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Building Products April 2017

INSULATION AND ACOUSTICS DO NOT DISTURB With the acoustic factor playing an important part in how suitable a building is for its intended purpose, Paul Howard focuses on what should be considered in order to ensure that the future occupants’ health and wellbeing are not affected by poor acoustic design. Whether it is a residential or APRIL 2017 | BUILDING PRODUCTS 27 commercial building, poor acoustic design can lead to all manner of problems. For example, a noisy workplace can reduce the productivity of employees – perhaps leading to stress and illness, which in turn can lead to absenteeism and staff turnover. Within hospitals, noise pollution can elevate psychological and physiological stress, which can be indicated by anxiety, annoyance and increased heart rate and blood pressure. In fact, some evidence suggests that noise may contribute to increased lengths of hospital stay. With this in mind, it is vital that the principles of acoustic design are understood. There are three key aspects to the acoustic design of a building: sound insulation, quality of sound, and controlling noise levels. On the first point, the main question is whether it is possible for the occupants to utilise the building without being disturbed by adjacent activities. Indeed, sound insulation is obtained by the careful design of all of the building elements that surround the space. The quality of sound refers to the design of rooms within the building so that the acoustic environment supports the intended use of the space. This factor is especially important within spaces such as lecture theatres or music practice rooms, where the acoustic environment can seriously compromise the activities within if not correctly designed. For example in lecture theatres, if the room causes too much sound reflection, speech will become distorted and difficult to understand. And too little reflection will mean that people sitting at the back of the theatre will not be able to hear what the lecturer is saying. As such, an optimum amount of reflection is required for speech clarity. When it comes to controlling noise, it needs to be ensured that spaces where noise levels may be higher have been designed accordingly; in atrium spaces, noise levels can become unbearably loud and within open plan offices it can become uncomfortable. Therefore, providing an appropriate reverberation time within these spaces will control the noise levels. To control noise levels within a building, sound insulation is also vital – and that includes the specification of systems with high levels of acoustic performance where required. Sound insulation is the reduction of noise that passes between two spaces separated by a dividing element. The sound transmitted between two spaces can either enter via the dividing element (direct transmission) or through the surrounding structure (indirect or flanking transmission) and as such, it is important to consider both of these factors when designing for acoustic control. With any existing sound insulation problem, it is essential to identify the weakest parts of the composite construction. Indeed, Building Regulation requirements regarding the sound Continued on page 28 >>>


Building Products April 2017
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