Section 8 Noise transmission between cabins
Clasification Society 2024 - Version 9.40
Clasifications Register Guidance Information - Ship Vibration and Noise Guidance Notes - Chapter 8 Noise - Section 8 Noise transmission between cabins

Section 8 Noise transmission between cabins

8.1 The airborne sound insulation properties for bulkheads and decks within the accommodation should comply with the weighted apparent sound reduction indices (R’w) according to ISO 717 given in Table 8.8.4 Weighted apparent sound reduction indices, R’w .

Table 8.8.1 Test conditions

At sea:
Draught: Loaded or ballast.
Power: Not less than 80% m.c.r.
Speed: Normal service speed.
Ventilation: Running at full capacity.
Equipment: Auxiliary machinery to be operated normally.
Radio room: Equipment in operation but without audible signals.
Wheelhouse: All equipment in operation, for example, radar, radio, window wipers. Weather side door and windows closed; lee side open and then closed
Bridge wings: As far as practical with wind speed 5-10 knots and headings with wind ahead, astern and on both beams.
Ship’s whistle: To be sounded for measurements at listening posts.
Emergency diesel, fire pump(s): Measurements in the equipment spaces with it working. Not necessary in adjacent spaces with pump(s) operating unless equipment used for other than emergency and drills.
Weather: Wind force 4 (moderate breeze) and sea state 3 (slight) should not be exceeded.
In port:
Engine room: Auxiliary machinery operating in “in port” condition.
Cargo gear: Operating.
Car decks: Measurements during loading and discharging.

Table 8.8.2 Measuring positions

Accommodation
General: At least one measurement in every occupied space in the centre of the room with doors and windows closed. If noise level varies throughout space then extra readings at 7 m intervals including position of maximum noise should be taken.
Wheelhouse: One extra reading at an open window.
Bridge wings: At control positions on both wings when on leeside of wind.
Radio room: In centre and at work position.
Galley/pantry: With equipment not working and at 1m away from working equipment.
Ship’s whistle: Measured at listening posts (bridge wings, forecastle).
Machinery spaces
General: 1m from and at intervals not greater than 3 m around machinery.
Large engine rooms: If readings at 3m intervals do not vary much, then four measurements on each level.
Spaces: Machinery and cargo control rooms, workshops, stores, fan rooms, pump rooms, refrigerator rooms, steering gear room, access routes.
Machinery: Engines at each level and local control stations, main gearing, turbo-blowers, purifiers, alternators, firing platforms, fans, compressors, cargo pumps. Machines under 5 kW may be excluded unless significant noise sources.
Unoccupied spaces
Measurements are not required in normally unoccupied spaces, holds, or deck spaces which are remote from noise sources and a rough check shows that the noise levels are well below the limits.

Table 8.8.3 Acceptable maximum noise levels for crew

Working areas
Radio room (equipment working, but no audio signals) 60 dBA
Wheelhouse, chartroom 65 dBA
Listening post, including bridge wings and windows 70 dBA
  Recommended level in 250 Hz octave band 68 linear
  Recommended level in 500 Hz octave band 63 linear
Galleys, pantries and serveries (equipment not working) 75 dBA
Machinery control rooms 75 dBA
Workshops 85 dBA
Normally unoccupied spaces, e.g. holds, decks 90 dBA
Machinery space, continuously manned, e.g. stores 90 dBA
Machinery space, not continuously manned, e.g. pump, refrigerator, thruster or fan rooms. 110 dBA
Accommodation
Sleeping cabins, hospitals 60 dBA
Day cabins 65 dBA
Offices, conference rooms 65 dBA
Mess rooms, lounges, recreation areas within accommodation 65 dBA
Recreation areas on open deck 75 dBA
Alleyways, changing rooms, bathrooms, lockers 80 dBA
Ship’s whistle, at bridge wings or forecastle 110 dBA
Hearing protection
Protection required when noise level exceeds 85 dBA
Overriding limits
Maximum noise level, even when ear protection worn 120 dBA

Table 8.8.4 Weighted apparent sound reduction indices, R’w

Crew accommodation
Cabin to cabin 30 dB
Messrooms, recreation rooms to cabins and hospitals 45 dB

Table 8.8.5 RASTI Rating

RASTI Index Intelligibility
0 - 0.3 Bad
0.3 - 0.45 Poor
0.45 - 0.6 Fair
0.6 - 0.75 Good
0.75 - 1.0 Excellent
Parent topic: Chapter 8 Noise
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