The grey area of acoustic design

The importance of getting acoustic design right from the beginning

 In many of life’s endeavors, we might have the option of failing at our chosen project once or twice, before succeeding on the third occasion. Hence the common expression, ‘third time lucky’. There are some contexts though, where getting things right first-time round is especially important. Here, Adam Fox, director of vibration isolation specialist Mason UK, elaborates on the grey area of acoustic design and explains the importance of getting the engineering right the first-time round.

We often find architects or acoustic consultants knocking on our door and asking if we can help solve a vibration problem. Although the answer is invariably yes we can, it also gives rise to a further question: ‘I wonder how much money and hassle they could have saved if only they came to us sooner’.

The issue is that many common problems and pitfalls are presented to us retrospectively. In fairness to the acoustic consultant or the architect, these problems are located in what you might think of as the grey area of acoustic design.

The grey area

Suppose, for example, an acoustic consultant knows that a floating floor will be required to prevent vibration from being transmitted through a structure. However, he or she might not necessarily know how thick it needs to be or what are the practical ramifications of its installation.

If the architect knows from early on in the project that thick floating floors will be required, they can adapt the design accordingly to make the necessary space allowance. Yet we often find the structure has been designed or built prior to these considerations and more costly, retrospective action is required.

Similarly, knowing what to specify is very different from knowing how to actually do it. Imagine a scientific laboratory or a factory with lots of equipment and stringent vibration requirements. An acoustic consultant is brought on board and quickly realizes that vibration isolation will be required. If the existing facility was designed with everything pre-installed, it is unlikely that there will be the right space allowances for the necessary springs and mounts. This requires detailing, designing around constraints and accounting for movement from thermal expansion as well as vibration which may not have been previously considered.

We encountered a project like this recently, and while we were able to solve the problem, it reaffirms the importance of having both an acoustic consultant and a vibration specialist involved in the project from the earliest possible stage.

Although space allowance is a frequent problem in this grey area, it is not the only common consideration that architects and acousticians need to be aware of. Another is structural isolation, and it is common that insufficient space is left for well-engineered bearings and correctly detailing surrounding structures such as retaining walls.

Quality matters

Retrospective action is also often required where a low-quality product was used or an installation was not done properly. Let’s say a hanger has been specified and the contractor takes the specification and is persuaded to go for the cheapest product, which may have poor longevity, insufficient acoustic performance or no capacity to accept construction tolerances.

We are often called upon to devise a solution to a noise problem that has emerged because of a poor-quality product or a product that was not installed properly. Technically speaking, the original contractor has fulfilled the requirement in the specification, but they are long gone by the time the customer has a noise problem they were not anticipating.

The unfortunate truth is that in most of these situations, you cannot simply swap out the faulty product for a superior one. A hanger, to continue the example above, is often very difficult to access once installed. Experienced acoustic consultants know the value of higher quality products and the track record they offer, as well as the benefits of suppliers who can offer installation expertise and other assistance on site.

There are many situations where you might have the benefit of being lucky at the third attempt. When it comes to acoustic design, however, it pays to get things right the first time around. The grey area of acoustic design can be difficult to navigate, even for experienced acousticians. Making sure your project can call upon the necessary expertise at the earliest possible stage removes the risks of unanticipated problems further along.

Mason UK is a specialist in vibration isolation products for architectural noise control, mechanical and electrical (M&E) systems and HVAC isolation. For assistance with your project call (01252)716610 or email info@masonuk.co.uk