The Calculation of the Resonant Sound Reduction Index for Use in EN12354
The application of the EN12354 prediction method to lightweight building constructions which typically have critical frequencies in or above the frequency range of interest requires the estimation of the resonant sound reduction index. Since the resonant sound reduction index can not be directly measured, the value must be estimated from measured data or calculated theoretically. Several methods of estimating the resonant sound reduction index have been evaluated. An alternative method of calculating the flanking sound reduction index as proposed by Villot and Guigou-Carter has also been evaluated. The evaluation was conducted by comparing the predicted flanking sound reduction indices which were calculated using the different methods of calculating the resonant sound reduction index to the measured flanking intensity sound reduction index for several different lightweight building element constructions.The constructions included single, homogeneous elements as well as double leaf elements. The alternative method of predicting the flanking sound reduction index as proposed by Villot and Guigou-Carter is recommended.