Noise on board RO-Pax vessels: Measured levels on existing ships and new pre-normative requirements

The problem of noise annoyance on board ships has been addressed since a long time. The first document setting limits on onboard noise was the "Code on noise levels on board ships", issued by the International Maritime Organisation in 1981. More recently all the major Classification Societies introduced in their requirements the so called "Comfort Classes". They generally provide different ratings of the acoustic comfort of ships. The growing needs of passengers and workers for acoustical comfort on board pushed both Classification Societies and IMO to consider an update of limits and criteria for noise annoyance assessment. The normative framework in the field is therefore presently in an evolution phase. In the present work, a series of existing measurements of noise carried out on a set of Ro-Pax vessels is analysed and compared with the existing requirements and with the new proposals of the SILENV collaborative project (Ships oriented Innovative soLutions to rEduce Noise & Vibrations), funded within the 7th Framework Programme of the E.U. and running in the period 2009-2012. The comparison provides an indication of the possibility for shipbuilding to cope with the new requests in terms of noise performances, provided that such requests are inserted in the design process. Further efforts are needed similar to those already implemented to fulfill the present formulations of compulsory requirements and reflected in the measured values