Acoustics of industrial buildings

Abstract

Industrial halls have significantly different shapes as rooms for other purposes. Typically these enclosures are very large and/or flat, which means that the room height is usually very much smaller than width and length. Sound fields in these types of enclosures cannot be expected to have an approximate diffuse sound field. Instead, the decay curves are bent, while sound level versus distance (sound propagation curve) is declining. This contribution summarizes physical properties of sound fields in flat and long rooms, gives some examples of predictions based on image sources, on Kuttruffs integral equation, results of scale model experiments and ray-tracing algorithms with two different levels of complexity. It can be shown that in many cases predictions can yield sufficiently accurate results. However, problems will occur in cases where rooms are heavily filled with scattering objects (fittings). On the other hand, the exact spatial distribution of sound in these nondiffuse cases has shown to have less influence on the perceived annoyance than expected. Accordingly, predictions of sound levels with reasonable accuracy should be sufficient to describe the subjective effect of listening, unpleasantness and annoyance in industrial halls.