1. Building Environment Acoustics The design consists of large areas of exposed insitu concrete walls, both on the interior and exterior faces of the building. To counteract this, acoustic insulation will be provided in the form of the formwork cladding system which has been designed. Through acoustics calculations, formwork will be permanently left in place to provide acoustic insulation. These bespoke panels will consist of an extra layer of acoustic boarding which has been specified and installed during the off-site manufacturing process. We will look at the worst case scenario: the gym area, where the walls and ceiling are cast in-situ. The floor is finished in conrete screed. We expect a very poor reverberation time calculation for this space due to the concrete core structure.
Acoustic Insulation - Absorption coefficient of 0.9. Image provided by VINCO Cross Section - Acoustic Insulation of permanent formwork cladding
We will be using Sabine’s equation (above) to determine the Reverberation time for the gym space. The volume of this space is calculated to be 2120m3 Floor Ceiling Wall Glazing Total Absorption
Area (m2) Absorption Co-efficient (at 500 Hz) 335 6.7 335 6.7 530 10.6 100 18 42
Material Concrete Poured (0.02) Concrete Poured (0.02) Concrete Poured (0.02) Ordinary Glazing (0.18)
The information above calculates effective/average Area (m2) Absorptionfrequency, Co-efficient (at 500to Hz) beMaterial absorption rate at 500Hz a total of 42. Floor Ceiling Wall Glazing Acoustic Insulation Total Absorption
235 235 280 100 450
V=2120m3 0.161 x V 0.161 x 2120 = 341.32 T = 341.32/42 T = 8.12s
4.7 4.7 5.6 18 405 420
Concrete Poured (0.02) Concrete Poured (0.02) Concrete Poured (0.02) Ordinary Glazing (0.18) Ordinary Glazing (0.9)
An acceptable reverberation time is around 0.8s. This result informs us that having a bare concrete interior would result in a very poor acoustic space with a reverberation time which is x10 times worst than the accepted parameters.
Plan - Gym area (Not to Scale) 16 | Technical Report
Philip Win | 4236190
