Marine Installation Manual 2022-03 7-6
7 Engine Emissions
7.2 Engine noise
X62DF-S2.0
7.2 Engine noise
As the ship’s crew/ passengers must be protected from the effects of machinery
space noise, the maximum acceptable noise levels are defined by rules. In gen-
eral, for new building projects, the latest IMO Resolution MSC.337 ‘Code of
Noise Levels Onboard Ships’ is applied.
The main change introduced by the new IMO MSC.337, compared to the pre-
vious Resolution A468(XII), is that in large rooms with many measurement po-
sitions, the individual positions must be compared to the maximum admissible
limit.
7.2.1 Air-borne noise
Figure 7-4,  7-7 shows the average surface sound pressure level. The data in the
graph are related to:
• Distance of 1 m from engine
• Average values Lp in dB, in comparison with ISO NR-Curves
• Overall average values LpA in dB(A) and expected maximal overall single
point values
• Free field conditions
Near the turbocharger (air intake), the maximum measured noise level will nor-
mally be 3-5 dB(A) higher than the average noise level of the engine.
Standard noise reduction
& additional
noise reduction
The present document includes the expected maximum overall value for a single
point. Figure 7-4,  7-7 distinguishes between standard noise reduction and ad-
ditional noise reduction on turbocharger air side. The turbocharger suppliers are
currently developing different silencer solutions to comply with the new noise
limit regulation of 110 dB(A) for single point.
NOTE
The noise level graphs in Figure 7-4,  7-7, Figure 7-6,  7-9 and
Figure 7-7,  7-10 show typical values for MCR. As the rating depend-
ency is marginal, the values can be used for all ratings.
NOTE
The single point noise limit of 110 dB(A) for machinery spaces may be
exceeded if standard silencers are applied.
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