In September I presented at the TABS expert meeting in Sweden. Below is a 17 minute video of the presentation.
In this presentation I looked at how the design of buildings has evolved over time and how this has affected the acoustics. Key points include
- Background noise is important– Now that we are moving away from mechanical ventilation, we have lost the steady background noise that assist in the acoustics of both open plan offices and meeting rooms.
- We are designing building that are Thermally Active Building (TAB)- In the UK we tend to refer to this as exposed thermal mass.
- We don’t use ceilings any more- Certainly in education, and now moving into offices, these ceilings would previously absorb noise.
- Open plan privacy- Acoustic rafts mean that an open plan office can still be a collaborative environment with conversation that do not disturb everyone
- Measurements- Reverberation time is a useless descriptor in large, open plan offices. It varies so much (depending on source and receiver location) that it does not give a true reflection of the space.
Our Birmingham office as a case study
We looked to create an office which showcases good design with acoustic findings including;
- Background noise is important– Between 8.00am and 6.00pm there is consistent 43 dBA (± 1 or 2 dB)
- Thermally Active Building (TAB)- Exposing the soffits harness some of the building’s thermal mass
- We don’t use ceilings any more- We removed the wet press mineral fibre Class D ceilings to gain an extra 1m ceiling height and exposed the services we design, adding acoustic rafts to aid noise absorption. When looking at the spatial decay of noise within a space, there did not appear to be much difference between rafts or ceilings- so, less is more!
- Open plan privacy- Using STI as a measurement, there is a privacy distance of about 13m and distraction distance of 6m. Occupants have been raving about this.
- Measurements- Tested to ISO3882 which is not common in the UK, which we understood why as this was a difficult and time-consuming process.
- Find out more about Cundall – http://www.cundall.com/