PREDICTION OF NOISE FROM MACHINERY IN TIMBER-FRAME BUILDINGS USING TRANSMISSION FUNCTIONS

摘要

To ensure that building regulations are satisfied, the sound pressure level due to machinery has to be predicted at the design stage of a new building. With the increasing popularity of multistory timber dwellings, prediction becomes an important issue for designers and consultants. At present previous project experience is often used when considering the design of wall and floor constructions and the mounting positions for machinery. Simple tools to calculate the sound pressure levels in rooms based on machinery data and construction details are not currently available. The approach involves two stages: firstly the description of the source and secondly the prediction of vibration transmission across the building and sound radiation into the rooms. In this paper a simple empirical model is proposed for the second stage. This approach is based on measured transmission functions that are defined as the average sound pressure level in a receiving room relative to the injected structure-borne sound power. This is a logical extension of approaches to characterize structure-borne sound sources that also use a power based descriptor (e.g. prEN 15657:2016-02: Acoustic properties of building elements and of buildings - Laboratory measurement of structure-borne sound from building service equipment for all installation conditions) and provides a simple method to estimate the sound pressure level in a room.