A replacement of the ISO 717-1 standard for the calculation of the single number ratings for airborne sound insulation has been proposed. The proposed replacement, ISO 16717-1 introduces new single number ratings for airborne sound insulation. The weighted sound reduction index which has traditionally been calculated from the sound reduction index measured in the 1/3 octave bands from 100 Hz to 3150 Hz will be replaced by a new single number rating R living which is calculated from the 1/3 octave bands between 50 Hz and 5000 Hz. The uncertainty of the proposed single number ratings has been estimated using the ISO Guide to the Expression of Uncertainty in Measurement (GUM) and validated using Monte Carlo simulations. The uncertainty of the single number ratings of 200 building elements was evaluated. It was found that the uncertainty of the single number ratings is highly dependent on the shape of the sound reduction index curve. The uncertainty of the new single number rating R living was found to be greater than the uncertainty of the traditional weighted sound reduction index for 98% of the 200 lightweight building elements included in the evaluation. It is recommended that the current weighted sound reduction index be maintained in the replacement standard until the uncertainty of the calculation of the sound reduction index at the low frequencies can be reduced through a redefinition of the measurand.

No abstract

There is much interest in applying EN12354-1 to lightweight buildings elements which may have critical frequencies above the frequency range of interest. The standard requires that only the resonant component of the sound reduction index be used in the predictions and therefore a reliable method of calculating the resonant component is needed for these elements. Several methods of calculating the resonant component are examined in this study. It was found that the various predictions of the resonant component can differ by as much as 18 dB. Calculation of the resonant component by subtracting the theoretical non-resonant component from the measured value was unreliable due to measurement uncertainty. Calculation of the resonant component using correction factors based on the components of the mean square velocity may be possible but may also be susceptible to measurement uncertainty. Definitive guidance for calculating the resonant component is needed in future revisions of EN12354-1 if it is to be applied to lightweight constructions.

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=27e0a78f-5739-4b23-90e1-442155ff4d25 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=27e0a78f-5739-4b23-90e1-442155ff4d25 ScopeThis Report presents the results from experimental studies of airborne sound transmission, together with an explanation of calculation procedures to predict the apparent airborne sound transmission between adjacent spaces in a building whose construction is based on cross-laminated timber (CLT) panels.There are several types of CLT constructions which are commercially available in Canada, but this study only focused on CLT panels that have adhesive between the faces of the timber elements in adjacent layers, but no adhesive bonding the adjacent timber elements within a given layer. There were noticeable gaps (up to 3 mm wide) between some of the timber elements comprising each layer of the CLT assembly. These CLT panels could be called F ce-L CLT P as CLT panels in this Report.Another form of CLT panels has adhesive between the faces of the timber elements in adjacent layers as well as adhesive to bond the adjacent timber elements within a given layer. These are referred to as F -B CLT P in this Report.Because fully-bonded CLT panels have different properties than face-laminated CLT panels, the sound transmission data and predictions in this Report do not apply to fully-bonded CLT panels.

No abstract

No abstract

In this second paper, the separation of the resonant and non-resonant components of the mean square velocity of lightweight building elements is investigated for use with EN12354. Two methods for separating the components are presented. The first involves measuring the mean square velocity of a series of panels, each with a different amount of damping. A modified least squares approach is then used. The second method uses the velocity level difference between building elements measured according to EN10848 and the measurement of the mean square velocity of the elements due to excitation by an airborne noise source. This offers advantages since it adds a few additional steps to the measurements for EN10848. However this method was not successful over the entire frequency range when applied to the elements used in this study.

Although reliable methods exist to predict the apparent sound reduction index of heavy, homogeneous isotopic building constructions, these methods are not appropriate for use with lightweight building constructions which typically have critical frequencies in or above the frequency range of interest. Three main methods have been proposed for extending the prediction of flanking sound transmission to frequencies below the critical frequency. The first method is the direct prediction which draws on a database of measurements of the flanking transmission of individual flanking paths. The second method would be a modification of the method in existing standards. This method requires the calculation of the resonant sound transmission factors. However, most of the approaches proposed to calculate the resonant sound transmission factor work only for the case of single leaf homogeneous isotropic building elements and therefore are not readily applicable to complex building elements. The third method is the measurement or prediction of the resonant radiation efficiency and the airborne diffuse field excited radiation efficiency which includes both the resonant and the non-resonant radiation efficiencies. The third method can currently deal with complex building elements if the radiation efficiencies can be measured or predicted. This paper examines these prediction methods.