1.1 In order to obtain a noise reduction on board
ships to comply with the limits given in chapters
4 and 5 of the Code, careful consideration
should be given to means of such reduction. This appendix is intended
to provide information for the design of a ship in this respect.
1.2 Design and construction of noise control measures
should be supervised by persons skilled in noise control techniques.
1.3 Some of the measures which can be taken to
control the noise level or reduce the exposure of seafarers to potentially
harmful noise are indicated in sections 2 to 10 of this appendix.
It is emphasized that it will not be necessary to implement all or
any of the measures recommended in this appendix on all ships. This
Code does not provide detailed technical information needed for putting
constructional noise control measures into effect, or for deciding
which measures are appropriate in particular circumstances.
1.4 In applying noise control measures, care should
be taken to ensure that rules and regulations concerning ship structure,
accommodation and other safety matters are not infringed and the use
of sound reduction materials should not introduce fire, safety or
health hazards nor should such material, by virtue of flimsy construction
or attachment, introduce hazards that may tend to impede either evacuation
or de-watering of the spaces.
1.5 The need for noise control should be taken
into account at the design stage when deciding which of different
designs of engines and machinery are to be installed, the method of
installation and the siting of machinery in relation to other spaces,
and the acoustic insulation and siting of the accommodation spaces.
1.6 Due to the normal method of ship construction,
it is most probable that noise originating from machinery and propellers
reaching the accommodation and other spaces outside the machinery
spaces will be of the structure-borne type.
1.7 When designing efficient and economic measures
for noise control of machinery installations in existing ships, the
measurement of sound produced in terms of A-weighted sound level may
need to be supplemented by some form of frequency analysis.