3.11.1 Measurements shall be taken at the principal
working and control stations of the seafarers in the machinery spaces
and in the adjacent control rooms, if any, special attention being
paid to telephone locations and to positions where voice communication
and audible signals are important.
3.11.2 Measurements should not normally be taken
closer than 1 m from operating machinery, or from decks, bulkheads
or other large surfaces, or from air inlets. Where this is not possible,
measurement shall be taken at a position midway between the machinery
and adjacent reflecting surface.
3.11.3 Measurements from machinery which constitutes
a sound source should be taken at 1 m from the machinery. Measurement
should be made at a height of between 1.2 m to 1.6 m above the deck,
platform or walkway as follows:
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.1 at a distance of 1 m from, and at intervals
not greater than 3 m around, all sources such as:
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- main turbines or engines at each level
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- main gearing
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- turbo-blowers
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- purifiers
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- electrical alternators and generators
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- boiler firing platform
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- forced and/or induced draught fans
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- compressors
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- cargo pumps (including their driving motors
or turbines)
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In order to avoid an unnecessarily large and impractical
number of measurements and recordings in the case of large engines
and of machinery spaces where the measured sound pressure level in
dB(A) at the intervals above does not vary significantly, it will
not be necessary to record each position. Full measurement at representative
positions and at the positions of maximum sound pressure level shall,
however, be made and recorded, subject to at least four measurements
being recorded at each level;
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.2 at local control stations, e.g. the main manoeuvring
or emergency manoeuvring stand on the main engine and the machinery
control rooms;
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.3 at all other locations not specified in .1
and .2 which would normally be visited during routine inspection,
adjustment and maintenance;
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.4 at points on all normally used access routes,
unless covered by positions already specified above, at intervals
not greater than 10 m; and
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.5 in rooms within the machinery space, e.g. workshops.
In order to restrict the number of measurements and recordings, the
number of recordings can be reduced as in .1, subject to a total of
at least four measurements (including those specified in this paragraph)
being recorded at each machinery space level up to upper deck.