Apparent sound insulation in cross-laminated timber buildings

With the 2015 National Building Code now in effect in Canada, predicting the apparent sound insulation in buildings from laboratory measurements is becoming increasingly relevant for architects and designers. In North America, the apparent sound insulation is classified in terms of Apparent Sound Transmission Class (ASTC). The ASTC rating includes both the transmission through the separating assembly and the transmission via flanking paths. The National Research Council Canada has published a number of guideline documents that detail the calculation procedure for ASTC and provide the required laboratory data for various construction types. In NRC Research Report RR-335, “Apparent Sound Insulation in Cross-Laminated Timber Buildings” the focus is on buildings which are constructed from cross-laminated timber (CLT) panels. Measurements of the direct sound insulation of CLT panels and the vibration attenuation at their junctions were conducted at the NRC in recent years. The report RR-335 describes how to combine the relevant data to obtain estimates of the apparent transmission loss and the ASTC rating for a given CLT construction. This presentation will present highlights of the report and demonstrate the use of the Simplified Method and the Detailed Method to calculate the ASTC rating.