dBx Acoustics

Acoustic Design and the WELL Building Standard

Various environmental characteristics can have direct impacts on mental health and well-being, such as housing, crowding, noise, indoor air quality, and light

The WELL Building Standard, originally introduced in the US, is steadily gaining importance in the design of UK office buildings. The intent of this performance-based standard is to produce workplaces which have a positive impact on human behaviours related to health and wellbeing. The standard covers things you would expect, such as air quality, light and of course acoustics. However, it also requires designers and occupiers to consider the nutrition, fitness and cognitive and emotional health of building occupants.

What’s the point?

At first glance, aiming for WELL standard (whether formally accredited or not) might seem off-puttingly costly. It’s important to remember that the biggest cost to any business is its people. Therefore, anything done to reduce sickness, improve productivity and enhance workplace satisfaction actually becomes a crucial investment. If you’re a regular reader of our blog, you’ll know that we firmly believe that an investment in acoustic design will quickly pay for itself – studies have shown that distracting noise can contribute up to a 66% decline in performance on office related tasks. If you add in the effect of other environmental factors, the quality of our working environment is evidently crucial to our individual and corporate success.

WELL Building Standard Features – Acoustics

The standard consists of a number of ‘features’ (rather than credits) against which we can assess buildings. This includes a thorough consideration of acoustic items under the following six headings. You can access the full information on each feature here.

Exterior Noise Intrusion (Feature 74)

This one is an ‘easy win’ for UK office design, with a less stringent criterion than that recommended by the BCO Guide to Specification 2014 and BS 8233:2014. We’d continue to recommend that reducing exterior noise intrusion (e.g. traffic noise, plant noise) in line with current design standards is best practice. dBx Acoustics can help you here, by carrying out environmental noise surveys and acoustic modelling for new buildings to advise on facade requirements and ventilation strategy. For existing buildings, we can carry out a noise survey to establish what current noise intrusion levels are.

Internally Generated Noise (Feature 75)

Something we love about this two-stage feature is the requirement to begin with an acoustic planning exercise to identify loud and quiet zones, and noisy equipment. This information allows us to design the space intelligently to minimise disturbance and distraction. Once again, we would recommend carefully considering this when planning any work space. Not only will this help with space planning, it will enable early integration of the acoustic features suggested in Feature 80 and Feature 81. Allowing for intelligent value engineering of the acoustic design.

This feature also covers the control of noise from building services, both in the system design and in ensuring best practice in installation to minimise noise issues. dBx Acoustics can not only help specify noise limits for individual plant items; we can calculate requirements for silencers and crosstalk attenuators, predict the risk of regenerated noise within the system, and advise on maximum duct velocities to help keep regenerated noise under control.

There are also criteria for noise within schools, which are in conflict with the current UK best practice set out in Building Bulletin 93, and for ‘disruptive music’, which may be in conflict with the requirements of Local Planning Authorities. In both instances, we would advise clients to meet their statutory obligations. Which, in the majority of cases, will provide a better condition than the WELL Building Standard.

Reverberation Time (Feature 78)

Reverberation time is, in essence, how ‘echoey’ a space is. You can learn more about this in our Jargon Buster article. WELL sets relatively stringent criteria for conference rooms and open plan office spaces which are appropriate to ensure that noise build-up is controlled, and that colleagues can comfortably communicate. Reverberation time is controlled by the use of ‘sound reducing surfaces,’ addressed in Feature 80 of the Standard.

Sound Masking (Feature 79)

We use sound masking systems to artificially introduce broadband noise into the workplace. The intent of this is to raise the background noise level to provide some speech privacy across the floorplate, without the noise itself being distracting in nature. Our experience is that such systems are common in the US. Typically they are only used in the UK where the ‘natural’ background noise is too low. These systems can be costly and we’d therefore recommend using building services and a level of controlled noise intrusion to provide this sound masking organically wherever possible. Fortunately, this is considered an ‘optimisation’ by WELL rather than a precondition of awarding certification.

Sound Reducing Surfaces (Feature 80)

We have to admit, this feature seems somewhat redundant when considered against Feature 78 (reverberation time). Both features are ‘optimisations’ and perhaps the intent is to allow designers to take an either-or approach (or to be able to achieve this feature without the aid of an acoustic consultant!). This feature recommends minimum acoustic absorption performance and percentage areas for wall, ceiling and floor finishes. This will have the effect of controlling reverberation time throughout the space.

Sound Barriers (Feature 81)

Finally, another ‘optimisation’ feature offers best practice and some design guidance for acoustic separation between spaces, and for the acoustic specification of doors and walls. Most aspects of this feature should already be considered in a good office acoustic design and recommendations are provided by BCO and BS 8233:2014. Residential acoustic privacy is already covered in the UK by Approved Document E of the Building Regulations, with a requirement for pre-completion acoustic testing.

On average, employees lose 80 minutes each working day due to distractions

Feeling Better?

Overall, we’d like to see the WELL Building Standard take off in the UK. The holistic design of buildings to make our lives better should surely be the intent of all designers. A framework to work against can only be a good thing. Some aspects of the standard are contradictory and may need some refinement. It would be good to see a UK version for the UK based on our existing standards and best practice which in many cases exceed the US requirements. This shouldn’t take away from the effort to create a better, more pro

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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