building acoustics2

Building Acoustics

How sound behaves in a building can have a dramatic effect on the experience people have using the space. When done properly, acoustic design improves the educational attainment of children and helps hospital patients recover more quickly. Productivity in offices increases along with staff satisfaction. And, of course, a concert hall isn’t a concert hall if it doesn’t sound amazing.

By using an acoustic consultant on your project, problems such as a lack of privacy between hotel rooms, a highly reverberant restaurant where the noise is unbearable, or being unable to sleep because of the sound of a nearby road, are all easily avoided.

Read on to find out more about our building acoustics expertise

Room Acoustics

Nobody should have to suffer an environment where they can’t easily understand what is being said, where music turns into a mess of noise instead of a transforming experience, or where they can’t concentrate because of the mush of noise all around them. Yet lots of us accept this as part of our everyday lives.

We work in conjunction with the architect and design team to integrate acoustic treatments into a space so they are sympathetic to the design intent as well as meeting the client’s acoustic aspirations for the space.

Using the ODEON acoustic modelling package, we can examine and predict a wide range of acoustic parameters, allowing us to optimise the quantity and placement of acoustic treatments while providing value to our clients.

Sound Insulation

Sound insulation is the level of acoustic separation between spaces. This can be both airborne (e.g. controlling voices, music) and impact (controlling footfall, for example).

It is important to consider sound insulation in any building where acoustic separation and privacy between spaces is essential to their use. This includes residential, educational and commercial settings, mixed use developments with cafes and commercial space directly under apartments and even spaces as diverse as police interview rooms, and music rehearsal rooms.

We control sound insulation by optimising the specification of floor and wall partitions, matching their performance to the specific source we are trying to control. For example, the solution for low frequency music is not the same as for mid frequency speech. Acoustic detailing at partition junctions and for services penetrations is key in ensuring the performance of the wall or floor is not compromised.

Facade Sound Insulation and Ventilation Strategy

In the crossover between environmental noise and building acoustics – quite literally – sit building facades. We use the data gathered from our noise survey, and sometimes from the acoustic model of the site, to assess the level of sound insulation needed to ensure people are not disturbed as they go about their lives. This includes consideration of appropriate noise levels for sleep and rest (BS 8233) and noise levels for commercial and office space where a controlled level of background noise can, in fact, be desirable.

As well as specifying the acoustic performance of glazing and the wall build up, we examine whether external noise levels are such that windows can be opened to provide everyday ventilation or whether alternative systems, from trickle vents to MVHR, are needed. Even in noisy areas, however, we never advocate for sealed windows, believing that occupants should have control over their environment.

Noise from Building Services

Most commercial and performing arts buildings are mechanically ventilated, however, it is becoming a popular option in residential and educational developments. Mechanical ventilation systems generate noise, both from the machinery and fans themselves and from regenerated noise as air flows through the ductwork.

dBx Acoustics’ consultants review the noise data for services equipment and calculate the level of noise transfer to the room served. This includes duct losses and regenerated noise and the effect of the room itself, and using the results, we can specify acoustic attenuators to be installed within the system to control noise levels as required. We also review proposed M&E layouts to identify potential problems and suggest modifications before design is finalised.

Here’s our recent work

dBx Case Studies - Education

There is a proven link between acoustic conditions in schools and educational outcomes. Building Bulletin 93 (BB93) mandates minimum standards in primary and secondary schools for noise levels and room acoustics, as well as acoustic separation between teaching spaces.

The dBx Acoustics team can help you comply with BB93, but our expertise goes even further. We have extensive experience designing environments for pupils with additional needs, including autism and hearing loss, as well as higher education and noisier, practical workshop spaces.

New and refurbished school buildings must comply with Building Regulation E4 and the acoustic performance standards of Building Bulletin 93 (BB93) ‘Acoustic Design of Schools’. Whilst BB93 is not mandatory for higher education establishments, it typically forms the basis of the initial design for such establishments, with modifications as appropriate to allow for specific HE uses. Where projects are being designed with BREEAM in mind, credits HEA05 and POL05 are also relevant.

There are a number of different acoustic aspects which come together to ensure that acoustic conditions in schools are appropriate to support learning, and it’s so important to get it right – studies have shown that educational attainment can be directly correlated to acoustic conditions.

Our involvement often begins at the planning stage with an environmental noise survey, which allows us to advise on ventilation and glazing requirements to control noise ingress to the building. If mechanical ventilation is proposed, if there is an external MUGA, or if community use is proposed, the noise survey also allows noise emission limits to be set to ensure that existing neighbours are not adversely affected by noise.

Internal ambient noise levels in teaching spaces are also affected by mechanical ventilation, and we work with the M&E consultant to specify appropriate noise control measures, such as silencers.
When it comes to the design of the building itself, BB93 requires us to specify partitions and floors to control airborne and impact sound transmission between teaching spaces, based on their relative sensitivity and noise generation characteristics. The detailing of junctions and sealing of any services penetrations is critical in maintaining acoustic separation between adjacent rooms.

Having provided a suitably quiet teaching environment which won’t be adversely affected by activity in other classrooms, our focus moves to room acoustics and control of reverberation. Often this is as simple as specifying the acoustic performance of a suspended ceiling, but for large spaces such as Assembly Halls and Sports Halls, we undertake acoustic modelling to optimise the specification and placement of acoustic finishes. Where an exposed soffit is preferred, we calculate the specification and quantity of finishes, such as acoustic rafts and wall panels to control room acoustic conditions.

Finally, we carry out pre-completion acoustic testing on-site to ensure that all of the acoustic criteria for the project have been complied with on-site.

The dBx Acoustics team also have a particular interest in acoustic design for SEN schools, particularly schools catering to neurodiverse pupils. BB93 specifies design criteria for “children with special hearing and communication needs”, which is intended to include autism, ADHD and auditory processing difficulties, and assists in providing an environment in which speech transmission is clear and effective. The standard does not, however, consider the other acoustic aspects of school life which affect such pupils, including auditory sensitivities and the need to provide spaces to allow a retreat from the noise and bustle of daily school life. Our team’s direct and personal experiences of neurodiversity, both as parents and as individuals, helps us to understand the requirements of individual educational clients, and help guide the design of educational buildings to provide an acoustically diverse and appropriate environment.

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