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As per IMO “Code On Noise Levels onBoard Ships”,Explain the requirements regarding Measuring conditions, procedure and equipment.

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  • As per IMO “Code On Noise Levels onBoard Ships”,Explain the requirements regarding Measuring conditions, procedure and equipment.

    As per IMO “Code On Noise Levels onBoard Ships”,Explain the requirements regarding Measuring conditions, procedure and equipment.
    Last edited by mohit; 12-21-2017, 09:26 AM.

  • #2
    MEASURING CONDITIONS

    a. Operating conditions at sea trials

    • Measurements should be taken with the ship in the loaded or ballast state

    • Noise measurements shall be taken at normal service speed and, unless otherwise addressed in the provisions below, no less than 80% of the maximum continuous

    rating (MCR).


    • All machinery, navigation instruments, radio and radar sets, etc., generally in use at normal seagoing condition and levels, including squelch shall operate throughout

    the measurement period. However, neither energized fog signals nor helicopter operations shall take place during the taking of these measurements


    • Measurements in spaces containing emergency diesel engine driven generators, fire pumps or other emergency equipment that would typically be run only in

    emergency, or for test purposes, shall be taken with the equipment operating


    • Mechanical ventilation, heating and air-conditioning equipment shall be in normal operation, taking into account that the capacity shall be by the design conditions.

    • Doors and windows should, in general, be closed

    • Ships fitted with bow thrusters, stabilizers, etc., may be subject to high noise levels when this machinery is in operation. For thrusters, measurements shall be made at

    40% thruster power, and the ship's speed shall be appropriate for thruster operation


    b. Operating conditions at port

    • When the noise from the ship's cargo handling equipment may lead to noise above maximum levels in duty stations and accommodation spaces affected by its

    operation, measurements should be taken


    • Where the ship is a vehicle carrier and noise during loading and discharging originates from vehicles, the noise level in the cargo spaces and the duration of the

    exposure should be considered in conjunction


    MEASURING PROCEDURES

    a. During noise level measurement, only seafarers necessary for the operation of the ship and persons taking the measurements shall be present in the space concerned

    b. Sound pressure level readings shall be taken in decibels using an A-weighting (dB(A)) and C-weighting (dB(C)) filter and if necessary also in octave bands between 31.5

    and 8,000 Hz.


    c. The noise level measurements shall be taken with the integrating sound level meter using spatial averaging and over a period until stable readings are found or at least

    15 s to represent the average value from variations due to intermittent operation or differences in the sound field. Readings shall be made only to the nearest decibel.


    d. If first decimal of the dB reading is 5 or higher, the reading shall be made to the nearest higher integer.

    e. Measurements shall be taken with the microphone at the height of between 1.2 m (seated person) and 1.6 m (standing person) from the deck.

    f. The distance between two measurement points should be at least 2 m, and in large spaces not containing machinery, measurements should be taken at intervals not

    greater than 10 m throughout the area including positions of the maximum noise level. In no case shall measurements be taken closer than 0.5 m from the boundaries of

    a space


    g. Measurements shall be made at the principal working and control stations of the seafarers in the machinery spaces and the adjacent control rooms, if any, particular

    attention being paid to telephone locations and to positions where voice communication and audible signals are essential


    h. Measurements should not usually 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, the measurement shall be taken at a position midway between the machinery and adjacent reflecting surface.


    i. Measurements shall be taken on both navigating bridge wings but should only be considered when the navigating bridge wing to be measured on the lee side of the

    ship


    j. The number of measurement cabins shall be not less than 40 percent of a total number of cabins. Cabins which are apparently affected by noise, i.e. cabins adjacent to

    machinery or casings, must be considered in any case.


    MEASURING EQUIPMENT

    a. Equipment Specification

    • Sound Level Meters: Measurement should be carried out using precision grade sound meters, industrial grade sound meters, integrating sound meters

    • Octave Filter set: Used alone or in conjunction with sound level meters

    • Measurement Microphones: Should be of random incidence type

    b. Selection of Equipment

    • It is recommended that where noise level is closer to limits; precision type to be used

    • When measuring fluctuating type noise; integrated sound level meter to be used

    • Sound level meter and calibrator should be calibrated by shore at interval not more than 2 years

    • A microphone windscreen to be used when measuring noise outside

    • Measuring equipment not be used in flammable gas/air mixture areas, unless equipment certified intrinsically safe

    Last edited by deepak; 12-20-2017, 12:33 PM.

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