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This Report presents the results from experimental studies of the airborne sound transmission of mass timber assemblies, together with an explanation of the calculation procedures to predict the apparent sound transmission class (ASTC) rating between adjacent spaces in a building constructed of mass timber assemblies. The experimental data which is the foundation for this Report includes the laboratory measured sound transmission loss of wall and floor assemblies constructed of Cross Laminated Timber (CLT), Nail-Laminated Timber (NLT) and Dowel-Laminated Timber (DLT), and the laboratory measured vibration reduction index between assemblies of junctions between CLT assemblies. The presentation of the measured data is combined with the presentation of the appropriate calculation procedures to determine the ASTC rating in buildings comprised of such assemblies along with numerous worked examples. Several types of CLT constructions are commercially available in Canada, but this study focused on CLT assemblies with an adhesive applied between the faces of the timber elements in adjacent layers, but no adhesive bonding between the adjacent timber elements within a given layer. These CLT assemblies could be called “Face-Laminated CLT Assemblies” but are simply referred to as CLT assemblies in this Report. Another form of CLT assemblies does have adhesive applied 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 assemblies are referred to as “Fully-Bonded CLT Assemblies” in this Report. Because fully-bonded CLT assemblies have different properties than face-laminated CLT assemblies, the sound transmission data and predictions in this Report do not apply to fully-bonded CLT assemblies.

In recent years, the science and engineering for controlling sound transmission in buildings have shifted from a focus on individual assemblies such as walls or floors, to a focus on performance of the complete system. Standardized procedures for calculating the overall transmission, combined with standardized measurements to characterize sub-assemblies, provide much better prediction of sound transmission between adjacent indoor spaces. The International Standards Organization (ISO) has published a calculation method, ISO 15712-1 that uses laboratory test data for sub-assemblies such as walls and floors as inputs for a detailed procedure to calculate the expected sound transmission between adjacent rooms in a building. This standard works very well for some types of construction, but to use it in a North American context one must overcome two obstacles – incompatibility with the ASTM standards used by our construction industry, and low accuracy of its predictions for lightweight wood or steel frame construction. To bypass limitations of ISO 15712-1, this Guide explains how to merge ASTM and ISO test data in the ISO calculation procedure, and provides recommendations for applying extended measurement and calculation procedures for specific common types of construction. This Guide was developed in a project established by the National Research Council of Canada to support the transition of construction industry practice to using apparent sound transmission class (ASTC) for sound control objectives in the National Building Code of Canada (NBCC). However, the potential range of application goes beyond the minimum requirements of the NBCC – the Guide also facilitates design to provide enhanced sound insulation, and should be generally applicable to construction in both Canada and the USA. This publication contains a limited set of examples for several types of construction, to provide an introduction and overview of the ASTC calculation procedure. Additional examples and measurement data can be found in the companion documents to this Guide, namely NRC Research Reports RR-333 to RR-337. Furthermore, the calculation procedure outlined and illustrated in this Guide is also used by the software web application soundPATHS, which is available for free on the website of the National Research Council of Canada (see the references in Section 7 of this Guide for access details).

The 2015 edition of the National Building Code of Canada (NBCC) includes significant changes to the acoustic requirements for residential constructions. The 2015 edition defines the acoustic requirements in terms of the Apparent Sound Transmission Class (ASTC) rating which includes contributions from flanking transmission and therefore is a better descriptor of how well the sound insulation of a building will actually protect the inhabitants of the building from unwanted noise than the STC rating which was used in earlier editions of the NBCC. The 2015 NBCC requires an ASTC rating ≥ 47 for constructions between dwelling units. The ASTC rating that a construction will achieve depends on the design of the building elements including the gypsum board, the framing and the thermal insulation as well as the design of the junctions between the building elements. Changes to the building elements or the junctions will change the ASTC rating. Fifty five examples of the calculation of the ASTC rating for typical mid-rise wood constructions (single and triple staggered wood stud walls and floors constructed of I-joists) with 15.9 mm (5/8”) SilentFX® QuickCut gypsum board, 15.9 mm CertainTeed Type X gypsum board and CertainTeed Sustainable fiberglass insulation are presented. All of the constructions shown in the examples have an ASTC rating which is greater than 47. In addition to the examples for mid-rise wood framing, an example using 15.9 mm SilentFX® QuickCut gypsum board as a lining on a cross laminated timber (CLT) construction is also presented., 3rd edition supersedes 1st and 2nd editions

This 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 class (ASTC) rating between adjacent spaces in a building with walls and floors of precast concrete. This Report was developed in a project established by the National Research Council of Canada and The Canadian Precast/ Prestressed Concrete Institute to support the transition of construction industry practice to using the ASTC rating rather than STC for sound control objectives in the National Building Code of Canada (NBCC). However, the potential range of application goes beyond the minimum requirements of the NBCC. The Report also facilitates design to provide enhanced levels of sound insulation, and should be generally applicable to buildings with precast concrete walls and floors in both Canada and the USA. Buildings assembled from precast concrete elements commonly have floors of hollowcore precast concrete slabs combined with wall panels of solid reinforced concrete. The building may also include linings on the precast concrete wall, ceiling, or floor surfaces, but this Report focusses primarily on performance of the base constructions of precast concrete.

The 2015 edition of the National Building Code of Canada (NBCC) introduced significant changes to the acoustic requirements for residential constructions. The 2015 edition of the NBCC changes the acoustic requirements for residential constructions from requirements based on a Sound Transmission Class (STC) rating to requirements based on an Apparent Sound Transmission Class (ASTC) rating. The ASTC rating includes contributions from both the direct transmission through the common building element as well as flanking transmission through the attached junctions and elements. The ASTC rating is therefore a better metric than the STC rating for describing the sound insulation of a building construction. The 2015 NBCC requires an ASTC rating ≥ 47 for constructions between dwelling units. The ASTC rating that a building constitution will achieve depends on the design of the building elements including the gypsum board, the framing and the thermal insulation as well as the design of the junctions between the building elements. Changes to the building elements or the junctions may change the ASTC rating. This report includes twenty-two examples of the calculation of the ASTC rating for lightweight (25 gauge) steel stud walls typically used high-rise constructions in conjunction with concrete floors and ceilings. The gypsum board installed on the lightweight steel stud walls in the examples includes combinations of 15.9 mm (5/8”) SilentFX® QuickCut gypsum board and 15.9 mm CertainTeed Type X gypsum board directly fixed to the steel studs. The examples include both lightweight and concrete masonry façade walls. All of the constructions shown in the examples achieved an ASTC rating of 47 or greater.

The 2015 edition of the National Building Code of Canada (NBCC) includes significant changes to the acoustic requirements for residential constructions. The 2015 edition defines the acoustic requirements in terms of the Apparent Sound Transmission Class (ASTC) rating which includes contributions from flanking transmission and therefore is a better descriptor of how well the sound insulation of a building will actually protect the inhabitants of the building from unwanted noise than the STC rating which was used in earlier editions of the NBCC. The 2015 NBCC requires an ASTC rating ≥ 47 for constructions between dwelling units. The ASTC rating that a construction will achieve depends on the design of the building elements including the gypsum board, the framing and the thermal insulation as well as the design of the junctions between the building elements. Changes to the building elements or the junctions will change the ASTC rating. Fifty five examples of the calculation of the ASTC rating for typical mid-rise wood constructions (single and triple staggered wood stud walls and floors constructed of I-joists) with 15.9 mm (5/8”) SilentFX® QuickCut gypsum board, 15.9 mm CertainTeed Type X gypsum board and CertainTeed Sustainable fiberglass insulation are presented. All of the constructions shown in the examples have an ASTC rating which is greater than 47. In addition to the examples for mid-rise wood framing, an example using 15.9 mm SilentFX® QuickCut gypsum board as a lining on a cross laminated timber (CLT) construction is also presented., 2nd edition superseded by 3rd edition

This report includes ten examples of calculations of the ASTC ratings for constructions consisting of bare concrete masonry walls connected to bare 203 mm (8") precast concrete hollowcore floors. Examples using concrete hollowcore slabs of three different mass per unit areas are presented (269 kg/m2, 301 kg/m2 and 338 kg/m2 without grout or 273 kg/m2, 305 kg/m2 and 344 kg/m2, respectively with grout). The ASTC rating is also calculated for the addition of linings on the floor of 301 kg/m2 concrete hollowcore slabs. The examples using the detailed method show that constructions of bare (no liners, unpainted) normal weight 190 mm thick hollow concrete block masonry walls connected to bare 203 mm (8”) thick precast/prestressed concrete hollowcore slabs can achieve an ASTC rating of at least 47. Based on the findings from this study, it is expected that constructions of hollow concrete block masonry walls with a mass per unit area of or greater to 238 kg/m2 connected to precast concrete hollowcore floors with a mass per unit area equal to or greater than 273 kg/m2 (with grout) will achieve ASTC ratings which are equal to or greater than 47., On the title page: Canadian Precast/Prestressed Concrete Institute

Measurements of the vibration reduction index (Kij ) were made in full accordance with the standard, ISO 108048 on junctions constructed from 190 mm thick hollow concrete block masonry walls connected to 203 mm (8”) thick precast prestressed hollow core slabs, with the objective to collect the data required to determine the Apparent Sound Transmission Class (ASTC) rating of building constructions which use these elements. The vibration reduction index measured in the laboratory was equal to or higher than that predicted using the theory outlined in Annex E of the standard, ISO 15712-1 over the frequency range of interest. Based on the distribution of the velocity levels measured on the concrete masonry walls and the precast hollow core floors, it was determined that these elements behave as homogeneous elements for the purpose of calculating the ASTC rating of this construction. Therefore, the results of this study suggest that theoretical calculations of the vibration reduction indices found in Annex E of ISO 15712 can be used to predict the vibration reduction index of other junctions between concrete masonry walls and precast hollow core floors with a mass per area greater than or equal to 323 kg/m2. Based on the findings from this study, it is expected that constructions of hollow concrete block masonry walls with a mass per unit area greater than 238 kg/m2 connected to precast hollow core floors with a mass per unit area greater than 323 kg/m2 will achieve ASTC ratings which are equal to or greater than 47. This report includes examples of calculations of the ASTC ratings for constructions consisting of bare concrete masonry walls connected to bare precast hollow core floors. The examples using the simplified and detailed methods show that constructions of bare (no liners, unpainted) normal weight 190 mm thick hollow concrete block masonry walls connected to bare 203 mm (8”) thick precast prestressed hollow core slabs can achieve an ASTC rating of 48 for side-by- side rooms (horizontal transmission) and an ASTC rating of 55 for one-above-the-other rooms (vertical transmission). The installation of linings on the floor, ceiling or walls would increase the ASTC ratings. Although the values of the vibration reduction index which were measured for this study were for junctions with the continuous voids of the hollow core planks oriented perpendicular to the concrete masonry walls, the results may also be used for the case where the voids are oriented parallel to the walls. The vibration reduction indices are expected to be higher for the case where the continuous voids are oriented parallel to the concrete masonry walls and so using vibration reduction index values for the case of voids oriented perpendicular to the concrete masonry walls may yield more conservative values than may be found in practice. The benefit of using the same results for both cases is that it eliminates the risk of using the wrong set of data for the calculation of the ASTC rating., On title page: Canadian Concrete Masonry Producers Association

The 2015 edition of the National Building Code of Canada (NBCC) includes significant changes to the acoustic requirements for residential constructions. The 2015 edition defines the acoustic requirements in terms of the Apparent Sound Transmission Class (ASTC) rating which includes contributions from flanking transmission and therefore is a better descriptor of how well the sound insulation of a building will actually protect the inhabitants of the building from unwanted noise than the STC rating which was used in earlier editions of the NBCC. The 2015 NBCC requires an ASTC rating ≥ 47 for constructions between dwelling units. The ASTC rating that a construction will achieve depends on the design of the building elements including the gypsum board, the framing and the thermal insulation as well as the design of the junctions between the building elements. Changes to the building elements or the junctions will change the ASTC rating. Forty-two examples of the calculation of the ASTC rating for typical mid-rise wood constructions (single and triple staggered wood stud walls and floors constructed of I-joists) with 15.9 mm (5/8”) SilentFX® QuickCut gypsum board, 15.9 mm CertainTeed Type X gypsum board and CertainTeed Sustainable fiberglass insulation are presented. All of the constructions shown in the examples have an ASTC rating which is greater than 47. In addition to the examples for mid-rise wood framing, an example using 15.9 mm SilentFX® QuickCut gypsum board as a lining on a cross laminated timber (CLT) construction is also presented., 1st edition superseded by 3rd edition