We presented our new method for the acoustic design of open plan offices at the annual Institute of Acoustics Spring Conference 2019, held in Milton Keynes. Our method is particularly suited to acoustic design in agile or activity-based working offices. Since we wrote this paper, we have updated and refined the method, which we will present at the International Congress on Acoustics in Aachen, Germany, September 2019.
Since the room acoustic parameters in ISO 3382-3 were published, there have been various international attempts to classify offices achieving different values. However, recent summaries of acoustic satisfaction demonstrate little correlation with the room acoustic parameters that may drive the design.
A new approach – the Apex Method – is proposed to assess acoustic conditions within activity-based working (ABW) offices. The Liveliness parameter is used to characterise suitable acoustic environments for different types of activities; background sound levels are attributed by measurement or design. A matrix of signal-to-noise ratios can then be proposed, to account for source level vibrancy and receiver sensitivity. This enables a design framework for the in-situ attenuation of speech between workstations, Dn, A, s. From the in-situ attenuation requirement, the layout design can be developed accordingly. This method can identify potential for conflicts between different types of use or activity where there is insufficient attenuation between them, to inform the workspace designer where enhanced in-situ attenuation can improve the acoustic conditions for occupants.
The theory that reducing the intelligibility of unwanted speech can improve acoustic satisfaction is well established and demonstrated in laboratory studies. However, acoustic satisfaction in real workplaces is only loosely correlated with the radius of distraction, rD, measured over the floor plate. If acoustic designers are only motivated and equipped to propose features in the pursuit of achieving lower values of rD, the inferred design requirements may be in conflict with other aesthetic aspirations for the office; more importantly, the overall goal of acoustic satisfaction and workplace efficacy may be missed entirely.
Control over one’s environment is likely to be a stronger indicator for worker’s acoustic satisfaction than any technical acoustic features. As the nature of the workplace changes to become more fluid and less based on assigned workstations, people’s tolerance to intrusive sounds may well also adapt.
The Apex Method is proposed to extend the concept of the impact of unwanted speech and intrusive sounds; these preferences can be used to determine in-situ attenuation requirements between specific workstations. The Apex Method supports, rather than conflicts, the work of the workplace designer.
This method won an Innovation Award, and received “Highly Commended” in the Workplace Acoustics category at the Association of Noise Consultants Awards 2019.
We were honoured to receive “Highly Commended” in the Soundscape category of the John Connell Awards 2019 for this method.
We are organising a one-day meeting on open plan office acoustics, Birmingham, December 5th 2019.
Contact us to organise an in-house CPD on open plan office acoustics.
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