Airborne noise emitted by earth-moving machinery

1991 ◽  
Keyword(s):  
Airborne Noise

scholarly journals ACOUSTIC ANALYSIS AND MEASUREMENTS OF MEGA YACHTS DURING CONSTRUCTION

2019 ◽  
Author(s):  
M Insel ◽  
S Gokcay ◽  
Z Saydam ◽  
T Soyaslan ◽  
C Soyaslan
Keyword(s):  
Final Stage ◽  
Critical Parameter ◽  
Sound Pressure ◽  
Acoustic Analysis ◽  
Prediction Tool ◽  
Transmission Losses ◽  
Sea Trial ◽  
Airborne Noise ◽  
Building Project

Noise is a critical parameter for super/mega yachts which can be verified only in the final stage of a mega yacht building project. Although there are more and more advanced methods to predict noise prior to the sea trials, verification has to be delayed until the noise survey is conducted during the sea trial. A new methodology is proposed based on measurements during construction to determine the transmission losses of both airborne and structure borne noise and propagation of the sound from the source to the receiver using these measurements. A 66 meter mega yacht case study is presented with measurements of airborne noise emitted through an omni-directional dodecahedron loudspeaker and measurements of structure borne noise generated by a tapping device. Both sound pressure levels and vibrations are measured to derive the transmission losses. A source-path-receiver method-based prediction tool, SNoPP, is employed to project the measurements into the final noise predictions. Comparisons between the measurements and the predictions are also presented.

Noise Control Decision Process for Marine Vessels

2014 ◽  
Author(s):  
Raymond W. Fischer ◽  
Louis M. Pettit
Keyword(s):  
Marine Mammals ◽  
Noise Control ◽  
Regulatory Body ◽  
Noise Levels ◽  
Radiated Noise ◽  
Underwater Radiated Noise ◽  
Sound Levels ◽  
Airborne Noise ◽  
Control Decision ◽  
Marine Vessels

There is a price to be paid to achieve compliance with the acoustic requirements imposed by regulatory agencies. Acoustic requirements typically appear in ship specifications as airborne and/or underwater radiated noise limits as the need to preclude hearing loss for crew members and the need to control sound levels experienced by marine mammals receive more recognition. Recent changes and additions to regulatory body requirements addressing compartment airborne noise and underwater radiated noise can be found in IMO Resolution MSC.337(91) Annex 1 and Annex 2 which state that IMO Resolution A.468(XII) “Code on Noise Levels Onboard Ships” shall take effect on 1 July 2014 for all SOLAS compliant vessels. Thus the airborne noise levels in compartments and at on-deck work stations onboard as-built ships seeking a SOLAS certificate will need to be measured, and must demonstrate compliance with noise limits stated in paragraph 4.2 of IMO Resolution A.468(XII). IMO “Guidelines for the Reduction of Underwater Noise from Commercial Shipping to Address Adverse Impacts on Marine Life” dated 7 April 2014 and agencies such as ICES and DNV have established guidance and/or criteria for control of underwater radiated noise from vessels, and these too are now commonly appearing in ship specifications. Specifications referencing such criteria typically require that compliance be demonstrated by at-sea testing of underwater radiated noise. Making the correct decisions during the ship design process will minimize costs for noise control and will provide a positive return on investment. The process of how best to comply with noise limits while minimizing costs through optimization of noise control treatments and design approaches is discussed.

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