Noise risk assessment

Provisions on noise risk assessment and factors to be taken into account are included in the Finnish Government Decree on the protection of workers from risks arising from noise (85/2006). At least some of the factors mentioned in the provisions can only be determined with the help of occupational health care professionals. Others require a thorough understanding of the circumstances in the workplace. The risk assessor must also have access to data on noise exposure levels and the characteristics of the noise, and they must be familiar with different noise measuring techniques and the impact of noise. Employers are therefore advised to involve both their occupational health care provider and an occupational hygiene specialist in any noise risk assessment.

Noise risk assessment can be incorporated into the workplace survey or conducted separately. The findings of the assessment must be documented and the report kept available for employees to check their own results. A new assessment must be carried out whenever factors that can have an impact on the risk, such as procedures or working conditions, change to a material degree or if an employee is diagnosed with hearing loss resulting from exposure to noise at work.

Noise exposure assessment and measurements

It is the employer’s duty to determine each of their employees’ daily noise exposure and the maximum peak sound pressure or level during a typical working day. If noise levels in the workplace vary substantially from one day to the next, a five-day average must also be established.

As it is practically impossible to estimate noise exposure or peak sound pressure, measuring is usually required for a noise risk assessment to achieve its purpose. Measuring is the only option if an operation generates impulsive noise or if noise levels are so high that workers have to raise their voice in order for a person standing two metres away to be able to make out what they are saying.

A reliable noise exposure assessment usually requires hiring a professional with proper measuring equipment and the competence to measure and analyse noise levels. A successful assessment gives the employer reliable information about each worker’s noise exposure levels relative to the exposure action values and limit values, which they can use to decide what steps to take to protect their employees against hearing loss.

Retention of exposure data and reassessment

Employers have a duty to keep records of noise measurements and assessments pertaining to each of their employees. A new assessment must be carried out and new measurements taken if the circumstances in which a worker is exposed to noise change to a material degree.

Evaluation of other harmful effects of noise

The previous paragraphs mostly relate to assessing the risk of hearing loss. Employers who wish to study the other potential harmful effects of noise should ideally consult a specialist who can tell them what to factor in and what kinds of measurements to take.

Factors to be taken into account in noise risk assessment

Any plan to reduce noise exposure in a workplace should factor in the following:

• the level, type and duration of exposure
  • higher noise levels pose a greater risk
  • impulsive noise and steady-state noise together pose a greater risk
  • noise concentrated at certain frequencies poses a greater risk
  • sudden sharp and unexpected noises pose a greater risk
  • the risk is greater if the exposed individual is unable to control the noise themselves
  • the risk increases with the duration of exposure
  • allowing enough time to elapse between exposures lowers the risk
     
• the exposure limit values and the exposure action values
  • if a worker’s exposure exceeds these values, certain action must be taken by both the employer and the exposed employee
  • the greater the overexposure, the more urgently action must be taken
     
• any effects concerning the health and safety of workers belonging to particularly sensitive risk groups
  • special steps must be taken to reduce the risk if a particularly sensitive worker is exposed to noise
     
• any effects resulting from interactions between noise and ototoxic substances
  • the presence of ototoxic substances increases the risk compared to noise alone
  • such substances include, among others,
    • trichloroethylene
    • xylene
    • styrene
    • toluene
    • hydrogen cyanide
    • carbon disulphide
    • lead
    • carbon monoxide
       
• any effects resulting from interactions between noise and vibrations
  • vibration and noise together increase the risk of hearing loss
     
• any effects resulting from interactions between noise and warning signals or between noise and other factors
  • workers’ inability to hear warning sounds can lead to accidents
  • noise and internal or other traffic together pose a greater risk
  • operating lifting equipment in a noisy environment increases the risk
     
• information on noise emissions from work equipment
  • operating instructions for machinery must explain how much noise the machinery generates in the workspace
  • technical specifications included in brochures of machinery must also show noise emissions
• the existence of alternative work equipment designed to reduce noise exposure
• the extension of exposure to noise beyond normal working hours under the employer’s responsibility, such as on board a ship, impedes recovery and increases the risk
• other relevant information
  • results of hearing tests
• scientific publications about the effect of noise on workload
• the availability of hearing protectors with adequate attenuation properties.

An operation is deemed to carry a greater risk if less noisy work equipment would be available than if no such alternative exists.

Protection of workers belonging to particularly sensitive risk groups

Employers who expect their employees to work in noisy conditions must ask their occupational health care provider to identify any workers whose personal characteristics make them particularly sensitive to noise. The health and safety of these workers must be given special attention.

Actions after a hearing loss diagnosis

If a worker is diagnosed with a hearing impairment that is likely to have been caused by noise, the employer must revise their noise exposure and noise risk assessment procedures and evaluate whether the steps taken to prevent hearing loss are adequate and sufficiently effective.