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How to reduce hearing damage risk by 75%-90%

Noise risk reduction has failed: it's time to change - Nil NIHL campaign

Many employees and others are suffering unnecessary hearing damage at work because current risk management procedures are not best practice. They have not been effective despite the resources poured into noise assessments and PPE. The cost of Noise-Induced Hearing Loss (NIHL) to the UK economy is estimated at c £25 billion pa and even moderate NIHL increases dementia risk by x3, making it the largest single modifiable risk factor...

Introducing the following 3 changes to the current default approach would reduce NIHL risk by 75%-90% quickly and more cost-effectively than current expenditure.

  • learn to evaluate accurately the real-world performance of hearing protection and modify risk management procedures to increase performance and reduce exposure
  • eliminate most of the costly placebo risk assessment and reporting processes in favour of effective actions that include using smartphones and other new technology to access low-cost engineering noise control solutions to plant noise
  • consider changing from conventional audiometry to otoacoustic emission (OAE)

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hearing protection PPE does not work well...

Our British Safety Council article highlights these changes to reduce Noise Induced Hearing Loss (NIHL). A BOHS noise risk management webinar video also brings together 3 leading experts and innovators in the key fields of noise control and risk assessment, PPE and health surveillance detailing how to aim for Nil NIHL. We also provide noise training workshops covering the new best practice, both online and in person.

nil noise induced hearing loss NIHL

Hearing protector performance - 3dB attenuation when you expected 30dB

It has been known for decades that it is virtually impossible to guarantee adequate protection from hearing protectors at noise levels above c 95dB(A). Consequently, it should not have been news that research by the Health and Safety Laboratory (report RR720) proved that the common assumption that PPE is a reliable “solution” to hearing damage risk problems is false. This assumption has left many personnel at risk and companies are open to claims if their hearing conservation policy is based on PPE use. Some of the key findings of the research are:-

  • PPE in 25% of the companies visited was so ineffective that it provided negligible or no protection for most
  • even in companies with effective PPE use, 14% of workers did not wear protectors when and where required
  • 40% of the workers who should have been wearing protectors got no protection at all
It is almost impossible to guarantee adequate PPE protection above 90dB(A)…
hearing damage claim costs

The inadequacy of PPE performance in many real-world situations is also born out by the continuing tidal wave of hearing damage claims of £400 million in one year (2014 - IFA UK deafness working party), despite (or even because of) the over-reliance on PPE without understanding the performance limitations away from the lab. This also brings into sharp focus the need to reduce noise levels to reduce risk, even when the levels cannot be reduced to below 85dB(A).

As a rule of thumb, it has been known for decades that provided effective management systems are in place, most good quality PPE can only be made to work up to noise exposure levels of around 90dB(A) to reduce operator exposure to below 80dB(A). Above this level, as attenuation of more than 10dB is required, it becomes seriously difficult to guarantee adequate protection. At noise levels above c 95dB(A) - 100dB(A), it is virtually impossible without introducing very stringent, time-consuming controls - and even then it may not be practical... INVC hearing protection article

field protection provided by hearing protectors

Most organisations have hearing conservation programmes that are not based on this information. Consequently, millions of workers have suffered unnecessary hearing damage. The key issues are:-

  • earplugs are rarely correctly fitted. This can cut the attenuation from 30dB down to as little as 2dB as shown in the top plot
  • earmuffs should be assumed to provide a maximum workplace use attenuation of c 10dB - 17dB as indicated in the second graph, whatever the protector
  • wear rate should be 100%, but virtually never is - and could you prove it is? Every day? No PPE for a total of 10 minutes a day limits the attenuation to < 17dB
Manufacturers' PPE data says assumed protection of 27dB. Assumption: we're good for 107dB(A). Reality: they may be providing only 3dB - 10dB of attenuation as used which means adequate protection up to only 83dB(A) - 90dB(A)...

real world PPE performance

The key (and very often missing) factors necessary to improve real-world hearing protection are:-

  • you must have a system in place to audit wear rate. It is unbelievable that most organisations do not log wear rates and consequently have no idea of the effectiveness of their PPE.
  • you must train staff in the correct fitting and use of PPE (fit testing). This is particularly critical for earplugs where the assumed protection of 30dB (manufacturer) can often drop as low as 3dB in use
  • consider using the new generation of intelligent PPE that continuously logs wear rate and attenuation automatically, providing automated verifiable evidence that users are sufficiently protected to monitor the efficacy of programme and to guide improvements
Don't repeat placebo noise risk assessments, add noise control

Don't repeat assessments - or repeat assessments. Update elements if noise levels have changed significantly. The HSE says you do not even need to measure with a meter and that you should start to implement noise exposure risk reduction measures as soon as you know the levels are likely to be above 80dB(A). Reports without practical information on noise control are, by definition, inadequate.

Investing in a Noise Control Audit (NCA) is best practice. This is an engineering evaluation that generates a cost/benefit analysis of the noise control options for plant or provide the information needed to plan the most cost-effective risk reduction programme. This analysis allows you to balance the reduced risk against costs (capital, reduced PPE, audiometry and management costs, improved working conditions, productivity...).

Anyone can make a basic evaluation of the likely control options from online information or by using of our free email analysis service. The regulations state that PPE cannot be used for long-term risk management unless you can prove that noise control is impractical. We provide noise control training workshopson the current state of the art, both in person and online.

In the entertainment and music industries, there are fewer noise control options due to the nature of the noise exposure. However, there is a range of exposure-reducing measures that can be implemented - without ruining the experience...

Noise control made simple

General knowledge about modern noise control best practice (even amongst noise specialists ) is abysmal. As a result, good, costed control advice in noise reports is conspicuous by its absence.

The following is the relationship between reduction in noise (dB) and reduction in risk (%).

rip ppe
  • -3dB - 50% risk reduction
  • -5dB - 67% risk reduction
  • -7dB - 80% risk reduction
  • -10dB - 90% risk reduction

This means, for example, reducing noise from 97dB(A) to 90dB(A) cuts employee risk by 80%. Whilst personal hearing protection is still required, the risk has been reduced by 80% and it is much easier to guarantee adequate PPE performance. Most organisations can cut risk 50%-90% at little cost (or even at a profit) by using the latest noise control technology. The question is...

Q: "How do I find the best noise control options?"

A: consult freely available online engineering noise control case study databases e.g. HSE, INVC

A: use our free online noise control option analysis service (email smartphone video clip and photos) for a cost/benefit analysis of the options based on current best technology

Many noise problems have simple solutions that can be found online and implemented by any competent engineer e.g. "Detailed solutions to the 10 most common industrial noise control problems"

Health surveillance screening
Tradition audiometry is essentially a costly check-box placebo exercise. Discuss...
oae testing

Conventional audiometry provides data that is of little use in risk management as it just catalogues failures in risk reduction strategy years later. Whilst it can be useful as a motivational tool, traditional audiometric testing is essentially a costly check-box exercise to comply with regulatory stipulations. Quoting the HSE: "Audiometry is a tax on the failure to control risk..."

pure tone audiometry v otoacoustic emission (OAE)

The newer Otoacoustic Emission (OAE) hearing tests, however, can detect the early stages of damage, making it an effective tool to assess the efficacy of hearing damage risk management programmes. This allows you to monitor how well the hearing protection programme is working and provides a valuable educational and motivational tool.

How much motivation would the statement "You had 12% damage last year, this year it is 18%" provide?

The British Society of Audiology recommended OAE be used in the music industry in 2022 as they allow earlier identification of cochlear damage before it is evident through routine audiometry.

OAE expertise provided by Rob Shepherd:

Learn how to implement NIL NIHL

Contact us to be kept up to date with our online workshops or enrole in one of our public certificate of competence in workplace noise risk assessment and management courses.

Combining NIHL risk reduction measure examples

By combining the techniques described above, it is possible to reduce the risks to hearing by 75%-90% or more in virtually every case and at zero or negligible - and often with a cost saving.

Taking typical examples:-

Food processing plant: 35 staff in area


Noise dose = 88dB(A)

Mandatory PPE attenuation as used was 3dB to 5dB, so operator exposures = 85dB(A)

Noise assessment, PPE and audiometry costs = £11k pa

After noise control

Noise level = 81dB(A) (-7dB) via hygienic noise control

Operator exposures - advisory PPE only = 78dB(A)

Noise control costs £9k + £1k pa savings in compressed air. Nil

NIHL programme in profit after c 9 months, thereafter saving c £6k pa.

Heavy industry (power press): 15 staff in area


Noise dose = 3 operators @ 102dB(A), 12 operators @ 96dB(A)

Mandatory PPE attenuation as used assessed as 5dB - 10dB, so operator exposures = 2 @ 97dB(A), 12 @ 91dB(A)

Noise assessment, PPE and audiometry costs = £4k pa

After noise control and improved PPE

Noise control: silencer, damping, strip vibration control, pneumatic nozzles.

Noise dose = 2 operators @ 92dB(A), 12 operators @ 83dB(A)

PPE attenuation improved to an automatically monitored and guaranteed 15dB minimum using intelligent earmuffs, so operator exposures = 2 @ <77dB(A) +12 @ <75dB(A)

Noise control costs £11k + £3k pa savings in compressed air.

Nil NIHL programme in profit after 15 months, thereafter saving c £4k pa.

Bakery: c 60 staff in area

Noise dose = 12 operators @ 95dB(A), 48 operators @ c 87dB(A)

Mandatory PPE attenuation as used was 3dB to 5dB, so operator exposures = 89dB(A) and 84dB(A)

Noise assessment, PPE and audiometry costs = £23k pa

After noise control and improved PPE

Noise level = 12 operators @ 90dB(A) + 48 operators @ 79dB(A) via hygienic noise control

PPE attenuation improved to an automatically monitored and guaranteed 15dB minimum using intelligent earmuffs for 12 staff only, so operator exposures = 75dB(A)

Noise control costs £25k + £2k pa savings in compressed air.

Nil NIHL programme in profit after c 1 year, thereafter saving c £16k pa.

Noise risk management - It's Time to Change

Current noise risk management procedures have failed to protect staff sufficiently from avoidable noise-induced hearing loss. As a result, millions have suffered unnecessary damage including hearing loss and tinnitus. The damage caused by noise exposure also includes a 9% - 27% increased risk of dementia, making noise the dominant modifiable dementia risk factor.

The improvements detailed here can reduce these risks by 75% - 90% at zero or negligible cost compared with current practices.

It’s time to change, it's time to aim for Nil NIHL...

nil noise induced hearing loss NIHL