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Reduce the Effect of Noise

Published: 10th Apr 2007

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A preventative approach to noise control

Recent research cited by the HSE estimates that over 2 million people are exposed to potentially harmful levels of noise during work. Nearly 200,000 people are believed to suffer from partial deafness, tinnitus or other hearing complaints due to excessive workplace noise exposure. Civil compensation for noise induced hearing loss (NIHL) rose dramatically after the Noise at Work Regulations 1989 were introduced in 1990. This legislation provided employees with statutory protection from noise in the workplace by setting clear noise exposure limits, which required employers to assess noise levels in the workplace against these limits, deciding whether they complied and then to provide suitable protection to employees where relevant.

Although the 1989 regulations provided protection above 85dB(A), recent medical evidence strongly suggests that NIHL may be a factor in some people at levels as low as 70dB(A). With this issue in mind the new Control of Noise at Work Regulations, in force since April 2006, provided more protection for a greater number of employees than previously. Where the 1989 regulations put in place a basic structure to measure and protect employees from NIHL, the new legislation emphasises proactive management and elimination of noise at source (Regulation 6) rather than simple measurement against legal limits. In addition new lower action values have been set (Regulation 4). Such changes will undoubtedly lead to a rise in litigation in coming years as employers struggle to come to terms with more complex compliance issues the new regulations bring.

What is hearing loss?

Hearing loss is the process of losing hearing sensitivity, which can occur naturally over time and as a result of environmental influences. The likelihood of hearing loss is a combination of noise level and the period of exposure; however, the levels at which individuals are affected can vary from person to person.

There are four main types of hearing loss:

  • Temporary threshold shift (TTS) TTS is experienced after several hours of exposure to noises near to the new exposure limit of 80dB(A). Most of this temporary loss of hearing occurs during the first two hours of being in a noisy location but does not get significantly worse in the subsequent hours. However, the person’s hearing threshold will recover after approximately sixteen hours if removed from the noisy location. Temporary threshold shift can become permanent if the person’s hearing is not given respite. The first signs of damage can be signalled by tinnitus
  • Tinnitus Tinnitus can take a variety of forms such as buzzing, ringing, whistling, hissing or a range of other sounds. Affected people often only notice these sounds when it is very quiet, especially at night. Although also caused by medication, stress and illness, constant exposure to loud noises is a well known cause of tinnitus. Where noise exposure is an issue, tinnitus can be an early indicator of hearing damage
  • Permanent threshold shift Permanent threshold shift is a gradual change that takes place over a period of years. Hearing loss will be most pronounced in the first few years of long term exposure to noise. Permanent threshold shift is caused by physical damage in the ear which limits an affected person’s ability to hear certain frequencies. The first signs of permanent hearing loss are generally losing the ability to hear higher frequencies, like children’s voices. When hearing damage gets to this stage the problem is irreversible
  • Acoustic trauma Acoustic trauma occurs as a result of a very short but loud noise occurrence. This problem is often seen as a result of explosions and unprotected use of heavy machinery, which causes severe physical damage to the ear and the neural functions. This form of hearing damage is generally irreversible

Employer’s duty of care

Employers have a duty to protect their workforce from noise (or any other risk or hazard in the workplace). Failure to do so could be negligent, a breach of statutory duty (such as non-compliance with the Regulations), or both. As a minimum, employers should assess the risks associated with noise in the workplace by way of an accurate assessment by a competent person. That assessment should then be used to put reasonable measures in place to protect the workforce accordingly. Not doing so could lead to NIHL amongst the workforce, thus leaving the employer open to litigation.

In order to make a causal link between workplace and NIHL, first there needs to be medical evidence of changes in hearing thresholds. In addition there needs to be an absence of any other explanation for the NIHL and evidence that noise in the workplace has not been adequately managed and for how long.

Should a workplace NIHL claim be established, the compensation levels will primarily depend on the extent of hearing loss and any subsequent loss of earnings. However, a successful claim requires adequate evidence that the employer has breached their Duty of Care with regards to protecting the employee from noise.

The likelihood of a successful claim also greatly depends on the level of noise present in the workplace and how far above or below the statutory limits these levels were. Good, accurate noise data is one of the most crucial pieces of information to defend an employer against claims.

The old and new regulations - A comparison

The 1989 regulations set two main exposure limits. These limits have been lowered in the new regulations:

The 2005 regulations include a number of subtle changes from the previous law. These include:

  • A 5dB lowering of the 2 ‘action level’ values with new ‘peak noise’ levels of 135dB and 137dB
  • The addition of an exposure limit value of 87dB(A) (average daily exposure) which must not be exceeded and can take into account hearing protection
  • Less reliance on measurement and hearing protection, greater requirement to complete a risk assessment
  • Elimination or control of noise at source
  • Provision of health surveillance
  • A change in the averaging period from 8 hours to a full working week, to take into account fluctuations day-to-day

Action levels

Both the old and the new Regulations provide employees protection from noise by setting two basic ‘action levels’, above which employers must put controls in place.

First Action Level/Lower Exposure Action Level (LEAV): now set at 80dB(A) over the required averaging period. Exceeding this level requires hearing protection to be made available, on request, to any employee. The employer should also provide training and education and management of noise to reduce levels as far as practicable. In addition, the peak pressure sound level must not exceed 135dB.

Rule of thumb - 80dB is the level at which two colleagues can converse at a distance of two metres apart without the need to raise their voices. Above this level, over a long period, damage to hearing could be an issue.

2005 Regulations Average/Peak 1989 Regulations
First action level: 80 dB(A) / 135 dB 85 dB(A)
Second action level: 85 dB(A) / 137 dB 90 dB(A)
Peak action level: 87 dB(A) / 140 dB 200 Pascal

If the employer thinks that they may have employees exposed to these conditions for over 6 hours in any working day, a noise risk assessment should be completed.

Second Action Level/Upper Exposure Action Level (UEAV): now set at 85dB(A), the 1989 first action level. If the measured noise exceeds this level the employer should take measures to reduce the noise below 85dB(A). If an employer is unable to reduce the level of noise to below the second action value, then the use of personal hearing protection must be made mandatory. The area concerned must also be designated a Hearing Protection Zone and clearly signed accordingly.

In addition, the peak pressure sound level must not exceed 137dB.

Rule of thumb - 85dB is the level at which two colleagues need to shout to each other to be heard when two metres apart.

If the employer thinks that they may have employees exposed to these conditions for over 2 hours in any working day, a noise risk assessment should be completed.

Exposure Limit Value (ELV): Noise levels should never exceed 87dB(A). Exceeding this peak action level means that employers must put noise abatement measures immediately in place to reduce to below 87dB(A). Abatement can be in the form of suitable hearing protection. In addition, the peak pressure sound level must not exceed 140dB at any time.

If employees have to shout to be heard at 1m apart, this indicates noise levels of 90dB. Exposure to these levels for over 15 minutes strongly indicates that a noise risk assessment should be completed. It is rare to exceed the ELV, although certain industries may be affected such as stamping and punching processes.

Structure of the new regulations - Hierarchy of controls

The old regulations relied heavily on measurement of noise levels and provision of protection. The requirements of the new regulations, however, follow the hierarchy of control as detailed in Schedule 1 of the Management of Health and Safety at Work Regulations 1999.

The basic structure of the new regulations requires employers to:

  • Assess the risks - assess the noise risks to help manage noise levels
  • Reduction - take action to reduce noise exposure
  • Protection - provide hearing protection where reduction at is not possible
  • Compliance - ensure the noise limits are not exceeded
  • Information - provide workers with information and training
  • Surveillance - provide health surveillance for workers at risk of hearing damage

Risk assessment

Risk assessment is a fundamental route to complying with the new regulations rather than just relying on measurement and protection. Based on the ‘rule of thumb’ descriptions listed earlier, if the employer is satisfied that the levels are likely to be below the first action level it is sufficient for this to be noted and for no further action to be taken unless changes occur on site. The risk assessment does not need to contain actual measurements of individual noise exposures, but it does need to accurately estimate whether the limit values are likely to be exceeded.

In addition to using the ‘rule of thumb’ descriptions, consulting published industry and equipment manufacturer’s information is useful. The assessment needs to take into account any specific issues in the workplace, such as machinery types and state of maintenance, different working practices, the size and shape of the building and the materials being used in each process.

When completing a noise risk assessment the following factors need to be considered carefully:

Level, type and duration of noise exposure: this is critical to any noise risk assessment. The higher the noise level or the longer the exposure period the greater the risks involved are. The level of risk can also change depending on the ‘character’ of the noise present.

Specific sensitive employees on site: young employees are especially at risk from high levels of noise. However, the risk assessment should aim to highlight any especially high risk employees, such as people with pre-diagnosed hearing conditions.

Combined exposures to noise, vibration and hazardous materials: medical studies suggest that exposure to materials such as solvents can increase the potential for NIHL. In addition vibrating hand tools can also make employees more vulnerable to NIHL. Such issues should be noted in the risk assessment and controlled in the workplace.

Indirect risks (such as masked emergency alarms): the effect of workplace noise on general site safety needs to be considered in the risk assessment. Fire alarms can often be drowned out by the presence of workplace noise or rendered useless by hearing protection.

Manufacturer’s data: the risk assessment should include any manufacturer’s data relating to noise emission, if the levels are sufficiently high. The Supply of Machinery (Safety) Regulations 1992 requires equipment suppliers to provide noise emission data in any sales literature (the limits are 70db or peak sound of 130dB at the operator’s normal working location).

Extended working hours: the effects of varied shift patterns in different areas across the workplace needs to be considered in any risk assessment. Rest rooms can be near the first action level in very noisy workplaces. In addition, the employer needs to be satisfied that any rest rooms are sufficiently quiet to provide proper hearing respite.

Management of health surveillance data: holding and reviewing this data will help assess whether the risk management process is working and whether new cases of NIHL are occurring at an early stage.

Consultation: any risk assessment should be carried out with the help of the workforce, as they may understand the shop floor issues better than any one and can suggest specific courses of action. Completing a noise risk assessment also helps employee buy-in and makes sure they know you have their safety in mind.

Regular review: the assessment should be regularly reviewed to take into account any process changes, issues that health surveillance highlights, or when new technology that reduces noise levels is available and viable for use. The assessment should be reviewed at least every two years or more regularly if changes have occurred.

Measurement

If the employer is not totally confident as to whether their workplace falls into any of the subjective ‘rule of thumb’ categories listed or does not have good supporting information to complete their assessment, it will be necessary to carry out detailed noise measurements to confirm levels across the site to support the risk assessment. Not having up to date measurement data in noisy work locations can also leave an employer in difficulties with regards proving any form of defence against a NIHL claim.

Noise measurements should be completed by a competent person and presented in the form of a full interpretative report with detailed noise maps. If this work is completed by a third party, you should expect them to provide relevant recommendations to help ensure compliance.

Competent persons

Unfortunately, the regulations do not define the term ‘competent person’ but they will be a person who fully appreciates noise, the associated risks and how to manage it effectively. Should the employer not have anyone in-house with such competency, the services of a Registered Occupational Hygienist should be sought (the BOHS Consultant’s directory is a good place to start)

Reduction

The requirement of the new regulations to control noise at source will, potentially, require many to invest heavily in new low noise emissions equipment. The ‘reasonably practicable’ argument provides employers with some breathing space where cost outweighs risk, however the HSE will take a dim view if this policy is adopted long term.

Well-targeted redesign of equipment and the workplace can mitigate any expenditure required. Improved maintenance, use of alternative materials, layout redesign and acoustic enclosure can yield good reductions in noise. Whenever new equipment needs to be bought, a low-noise purchasing policy should be adopted.

Third party expertise from an acoustic consultant will help diagnose and characterise noise emissions, which will help target and maximise any potential alterations.

Protective equipment

Where reduction or control at source is not feasible or not sufficiently effective to bring noise levels down to below the action levels, employers will need to provide suitable hearing protection. The two main forms of protection are muffs and plugs.

Completing a full noise measurement exercise is the best way to assess the suitability of hearing protection. The hearing protection has to be fit for use, taking into account the character of the noise in question, the level and the type of work being completed. Noise measurement data can be plugged into the HSE’s Ready Reckoner (www.hse.gov.uk/noise/calculator) to determine the best attenuation provided by each type of protection for each noise type and level.

Wearer comfort and preference should always be taken into account when choosing personal protective equipment, as employees will inevitably not wear uncomfortable or badly fitting PPE. If possible, a choice should be made available to employees.

The use of protective equipment must be enforced if noise levels are close to or above the upper action level and formal training must be provided to ensure the equipment’s correct use.

Health surveillance

Health surveillance is mentioned in other recent pieces of health and safety law. However, Regulation 91 of the new noise legislation is more prescriptive and ‘requires’ health surveillance to be carried out to assess the impact of noise in the workplace. In the case of noise exposure, health surveillance simply means audiometric testing.

Employees should be included in the surveillance programme if they are regularly exposed to noise levels at or above the higher action level of 85dB(A). It is acceptable for the test to be conducted by a ‘suitably qualified person’, but where an employee is found to have identifiable hearing damage, this should be referred to a doctor. A pre-employment test should also be conducted to provide baseline data to determine the effects of exposure whilst working for the employer.

Exposure to noise less than 16 hours before audiometric testing can cause temporary threshold shift (TTS), generating an adverse but inaccurate result.

HSE guidance recommends that employers ensure at risk employees have annual tests for the first two years of employment. After this period audiometric testing should only need to be repeated every three years unless significant deterioration is encountered.

Where testing shows a degeneration of hearing and a causal link can be drawn between this issue and the work that person does the employer has a duty to inform the employee accordingly and put into place changes to prevent any further loss (such as role change and review of control measures in place)

Conclusions

The Control of Noise at Work 2005 regulations protects an additional 750,000 workers whose noise exposure is over the new 80dB(A) first action level. Employers need to be aware that if they have sources of noise exposure but were previously outside the scope of the 1989 regulations, they may now come under its remit.

At first glance, the regulatory changes appear very subtle. In fact they require a significant change in attitude to noise control in the workplace. Where the 1989 regulations required simple measurement of noise and comparison to the legal limits, the new regulations require employers to fully understand the noise issues that affect their workplace and manage them effectively by assessing the risk, putting effective control measures in place (with an emphasis on source reduction) and confirming that noise exposure is under control through regular health surveillance. The new regulations widen the statutory obligations placed on employers, therefore the level of NIHL claims will undoubtedly increase over time. However, employers can protect themselves and their workforce by assessing whether they now fall within the regulation’s scope and by having a more preventative and holistic approach to noise control.

For more information on hearing protection please visit http://www.osedirectory.com/product.php?type=health&product_id=6

Published: 10th Apr 2007 in Health and Safety International

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