CE marking of noise barriers

Noise barriers along roads must be CE marked according to EN 14388 – regardless of whether they are made of wood, aluminium, glass or plastic. The only exception to the CE marking requirement is barriers built on site from loose timber. However, if the elements are produced in the factory, the barriers must be CE marked.

Who is responsible?

What happens when the descriptions in the tender documents are vague or non-existent? Even if the client or information in the procurement documents does not specify that the barrier must be CE marked, this is an indispensable requirement that builders and suppliers must fulfil according to current legislation – and it is not allowed to mount non-CE marked barriers.

What does CE marking mean?

CE marking means that products have been tested or calculated on the basis of established conditions.

Is CE marking a guarantee for quality?

The fact that a noise barrier is CE marked does not automatically mean that it is a quality product or that it fulfils the requirements the client wishes to comply with. The point of the CE standard is to make it easier to set requirements, as all products have been tested or calculated according to the same criteria, but the requirements must be specified in order to be meaningful in relation to the product being delivered.

Do noise barriers have to be CE marked?

Yes.

Is it allowed to install non-CE marked noise barriers?

No.

Are there any exceptions?

Yes. A loose timber barrier built on site does not need to be CE marked. However, if the elements are produced in the factory, the barriers must be CE marked.

Who is responsible for ensuring that the product is CE marked?

Client and suppliers.

Which standard specifies the CE marking requirements?

CE standard EN 14388.

What specifications does the standard EN 14388 contain?

The CE standard EN 14388 consists of 14 different standards, each of which contain different levels or grades and the associated test procedure and/or declarations. The client should set requirements for most of these. It is important that the client or regulatory authority specifies the desired level within the respective standard. There is ongoing work to improve standard EN 14388, but so far the latest approved revision in force is from 2003.

How can descriptive texts be made clearer?

A CE marked noise barrier can be compared to a car. If performance requirements are not set, it is impossible to compare and know what the purchase entails. The client should set requirements for most of the 14 standards included in EN 14388. In some cases - for example, "The barrier must be able to withstand impact of stones" - there is only "Approved" or "Not approved", but requirements, according to which the barrier must pass the test, must be imposed.

WHICH REQUIREMENTS SHOULD BE IMPOSED ON A NOISE BARRIER?

Standard EN 14388 uses “Acoustic elements” as a designation for the noise-reducing part of the barrier. Posts and supporting parts are referred to as “Structural elements”.

Noise attenuation

Noise attenuation is divided into Sound absorption and Airborne sound insulation (weighted value of absorption and reflection – or what is generally considered noise attenuation). It is usually enough for an area to be shielded from the noise source by a noise reducing solution – for example, by a wall that reflects the sound. In addition, if noise absorption is required to prevent the noise from bouncing off the acoustic wall, the wall can be supplemented with absorbers. The noise reduction test is carried out with acoustic elements mounted on posts according to the supplier's instructions – in the same way as the barrier would be mounted in reality.

It is also important when choosing a noise barrier to ensure that it is high enough. Low-frequency noise has a swing diameter of 2.5 metres, so if a barrier is 2 metres high, the noise will roll over the barrier. A lorry with exhaust pipe on the roof has one of its noise sources 3 metres up in the air. Most often, the barrier should therefore be 3.5 meters or higher to achieve the desired noise reduction. A noise investigation can provide answers to what barrier height is required in relation to, among other things, terrain, road speed limit and noise requirement level.

• Sound absorption (Noise barrier with absorbent, EN 1793-1)
  Test values are provided in Category A0-A4, where A4 is the best and attenuates more than 11 dB on the DLα scale. A3 attenuates 8-11 dB.
  Recommendation: A4 (and often A3 as well) is extreme attenuation, which is difficult to reach and only needed in exceptional cases. Class A2 is normally sufficient when noise absorption is required.
  
  
• Airborne noise insulation (Traditional noise barrier or noise screen, EN 1793-2)
  Test values are provided in Category B0-B3, where class B3 is the best and attenuates more than 24 dB on the DLR scale. Class B2 is in the range 15-24 dB.
  Recommendation: A well-functioning barrier should attenuate more than 24 dB, which is why the requirement should be class B3.

Mechanical requirements

The mechanical requirements can be divided into requirements for acoustic elements (noise reduction) and requirements for load-bearing elements (usually posts). The requirements specify how much load the elements must withstand without breaking, as well as the movement of the elements at a certain load (e.g. wind or snow).

• Acoustic elements, specific gravity (EN 1794-1:B)
  In order to be able to design the posts and also see the bearing capacity of the acoustic elements, it must be shown how much the acoustic elements are bent down if they are mounted horizontally (instead of vertically, as is normal). The level is given in kN per element.
  
  
• Acoustic elements, maximum vertical load (EN 1794-1:B)
  Shows how much load an element can withstand if loaded straight from above. The level is given in kN/m.
  
  
• Acoustic elements, maximum horizontal load (Load from wind or wind pressure from vehicles, EN 1794-1:A)
  Shows how much load an acoustic element can withstand before it bends more than 50 mm (set as maximum limit). The supplier shall specify the maximum load in relation to the cc distance between posts, and the value shall be reported separately for each project. The maximum level is given in kN/m² and is shown in the declaration of performance of the barrier. In each given project, wind load conditions are specified based primarily on geographical location and the height of the barrier above ground. For example, “Wind load 24 m/s” and “Terrain type II” can be specified as normative in a certain project. The supplier shows an estimate (in relation to the height of the barrier, cc distance between posts, wind load zone and terrain type) of the deflection (in millimetres) the barrier can withstand at this load. The deflection must not exceed 50 mm.
  
  
• Acoustic elements, snow clearing load (Load from plough truck, EN 1794-1:E)
  Based on the speed limit of the road, a ploughing speed is specified, which the acoustic element must withstand over an area of 2x2 metres. The supplier must demonstrate that the acoustic element can handle a given load based on its height, width, distance from the road and given snow clearing load, without the screen breaking. This must be done by means of an estimate or in reference to physical tests that have been carried out.
  
  
• Bearing element, max. deflection (EN 1794-1:A)
  Displays the maximum deflection of a post based on a certain load from wind or wind pressure from vehicles. Specified to ensure that the design of the post in relation to its height is within the limit values. The load-bearing elements must be able to withstand the specified load in projects without bending more than 20 mm for a 2-metre high post (30 mm if the height of the post is 3-4.5 metres).
  
  
• Bearing element, max. snow load (EN 1794-1:E)
  Shows that a post can withstand the bending torque generated by the snow clearing load (must be stated for each project based on the specified plough speed).
  
  
• Stone impact test (EN 1794-1:C)
  Shows that the barrier can withstand certain impact of stones or lumps of ice from snow ploughing without breaking. Must be indicated as "Approved" or "Not Approved".
  
  
• Risk of falling objects (EN 1794-2:B)
  Shows that the screen can withstand collision with a vehicle without breaking or having parts falling off. Tests are carried out in different classes and are specified as, for example, “Class 3, Approved”, where Class 3 is the highest level.
  
  
• Light reflection (EN 1794-2:E)
  Shows how much light the barrier reflects. May be significant in terms of glare from the sun or from the headlights of other cars.
  
  
• Light transmission/Luminous transmittance (EN 1794-2:F)
  Shows how much light the screen lets through (for example, a coloured glass screen).
  
  
• Environmental declaration (EN 1794-2:C)
  The supplier reports any hazardous substances that are emitted during the production of the barrier, during its service life and if the barrier would start to burn. Also shows to what extent and how the screen can be recycled.
  
  
• Evacuation solution (EN 1794-2:D)
  The supplier must have a working solution in order to be able to evacuate through the noise barrier. It must not be possible to open the evacuation door from the outside without special tools.

EXAMPLES OF REQUIREMENTS SPECIFICATION

Noise attenuation (EN 1793-2)
Noise barriers must have documented category of at least Class B3.

Sound absorption (If absorption barrier is required, EN 1793-2)
Noise barrier including absorption must have documented category of at least Class A2.

Wind load (EN 1794-1, Appendix A)
Both acoustic and load-bearing elements must have a reported deflection at wind load (often the wind load requirement varies between 21 m/s and 26 m/s) according to EN 1991-7-4, terrain type II, e.g. "Windload 24 m/s, Terrain type II".

Snow clearing load on acoustic elements (EN 1794-1, Appendix E)
The acoustic element must be able to withstand snow clearing load according to Appendix E, ploughing speed 60 km/h (limit state), without permanent deformations (breaks).

Maximum bending torque on load-bearing elements (EN 1794-1, Appendix E)
Bearing elements (posts) must be reported as capable of withstanding a snow clearing load according to Appendix E, ploughing speed 60 km/h (limit state), without permanent deformations (breaks).

Risk of stone impact (EN 1794-1, Appendix C)
The barrier must be classified and Approved.

Light transmission (Specified in case of transparent barrier, EN 1794-2)
The light transmission of the barrier must be at least Tvis (Visible light transmission) 85%.

Environmental declaration (EN 1794-2)
The supplier must put the  environmental declaration on record.

IN CONCLUSION

This introduction to the CE marking standard for noise barriers has been developed by Hammerglass AB and is intended as support and assistance to regulatory bodies and contractors. Hammerglass Infrastructure offers CE-marked noise barriers and the premises in this introduction are based on the experiences we have had in connection with this task. Hammerglass AB is also a member of the committee working on the development of new CE standards. We disclaim any responsibility for any errors. If you have any questions or concerns about CE marking or about this publication, you are more than welcome to contact us.