISO 3745:2003)]
ICS 17.140.01
ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for Standardization (ISO), and
processed under the ISO-lead mode of collaboration as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member bodies for a parallel
five-month enquiry.
Should this draft be accepted, a final draft, established on the basis of comments received, will be
submitted to a parallel two-month approval vote in ISO and formal vote in CEN.
In accordance with the provisions of Council Resolution 15/1993 this document is circulated in
the English language only.
Conformément aux dispositions de la Résolution du Conseil 15/1993, ce document est distribué
en version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
©
International Organization for Standardization, 2010
---------------------- Page: 6 ----------------------
oSIST prEN ISO 3745:2010
ISO/DIS 3745
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©
ii ISO 2010 – All rights reserved
---------------------- Page: 7 ----------------------
oSIST prEN ISO 3745:2010
ISO/DIS 3745
Contents Page
Foreword .v
Introduction.vi
1 Scope.1
1.1 General .1
1.2 Types of noise and noise sources.1
1.3 Test room .1
1.4 Measurement uncertainty.1
2 Normative references.2
3 Definitions .2
4 Reference meteorological conditions .7
5 Test rooms .7
5.1 Acoustic criterion for adequacy of the test room .7
5.2 Criterion for background noise.8
5.3 Criterion for air temperature .10
6 Instrumentation .10
6.1 Instruments for acoustical measurements.10
6.2 Instruments for meteorological measurements.11
7 Definition, location, installation and operation of noise source under test.11
7.1 General .11
7.2 Auxiliary equipment .11
7.3 Noise source location .11
7.4 Mounting of the noise source .12
7.5 Operation of source during test.12
8 Measurement surface.13
8.1 Spherical measurement surface for use in a free-field test room.13
8.2 Hemispherical measurement surface for use in a hemi-free-field test room.13
9 Determination of sound power levels and sound energy levels .14
9.1 Measurements in the test room .14
9.2 Measurement of meteorological conditions.15
9.3 Microphone positions .15
9.4 Determination of sound power levels of a noise source which emits steady or non-steady
noise .17
9.5 Determination of sound energy levels for a noise source which emits impulsive noise.20
9.6 Calculation of directivity indices .23
9.7 Calculation of surface sound pressure level non-uniformity index.23
9.8 Frequency-weighted sound power level and sound energy level.23
10 Measurement uncertainty.24
10.1 Methodology .24
10.2 Determination of σ .24
omc
10.3 Determination of σ .25
R0
10.4 Typical upper bound values of σ .26
R0
10.5 Total standard deviation, σ , and expanded measurement uncertainty, U.27
TO
11 Information to be recorded.28
11.1 General .28
11.2 Noise source under test.28
© ISO 2010 – All rights reserved iii
---------------------- Page: 8 ----------------------
oSIST prEN ISO 3745:2010
ISO/DIS 3745
11.3 Test room. 28
11.4 Instrumentation. 28
11.5 Acoustical data . 28
12 Information to be reported. 29
Annex A (normative) General procedures for qualification of free-field and hemi-free-field rooms . 30
Annex B (normative) Qualification procedure for spaces within test rooms used in the
determination of sound power levels and sound energy levels of specific noise sources. 38
Annex C (normative) Calculation of A-weighted sound power levels and A-weighted sound
energy levels from one-third-octave band levels. 40
Annex D (normative) Array of microphone positions on a spherical measurement surface in a free
field. 42
Annex E (normative) Arrays of microphone positions on a hemispherical measurement surface in
a hemi-free field . 44
Annex F (normative) Coaxial circular paths of microphones on a hemispherical measurement
surface in a hemi-free field . 48
Annex G (normative) Meridional paths of microphones on a hemispherical measurement surface
in a hemi-free field . 49
Annex H (normative) Spiral paths of microphones on a hemispherical measurement surface in a
hemi-free field . 51
Annex I (informative) Guidance on the development of information on measurement uncertainty . 52
Bibliography. 63
iv © ISO 2010 – All rights reserved
---------------------- Page: 9 ----------------------
oSIST prEN ISO 3745:2010
ISO/DIS 3745
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 3745 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, and by
Technical Committee CEN/TC 211, Acoustics in collaboration.
This third edition cancels and replaces the second edition (ISO 3745:2003), which has been technically
revised.
© ISO 2010 – All rights reserved v
---------------------- Page: 10 ----------------------
oSIST prEN ISO 3745:2010
ISO/DIS 3745
Introduction
0.1 This International Standard is one of the series ISO 3740 to ISO 3747, which specify various methods for
determining the sound power levels and sound energy levels of noise sources including machinery, equipment
and their sub-assemblies. The selection of one of the methods from the series for use in a particular
application will depend on the purpose of the test to determine the sound power level or sound energy level
and on the facilities available. General guidelines to assist in the selection are provided in ISO 3740. The
series of standards of which this International Standard is a part gives only general principles regarding the
operating and mounting conditions of the machinery or equipment for the purposes of the test. It is important
that test codes be established for individual kinds of noise sources, in order to give detailed requirements on
mounting, loading and operating conditions under which the sound power levels or sound energy levels are to
be obtained and to select the appropriate measurement surface and microphone array from among those
specified in this International Standard.
0.2 The methods given in this International Standard require the source to be mounted in either a free-field
test room or a hemi-free-field test room having specified acoustical characteristics. The methods are then
based on the premise that the sound power or sound energy of the source is directly proportional to the mean
square sound pressure over a hypothetical measurement surface enclosing the source and otherwise
depends on the physical constants of air.
0.3 The methods given in this International Standard permit the determination of the sound power level and
the sound energy level in frequency bands and/or with frequency weighting ‘A’ applied. The methods give a
precision grade of accuracy (grade 1) as defined in ISO 12001. The resulting sound power levels and sound
energy levels include corrections to allow for any differences that might exist between the meteorological
conditions under which the tests are conducted and reference meteorological conditions.
0.4 For applications where there are large uncertainties due to operating conditions, or where reduced
accuracy is acceptable, reference can be made to the more practical methods of ISO 3744 or ISO 3746.
Guidance on evaluation of measurement uncertainty is given in Annex I.
vi © ISO 2010 – All rights reserved
---------------------- Page: 11 ----------------------
oSIST prEN ISO 3745:2010
DRAFT INTERNATIONAL STANDARD ISO/DIS 3745
Acoustics — Determination of sound power levels and sound
energy levels of noise sources using sound pressure —
Precision methods for anechoic test rooms and hemi-anechoic
test rooms
1 Scope
1.1 General
This International Standard specifies methods for measuring the sound pressure levels on a measurement
surface enveloping a noise source (machinery or equipment) in a free-field test room or a hemi-free-field test
room. The sound power level (or, in the case of impulsive or transient noise emission, the sound energy level)
produced by the noise source, in frequency bands of width one-third octave or with frequency weighting A
applied, is calculated using those measurements, including corrections to allow for any differences between
the meteorological conditions at the time and place of the test and those corresponding to a reference
characteristic impedance.
In general, the frequency range of interest includes the one-third-octave bands with mid-band frequencies
from 100 Hz to 10 000 Hz. In practice, the range is extended or restricted to frequencies beyond or within
these limits, to those between which the test room is qualified for the purposes of the measurements.
1.2 Types of noise and noise sources
The methods specified in this International Standard are suitable for all types of noise (steady, non-steady,
fluctuating, etc.) defined in ISO 12001.
The noise source under test may be a device, machine, component or sub-assembly. The maximum size of
the noise source depends on the requirements of clause 8 regarding the radius of the hypothetical sphere or
hemisphere used as the enveloping measurement surface.
1.3 Test room
The test rooms that are applicable for measurements made in accordance with this International Standard are
an anechoic test room or hemi-anechoic test room, also called, respectively, free-field room or a hemi-free-
field room.
1.4 Measurement uncertainty
Information is given on the uncertainty of the sound power levels and sound energy levels determined in
accordance with this International Standard, for measurements made in limited bands of frequency and with
frequency weighting A applied. The uncertainty conforms with that of the precision grade of accuracy
(grade 1) defined in ISO 12001.
© ISO 2010 – All rights reserved 1
---------------------- Page: 12 ----------------------
oSIST prEN ISO 3745:2010
ISO/DIS 3745
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
International Standard. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO
maintain registers of currently-valid International Standards.
ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results
ISO 9613-1:1993, Acoustics – Attenuation of sound during propagation outdoors – Part 1: Calculation of the
absorption of sound by the atmosphere
ISO 12001, Acoustics – Noise emitted by machinery and equipment – Rules for the drafting and presentation
of a noise test code
IEC 60942:2003, Electroacoustics – Sound calibrators
IEC 61183, Electroacoustics – Random-incidence and diffuse-field calibration of sound level meters
IEC 61260:1995, Electroacoustics – Octave-band and fractional-octave-band filters
IEC 61672-1:2002, Electroacoustics – Sound level meters – Part 1: Specifications
ISO/IEC Guide 98-3, Uncertainty in measurement – Part 3: Guide to the expression of uncertainty in
1)
measurement (GUM:1995)
3 Definitions
For the purposes of this document, the following definitions apply.
3.1
sound pressure
p
difference between instantaneous pressure and static pressure
[ISO 80000-8:2007, 8-9.2]
NOTE Sound pressure is expressed in pascals.
3.2
sound pressure level
L
p
ten times the logarithm to the base 10 of the ratio of the square of the sound pressure, p, to the square of a
reference value, p , expressed in decibels
0
2
p
L = 10lg dB (1)
p
2
p
0
–5
where the reference value, p , is 20 µPa (2 × 10 Pa)
0
NOTE 1 If specific frequency and time weightings as specified in IEC 61672-1 and/or specific frequency bands are
applied, this should be indicated by appropriate subscripts; e.g. L denotes the A-weighted sound pressure level.
pA
1) ISO/IEC Guide 98-3 is published as a reissue of the Guide to the expression of uncertainty in measurement (GUM).
2 © ISO 2010 – All rights reserved
---------------------- Page: 13 ----------------------
oSIST prEN ISO 3745:2010
ISO/DIS 3745
NOTE 2 This definition is technically in accordance with ISO 80000-8:2007, 8-22.
3.3
time-averaged sound pressure level
L
p,T
ten times the logarithm to the base 10 of the ratio of the time average of the square of the sound pressure, p,
during a stated time interval of duration, T (starting at t and ending at t ), to the square of a reference value,
1 2
p , expressed in decibels
0
t
2
1
2
p (t)dt
∫
T
t
1
L = 10lg dB (2)
p,T
2
p
0
where the reference value, p , is 20 µPa
0
NOTE 1 In general, the subscript “T” is omitted since time-averaged sound pressure levels are necessarily determined
over a certain measurement time interval.
NOTE 2 Time-averaged sound pressure levels are often A-weighted, in which case they are denoted by L , which is
A,
p T
usually abbreviated to L .
pA
NOTE 3 Adapted from ISO/TR 25417:2007, 2.3.
3.4
single-event time integrated sound pressure level
L
E
ten times the logarithm to the base 10 of the ratio of the integral of the square of the sound pressure, p, of an
isolated single sound event (burst of sound or transient sound) over a stated time interval T (starting at t and
1
ending at t ) to a reference value, E , expressed in decibels
2 0
t
2
2
p (t)dt
∫
t
1
(3)
L = 10lg dB
E
E
0
2 −10 2
where the reference value, E , is (20 µPa) s = 4 × 10 Pa s
0
T
NOTE 1 This quantity can be obtained by L +10lg dB , where T = 1 s.
0
p,T
T
0
NOTE 2 When used to measure sound immission, this quantity is usually called “single-event sound exposure level”.
3.5
measurement time interval
T
portion or a multiple of an operational period or operational cycle of the noise source under test, for which the
time-averaged sound pressure level is determined
NO
...
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