EN 16272-6:2023
(Main)Railway applications - Infrastructure - Noise barriers and related devices acting on airborne sound propagation - Test method for determining the acoustic performance - Part 6: Intrinsic characteristics - Airborne sound insulation under direct sound field conditions
Railway applications - Infrastructure - Noise barriers and related devices acting on airborne sound propagation - Test method for determining the acoustic performance - Part 6: Intrinsic characteristics - Airborne sound insulation under direct sound field conditions
This document describes a test method for measuring a quantity representative of the intrinsic characteristics of airborne sound insulation for rail noise barriers and related devices: the sound insulation index.
The test method is intended for the following applications:
- determination of the intrinsic characteristics of airborne sound insulation of noise barriers and related devices to be installed along railways, to be measured either on typical installations alongside railways or in laboratory conditions;
- determination of the intrinsic characteristics of airborne sound insulation of noise barriers and related 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 noise barriers and related devices (with a repeated application of the method);
- interactive design process of new products, including the formulation of installation manuals.
The test method is not intended for the determination of the intrinsic characteristics of airborne sound insulation of noise barriers and related devices to be installed in reverberant conditions, e.g. inside tunnels or deep trenches or under covers.
Results are expressed as a function of frequency in one-third octave bands, where possible, between 100 Hz and 5 kHz. If it is not possible to get valid measurement results over the whole frequency range indicated, the results need to be given in a restricted frequency range and the reasons for the restriction(s) need to be clearly reported.
Bahnanwendungen - Oberbau - Lärmschutzwände und verwandte Vorrichtungen zur Beeinflussung der Luftschallausbreitung - Prüfverfahren zur Bestimmung der akustischen Eigenschaften - Teil 6: Produktspezifische Merkmale - Luftschalldämmung in gerichteten Schallfeldern
Dieses Dokument beschreibt ein Prüfverfahren zur Messung einer Größe, die für die produktspezifischen Merkmale der Luftschalldämmung von Eisenbahnlärmschutzwänden und verwandten Vorrichtungen charakteristisch ist: den Schalldämmungsindex.
Das Prüfverfahren ist für die folgenden Anwendungen vorgesehen:
Bestimmung der produktspezifischen Merkmale der Luftschalldämmung von Lärmschutzwänden und verwandten Vorrichtungen, die entlang von Eisenbahnschienenwegen aufgebaut sind, und die entweder an typischen an Eisenbahnen ausgeführten Lärmschutzwänden oder unter Laborbedingungen zu messen sind;
Bestimmung der gegebenen produktspezifischen Merkmale der Luftschalldämmung von Lärmschutzwänden und verwandten Vorrichtungen im tatsächlichen Einsatz;
Vergleich der Bemessungsfestlegungen mit den tatsächlichen Leistungsdaten nach Abschluss der Bauarbeiten;
Überprüfung der Langzeitwirksamkeit von Lärmschutzwänden und verwandten Vorrichtungen (durch wiederholtes Anwenden des Verfahrens);
interaktiver Bemessungsprozess von neuen Produkten, einschließlich der Formulierung von Aufbauanleitungen.
Das Prüfverfahren ist nicht zur Bestimmung der produktspezifischen Eigenschaften der Luftschalldämmung für Lärmschutzwände und verwandten Vorrichtungen, die für die in halligen Umgebungen aufgebaut werden, z. B. innerhalb von Tunneln oder in ausgeprägten Tieflagen oder unter Abdeckungen.
Ergebnisse werden als Funktion der Frequenz in Terzbändern zwischen 100 Hz und 5 kHz angegeben, wo möglich. Wenn es nicht möglich ist, gültige Messergebnisse über den gesamten angegebenen Frequenzbereich zu erhalten, müssen die Ergebnisse in einem eingeschränkten Frequenzbereich angegeben werden, und die Gründe für die Einschränkung(en) müssen genau angegeben werden.
Applications ferroviaires - Infrastructure - Dispositifs de réduction du bruit - Méthode d'essai pour la détermination de la performance acoustique - Partie 6 : Caractéristiques intrinsèques - Isolation aux bruits aériens dans des conditions de champ acoustique direct
Le présent document décrit une méthode d'essai permettant de mesurer une grandeur représentative des caractéristiques intrinsèques de l'isolation aux bruits aériens des dispositifs de réduction du bruit ferroviaire : l'indice d'isolation acoustique.
La méthode d'essai est destinée aux applications suivantes :
- la détermination des caractéristiques intrinsèques de l'isolation aux bruits aériens des dispositifs de réduction du bruit destinés à être installés le long des voies ferrées et à être mesurés soit sur des installations types le long des voies ferrées soit en conditions de laboratoire ;
- la détermination des caractéristiques intrinsèques de l'isolation aux bruits aériens des dispositifs de réduction du bruit en service ;
- la comparaison des spécifications de conception avec les données de performance réelles de l'ouvrage de construction achevé ;
- la vérification des performances à long terme des dispositifs de réduction du bruit (par l'application régulière de la méthode) ;
- un processus interactif de conception de nouveaux produits, y compris l'élaboration de manuels d'installation.
La méthode d'essai n'est pas destinée à déterminer les caractéristiques intrinsèques de l'isolation aux bruits aériens des dispositifs de réduction du bruit destinés à être installés dans des conditions de champ réverbéré, par exemple à l'intérieur des tunnels, au fond des tranchées profondes ou sous des couvertures.
Les résultats sont exprimés en fonction de la fréquence, par bandes de tiers d'octave, si possible, entre 100 Hz et 5 kHz. S'il est impossible d'obtenir des résultats de mesure valables sur toute la gamme de fréquences indiquée, il est nécessaire que les résultats soient donnés pour une gamme de fréquences réduite et que les raisons de la ou des restrictions soient clairement consignées.
Železniške naprave - Infrastruktura - Protihrupne ovire in pripadajoče naprave, ki vplivajo na širjenje zvoka v zraku - Preskusna metoda za ugotavljanje akustičnih lastnosti - 6. del: Posebne karakteristike - Izolacija zvoka v zraku pri usmerjenem zvočnem polju
Ta evropski standard opisuje preskusno metodo za merjenje količine, ki predstavlja posebne karakteristike lastnosti na področju izolirnosti pred zvokom v zraku pri protihrupnih ovirah za železnico: indeksa izolirnosti pred zvokom.
Preskusna metoda je namenjena:
– ugotavljanju posebnih karakteristik izolacije pred zvokom po zraku protihrupnih ovir za namestitev ob železniški progi, ki se merijo na običajnih mestih namestitve ob železniški progi ali na ustreznem vzorčnem odseku;
– ugotavljanju posebnih karakteristik izolacije pred zvokom v zraku protihrupnih ovir na kraju samem pri dejanski uporabi;
– primerjavi specifikacij zasnove s podatki o dejanskih lastnostih po koncu izgradnje;
– preverjanju dolgoročnih lastnosti protihrupnih ovir (z večkratno izvedbo metode);
– interaktivnemu postopku zasnove novih izdelkov, vključno s pripravo navodil za namestitev.
Preskusna metoda ni namenjena:
– ugotavljanju posebnih karakteristik na področju izolirnosti pred zvokom v zraku pri protihrupnih ovirah za namestitev v odmevnih pogojih, npr. v predorih, v globokih jarkih ali pod pregradami.
Rezultati so izraženi kot funkcija frekvence v tretjinskih oktavnih pasovih med 100 Hz in 5 kHz, kadar je to mogoče. Če ni mogoče dobiti veljavnih rezultatov meritev za celo opredeljeno frekvenčno območje, se rezultati navedejo za omejeno frekvenčno območje, razlog(-i) za omejitev območja pa jasno opredelijo.
Vse protihrupne naprave, ki ne spadajo med protihrupne ovire in pripadajoče naprave, ki vplivajo na širjenje zvoka po zraku, npr. naprave za zmanjšanje talnih vibracij in naprave v vozilih, niso zajete v tem evropskem standardu.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2024
Železniške naprave - Infrastruktura - Protihrupne ovire in pripadajoče naprave, ki
vplivajo na širjenje zvoka v zraku - Preskusna metoda za ugotavljanje akustičnih
lastnosti - 6. del: Posebne karakteristike - Izolacija zvoka v zraku pri usmerjenem
zvočnem polju
Railway applications - Infrastructure - Noise barriers and related devices acting on
airborne sound propagation - Test method for determining the acoustic performance -
Part 6: Intrinsic characteristics - Airborne sound insulation under direct sound field
conditions
Bahnanwendungen - Oberbau - Lärmschutzwände und verwandte Vorrichtungen zur
Beeinflussung der Luftschallausbreitung - Prüfverfahren zur Bestimmung der
akustischen Eigenschaften - Teil 6: Produktspezifische Merkmale - In-situ-Werte zur
Luftschalldämmung in gerichteten Schallfeldern
Applications ferroviaires - Infrastructure - Dispositifs de réduction du bruit - Méthode
d'essai pour la détermination des performances acoustiques - Partie 6 : Caractéristiques
intrinsèques - Isolation aux bruits aériens dans des conditions de champ acoustique
direct
Ta slovenski standard je istoveten z: EN 16272-6:2023
ICS:
17.140.30 Emisija hrupa transportnih Noise emitted by means of
sredstev transport
93.100 Gradnja železnic Construction of railways
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 16272-6
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2023
EUROPÄISCHE NORM
ICS 93.100 Supersedes EN 16272-6:2014
English Version
Railway applications - Infrastructure - Noise barriers and
related devices acting on airborne sound propagation -
Test method for determining the acoustic performance -
Part 6: Intrinsic characteristics - Airborne sound insulation
under direct sound field conditions
Applications ferroviaires - Infrastructure - Dispositifs Bahnanwendungen - Oberbau - Lärmschutzwände und
de réduction du bruit - Méthode d'essai pour la verwandte Vorrichtungen zur Beeinflussung der
détermination de la performance acoustique - Partie 6 : Luftschallausbreitung - Prüfverfahren zur Bestimmung
Caractéristiques intrinsèques - Isolation aux bruits der akustischen Eigenschaften - Teil 6:
aériens dans des conditions de champ acoustique Produktspezifische Merkmale - In-situ-Werte zur
direct Luftschalldämmung in gerichteten Schallfeldern
This European Standard was approved by CEN on 8 October 2023.
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, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 16272-6:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 4
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, symbols and abbreviations . 9
3.1 Terms and definitions . 9
3.2 Symbols and abbreviations . 14
4 Sound insulation index measurements . 16
4.1 General principle . 16
4.2 Measured quantity . 16
4.3 Test arrangement . 17
4.3.1 General . 17
4.3.2 Tests on purposely built full-size samples . 17
4.3.3 Tests on installed noise barriers and related devices . 17
4.3.4 Non-flat, inclined or curved noise barriers and related devices . 18
4.4 Measuring equipment . 23
4.4.1 Components of the measuring system . 23
4.4.2 Sound source . 24
4.4.3 Test signal . 24
4.5 Data processing . 25
4.5.1 Calibration . 25
4.5.2 Sample rate and filtering . 25
4.5.3 Background noise . 25
4.5.4 Scanning technique using nine microphones . 26
4.5.5 Adrienne temporal window . 27
4.5.6 Placement of the Adrienne temporal window . 28
4.5.7 Low-frequency limit . 29
4.6 Positioning of the measuring equipment . 31
4.6.1 Selection of the measurement positions. 31
4.6.2 Post measurements . 31
4.6.3 Additional measurements. 31
4.6.4 Reflecting objects . 31
4.6.5 Safety considerations. 32
4.7 Sample surface and meteorological conditions . 32
4.7.1 Condition of the sample surface . 32
4.7.2 Wind . 32
4.7.3 Air temperature . 32
4.8 Single-number rating . 32
5 Measurement uncertainty . 32
6 Measuring procedure . 33
7 Test report . 33
Annex A (informative) Low-frequency limit and window width . 35
Annex B (informative) Measurement uncertainty . 39
B.1 General . 39
B.2 Measurement uncertainty based upon reproducibility data . 39
B.3 Standard deviation of repeatability and reproducibility of the sound insulation
index . 39
Annex C (normative) Template of test report on airborne sound insulation of rail noise
barriers and related devices acting on airborne sound propagation. 42
C.1 General . 42
C.2 Test setup (example) . 44
C.3 Test object and test situation (example). 46
C.4 Results (example) . 49
C.4.1 Part 1 – Results for ‘element’ in tabular form . 49
C.4.2 Part 2 – Results for ‘element’ in graphic form . 50
C.4.3 Part 3 – Results for ‘post’ in tabular form . 51
C.4.4 Part 4 – Results for ‘post’ in graphic form. 52
C.4.5 Uncertainty (example) . 52
Annex D (informative) Indoor measurements for product qualification . 55
D.1 General . 55
D.2 Parasitic reflections . 55
D.3 Reverberation time of the room . 55
Bibliography . 56
European foreword
This document (EN 16272-6:2023) has been prepared by Technical Committee CEN/TC 256 “Railway
applications”, the secretariat of which is held by DIN.
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 May 2024 and conflicting national standards shall be
withdrawn at the latest by May 2024.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 16272-6:2014.
With respect to the superseded document, the following changes have been made:
— The scanning technique is based on a nine-microphone grid; the use of a single microphone displaced
in nine positions has been abandoned.
— A detailed annex on the relationship between low-frequency limit and window width has been added
(Annex A).
— The way to evaluate the uncertainty of the measurement method has been improved, basing on
reproducibility data from the European project QUIESST (Annex B).
— A detailed example is given, including the evaluation of measurement uncertainty (Annex C).
— a new annex on indoor measurements has been added (Annex D);
EN 16272-6 is part of a series and should be read in conjunction with the other parts. All parts are listed
below:
EN 16272-1, Railway applications — Infrastructure — Noise barriers and related devices acting on
airborne sound propagation — Test method for determining the acoustic performance — Part 1: Intrinsic
characteristics - Sound absorption under diffuse sound field conditions
EN 16272-2, Railway applications — Infrastructure — Noise barriers and related devices acting on
airborne sound propagation — Test method for determining the acoustic performance — Part 2: Intrinsic
characteristics - Airborne sound insulation under diffuse sound field conditions (the present document)
EN 16272-3-1, Railway applications — Infrastructure — Noise barriers and related devices acting on
airborne sound propagation — Test method for determining the acoustic performance — Part 3-1:
Normalized railway noise spectrum and single number ratings for diffuse sound field applications
EN 16272-3-2, Railway applications — Infrastructure — Noise barriers and related devices acting on
airborne sound propagation — Test method for determining the acoustic performance — Part 3-2:
Normalized railway noise spectrum and single number ratings for direct sound field applications
EN 16272-4, Railway applications — Track — Noise barriers and related devices acting on airborne sound
propagation — Test method for determining the acoustic performance — Part 4: Intrinsic characteristics -
In situ values of sound diffraction under direct sound field conditions
EN 16272-5, Railway applications — Infrastructure — Noise barriers and related devices acting on
airborne sound propagation — Test method for determining the acoustic performance — Part 5: Intrinsic
characteristics - Sound absorption under direct sound field conditions
EN 16272-6, Railway applications — Infrastructure — Noise barriers and related devices acting on
airborne sound propagation — Test method for determining the acoustic performance — Part 6: Intrinsic
characteristics - Airborne sound insulation under direct sound field conditions
CEN/TS 16272-7, Railway applications — Track — Noise barriers and related devices acting on airborne
sound propagation — Test method for determining the acoustic performance — Part 7: Extrinsic
characteristics - In situ values of insertion loss
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
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, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
Noise barriers and related devices acting on airborne sound propagation alongside railways should
provide adequate sound insulation so that sound transmitted through the device is not significant
compared with the sound diffracted over the top. This document specifies a test method for assessing the
intrinsic airborne sound insulation performance for noise barriers and related devices designed for
railways in non-reverberant conditions. It can be applied indoors or outdoors. Indoors, it can be applied
in a purposely built test facilities, e.g. inside a laboratory. Outdoors, it can be applied in a purposely built
test facilities, e.g. near a laboratory or a factory, as well as in situ, i.e. where the noise barriers and related
devices are installed. The method can be applied without damaging the surface of the noise barriers and
related devices.
The method can be used to qualify products to be installed along railways as well as to verify the
compliance of installed noise barriers and related devices to design specifications. Regular application of
the method can be used to verify the long-term performance of noise barriers and related devices.
The method requires the averaging of results of measurements taken at different points behind the device
under test. The method is able to investigate flat and non-flat products.
The method uses the same principles and equipment for measuring sound reflection (see EN 16272-5)
and airborne sound insulation (the present document).
The measurement results of this method for airborne sound insulation are comparable but not identical
with the results of the EN 16272-2 method, mainly because the present method uses a directional sound
field, while the EN 16272-2 method assumes a diffuse sound field (where all angles of incidence are
equally probable). Research studies suggest that good correlation exists between laboratory data,
measured according to EN 16272-2 and field data, measured according to the method specified in the
present document [4-9], [17-18].
The test method specified in this document should not be used to determine the intrinsic characteristics
of airborne sound insulation for noise barriers and related devices to be installed in reverberant
conditions, e.g. inside tunnels or deep trenches or under covers.
For the purpose of this document, reverberant conditions are defined based on the geometric envelope,
e, across the road formed by the barriers, trench sides or buildings (the envelope does not include the
road surface) as shown by the dashed lines in Figure 1. Conditions are defined as being reverberant when
the percentage of open space in the envelope is less than or equal to 25 %, i.e. reverberant conditions
occur when w/e ≤ 0,25, where e = (w+h +h ).
1 2
This document introduces a specific quantity, called sound insulation index, to define the airborne sound
insulation of noise barriers and related devices. This quantity should not be confused with the sound
reduction index used in building acoustics, sometimes also called transmission loss.
This method may be used to qualify noise barriers and related devices acting on airborne sound
propagation for other applications, e.g. to be installed nearby industrial sites. In this case the single-
number ratings (see EN 16272-3-2) should be calculated using an appropriate spectrum.
a) Partial cover on both sides of the railway; b) Partial cover on one side of the railway;
envelope, e = w+h +h envelope, e = w+h , h = 0
1 2 1 2
c) Deep trench; envelope, e = w+h +h d) Tall barriers or buildings; envelope,
1 2
e = w+h +h
1 2
e) Train passing close to a noise barrier; f) Train passing close to a platform at the
envelope, e = w+h +h station. envelope, e = w+h +h
1 2 1 2
Key
r rail surface
w width of open space
h developed length of element, e.g. cover, trench side, barrier or building
h2 developed length of element, e.g. cover, trench side, barrier or building
NOTE Figure 1 is not to scale.
Figure 1 — Sketch of the reverberant condition check in some cases
1 Scope
This document describes a test method for measuring a quantity representative of the intrinsic
characteristics of airborne sound insulation for rail noise barriers and related devices: the sound
insulation index.
The test method is intended for the following applications:
— determination of the intrinsic characteristics of airborne sound insulation of noise barriers and
related devices to be installed along railways, to be measured either on typical installations alongside
railways or in laboratory conditions;
— determination of the intrinsic characteristics of airborne sound insulation of noise barriers and
related 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 noise barriers and related devices (with a repeated
application of the method);
— interactive design process of new products, including the formulation of installation manuals.
The test method is not intended for the determination of the intrinsic characteristics of airborne sound
insulation of noise barriers and related devices to be installed in reverberant conditions, e.g. inside
tunnels or deep trenches or under covers.
Results are expressed as a function of frequency in one-third octave bands, where possible, between
100 Hz and 5 kHz. If it is not possible to get valid measurement results over the whole frequency range
indicated, the results need to be given in a restricted frequency range and the reasons for the
restriction(s) need to be clearly reported.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
EN 16272-3-2, Railway applications – Infrastructure – Noise barriers and related devices acting on airborne
sound propagation – Test method for determining the acoustic performance – Part 3-2: Normalized railway
noise spectrum and single number ratings for direct sound field applications
EN 16951-1, Railway applications - Track - Noise barriers and related devices acting on airborne sound
propagation - Procedures for assessing long term performance - Part 1: Acoustic characteristics
EN 61672-1, Electroacoustics — Sound level meters — Part 1: Specifications (IEC 61672-1)
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
3 Terms, definitions, symbols and abbreviations
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp/
NOTE For the purpose of this document, the following definitions take precedence over other definitions from
the above websites.
3.1 Terms and definitions
3.1.1
noise barrier
noise reducing device, which obstructs the direct transmission of airborne sound emanating from
railways and which will typically span between posts and also may overhang the railway
Note 1 to entry: Noise barriers are generally made of acoustic and structural elements (see 3.1.3 and 3.1.4).
3.1.2
cladding
noise reducing device, which is attached to a wall or other structure and reduces the amount of sound
reflected
Note 1 to entry: Claddings are generally made of acoustic and structural elements (see 3.1.3 and 3.1.4).
3.1.3
acoustic element
element whose primary function is to provide the acoustic performance of the device
3.1.4
structural element
element whose primary function is to support or hold in place acoustic elements
3.1.5
added device
added component that influences the acoustic performance of the original noise-reducing device (acting
primarily on the diffracted energy)
Note 1 to entry: In some noise barriers, the acoustic function and the structural function cannot be clearly
separated and attributed to different components.
3.1.6
railway side exposure
use of the product as a noise reducing device installed alongside railways
3.1.7
sound insulation index
quantity representing the amount of sound transmitted through the device under test, specified by
Formula (1)
Note 1 to entry: This is the result of an airborne sound insulation test according to the present document.
3.1.8
reference height
height h equal to half the height, h , of the noise barrier or related device under test: h = h /2
S B S B
Note 1 to entry: See Figures 2, 4, 6, 7 and 8.
Note 2 to entry: When the height of the device under test is greater than 4 m and, for practical reasons, it is not
advisable to have a height of the source h = h /2, it is possible to have h = 2 m, accepting the corresponding low
S B S
frequency limitation (see 4.5.7).
3.1.9
source reference surface for sound insulation index measurements
ideal, smooth surface facing the sound source side of the noise barrier or related device under test and
just touching the most protruding and significant parts of it within the tested area
Note 1 to entry: The reference surface is as smooth as possible, and follows the inclination or curve of the device
under test within the tested area. For vertical and flat noise barriers and related devices, the reference surface is a
vertical plane. For inclined and flat noise barriers and related devices, the reference surface is a plane with the same
inclination. For curve and flat noise barriers and related devices, the reference surface is a curve surface with the
same curvature.
Note 2 to entry: See Figures 2, 7 and 8.
Note 3 to entry: The device under test includes both structural and acoustic elements.
3.1.10
microphone reference surface
ideal, smooth surface facing the receiver side of the noise barrier or related device under test and just
touching the most protruding and significant parts of it within the tested area
Note 1 to entry: The reference surface is as smooth as possible, and follows the inclination or curve of the device
under test within the tested area. For vertical and flat noise barriers and related devices, the reference surface is a
vertical plane. For inclined and flat noise barriers and related devices, the reference surface is a plane with the same
inclination. For curve and flat noise barriers and related devices, the reference surface is a curve surface with the
same curvature.
Note 2 to entry: See Figures 2, 7 and 8.
Note 3 to entry: The device under test includes both structural and acoustic elements.
3.1.11
source reference position
position facing the side to be exposed to noise when the device is in place, located at the reference height
h and placed so that its horizontal distance to the source reference surface is d = 1 m
S s
Note 1 to entry: See Figures 2, 4, 6, 7 and 8.
Note 2 to entry: The actual dimensions of the loudspeaker used for the background research on which this
document is based are: 0,40 m × 0,285 m × 0,285 m (length × width × height).
3.1.12
measurement grid for sound insulation index measurements
measurement grid constituted of nine equally spaced microphones in a 3x3 squared configuration
Note 1 to entry: The orthogonal spacing between two subsequent microphones, either vertically or horizontally,
is s = 0,40 m.
Note 2 to entry: See Figures 2, 3, 4, 6, 7, 8 and 4.5.4.
3.1.13
measurement grid reference position
position facing the receiver side of the device under test, located at the reference height h and placed so
S
that its horizontal distance to the microphone reference surface is d = 0,25 m
M
Note 1 to entry: See Figures 2, 6, 7 and 8.
3.1.14
barrier thickness for sound insulation index measurements
distance t between the source reference surface and the microphone reference surface at a height equal
B
to the reference height h
S
Note 1 to entry: See Figures 2, 6, 7 and 8.
3.1.15
free-field measurement for sound insulation index measurements
measurement taken with the loudspeaker and the microphone in an acoustic free field in order to avoid
reflections from any nearby object, including the ground, keeping the same geometry as when measuring
across the noise reducing device under test
Note 1 to entry: See Figure 6.
3.1.16
Adrienne temporal window
composite temporal window having a leading edge with a left-half Blackman-Harris shape and a fixed
length of 0,5 ms, followed by a flat portion and a trailing edge having a right-half Blackman-Harris shape,
so that the lengths of the flat portion and the right-half Blackman-Harris portion have a ratio of 7/3
Note 1 to entry: This type of window is specified in 4.5.5.
3.1.17
background noise
noise coming from sources other than the source emitting the test signal
3.1.18
signal-to-noise ratio
difference in decibels between the level of the test signal and the level of the background noise at the
moment of detection of the test signal (within the Adrienne temporal window)
3.1.19
impulse response
time signal at the output of a system when a Dirac function is applied to the input
Note 1 to entry: The Dirac function, also called δ function, is the mathematical idealisation of a signal that is
infinitely short in time which carries a unit amount of energy.
Note 2 to entry: It is impossible in practice to create and radiate true Dirac delta functions. Short transient sounds
can offer close enough approximations but are not very repeatable. An alternative measurement technique,
generally more accurate, is to use a period of deterministic, flat-spectrum signal, like maximum-length sequence
(MLS) or exponential sine sweep (ESS), and transform the measured response back to an impulse response.
Key
1 noise barrier or related device height, hB [m] 5 loudspeaker front panel
2 source reference surface 6 distance between the loudspeaker front panel and source
reference surface, d [m]
S
3 microphone reference surface 7 microphone grid
4 reference height, hs [m] 8 distance between the microphone grid and the microphone
reference surface [m]
Figure 2 — (not to scale) Sketch of the loudspeaker and the microphone grid close to the noise
barrier or related device under test for sound insulation index measurements
Key
1 noise barrier height hB [m] 2 reference height hS [m]
3 orthogonal spacing between two subsequent
microphones s [m]
Figure 3 — (not to scale) Measurement grid for sound insulation index measurements in front of
the device under test (receiver side); the yellow circles indicate the microphone positions,
labelled from M1 to M9
Key
1 loudspeaker front panel 5 noise barrier or related device thickness tB at height hS [m]
2 measurement grid 6 horizontal distance microphone 5 - microphone reference
surface d at height h [m]
M S
3 reference height hS [m] 7 horizontal distance loudspeaker - microphone 5 dT at height
[m]
hS
4 horizontal distance loudspeaker - source
reference surface d at height h [m]
S S
NOTE d= dt++d ; see Formula (5).
T SB M
Figure 4 — (not to scale) Sketch of the set-up for the reference “free-field” sound measurement
for the determination of the sound insulation index
3.2 Symbols and abbreviations
For the purposes of this document, the symbols and abbreviations in Table 1 apply.
Table 1 — Symbols and abbreviations
Symbol or Designation Unit
abbreviation
a major axis of the ellipsoid of revolution used to define the maximum m
sampled area at oblique incidence
a0, a1, a2, a3 Coefficient for the expression of the four-term full Blackman-Harris window -
b Depth of the surface structure of the sample under test m
s
b Width of a portion of material of the sample under test m
m
c Speed of sound in air m/s
d Horizontal distance from the microphone reference surface to the m
M
measurement grid; it is equal to d = 0,25 m
M
d Horizontal distance from the front panel of the loudspeaker to the sound m
S
source reference surface; it is equal to: d = 1 m
S
d Horizontal distance from the front panel of the loudspeaker to the m
T
measurement grid; it is equal to: d + t + d
S B M
DL Single-number rating of sound insulation index dB
SI
Δf Width of the j-the one-third octave frequency band Hz
j
F Symbol of the Fourier transform -
f Frequency Hz
f Low frequency limit of sound reflection index measurements Hz
min
f Sample rate Hz
s
f cut-off frequency of the anti-aliasing filter Hz
co
h Height of the device under test m
B
h Reference height m
S
h (t) Incident reference component of the free-field impulse response at the k-th -
i,k
measurement point
h (t) Transmitted component of the impulse response at the k-th measurement -
t,k
point
h (t) Background noise component of the impulse response at the k-th -
n,k
measurement point;
j Index of the j-th one-third octave frequency band (between 100 Hz and -
5 kHz, where possible)
k Index of the k-th measurement point (k = 1 … n) -
k Coverage factor -
p
k Constant used for the anti-aliasing filter -
f
L Length of an acoustical element m
E
Symbol or Designation Unit
abbreviation
L Sample period length of a non-homogeneous noise reducing device m
p
n Number of measurement points on which to average (n = 9) -
r Radius of the maximum sampled area at normal incidence m
SI Sound transmission index in the j-th one-third octave frequency band -
j
s Orthogonal spacing between two subsequent microphones m
s Standard deviation of repeatability -
r
s Standard deviation of reproducibility -
R
Standard deviation of reproducibility of the single-number rating for -
s
R,DL
SI ,E
“elements”
Standard deviation of reproducibility of the single-number rating for “posts” -
s
R,DL
SI ,P
Standard deviation of reproducibility of the single-number rating for -
s
R,DL
SI ,G
“global”
S/N Signal-to-noise-ratio at the k-th microphone dB
k
S/N Signal-to-noise-ratio at the k-th microphone in the j-th one-third frequency dB
j,k
band
t Time s
t Thickness of the device under test at the height h m
B S
t Air temperature °C
C
T Length of the Blackman-Harris trailing edge of the Adrienne temporal s
W,BH
window
T Total length of the Adrienne temporal window s
W,ADR
u Standard uncertainty -
U Expanded uncertainty -
wi,k(t) Reference free-field component time window (Adrienne temporal window) -
at the k-th measurement point
w (t) Time window (Adrienne temporal window) for the transmitted component -
t,k
at the k-th measurement point
4 Sound insulation index measurements
4.1 General principle
The sound source emits a transient sound wave that travels toward the device under test and is partly
reflected, partly transmitted and partly diffracted by it. The microphone placed on the other side of the
device under test receives both the transmitted sound pressure wave travelling from the sound source
through the device under test, and the sound pressure wave diffracted by the top edge of the device under
test (for the test to be meaningful the diffraction from the lateral edges should be sufficiently delayed). If
the measurement is repeated without the device under test between the loudspeaker and the
microphone, the direct free-field wave can be acquired. The power spectra of the direct wave and the
transmitted wave give the basis for calculating the sound insulation index.
The sound insulation index shall be the logarithmic average of the values measured at nine points placed
on the measurement grid (scanning points). See Figure 3 and Formula (1).
The measurement shall take place in a sound field free from reflections within the Adrienne temporal
window. For this reason, the acquisition of an impulse response having peaks as sharp as possible is
recommended: in this way, the reflections coming from other surfaces can be identified from their delay
time and rejected.
4.2 Measured quantity
The expression used to compute the sound insulation index SI as a function of frequency, in one-third
octave bands, is:
Fh t ⋅w t df
() ()
n
tk,,tk
∫
1 ∆f
j
SI =−⋅10 lg (1)
j ∑
n
k=1
Fh t ⋅w t df
() ()
i,,k i k
∫
∆f
j
where
h (t) is the incident reference component of the free-field impulse response at the k
i,k th
scanning point;
th
h (t) is the transmitted component of the impulse response at the k scanning point;
t,k
w (t) is the time window (Adrienne temporal window) for the incident reference component
i,k
th
of the free-field impulse response at the k scanning point;
w (t) is the time window (Adrienne temporal window) for the transmitted component at the
t,k
th
k scanning point;
F is the symbol of the Fourier transform;
j is the index of the j-th one-third octave frequency band (between 100 Hz and 5 kHz,
where possible);
Δf is the width of the j-th one-third octave frequency band;
j
n = 9 is the number of scanning points.
4.3 Test arrangement
4.3.1 General
The test method can be applied either on noise barriers and related devices installed alongside railways
or on real-size samples purposely assembled to be tested (indoors or outdoors) using the method
described here.
4.3.2 Tests on purposely built full-size samples
For applications on full-size samples purposely built to be tested using the method described here, e.g. in
an outdoor test facility, the specimen shall be built as follows (see Figure 5):
— a part, composed of acoustic elements, that extends at least 4 m and is at least 4 m high;
— a post 4 m high (if applicable for the specific noise reducing device under test).
— a part, composed of acoustic elements, that extends at least 2 m and is at least 4 m high;
The test specimen shall be mounted and assembled in the same manner as the manufactured device is
used in practice with the same connections and seals between components parts.
The tested area is a circle having a radius of 2 m centred on the middle of the measurement grid. The
sample shall be built large enough to completely include this circle for each measurement.
For qualifying the sound insulation index across posts only, it is only necessary to have acoustic elements
that extend 2 m or more on either side of the post (see Figure 5).
If the device under test has a post-to-post distance less than 4 m, the distance between posts should be
reduced accordingly but the overall minimum width of the construction should be the same as shown in
Figure 5.
4.3.3 Tests on installed noise barriers and related devices
For applications on noise barriers and related devices that are already installed along railways, the test
specimen shall be constructed as follows:
— for installed noise barriers and related devices using single acoustic elements to achieve full height:
• the test specimen shall be constructed as a single element which is representative of the specific
application;
• where the test specimen cannot be constructed as a single element or where the installed noise
reducing device is lower than 4 m, the test specimen shall be centred on the loudspeaker axis (at
reference height h = 2 m above the ground) and built up to 4 m high using smaller height
S
acoustic elements at the base and top as appropriate;
— for installed noise barriers and related devices using stacked elements to achieve full height:
• the test specimen shall be constructed as used in the specific application.
For applications on noise barriers and related devices that are already installed along railways, if there is
a plinth under the device, it shall be considered part of the “sample under test”.
4.3.4 Non-flat, inclined or curved noise barriers and related devices
For flat or curved, vertical or inclined road traffic noise reducing devices, Figures 7 and 8 apply. For cases
not covered by these figures, measurements should be carried out in accordance with the following
general principles:
— the plane of the microphone grid is parallel to the microphone reference surface;
— the axis loudspeaker-microphone 5 is horizontal and directed toward the sound source reference
surface;
— microphone 5 is as close as possible to the mid-height of the screen;
— the shortest distance of microphone 5 to the microphone reference surface is d = 0,25 m.
M
Noise barriers and related devices consisting of a horizontal or vertical juxtaposition of several distinct
types of screens (composition of shapes or structures of very large dimensions) shall be characterized in
detail: each shape or structure shall be specifically characterized under the conditions described in this
document.
For structures that do not allow the unequivocal application of these rules, measurements may be carried
out in strict compliance with the provisions of this document. The responsibility for adapting the method
is left to the opera
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