How are acoustic louvres tested?
As well as allowing adequate airflow, acoustic louvres must also be tested to assess sound attenuation.
In a nutshell:
- Acoustic louvres are designed to reduce noise pollution while allowing airflow.
- Like performance louvres, acoustic louvres benefit from performance testing.
- BS EN ISO 10140-2 is a key standard for acoustic performance (sound reduction).
- Sound Reduction Index (SRI), decibels (dB) and Weighted Sound Reduction Index (Rw) are used to assess louvre acoustic performance.
Acoustic louvres are a specialised type of performance louvre. Their primary function is to minimise noise transmission while still allowing for adequate airflow. This is crucial in applications like plant rooms, generator rooms, and near noise-sensitive areas. Therefore, testing goes beyond simple airflow and focuses heavily on sound attenuation.
What standards apply to acoustic louvres?
While BS EN 13030:2001 is relevant for airflow performance, the key difference with acoustic louvres is the addition of acoustic performance testing.
The relevant standard here is BS EN ISO 10140-2: Acoustics - Laboratory measurement of sound insulation of building elements. This standard provides frameworks for measuring the sound insulation performance of various building elements, such as louvres.
Organisations like the BSRIA (Building Services Research and Information Association) can test both the airflow and acoustic performance of louvres. Independent acoustic testing laboratories are also crucial for assessing sound attenuation.
How is acoustic performance measured?
The sound insulation performance is typically expressed as a sound reduction index (SRI) in decibels (dB) across a range of frequencies. A single-number rating, such as a Weighted Sound Reduction Index (Rw), may also be used to characterise the overall acoustic performance.
The acoustic testing process involves installing a louvre between two calibrated test rooms. A noise source generates sound in the source room, and the noise levels are then measured in the receiving room on the other side of the louvre. The difference in noise levels between the two rooms determines the level difference. By combining this data with information about the size, area, volume, and sound absorption characteristics of the rooms, the sound reduction indices can be calculated.
To evidence compliance, manufacturers should be able to provide test reports from accredited acoustic laboratories.