What is Acoustic Fencing?

When you hear the term acoustic fencing, you could be  thinking of a specialised form of fencing that is aimed not at marking boundaries or as a means of visual screening but to a large extent, weakening unwanted sound entering or leaving a site. Contrary to the traditional timber or panel fences, the acoustic fencing is designed to either absorb, reflect or block the noise waves, and this makes it suitable for busy road sides, industrial areas, in schools, railways and even residential gardens.

This paper will discuss the nature of acoustic fencing, how it works, its advantages, important points to consider when installing it and the process of selecting the right product.

How Acoustic Fencing Works

In its simplest form, Acoustic Fencing is effective through the discontinuity of sound wave propagation. There are two major mechanisms:

• Reflect: The fence panel is a reflector that reflects a sound wave and it does not allow the wave to pass through.
• Absorption: In some acoustic fences, there are layers or materials which take in acoustic energy and change it into a low level of heat or spread it, and hence, the level of noise that is transmitted will be reduced.

The distinguishing characteristics between acoustic fencing and conventional fencing are: increased thickness / mass, reduced spacing between boards / panels, increased height and special posts / fixings to reduce the leakage of sound.

There are many materials and types of acoustic fencing.

There are many types of acoustic fencing available in different materials and systems, depending on the type of noise and the level of budget:

• Timber acoustic fencing: This type uses pressure-treated timber in thick tongue and groove construction, usually with interlocking systems to produce the minimum gaps. Usually used in residential and less serious commercials.
• Composite or recycled-plastic systems: Modern systems are made of recycled plastic or composite boards having acoustic cores to make them more durable and consummated with less maintenance.
• Steel/metal acoustic panels: These are used in any commercial or infrastructure level (e.g. beside a motorway or a railway) where heavy duty and high-performance is needed.
• Hybrid systems (reflective + absorptive): A reflective face (modem, noise) and an absorptive face (modem, protected area) are used to achieve a maximum amount of noise reduction.

The material used is not essential, but it is critical to select a system that has been rated as an acoustic performer (such as by BS EN standards in the UK).

Advantages of Acoustic Fencing.

Acoustic fencing can provide a number of hard benefits when invested in by a homeowner, garden or commercial location.

Quieter Flights and Better Health.

Acoustic fencing that is of high quality will result in a significant reduction in noise. Other systems boast of up to 25-32 decibel reduction with proper installations.

Reduction in noise will result in improved concentration, reduced stress levels, sleep and enjoyment of outdoor activities.

Enhanced Privacy & Security

Being heavier and taller, as well as frequently being built without openings, acoustic fences provide enhanced privacy and serve as more powerful physical obstacles.

In the case of commercial locations, it can be enhanced security of the boundaries; in the case of homes, more peaceful gardens.

Increase in Real Estate Price and Beauty.

Buyers or tenants tend to be more interested in buying or renting a quieter, better screened property. Acoustic fencing provides the element of high specification, which can lead to value addition.

Contemporary acoustic fencing is available in many types of finishes and profiles allowing it to be used to enhance architectural styles but not ruin them.

Durability & Low Maintenance

Most of the systems are built to last, and they include treated timber, corrosion-resistant posts and materials that are resistant to outdoor environmental conditions. Other manufacturers provide long service-life (e.g., 20-30 years) under suitable installation and maintenance.

Selecting the Best Acoustic Fencing for Your Site.

The choice of an appropriate acoustic fencing system should be determined by a number of criteria:

Assess the Noise Source

• Is it the sound of a busy road, railway, neighbouring business, or a construction site?
• What is the altitude and range of the origin of your boundary? These are the factors which influence the performance of a fence.

Height, Mass and Construction.

• The higher the fence when compared to the noise source, the higher the performance.
• The denser and heavier the panel (mass per m 2 ) the better the reduction of sound.
• Search for as few gaps as possible; tongue and groove boards should interlock or have sealed joints to avoid sound escaping.

Finish and Warranty Material.

• Make sure that materials are appropriate to your climate and exposure (e.g. treated timber, steel that is not corroded by elements).
• Check warranty, anticipated life expectancy and finishes (paint, stain) compatibility with the acoustic system.
• A reflective panel (noise on a single side) or absorptive/combination panel (noise on two or more sides) are to be considered depending on the noise.

Planning & Installation

• Determine the height of the fence or the distance to the road has to be planned (in the UK, fences exceeding 2m or those near a public highway may need planning permission).
• Acoustic fencing will require professional installation: the proper anchoring of posts, structural stability (where the wind is strong), and proper alignment are critical to performance.
• Take into account site drainage, vegetation trimming and access.

Maintenance and Service Life of Acoustic Fencing.

When properly installed and maintained, an acoustic fence may serve a lifetime. There are systems that have a projected service life of 20-30 years.

Maintenance tips:

• Fixings check and annual posts to be checked so as to ensure that there is no movement or loosening.
• There should be clear vegetation and debris at the bottom because the foliage may retain moisture and speed up decomposition (in timber systems).
• Protective finishes or stains should be applied again to timber when it starts to wear.
• Look at gaps or upraised boards – even minor holes diminish the performance of sound.
• In the case of commercial sites, have acoustic performance tests done periodically to verify that the system is still capable of meeting the necessary noise level reduction.

Summary & Final Thoughts

Acoustic Fencing is not a boundary as such, and it is a multi-purpose service to provide a reduction in noise, privacy, security and beauty enhancement. It may be a home garden bordering a major highway or a commercial property where the industrial noise pressure is rife, but the appropriate acoustic fencing system will change the outdoor area into a haven of peace.

You can make sure you enjoy all the advantages of this investment by learning how acoustic fences operate, choosing materials that fit your purpose, taking into consideration the installation and maintenance, etc. Acoustic fencing is a long term investment in your property when properly defined.