Acoustic Design Case Studies
Acoustic Design - School and Educational Acoustics
A Manchester primary school appointed Dragonfly Acoustics to carry out an assessment of noise environment within the school hall.
The aim of the assessment was to establish whether this environment was suitable for its current use as a school assembly space and what steps could be taken to improve the acoustic performance for that purpose. The noise assessment was conducted broadly in accordance with ISO 3382-2 (2008) Measurement of room acoustic parameters - Part 2: Reverberation time in ordinary rooms.
Measurements of reverberation time were undertaken at various points throughout the room and this data was used to build up a picture of the acoustic environment within this assembly hall. Comparisons were then made between this data and the reverberation time criteria for an assembly hall as detailed within Building Bulletin 93 (BB93) of the Building Regulations 2000.
The assessment showed that an increase in absorptive area of 60m2 with an absorption coefficient of at least 0.9 would be required in order to reduce the Tmf to below 1.2 seconds as recommended by BB93.
Dragonfly Acoustics further recommended that reducing the break-in of external noise into the school hall would increase speech intelligibility within the hall. Noise break-in through the external facade could be reduced through the use of secondary glazing.
This would have a significant impact on the quality of the noise environment within the assembly hall.
Acoustic Design - Sound Insulation Testing
Dragonfly Acoustics was commissioned by a design and build contractor to test the airborne and impact sound insulation of one party wall and one party floor within a conversion of a former stable building at a site, Near Scorton, Richmond.
The development was to provide two one bedroom flats with a group dormitory above. The tests had been requested by the building control body responsible for the development.
The tests were conducted between two ground floor flats and a first floor dormitory and a ground floor flat at the former stables building.
The testing method for airborne sound insulation was in full accordance with the suggested methods presented in BS EN ISO 140-parts 4 and 7: 1998 Field Measurements of Airborne Sound Insulation Between Rooms. The results of the tests were analysed in accordance with BS EN ISO 717-parts 1 and 2: 1997.
All of the walls and floors tested met the required standard under the Building Regulations 2000 (Approved Document E 2004).
Therefore no remedial works were required to improve the airborne sound insulation of the structures tested.
All testing is undertaken to a high standard, by competent staff, all of whom are members of the Institute of Acoustics. This ensures the consistent quality and accuracy of measurements undertaken to indicate compliance with the Building Regulations. All site testing is compliant with Dragonfly Acoustics own stringent internal quality system.