prEN 1794-2

Road traffic noise reducing devices - Non-acoustic performance - Part 2: Methods of determination of the general safety and environmental characteristics

This document specifies methods and criteria for assessing the general safety and environmental performance of road traffic noise reducing devices under typical roadside conditions. Appropriate test methods are provided where these are necessary. The treatment of each topic is covered separately in Annexes A to E.

Lärmschutzvorrichtungen an Straßen - Nichtakustische Eigenschaften - Teil 2: Methoden zur Bestimmung der allgemeinen Sicherheits- und Umwelteigenschaften

Dieses Dokument legt Verfahren und Kriterien zur Bewertung von Lärmschutzvorrichtungen hinsichtlich der Sicherheit und des Umweltschutzes im Allgemeinen unter für den Straßenrand typischen Bedingungen fest. Sofern erforderlich, sind geeignete Prüfverfahren angegeben. Diese Aspekte werden in Anhang A bis Anhang E einzeln behandelt.

Dispositifs de réduction du bruit du trafic routier - Performances non acoustiques - Partie 2 : Méthodes de détermination des caractéristiques générales de sécurité et des caractéristiques environnementales

Le présent document spécifie les méthodes et les critères d’évaluation de la sécurité générale ainsi que des performances relatives à l’environnement des dispositifs de réduction du bruit du trafic routier dans des conditions classiques d’installation en bordure de route. Des méthodes d’essai appropriées sont données chaque fois que cela est nécessaire. Chaque sujet est traité séparément dans les Annexes A à E.

Protihrupne ovire za cestni promet - Neakustične lastnosti - 2. del: Metode ugotavljanja splošnih značilnosti glede varnosti in varovanja okolja

General Information

• Status: Not Published
• Publication Date: 07-Jan-2024
• ICS: 93.080.30 - Road equipment and installations
• Technical Committee: CEN/TC 226 - Road equipment
• Drafting Committee: CEN/TC 226/WG 6 - Noise reducing devices
• Current Stage: 4599 - Dispatch of FV draft to CMC - Finalization for Vote
• Start Date: 13-Jan-2023
• Due Date: 10-Aug-2022
• Completion Date: 13-Jan-2023
• Ref Project: oSIST prEN 1794-2:2022 - Road traffic noise reducing devices - Non-acoustic performance - Part 2: Methods of determination of the general safety and environmental characteristics

Relations

• Revises: EN 1794-2:2020 - Road traffic noise reducing devices - Non-acoustic performance - Part 2: General safety and environmental requirements
• Effective Date: 18-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
oSIST prEN 1794-2:2022
01-februar-2022
Protihrupne ovire za cestni promet - Neakustične lastnosti - 2. del: Metode
ugotavljanja splošnih značilnosti glede varnosti in varovanja okolja

Road traffic noise reducing devices - Non-acoustic performance - Part 2: Methods of

determination of the general safety and environmental characteristics

Lärmschutzvorrichtungen an Straßen - Nichtakustische Eigenschaften - Teil 2: Methoden

zur Bestimmung der allgemeinen Sicherheits- und Umwelteigenschaften

Dispositifs de réduction du bruit du trafic routier - Performances non acoustiques - Partie

2 : Méthodes de détermination des caractéristiques générales de sécurité et des
caractéristiques environnementales
Ta slovenski standard je istoveten z: prEN 1794-2
ICS:
13.020.99 Drugi standardi v zvezi z Other standards related to
varstvom okolja environmental protection
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
oSIST prEN 1794-2:2022 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 1794-2:2022
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oSIST prEN 1794-2:2022
DRAFT
EUROPEAN STANDARD
prEN 1794-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2021
ICS 93.080.30 Will supersede EN 1794-2:2020
English Version
Road traffic noise reducing devices - Non-acoustic
performance - Part 2: Methods of determination of the
general safety and environmental characteristics

Dispositifs de réduction du bruit du trafic routier - Lärmschutzvorrichtungen an Straßen - Nichtakustische

Performances non acoustiques - Partie 2 : Méthodes de Eigenschaften - Teil 2: Methoden zur Bestimmung der

détermination des caractéristiques générales de allgemeinen Sicherheits- und Umwelteigenschaften

sécurité et des caractéristiques environnementales

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 226.

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-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, Turkey 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
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 1794-2:2021 E

worldwide for CEN national Members.
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oSIST prEN 1794-2:2022
prEN 1794-2:2021 (E)
Contents Page

European foreword........................................................................................................................................ 3

Introduction ..................................................................................................................................................... 4

1 Scope ..................................................................................................................................................... 5

2 Normative references ..................................................................................................................... 5

3 Terms, definitions and symbols .................................................................................................. 5

3.1 Terms and definitions .................................................................................................................... 5

3.2 Symbols ................................................................................................................................................ 6

4 Characteristics .................................................................................................................................. 7

4.1 Safety in case of brushwood fire ................................................................................................. 7

4.2 Resistance to dynamic loads: risk of falling debris .............................................................. 7

4.3 Environmental protection ............................................................................................................ 7

4.4 Access for maintenance and emergency exits ....................................................................... 7

4.5 Light reflection .................................................................................................................................. 7

4.6 Transparency..................................................................................................................................... 7

5 Test report .......................................................................................................................................... 7

Annex A (normative) Safety in case of brushwood fire ................................................................... 8

Annex B (normative) Resistance to dynamic loads: risk of falling debris ..............................10

Annex C (normative) Environmental protection .............................................................................14

Annex D (normative) Access for maintenance and emergency exits .......................................15

Annex E (normative) Light reflection ..................................................................................................17

Annex F (informative) Transparency...................................................................................................19

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oSIST prEN 1794-2:2022
prEN 1794-2:2021 (E)
European foreword

This document (prEN 1794-2:2021) has been prepared by Technical Committee CEN/TC 226 “Road

equipment”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 1794-2:2020.

This document is part of a series that consists of the following parts under the general title “Road traffic

noise reducing devices — Non-acoustic performance”:

— Part 1: Methods of determination of the mechanical and stability characteristics

— Part 2: Methods of determination of the general safety and environmental characteristics

— Part 3: Reaction to fire – Burning behaviour of noise reducing devices and classification

The main change compared to the previous edition is:

— The Annexes A to F: the acceptance criteria given in the previous version of this standard have

been deleted and transferred to EN 14388:2021.
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oSIST prEN 1794-2:2022
prEN 1794-2:2021 (E)
Introduction

While performing their primary function, road traffic noise reducing devices should not pose hazards

to road users or other people in the vicinity or to the environment at large. Noise reducing devices

should not reflect light in such a way as to prejudice road safety. They should be made from materials

which do not emit noxious fumes or leachates as the result of natural or industrial processes, or as the

result of fire. Noise reducing devices should allow a means of escape by road users and access by

operatives in the event of an emergency or for maintenance.
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oSIST prEN 1794-2:2022
prEN 1794-2:2021 (E)
1 Scope

This document specifies methods and criteria for assessing the general safety and environmental

performance of road traffic noise reducing devices under typical roadside conditions. Appropriate test

methods are provided where these are necessary. The treatment of each topic is covered separately in

Annexes A to E.
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.

prEN 1794-1:2021, Road traffic noise reducing devices - Non-acoustic performance - Part 1: Mechanical

performance and stability requirements

EN ISO 2813:2014, Paints and varnishes - Determination of gloss value at 20°, 60° and 85° (ISO

2813:2014)
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological 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
3.1.1
road traffic noise reducing device
RTNRD

device designed to reduce the propagation of traffic noise away from the road environment

Note 1 to entry: The NRD may comprise acoustic elements (3.1.2) only or both structural (3.1.3) and acoustic

elements.

Note 2 to entry: Applications of NRD include noise barriers (3.1.4), claddings(3.1.5), covers (3.1.6) and added

devices(3.1.7).
3.1.2
acoustic element

element whose primary function is to provide the acoustic characteristic of the device

3.1.3
structural element
element whose primary function is to support or hold in place acoustic elements
3.1.4
noise barrier

noise reducing device which obstructs the direct transmission of airborne sound emanating from road

traffic
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oSIST prEN 1794-2:2022
prEN 1794-2:2021 (E)
3.1.5
cladding

noise-reducing device which is attached to a wall or other structure and reduces the amount of sound

reflected
3.1.6
cover
noise-reducing device which either spans or overhangs the road
3.1.7
added device

additional component that influences the acoustic characteristic of the original noise-reducing device

Note 1 to entry: The added device is acting primarily on the diffracted energy.
3.2 Symbols
For the purposes of this document, the following symbols apply.

ϕ angle at which reflections from the surface of the transparent material obscure

the view through the material, in degrees;
ϕ angle between the visual axis and the normal to the noise reducing device (see
Figure F.2) in degrees;
ϴ angle of incidence
angle of transparency (see Figure F.2) in degrees;
α angle (see Figure B.1)
ß angle of opacity (see Figure F.2) in degrees;
η angle of the transparent Elements
µ terms of refractive index
t function of the angle of incidence
K visual acuity factor (see Figure F.1) in degrees;
k Parameter
L light transmission index (as determined in accordance with EN 410 or
EN 2155-5), in percent;
L overall transparency for different material thickness t’
L /100 coefficient
r radius (see Figure B.1)
S area of opaque features within transparent elements, in square millimetres;
S total area of transparent elements, including horizontal features, in square
millimetres;
t/t’ material thickness/ different material thickness
T transparency, in percent;
T transparency looking right, in percent;
T transparency looking left, in percent;
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prEN 1794-2:2021 (E)
T dynamic transparency, in percent;
T static transparency, in percent.
u estimated uncertainties
u sum of the estimated combined uncertainties
u the square of the uncertainty in T
w weights
4 Characteristics
4.1 Safety in case of brushwood fire
The safety in case of brushfire shall be determined in accordance with Annex A.
4.2 Resistance to dynamic loads: risk of falling debris

When secondary safety has to be determined, this shall be done in accordance with Annex B.

4.3 Environmental protection

The constituent materials and their breakdown products shall be identified in accordance with

Annex C.
4.4 Access for maintenance and emergency exits

The acoustic and mechanical performances of doors or other means of escape shall be determined in

accordance with Annex D.
4.5 Light reflection

The results of a standard test of reflectivity shall be determined in accordance with Annex E.

4.6 Transparency

The results of a standard test of transparency should be determined in accordance with Annex F.

5 Test report

Every test report on aspects of performance shall include the following information:

a) number and year of this document;

b) full description of the element or system tested, including manufacturer(s), part numbers, place

and date of origin;

c) description of the method of sampling, description of the sampling procedure, if the performance

is determined by parts of manufactured elements;
d) place and date of determination, and the name of the responsible person(s);

e) sufficient description of any tests carried out, any results measured and the conclusions drawn

about the product together with any illustrations or photographs, all as specified in the

appropriate annex.
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prEN 1794-2:2021 (E)
Annex A
(normative)
Safety in case of brushwood fire
A.1 General

A road traffic noise reducing device can be exposed to fire arising from dry vegetation or other material

in close proximity. More severe fires from spilt fuel can arise as the result of traffic accidents.

Where a road traffic noise reducing device is in close proximity to property it can also be necessary to

consider the need to ensure that fire is not spread from the highway.

Where flammable systems are used, it is recommended that firebreaks of fire-resistant materials or

other design are incorporated into the road traffic noise reducing device in order to prevent the

propagation of fire. This annex is not applicable to such fire resistant material.

This annex describes a test for a representative panel of a vertical noise barrier under normal exposure

to brushwood fires at the roadside.

It does not provide information on the results of exposure to more severe conditions, e.g. ignition by

burning spilt fuel. The test should not be used to provide information on the fire safety of claddings

used for tunnels or partial covers over the highway.
A.2 Fire test

A.2.1 Acoustic elements of at least 2 m long by 1,5 m high shall be tested by exposure to localised

sources of fire at its base next to the front and rear faces independently. Panels shall be free of absorbed

water before testing; in the case of timber components, the moisture content shall be reduced to 18 %

by an approved drying method.

The mass and dimensions of the panel to be tested shall be measured and the panel shall be

photographed. An identical panel shall be examined to determine its construction; the dimensions of

its elements, including wall thickness of hollow sections, shall be measured and noted on a sketch at

1:20 scale.

A.2.2 Testing shall be carried out in an enclosed fireproof and draught-free chamber having a volume

of at least 150 m .

Fume extraction devices may be installed in or near the ceiling, but shall be prevented from fanning

any flames during the test.

The temperature of the chamber, including the floor, before the test begins shall be between 15 °C and

25 °C. The chamber should be fitted with an observation port or window in a suitable position to

observe the panel during the test.
A.2.3 Two identical sources of fire shall be prepared as follows:

a) a rectilinear wire mesh basket 300 mm by 200 mm by 300 mm high shall be made from welded

steel wire mesh, having a square mesh of 3 mm diameter drawn steel wire at 50 mm centres ;

b) in addition, three 3 mm diameter wires 300 mm long shall be secured in a vertical position inside

the basket, equispaced along the central line of the shorter dimension.
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oSIST prEN 1794-2:2022
prEN 1794-2:2021 (E)

The flammable material shall comprise shavings of spruce, 0,2 mm thick by 2 mm wide, and

approximately 50 mm long. The material shall be free from splinters and have a maximum moisture

content of 30 % ; it shall be acclimatised at 20 °C and 65 % humidity until its weight is constant.

600 g of shavings shall be lightly pressed down into each basket so that it is just filled.

A.2.4 The test panel shall be supported in a vertical position corresponding to its orientation in use,

on a plinth supporting the full length of the panel. The plinth shall be of masonry or concrete and have

a vertical step to a level of 250 mm above the floor of the chamber. The base of the test panel shall be

completely in contact with the plinth and the face to be tested shall be flush with the edge. The two

sources of fire shall be placed on the floor of the chamber with their longer dimension flush against

the plinth and the face of the test panel. Both sources shall be lit simultaneously, and the time taken

for the test shall start at this point.

A.2.5 The performance of the panel shall be observed during the test and the time at which any

significant change takes place recorded. After the sources of fire and any part of the panel which may

have ignited have burnt out, the panel shall be examined and the extent of any damage photographed

and measured. The opposite face of the panel shall not be tested until it and the floor of the chamber

have cooled to below 25 °C.
A.3 Test report

A.3.1 The test procedure shall be described together with the timing of significant stages, indication

of, for example maximum intensity of flames, the incidence of any observed changes to the test panel

and the number of samples tested.

The test report shall record the nature and extent of any flames and smoke produced during the test.

A.3.2 Photographs of the test panel before, during and after the test shall be supplied and shall

include an appropriate means of judging scale.
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Annex B
(normative)
Resistance to dynamic loads: risk of falling debris
B.1 General

Road traffic noise reducing devices can be mounted on structures or in such a way that if damaged

they could pose a hazard to road users or to others. In particular, even if the road traffic noise reducing

device is protected by the safety system on an elevated structure, there is a possibility of pieces or

whole panels from a noise barrier becoming detached as the result of a violent collision and for the

debris to fall, endangering those below.

Road traffic noise reducing devices which are to be used in a vulnerable position may be required to

be restrained by internal or external linkage between panels and/or elements to prevent them from

becoming detached and falling.

The standard provides some general indications of factors which need to be considered and also

provides a method of establishing the resistance of a product to a severe blow.

NOTE It is principally the responsibility of specifiers to consider the potential consequences of a barrier

becoming damaged and to provide protection accordingly.

Alternatively, a means of catching falling pieces detached from vulnerable barriers may be specified

for barrier systems which are not so restrained.
B.2 Characteristics
B.2.1 Behaviour under impact

Where it is known that any component of a device is liable to shatter if struck or shocked, this shall be

clearly stated.

NOTE Such a statement can be qualified by further evidence of the effectiveness of any restraining

mechanism.
B.2.2 Fastening of structural and acoustical elements

B.2.2.1 A road traffic noise reducing device shall be assumed to be safety fastened if the elements

are secured in such a way that they do not fall when they are deformed or broken. The restraint

systems shall be designed to withstand the self-weight of the relevant falling parts, multiplied by a load

factor of 4. The wet self-weight shall be used, calculated in accordance with prEN 1794-1:2021,

Annex B.

B.2.2.2 If structural and acoustical elements of this category of road traffic noise reducing device

are prevented from falling by a system of restraint linking them together, each link shall take the load

of all adjoining elements. It shall be assumed that the load applied by broken pieces of a device is the

weight of a single element acting at the most unfavourable position on the restraint system.

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oSIST prEN 1794-2:2022
prEN 1794-2:2021 (E)
B.3 Test method

NOTE This is the test method to access the characteristics of the falling debris produced by fixed energy

impacts.
B.3.1 Principle

The method of testing is to cause a heavy mass to strike normally to the centre or the most sensitive

point of the test specimen or other tested element or system, so that the test specimen is destroyed or

pushed out of the holding structure, o
...