In fairness, in the past, there was little guidance available for the architect, designer, or building services engineer on how to achieve the correct balance of acoustics in the complex, dynamic environment of a school. Working with the DfES, the BRE developed a new legislative framework, BB93 (Building Bulletin 93) to become part of the Building Regulations. This defines a quality standard of acoustic performance for new schools and academies, and a regulatory framework to aid those involved in the design process.

BB93 recommends that a structured approach is taken to acoustic design; right from the beginning from the selection of the site of the school, through to the fine detail such as the acoustic performance of doors, windows and ventilation openings. An example of this approach in practice was the design of the Thomas Deacon Academy (TDA) - one of the largest secondary schools in Europe and the largest UK City Academy. 

Thomas Deacon Academy

Occupying 13.4 hectares east of Peterborough city centre, TDA is home to 2200 students. TDA is sponsored by the Deacon's School Trust and Perkins Engines Company Ltd, and is supported by Peterborough City Council as part of its reorganisation of secondary schools in the area. TDA had as its predecessor schools two foundation schools and a community college and forms a £46m Academy that specialises in mathematics and science.

Designed by Foster + Partners, this unique and individual building is arranged over three levels with an internal floor space of 18,200m2. A central court runs through the middle of the building to serve as a pupil communication and circulation space. Arching over the concourse is a large atrium that encloses the space whilst providing ample natural daylight. The unique geometry of the roof, combined with a lot of glass and steel, ensured this was a key acoustic challenge at design stage, alongside the other vital areas such as lecture theatres and open plan spaces. 

Foster + Partners involved Harris, Grant Associates right at the beginning of the project, with a brief that covered environmental and architectural acoustics, individual room acoustic design, building services acoustics and the monitoring of all of these during the different phases of construction. Here we have outlined how a structured approach helps at each stage of the design and construction process.

Measure and predict

The first task is to measure the background noise over the whole site and boundaries to define the total noise exposure, as well as the frequency content, and how this varies over time. TDA is close to Peterborough city centre, so we were aware that traffic noise might be an issue. To this end, test stations on the site logged data over a typical week to get a feel for passing cars, aircraft or train noise, and how the ebb and flow of the local day affects the site. This also established a baseline which allowed us to predict the impact the Academy itself would have on its neighbours.

Design development

Having established a location ambient noise baseline, we can then produce a design matrix to establish the BB93 requirements for every room: room to room isolation, room to circulation isolation, room to exterior isolation, mitigation of vertical and horizontal impact noise transmission, room decay times, atrium and circulation decay times. In TDA's case we also analysed the requirements of the building facade and ventilation systems in order to develop a strategy for façade penetrations and windows. All of this data was taken into consideration during Foster + Partners design development for the building and then traded off as professionally practicable.

Modelling

In order to define the acoustic treatment in critical areas of the building, i.e. the central court and atrium at TDA, we computer modelled the space with alternative acoustic treatments using a program called CATT-Acoustic. This process allowed iterative progression of the design to ultimately reflect the finish, look, feel and requirements for this large and complex space.

Liaison

As a design progresses there are inevitably areas (in the case of the TDA, the atrium and classrooms that open on to the Atrium) that require either an easement, or the specific sign off of the sponsors, and the DfES. We assisted Foster + Partners in preparing a case and also attended the meetings to provide information as required for the appropriate decision to be reached.

Value engineering

As the design reaches tender stage, we can supply budget information to help assist in the development of the design in line with any financial constraints. Similarly, when a project moves to site, attending site meetings can help resolve issues that arise as work progresses.

Commissioning

As construction nears completion, we provide progress measurements in order to establish the amount of treatment required to minimise budget and optimise acoustic performance. On completion, a broader set of measurements are taken to provide the design team with data to back up the as-built package.

Achieving results

Rigorous acoustic design was required for the ambitious TDA building to achieve its ultimate potential. On any major design project a suitably qualified and experienced acoustic consultant should be appointed to carry out an initial noise survey, assist with design development, check design details and on-site construction, and to carry out acoustic tests to confirm that the building achieves the client's required acoustic performance.

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