CEN/TS 1793-4:2003
(Main)Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 4: Intrinsic characteristics - In situ values of sound diffraction
Road traffic noise reducing devices - Test method for determining the acoustic performance - Part 4: Intrinsic characteristics - In situ values of sound diffraction
This document describes a test method for determining the intrinsic characteristics of sound diffraction of added devices installed on the top of traffic noise reducing devices. The test method prescribes measurements of the sound pressure level at several reference points near the top edge of a noise reducing device with and without the added device installed on its top. The effectiveness of the added device is calculated as the difference between the measured values with and without the added devices, correcting for any change in height.
The test method is intended for the following applications:
· preliminary qualification, outdoors or indoors, of added devices to be installed on noise reducing devices;
· determination of sound diffraction index difference of added devices in actual use;
· comparison of design specifications with actual performance data after the completion of the construction work;
· verification of the long term performance of added devices (with a repeated application of the method).
The test method can be applied both in situ and on samples purposely built to be tested using the method described here.
Results are expressed as a function of frequency, in one-third octave bands between 100 Hz and 5 kHz. If it is not possible to get valid measurements results over the whole frequency range indicated, the results should be given in the restricted frequency range and the reasons of the restriction(s) should be clearly reported. A single-number rating is calculated from frequency data.
For indoors measurements see annex B.
Lärmschutzeinrichtungen an Straßen - Prüfverfahren zur Bestimmung der akustischen Eigenschaften - Teil 4: Produktspezifische Merkmale - Insitu-Werte der Schallbeugung
Dispositifs de réduction du bruit du trafic routier - Méthode d'essai pour la détermination des performances acoustiques - Partie 4 : Caractéristiques intrinsèques - Valeurs in situ de la diffraction acoustique
Le présent document décrit une méthode d'essai permettant de déterminer les caractéristiques intrinsèques de la diffraction acoustique des dispositifs additionnels installés au sommet des dispositifs de réduction du bruit. La méthode d'essai prescrit des mesures du niveau de pression acoustique en différents points de référence situés près du bord supérieur du dispositif de réduction du bruit, avec et sans dispositif additionnel installé au sommet. L'efficacité du dispositif additionnel est calculée comme étant la différence entre les valeurs mesurées avec et sans dispositifs additionnels, avec une correction pour tout changement de hauteur.
La méthode d'essai est destinée aux applications suivantes :
la qualification préliminaire, à l'extérieur ou à l'intérieur de bâtiments, des dispositifs additionnels à installer sur les dispositifs de réduction du bruit ;
la détermination de la différence d'indice de diffraction acoustique des dispositifs additionnels actuellement utilisés ;
la comparaison des spécifications de conception avec des données de performance réelles de l'ouvrage achevé ;
la vérification des performances à long terme de dispositifs additionnels (par l'application répétée de la méthode).
La méthode d'essai peut être appliquée in situ et sur des échantillons construits spécifiquement pour être soumis à essai selon la méthode décrite dans le présent document.
Les résultats sont exprimés en fonction de la fréquence, par bandes de tiers d'octave pour la plage comprise entre 100 Hz et 5 kHz. S'il est impossible d'obtenir des résultats de mesure valables sur toute la plage de fréquence spécifiée, il convient de donner les résultats pour la plage de fréquence réduite et de consigner clairement les raisons de la ou des restrictions. Un indice unique d'évaluation est calculé à partir des données de fréquence.
Voir l'annexe B pour les mesures à l'intérieur.
Protihrupne ovire za cestni promet - Preskusna metoda za ugotavljanje akustičnih lastnosti - 4. del: Bistvene lastnosti - Terenske vrednosti difrakcije zvoka
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2004
3URWLKUXSQHRYLUH]DFHVWQLSURPHW3UHVNXVQDPHWRGD]DXJRWDYOMDQMHDNXVWLþQLK
ODVWQRVWLGHO %LVWYHQHODVWQRVWL7HUHQVNHYUHGQRVWLGLIUDNFLMH]YRND
Road traffic noise reducing devices - Test method for determining the acoustic
performance - Part 4: Intrinsic characteristics - In situ values of sound diffraction
Lärmschutzeinrichtungen an Straßen - Prüfverfahren zur Bestimmung der akustischen
Eigenschaften - Teil 4: Produktspezifische Merkmale - Insitu-Werte der Schallbeugung
Dispositifs de réduction du bruit du trafic routier - Méthode d'essai pour la détermination
des performances acoustiques - Partie 4 : Caractéristiques intrinseques - Valeurs in situ
de la diffraction acoustique
Ta slovenski standard je istoveten z: CEN/TS 1793-4:2003
ICS:
17.140.30 Emisija hrupa transportnih Noise emitted by means of
sredstev transport
93.080.30 Cestna oprema in pomožne Road equipment and
naprave installations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL SPECIFICATION
CEN/TS 1793-4
SPÉCIFICATION TECHNIQUE
TECHNISCHE SPEZIFIKATION
December 2003
ICS 17.140.30, 93.080.30
English version
Road traffic noise reducing devices - Test method for
determining the acoustic performance - Part 4: Intrinsic
characteristics - In situ values of sound diffraction
Dispositifs de réduction du bruit du trafic routier – Méthode Lärmschutzeinrichtungen an Straßen - Prüfverfahren zur
d’essai pour la détermination des performances Bestimmung der akustischen Eigenschaften - Teil 4:
acoustiques – Partie 4 : Caractéristiques intrinsèques – Produktspezifische Merkmale - Insitu-Werte der
Valeurs in situ de la diffraction acoustique Schallbeugung
This Technical Specification (CEN/TS) was approved by CEN on 6 June 2003 for provisional application.
The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their
comments, particularly on the question whether the CEN/TS can be converted into a European Standard.
CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available. It
is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final decision about the possible
conversion of the CEN/TS into an EN is reached.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TS 1793-4:2003 E
worldwide for CEN national Members.
Contents
Foreword.4
Introduction .5
1 Scope .4
2 Normative references .5
3 Definitions and symbols .5
3.1 Definitions.5
3.2 Symbols .6
4 Diffraction index difference measurements.7
4.1 General principle.7
4.2 Dimensions and specifications .7
4.3 Positions of the sound source .8
4.4 Position of the microphones .8
4.5 Free-field measurements .9
4.6 Measured quantity .14
4.7 Measuring equipment.16
4.8 Data processing .18
4.9 Positioning of the measuring equipment .21
4.10 Diffraction index difference .22
DL
4.11 Single-number rating of diffraction index difference .22DDDI
4.12 Sample surface and meteorological conditions.23
4.13 Measuring procedure .23
4.14 Test report .24
Annex A (Informative) Definition and usage of the MLS signal.26
Annex B (Informative) Indoor measurements for product qualification.28
Annex C (Informative) Bibliography .29
Foreword
This document (CEN/TS 1793-4:2003) has been prepared by Technical Committee CEN/TC 226 “Road
equipment”, the secretariat of which is held by AFNOR.
It should be read in conjunction with :
EN 1793-1, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 1 : Intrinsic characteristics of sound absorption
EN 1793-2, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 2 : Intrinsic characteristics of airborne sound insulation
EN 1793-3, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 3 : Normalized traffic noise spectrum
CEN/TS 1793-5, Road traffic noise reducing devices - Test method for determining the acoustic performance –
Part 5: Intrinsic characteristics – In situ values of sound reflection and airborne sound insulation.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to announce this Technical Specification: Austria, Belgium, Czech Republic, Denmark,
Finland, France, Germany, Greece, Hungary Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway,
Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom.
Introduction
Part of the market of road traffic noise reducing devices is constituted of products to be added on the top of noise
reducing devices and intended to contribute to sound attenuation acting primarily on the diffracted sound field.
These products will be called added devices. This standard has been developed to specify a test method for
determining the acoustic performance of added devices.
The test method can be applied in situ, i.e. where the traffic noise reducing devices and the added devices are
installed. The method can be applied without damaging the traffic noise reducing devices or the added devices.
The method can be used to qualify products before the installation along roads as well as to verify the compliance
of installed added devices to design specifications. Repeated application of the method can be used to verify the
long term performance of added devices.
NOTE – This method could be used to qualify added devices for other applications, e.g. to be installed along railways or nearby
industrial sites. In this case special care has to be taken into account in considering the location of the noise sources and the
single-number ratings should be calculated using an appropriate spectrum.
No other national or international standard exists about the subject of this standard.
1 Scope
This document describes a test method for determining the intrinsic characteristics of sound diffraction of added
devices installed on the top of traffic noise reducing devices. The test method prescribes measurements of the
sound pressure level at several reference points near the top edge of a noise reducing device with and without the
added device installed on its top. The effectiveness of the added device is calculated as the difference between the
measured values with and without the added devices, correcting for any change in height.
The test method is intended for the following applications:
• preliminary qualification, outdoors or indoors, of added devices to be installed on noise reducing devices;
• determination of sound diffraction index difference of added devices in actual use;
• comparison of design specifications with actual performance data after the completion of the construction work;
• verification of the long term performance of added devices (with a repeated application of the method).
The test method can be applied both in situ and on samples purposely built to be tested using the method
described here.
Results are expressed as a function of frequency, in one-third octave bands between 100 Hz and 5 kHz. If it is not
possible to get valid measurements results over the whole frequency range indicated, the results shall be given in
the restricted frequency range and the reasons of the restriction(s) shall be clearly reported. A single-number rating
is calculated from frequency data.
For indoor measurements see Annex B.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate place in the text and the publications are listed hereafter. For
dated references, subsequent amendments to or revisions of any of these publications apply to this European
Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the
publication applies.
EN 1793-3: 1997, Road traffic noise reducing devices - Test method for determining the acoustic performance -
Part 3: Normalized traffic noise spectrum.
EN 60651: 1979, Sound level meters.
3 Definitions and symbols
3.1 Definitions
For the purpose of this standard the following definitions apply:
3.1.1
structural elements
those elements whose primary function is to support or hold in place acoustic elements
3.1.2
acoustical elements
those elements whose primary function is to provide the acoustic performance of the device
3.1.3
noise barrier
noise reducing device which obstructs the direct transmission of airborne sound emanating from road traffic
3.1.4
added device
acoustic element added on the top of a noise reducing device and intended to contribute to sound attenuation
acting primarily on the diffracted sound field
3.1.5
roadside exposure
The use of the product as a noise reducing device installed alongside roads
3.1.6
diffraction index
The result of a sound diffraction test described by formula (1). DI refers to measurements on a reflective
refl
reference wall. DI refers to measurements on an absorptive reference wall. DI refers to in situ measurements
abs situ
3.1.7
diffraction index difference
difference between the results of sound diffraction tests on the same reference wall with and without an added
device on the top, described by formula (4)
3.1.8
test construction
construction on which the added device is placed. For in situ measurements it is an installed noise reducing device;
for qualification tests it is a reference wall (see 4.2)
3.1.9
reference plane of the test construction
the vertical plane passing through the midpoint of the top edge of the construction (reference wall or installed noise
reducing device) on which the added device has to be placed (see figures 1, 2, 4, 5, 8)
3.1.10
reference height of the test construction without the added device, h
ref,0
height of the highest point of the test construction in relation to the surrounding ground surface. This highest point
is not necessarily lying in the plane of longitudinal symmetry of the reference test construction, if this symmetry
exists (figure 1)
3.1.11
reference height of the test construction with the added device on the top, h
ref,add
height of the highest point of the added device installed on the test construction in relation to the surrounding
ground surface. This highest point is not necessarily lying in the plane of longitudinal symmetry of the reference
test construction, if this symmetry exists (figure 4)
3.1.12
free-field measurement for diffraction index measurements
Measurement carried out placing the loudspeaker and the microph
...
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