Noise

When you work in noisy environments it can cause accidents, injuries, and diseases. In this page you get a list of possible injuries and how to prevent them.

Contents

Working in areas with a lot of noise may cause accidents, injuries and illnesses.

Accidents that occur because noise prevents communication:

  • Injuries to hearing
  • Stress
  • Discomfort

When does noise damage hearing?

The maximum limits for noise an employee may be exposed to while working aboard a ship has been set to 85 dB(A) for an 8 hour working day. If the noise level is higher, however, technical or organisational measures must be taken to reduce the noise. If this is not possible, hearing protection must be worn. The Danish Maritime Authority has also determined the noise limits for individual working areas on the vessel. The Maritime Authority’s standards are all 5 dB(A) under the IMO (International Maritime Organisation) figures.

The stress caused by noise depends on its loudness and the duration of exposure. The Danish Maritime Authority has also laid down regulations stating that unnecessary noise must be avoided.. The figure below illustrates the link between noise level and duration of exposure to noise. All the combinations result in an equivalent noise impact of 85 dB(A) over 8 hours – which is in line with the limit.

85 dB(A) for an 8-hour working day equates to:

  • 80 dB(A) for 24 hours
  • 91 dB(A) for 2 hours
  • 97 dB(A) for 30 minutes
  • 102 dB(A) for 10 minutes
  • 105 dB(A) for 5 minutes
  • 112 dB(A) for 1 minute


On the other hand, you should not only concentrate on the fact that noise can damage hearing. In fact, noise can also lead to stress and prevent important communication. Legislation states that all unnecessary noise should be reduced. That means that even though, for example, ventilation plant is no noisier than the engine and the 110 dB(A) permitted in the engine room, you should try to reduce forced air noise if this is technically and financially feasible. This improves conditions aboard when the engine is stopped, when in port for example.

Noise aboard vessels

There are basically two types of noise aboard vessels depending on the way it is transmitted:

  • Airborne sound, which is noise transmitted through the air.
  • Structural sound, which is noise transmitted through the ship's hull.

Think of an alarm clock. When you hold it in your hand, you hear the ticking as an airborne sound. If you then put it on a shelf or a table, its ticking becomes louder - it is now structural sound radiated from the surface of the table. A great deal of structural sound originates from the engine and propellers. Structural sound is difficult to control as it is spread over the entire hull of the ship. Airborne sound, on the other hand, is more local and can be quickly reduced when it passes through bulkheads, decks, etc.
Noise prevention principles

Reduction of noise aboard, for example, by:

  • Boxing in the source - for example, it is quite possible to box in certain auxiliary engines and other small machinery.
  • Installing noise-absorption - that is to say, by cladding hard surfaces with mineral wool or by setting up acoustic screens close to the source of the noise or close to work areas.
  • Insulation of working areas and crew accommodation so that noise cannot penetrate crew accommodation. Use floating floors and viscoelastic materials.
  • Sound absorption can be installed in ducting, e.g. for the fans in the ventilation system.
  • Elastic machinery mountings prevent noise and vibration from being transmitted as structural sound.
  • Buy the quietest machines and tools.
  • Signs throughout the vessel showing when the crew should use hearing protection.
  • The final solution is to use hearing protection. Be sure to use well-known types with effective noise suppression.


In many cases, it is relatively easy to reduce noise. But problems may be caused by complications requiring assistance from experts in the field.

Noise aboard a ship

Here you can find a general description of typical sources of noise and different ways of reducing it. The areas include:

  • Galley
  • Control room
  • Workshop
  • Deck
  • Discotheque
  • Accommodation

You can use some of the ideas shown and carry them out yourself, while some of the ideas shown demand conversion or rebuilding, and the involvement of the company.

Reducing noise in the galley

Reducing noise in the control room

Air extraction

  • Clean filters
  • Point extraction


Ventilation

  • Sound dampers
  • Low air speeds


Reflected sound

  • Acoustic materials in the ceiling

Kitchen machinery

  • Choose quiet makes
  • Insulation


Impulse sounds from tools and cutlery

  • Rubber mats
  • Avoid banging
  • Muffle tables, drawers, etc.


Control desk

  • Elastic mounting
  • Tighten cable seals


Airborne sound

  • Bulkhead lining insulated with mineral wool
  • Under-floor insulation
  • Tighten cable seals


Windows

  • Heavy glass
  • Fit internal glazing


Doors

  • Tight-fitting
  • Heavy
  • Without ventilation apertures


Structural sound

  • Floating flooring
  • Viscoelastic insulation

 

Reducing noise in the galley

Reducing noise in the control room

 

Ventilation

  • Sound dampers
  • Low air speeds


Reflected sound

  • Sound-absorbing materials in ceiling and bulkheads
  • Acoustic cladding

 

Tools

  • The quietest equipment
  • Noise reduction


Airborne sound

  • Bulkhead linings
  • Insulation under flooring and on outer side of bulkheads


Crane tracks

  • Tighten seals


Doors to engine room

  • Tight-fitting
  • Heavy
  • No ventilation apertures


Structural sound

  • Floating flooring
  • Viscoselastic insulation


Reflected noise

  • Sound-absorbing materials in ceiling
  • Baffles


Ventilation

  • Large low speed fans
  • Sound dampers
  • Low air speeds
  • Dampers in ducting


Reefer containers

  • Acoustic screens
  • Locate away from working area


Hydraulics

  • Pulsation dampers
  • Elastic pipe suspension


Impulse noise

  • Avoid percussion
  • Rubber mats


Traffic

  • Slow driving speeds
  • Plan location/timing of work

 

Reducing noise in the discotheque

Reducing noise in accommodation

 

Loudspeakers

  • Place away from working areas
  • Use several smaller loudspeakers around the room


Impulse noise from glass and cutlery

  • Rubber mats placed in trays
  • Glass and cutlery firmly secured


Ventilation

  • Sound dampers
  • Low air speeds


Reflected noise

  • Acoustic ceilings and cladding

 

Windows

  • Inner windows in linings
  • Window units not attached to structure


Airborne sound

  • Bulkhead linings insulated with mineral wool
  • Insulation of steel bulkheads and deck


Rattling

  • Secure fastenings
  • Felt linings


Doors

  • Tight fitting
  • Without ventilation apertures to corridors


Structural sound

  • Floating flooring
  • Viscoelastic insulation
  • Reflected noise
  • Acoustic ceiling cladding and materials


Kitchen machinery

  • Opt for quiet makes
  • Insulation

Legislation

The rules about noise can be found in "Order no. 1283 of 11 November 2013 amending the order on Notice A from the Danish Maritime Authority, technical regulation on occupational health in ships". You can read about the rules here.

International regulation

 

Senior Occupational Health Consultant

Anne L. Ries

alr@seahealth.dk

+45 3311 1833

+45 2961 8860

I can help you with:

  • Safety Organization
  • Consultancy
  • Physical working environment
  • The program Health and Safety at Sea
  • Legislation at sea