The EN ISO 354 and EN ISO 11654 standards are used for laboratory measurement and evaluation of the sound absorption of acoustic elements used in interiors.
EN ISO 354 defines the measurement method in a reverberation room, where the reverberation time of the space is measured first without the sample and then with the tested element. The difference between the measured values at individual frequencies is used to calculate sound absorption.
EN ISO 11654 then converts these measured data into a clearer form for comparing products, mainly through the weighted sound absorption coefficient αw and the sound absorption class. The value of αw is expressed on a scale from 0.00 to 1.00, where a higher value indicates a higher ability to absorb sound.
Based on αw, products are classified into sound absorption classes A to E, where class A represents the highest level of absorption. This system enables transparent comparison of acoustic performance and helps to better assess the contribution of products to the acoustic comfort of a space.
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