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.

It has long been established that correlation-based measurement techniques, using, e.g., maximum length sequences and swept sines, outperform classical methods based on random Gaussian noise. Among the advantages of these modern techniques are better rejection of background noise and reduced measurement duration to achieve similar or better precision. These advantages are especially interesting in room and building acoustics, where many measurement positions typically have to be covered and background noise is often an issue, especially when measuring sound transmission loss or velocity level differences. Unfortunately, there is currently no provision in the ASTM standards on room and building acoustics that would allow the use of these modern measurement methods. To demonstrate the advantages of these methods, this contribution will present an example of measurements of the apparent sound transmission loss, i.e., measurements of sound pressure level differences and reverberation times. In addition to the standardized measurements according to ASTM E336, all measurements were repeated with maximum length sequences and swept sines. The results will be compared and the advantages of the modern techniques will be highlighted.

The proposed 2015 edition of the National Building Code of Canada sees a major change in sound insulation requirements. Instead of prescribing requirements for the separating assembly only (in terms of STC values), the Code now sets requirements for the sound insulation performance of the complete system (in terms of Apparent Sound Transmission Class (ASTC) values), including flanking sound transmission. The National Research Council Canada is actively supporting the change in the Code by conducting various projects with industry associations from different construction sectors, in order to provide tools, guidance, and the necessary data for compliance. This presentation focuses on an ongoing joint project between the National Research Council Canada and the Canadian Sheet Steel Building Institute. In the project, the direct and flanking sound transmission in steel-framed assemblies are being investigated. In the presentation, an overview of the project is given, and updates on the current status of the investigation are provided, including measured data concerning the flanking sound transmission in steel-framed constructions.

The communication performance of three general service respirators was evaluated. The evaluation procedure followed a NIOSH standard test procedure which is based on a modified rhyme test (MRT), wherein human participants are placed in a controlled acoustic environment and are asked to read out lists of test words. The number of words correctly identified by a listener panel when the talker is wearing the respirator is compared to the number of words correctly identified without the respirator, giving an overall performance rating. During the implementation of the experimental procedure, it was noted that the NIOSH test procedure is ambiguous on a number of potentially significant acoustical issues, e.g., the reverberation time of the test environment, the background noise spectrum at the listener position, and the talker voice level. This talk will present details of the study and discuss the relevant issues related to speech intelligibility testing of respirators that were evaluated as part of this project.

In the 2015 edition of the National Building Code of Canada (2015 NBCC, published in January 2016), sound insulation requirements between dwelling units are given in terms of Apparent Sound Transmission Class (ASTC). This is a significant change from the requirements in previous editions of the NBCC which were given in terms of Sound Transmission Class (STC). While the STC rating only accounts for sound transmission through the separating assembly, the ASTC rating also takes into account structural flanking transmission via adjoining building elements. An overview of the change in requirements and of NRC activities to support the code change was given at the ASA meeting in Jacksonville (November 2015). This presentation will provide an update on the implementation of the code change since it came into effect in federal regulations in early 2016. Tools and guidelines provided by the NRC such as Research Report RR-331, “Guide to Calculating Airborne Sound Transmission in Buildings” and the revised version of soundPATHS, NRC’s web application to calculate ASTC ratings, will be presented.

The 2015 edition of the National Building Code of Canada (NBCC) specifies sound insulation requirements between dwelling units in terms of Apparent Sound Transmission Class (ASTC). The ASTC includes both the direct sound transmission through the separating element between adjacent rooms as well as the sound transmission via flanking paths. One of the ways to establish compliance with the NBCC involves a calculation procedure based on ISO 15712-1, in which the flanking sound transmission is predicted from the measured sound transmission through individual building elements combined with the attenuation at their junction. The calculation can be performed in third-octave bands (“Detailed Method”) or using single-number ratings such as the STC (“Simplified Method”). This presentation will describe the two calculation procedures, before focusing on the differences between. In extended studies at the National Research Council Canada, it was found that the simplified method sometimes leads to misleading results. An alternative method for calculating the ASTC of walls with linings was proposed, which ensures that the simplified method yields more conservative results than the detailed method. To achieve the best possible estimate of the sound insulation performance of buildings systems with linings, the detailed method should be used.

The proposed 2015 edition of the National Building Code of Canada sees a major change in sound insulation requirements. Instead of prescribing requirements for the separating assembly only (in terms of STC values), the Code now sets requirements for the sound insulation performance of the complete system (in terms of Apparent Sound Transmission Class (ASTC) values), including flanking sound transmission. The National Research Council Canada is actively supporting the change in the Code by conducting various projects with industry associations from different construction sectors, in order to provide tools, guidance, and the necessary data for compliance. This presentation focuses on a joint project between the National Research Council Canada and the Canadian Concrete Masonry Producers Association. In the project, the direct and flanking sound transmission in concrete masonry and hybrid building systems were investigated. For masonry walls in combination with concrete floors, the ASTC values were calculated according to ISO 15712-1. For masonry walls in combination with wood joist floors, the ASTC values were measured according to ISO 10848. Furthermore, the effect of linings on concrete masonry walls was investigated. This presentation will provide an overview of each of these issues, including results and recommendations.

The proposed 2015 edition of the National Building Code of Canada sees a major change in sound insulation requirements. Instead of prescribing requirements for the separating assembly only (in terms of STC values), the Code now sets requirements for the sound insulation performance of the complete system (in terms of Apparent Sound Transmission Class (ASTC) values), including flanking sound transmission. The National Research Council Canada is actively supporting the change in the Code by conducting various projects with industry associations from different construction sectors, in order to provide tools, guidance, and the necessary data for compliance. This presentation provides an overview of the new requirements and of the different paths to compliance. Furthermore, various projects conducted at the National Research Council Canada to support the Code change are presented, including tools and guidance to help practitioners. Detailed descriptions of two of the projects are given in two complementary presentations.