Analysis of airborne noise emitted from ships

To assess and to control the environmental noise due to the main noise sources, including ports, the European Directive 2002/49/CE introduced a tool for the acoustic planning: The Noise Strategic Mapping (NSM). In any harbor, NSM can be obtained by evaluating the sound field for each type of sound sources standing in the port area and by superimposing all noise contributions. The present paper suggests a method to achieve such acoustical analysis of port noise. The method has a general purpose and is implemented in four steps: definition of the vessels category; measurements to characterize ship as a noise source; modeling of outdoor noise propagation; map drawing. All these subjects are discussed in the paper and some specific recommendations to get at a successful noise mapping of ports are reported, too. In the end, limit values to keep under control the problem of noise pollution due to ships are proposed.