Sound foundations
Acoustic design plays a vital role in every public space, from libraries and offices to schools and council chambers. In this article, Jack Harvie-Clark, Building Acoustics Group of the IOA, Stephen Turner, former president of the IOA, and Paul Shields president-elect of the IOA outline five essential pillars that help ensure buildings are inclusive, functional, and built to serve their communities
For many people, the word acoustics conjures up images of concert halls and performers, and the audience discussing whether or not the venue has good acoustics. Acoustics, though, concerns everything do with sound: how it is generated, how it is propagated and how it is perceived by those hearing it.
The acoustic quality of a public building – from the collaborative hum of a modern office to the focused quiet of a library – is fundamental to its success. It is a critical design aspect that directly determines whether a space succeeds or fails in its purpose, whether that is a foyer, a meeting room, a dining hall or a place for performing drama or music. When acoustics are overlooked, the results are usually more than just an annoyance. They can render multimillion-pound facilities unfit for purpose, create barriers for many users, and lead to costly, disruptive remedial work. Effective acoustic design is therefore fundamental to creating public buildings that achieve their desired function; are inclusive, and support the well-being of the communities they serve. This article outlines the key acoustic areas that must be addressed so that a new public building delivers on its promise.
The five pillars of acoustic design
Achieving good building acoustics requires a holistic approach, balancing five distinct but interconnected pillars of design. Getting any one of these wrong can compromise the entire building. Getting them right relies on the successful integration of the acoustic design with other aspects of internal environmental quality such as air quality and thermal comfort, as well integrating with the architectural design, the structure and mechanical services.
1. Keeping external noise out
A building’s façade – comprising its roof, walls, windows, and ventilation systems – must provide a robust barrier against environmental noise. Whether it is the constant rumble of traffic or the noise from a nearby industrial site, external sounds should not intrude such that activities within are disrupted. A library, for instance, cannot be a place of concentration if traffic noise is sufficiently audible that it causes distraction. Similarly, a council chamber cannot function effectively if external noise masks important discussions. To address external noise requires careful specification of glazing, wall constructions, and ventilation strategies to meet the specific noise challenges that might exist from the building’s location.
2. Controlling the building’s noise impact on neighbours
A public building must be a good neighbour, which means controlling the noise it generates so that any adverse effect on the surrounding community is appropriately managed. This external noise impact comes from two main sources: the activities within and around the building, and its building services. Noise from activities, such as children in a school playground or amplified music from an event space, can affect nearby residential areas. Similarly, fixed plant and machinery, like rooftop air conditioning or Air Source Heat Pump units, can adversely affect neighbours if not properly controlled. National and local planning policies describe how such noise is to be managed and these requirements must be met. Failure to do so at the design stage can lead to planning consent delays, costly retrospective mitigation, and lasting damage to community relations. A thorough acoustic design at an early stage will enable the potential noise impact to be assessed and solutions identified such as optimising the site layout, use of acoustic barriers, and careful selection of external equipment.
3. Controlling noise from building services
The systems that make a building comfortable, i.e. heating, ventilation, and air conditioning (HVAC) should not do so at the expense of acoustic comfort. The constant hum of fans, the rush of air through grilles, or the gurgle of water in pipes can create sound that is annoying, cause irritation or undermine concentration. These potential effects are best managed at the design stage by suitable specifications leading to selection of appropriate equipment, isolating plant rooms from surrounding noise sensitive rooms, and carefully designing the distribution systems to minimise noise. The goal is to create a calm background sound environment that allows the space to be used as intended without noise being a constant source of distraction.
4. Ensuring privacy and preventing disruption between spaces
A building must be designed to accommodate different activities simultaneously without them interfering with one another. The architectural concept for arranging the location of noise-generating and noise-sensitive activities is the starting point, and sets the context. The detailed design considers effective sound insulation between internal spaces, to achieve speech privacy where needed and prevent noise from one area disrupting the use of another. For example, sensitive conversations in a consultation room or a private office must remain confidential and not be overheard in adjacent corridors or rooms. Similarly, a noisy group activity in one classroom should not disturb the quiet study happening in the room next door. Achieving this outcome involves more than just specifying a solid wall; sound can also travel through flanking paths such as continuous structural or facade elements and ventilation ducts. A comprehensive acoustic design addresses all potential routes for sound, so that each space maintains its required level of acoustic privacy.
5. Controlling sound within each space
The acoustic character of a room itself must be designed to match its purpose. Sound generated in a room repeatedly reflects off hard surfaces like concrete, glass, and plasterboard, which leads to higher sound levels. This is known as reverberation. In a busy space, such hard surfaces can cause sound to build up to excessive, uncomfortable levels.This feature is often the most noticeable acoustic failing in public buildings. The reverberant sound level in a modern school dining hall or a minimalist café can be so loud that you cannot hold a comfortable conversation. Such excessive noise makes the space stressful, unpleasant, and exclusionary for many people, particularly those with hearing difficulties or neurodiverse sensitivities. Similarly, in an open-plan office, poor room acoustics can lead to a distracting build-up of noise, hampering concentration and productivity.
The solution is to incorporate the right amount of sound-absorbing material, strategically placed on surfaces like the ceiling or walls. This absorption controls reverberation, stops noise from building up, and makes speech clearer. The goal is to create an internal acoustic environment that is comfortable, functional, and fit for its intended use.
Other issues
Finally, the acoustic design of public buildings must also take account of requirements such as Public Address systems for emergency alarms or speech reinforcement in spaces, including hearing-aid loops.
Conclusion
As can be seen, the acoustic performance of a public building is not a matter of luxury or aesthetics; it is a core component of its fitness for purpose. From shielding occupants from external noise to ensuring conversations in a meeting room are clear and private, good acoustics are fundamental to creating spaces that are functional, inclusive, and support the well-being of their users.
Overlooking these principles at the design stage is a false economy. The cost of retrofitting acoustic solutions into a failing building is invariably disruptive and far more expensive than getting it right from the outset. By contrast, early engagement with an acoustic specialist allows these five pillars to be seamlessly and cost-effectively integrated into the architectural vision. For decision-makers overseeing public investment, prioritising acoustics is a direct investment in the long-term success of the building and the community it serves.
The Institute of Acoustics (IOA) is the professional body for those working in the fields of acoustics, sound, noise and vibration management.
