The prediction of occupational noise caused by machinery

This is a summarizing short report about new techniques to integrate machines of any complexity as noise sources in prediction calculations. Such machines may radiate differently from different parts of their structure and cannot be simulated by simple point or area sources. Realistic models can be created by using objects like blocks and plates with well defined acoustic properties like frequency dependent emission, absorption and transmission loss, but it is a problem to "calibrate" such models to reproduce exactly the free-field levels in the vicinity that are taken from measurements and corrected from environmental influence and background noise. The technique to determine the necessary emission of surface parts from these free field levels is shown and the control of the finally reached accuracy is performed by the simulation of a standardized determination of the final radiated sound power level. Newer techniques to implement such models of machines in extended plants with minimum effort are presented.