Building Bulletin 93 (BB93)
The BB93 standard sets classroom reverberation times for both new-build and refurbishment for a primary school classroom / teaching area.
Scotland, whilst not having a statutory standard, usually refers to the English & Welsh Building Bulletin 93, incorporating it into the brief as a performance standard.
Project: City of Glasgow College Riverside Campus
Country/city: UK / Glasgow
Architects: Michael Laird and Reich & Hall Ltd
Main contractor: Sir Robert McAlpine
Ceiling contractor: Roskel Contracts
Photographer: Sally Jubb Photography
Project size: Solo Baffle 500 m², Akusto Wall 6000 m²
The City of Glasgow College Riverside Campus, a £66m campus, accommodating 2000 students, is just part of the overall £228m scheme to replace 11 ageing buildings and change the very skyline of Glasgow. The City Centre Campus, which will connect to Riverside, was to be compleed in Aug 2016.
A large number of high profile architectural practises and contractors were in attendance, including: joint project architects Michael Laird and Reiach & Hall, as well as main contractor McAlpine. The guest speaker was Don Oeters of Arup Acoustics, who co-authored the updated BB93: Acoustic Design of Schools, published by DfES in February 2015. He was joined by Luke Robertson, project acoustician from Arup’s Glasgow office.
“The accurate predicted reverberation time of an extremely large number of varying teaching spaces was crucial in achieving a successful design. Arup Acoustics used the following steps to achieve this: the results of multiple calculation methods were compared to improve certainty; absorption coefficient data from Arup’s extensive library of both laboratory and in-situ commissioning measurements, along with Ecophon data, was drawn upon; optimal positioning of the acoustic baffles, rafts and wall panels was developed with the Architect to ensure maximum absorption efficiency and early testing of mock-up rooms was organised to verify the predictions. The result was close correlation between predicted and measured results, a successful design and a happy Contractor and Client,” says Luke Robertson.
Although BB93 is not mandatory in Scotland, as it is in England and Wales, it was utilised within the brief. Don Oeters explains the new changes, some of which he wrote, and which were adopted for the design:
“Criteria for sound insulation, internal ambient noise and reverberation control are similar to BB93 (2003). BB93 (2015) addresses some compliance issues including cross-ventilation from classrooms to circulation and specification of sound absorbing finishes to sports halls and gyms. There are now defined criteria for ‘Alternative Performance Standards’ and refurbished rooms. Other changes include the introduction of recommended noise limits from equipment such as projectors or fume cupboards, which are described in more detail in the Association of Noise Consultants online publication Acoustics of Schools: a design guide. Also, new standards, in line with the Equalities Act, now take into account students with a more broadly defined range of language and communication difficulties.”
Thousands of Ecophon baffles and rafts were utilised as part of the acoustic and thermal strategy, and were manufactured in Slate grey to compliment the exposed concrete soffit. This stunning campus has already picked up several awards including the RICS Award: Design through Innovation. The latest win came on 25th May when its architects lifted the Scottish Design Awards for Best Public Building and Architectural Grand Prix.