Marine noise and vibration

Get help throughout planning, building and operation

• Before you start building: Define noise and vibration requirements in the building specification

  At the beginning of a new ship building project it is vital to define noise and vibration comfort criteria. It is much easier to agree on comfort criteria before commencing the building project, and to implement and install reasonable noise and vibration mitigating measures during the project, rather than trying to rectify issues after the ship is build and has been delivered

  We can help ensure that the noise and vibration comfort criteria on your ship meets your expectations. We know the contents and limitations of the requirements of the International Maritime Organization, IMO, and classification society’s requirements/criteria and have vast experience measuring noise and vibration levels. This help us bridge possible gaps between the yard and the ship-owner requirements ensuring your ship building project comes off to a good start.

  In this phase we help you:

  • draft the building specifications for your ship regarding noise and vibration requirements
  • negotiate building specifications between yard and shipowner
  • understand and safeguard the expectations of the owner
  • ensuring the yard understands the consequences of noise requirements regarding noise and vibration mitigating measures and impact on the project.

  Which criteria to use?

  The International Maritime Organization (IMO) has a set of requirements in resolution MSC. 337(91) “Code on Noise Levels on Board Ships”, which are aimed at securing acceptable working conditions for the crew. However, in many cases the requirements are too relaxed - especially when it comes to passenger comfort.

  Major classification societies such as Lloyd’s Register, DNV, ABS etc. have non-mandatory requirements (both for passengers and for the crew) that can be applied to different types of ships. The requirement can be further divided into categories depending on your level of ambition regarding noise and vibration comfort. Bear in mind that specified noise and vibration requirements may be too relaxed compared to the actual expectations of crew, passengers, and ship-owner. Here we assist defining specific noise and vibration requirements for your project based on experience.  
  
  

• When you design your ship: Noise and vibration calculations and acoustics advice

  Designing a new ship is a complex task with many things to consider. When designing your ship remember to plan sufficient noise and vibration reducing measures to meet the agreed noise and vibration requirements. In this phase we assist you in validating, reviewing, and providing input for:

  • insulation plan drawings
  • general arrangement drawings
  • structural drawings
  • machinery drawings
  • machinery vibration isolation systems etc.

  Predicting noise and vibration levels

  We can calculate the expected noise and vibration levels in different areas of your ship by using various analytical tools. Our analytical tools help minimize the risk of noise and vibration issues after the ship is built, and help the yard and owner understand the impact of noise and vibration for different mitigating measures during progress of the project.

  For our analytical calculations we use tools such as Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), ray tracing acoustics etc. The tools enable us to predict:

  • noise and vibration levels internally on the ship
  • environmental noise from the ship
  • acoustic performance of different constructions
  • measures to minimize machinery noise and optimize vibration performance
• Building the ship: Laboratory test of noise and vibration, Acceptance tests and verification measurements

  When building a ship, it is important to know the actual acoustic properties and performance of the machinery and the individual building components before you install noise and vibration reducing measures on the ship.

  We can perform acoustical benchmarking test for your building components e.g. floating floors, windows, doors, and bulkheads. The tests enable you to determine which optimal components to choose for your ship.

  At our acoustics laboratory facilities, we test the building components you have in mind for:

  • sound insulation
  • impact noise reduction
  • acoustic absorption
  • apparent dynamic stiffness
  • sound pressure level / velocity insertion loss and the radiation index.

  We can also test machinery noise and vibration to determine the sound power levels of various products. These measurements you can used as documentation for product properties and performance.

  All our laboratory tests can be performed accredited or as guiding information.

  We participate and assist during factory acceptance of major machinery for pre-checking that requirements are met and provide consultancy for further improvement.

  Additionally, we perform structural tests, sound insulation tests etc. during the building phase to ensure analytical calculations comply with what is measured and to verify structural and building component properties at a relatively early stage of the project.

• Complete building the ship: Field measurements

  Once your ship is due for sea and harbor acceptance tests, we can help you make sure that noise and vibration levels are measured in accordance with the agreed measurement standards, operating conditions and comfort criteria. We can assist authoring protocols prior to measurements.

  The measurement must be performed by qualified personnel in order to document agreement with the building specification.  
  If the results indicate ships acoustics and vibration levels does not comply with the requirements we assist performing trouble-shooting measurements to advice on possible corrective actions.

  We perform in-field noise and vibration measurements during factory, harbor, and sea acceptance tests. Our noise and vibration measurements can be performed accredited. We also help you prepare noise and vibration protocols prior to acceptance test.

  We perform measurements in accordance with relevant standards e.g.:

  • Multi-channel noise and vibration measurements
  • Sound pressure level measurements
  • Vibration measurements
  • Sound insulation measurements
  • Impact noise measurements
  • Structural vibration testing, mobility, natural frequency, damping, operational deflection shapes etc.
  • Sound intensity measurements
  • Sound Power measurements
  • Order tracking measurements
  • Environmental noise measurements

  FORCE Technology is authorized by the Danish Maritime Authority to perform noise measurements on ships.
  
  

• At sea: Troubleshooting

  Noise and vibration issues might appear when the ship is in operation. In these cases, we can help you with noise and vibration trouble-shooting measurements to understand an adverse noise and vibration issue and detect the source of origin.

  Our vast experience with noise and vibration related issues from other ships and our state-of-the art measurement equipment provides you with a sound basis for providing trouble-shooting measurement assistance, so that your acoustics issues can be solved.