Good building acoustics is about controlling the quality of sound inside a building so that it is kept at a reasonable and comfortable level, while also suppressing noises coming from outside of the building. This will include:
- Achieving good speech intelligibility in a theatre, restaurant or railway station
- Enhancing the quality of music in a concert hall or recording studio
- Reduce echoes and noise within homes, schools and office buildings
How do acoustics work in a building?
The key parameter in achieving good building acoustics is reverberation time – a high reverberation time can make a room sound muffled, loud and noisy. Therefore, rooms where there will be a lot of speech, such as theatres and auditoriums, will need a low reverberation time to keep voices clear throughout large rooms. By contrast, concert halls and music venues will strive to achieve higher reverberation times to add depth to the music and muffle noises coming from elsewhere in the building.
The reverberation time of a room is defined as the time it takes for sound to decay by 60 dB after an abrupt termination. This is typically measured using a dodecahedron sound source and a Class 1 sound level meter. The sound source emits broadband noise and the sound level meter records the decay rate of sound within the space to calculate RT60 values across different frequency bands.
What are the factors affecting the acoustics of a building?
Building acoustics can be impacted by:
- The size and shape of the building
- How much noise is generated outside the building and preventing this from coming in
- Impact noise – noises generated from within the building, such as footsteps on the floor above
- Sound absorption – the loss of sound energy when waves come into contact with absorbent materials such as ceilings, walls and floors
- Airborne sound transmission – sounds transmitted through the air, such as TV noise, animals, people talking, etc
Sound planning for all of the above is vital at the design stage of a building to ensure you avoid any imbalanced noise issues.
Building acoustics regulations
In the UK, there are several standards to adhere to in the field of Building Acoustics, including:
- International Standards ISO 140 ISO 354 ISO 3382
- DIN 52210 and DIN EN ISO 16251-1
- Resistance to sound: Approved Document E, which outlines sound insulation requirements in houses, flats, rooms for residential use and schools and is split into four sections –
- E1 – Protection against sound from other parts of the building and adjoining buildings
- E2 – Protection against sound within a dwelling/house etc
- E3 – Reverberation in the common internal parts of buildings containing flats or rooms for residential purposes
- E4 – Acoustic Conditions in Schools
- BS 8233 – Guidance on sound insulation and noise reduction for buildings
Sound Insulation
Another key aspect of building acoustics controlling how sound travels and behaves between spaces. This is typically measured using airborne sound insulation and impact sound insulation.
Measurements are commonly expressed as:
- Rw / DnT,w – airborne sound insulation performance
- LnT,w – impact sound level performance
These measurements help verify that partitions and floors meet regulatory requirements.
How these can be measured and tested?
AcSoft provides a range of building acoustic measuring products for sale or rental that will ensure your building conforms to these standards.
If you need any support selecting the right product for your building’s needs then you can get in touch with us by calling 01234 639550 or emailing us.