What is acoustic attenuation and how is it measured?

Acoustic attenuation refers to the reduction in sound energy as it passes through a material or system, such as an acoustic louvre. In simple terms, it describes how effectively a louvre reduces noise from one side of a façade or enclosure to the other.

Acoustic performance is typically measured in decibels (dB) and presented as insertion loss across a range of frequencies. Insertion loss represents the difference in sound level before and after the acoustic louvre is installed within an opening. Because sound behaves differently at different frequencies, results are normally reported in octave bands (e.g., 63Hz to 8kHz), allowing acoustic consultants to assess how the louvre reduces noise across low, mid, and high frequencies.

Lower frequencies (such as those generated by large generators or plant equipment) are generally more difficult to attenuate and often require deeper blade sections or increased acoustic path length. Higher frequencies are typically easier to absorb using mineral wool or similar sound-absorptive media within the blade cavities.

Testing is usually carried out under controlled laboratory conditions in accordance with recognised acoustic standards. However, as with weather testing, real-world performance can be influenced by installation details, flanking paths, system integration, and downstream duct arrangements.

At Solinear, our SoundEX acoustic louvre systems are designed and tested to provide predictable acoustic attenuation performance, enabling consultants to model overall plant noise levels accurately. We collaborate closely with acoustic engineers to ensure the selected system achieves the required insertion loss without unnecessary compromise to airflow or façade integration.

For a clearer understanding of how ventilation systems are assessed, see What is insertion loss?