IOA Annual Conference - MACH Acoustics presents

The annual Institute of Acoustics Conference was held on 5^th and 6^th September in Kenilworth and MACH Acoustics’ Chris Jones was honoured to be invited to speak and present his paper. Chris has been researching “STANDARDISING THE TESTING AND MODELLING METHODS OF PREDICTING THE SOUND REDUCTION THROUGH OPEN WINDOWS” and this was extremely well received.

The current approach is to simply use a 10 - 15 dB reduction across the open window.  This does not account for the window type, open area or angle of incident sound.  Whilst research has been conducted into these factors, the lack of a standard method of testing, modelling and quantifying the acoustic performance has prevented the uptake of an improved method by acoustic and facade engineers.

This paper builds upon the research of collaboration with MACH Acoustics and The University of Bath - Blanco, Nunes and Lo (2014) and Jones (2015) in summarising the challenges in quantifying the performance by considering existing test methodologies from British Standards and extensive laboratory testing by Napier University (2007). 

The potential of using FEM and FDTD modelling as a tool of visualising and understanding sound propagation through an open window is summarised.  2D FDTD modelling by Jones (2015) has examined the effect of the window variables and the accuracy of simulations by recreating Napier University (2007) test data, before using this to propose the concept of a simple mathematical model.

Visualizing components of sound propagation through an open window

The aim of this paper is not to conclusively recommend a standardised method, but to present existing information and new research in a balanced manner that will inspire a discussion within the acoustics industry as to how such a method might be agreed.