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Most hearing conservation programmes are ineffective.
Most of the workers expected to use hearing protection either get no protection whatsoever or the performance of their PPE is inadequate. The implications of these findings published in the UK in a recent HSE report are far reaching. The common assumption that PPE is a reliable solution to hearing damage risk problems is simply untrue, leaving many personnel still at risk and many companies open to claims. Peter Wilson of the INVC summarises the results of the research and outlines the key factors required to make hearing conservation programmes as effective as possible.
The research – most hearing protection is inadequate
Despite the emphasis on noise control in the new noise regulations, hearing protection is often (wrongly) considered to be the first and only line of defence against the risks of hearing damage.
Noise problem? Issue PPE.
Problem solved. New research published in the UK by the HSE (RR720 2009), however, indicates that only 40% of PPE users get any protection whatsoever and that the real world performance of a substantial proportion of the remaining 60% is inadequate. Companies must become aware that issuing PPE is not a simple or reliable solution. The following is a summary of the main findings of the research based on both company visits and on laboratory testing.
No protection
• The use of PPE in 25% of the companies visited was so ineffective that is was likely to result in negligible or no protection for most users • Even in companies with generally effective hearing protector use, 14% of the workers did not wear protectors when and where it was required • Overall, 40% of the workers who should have been wearing protectors got no protection at all The main factors implicated in these results were: • Peer group pressure and group behaviour plus reluctance of supervisors to enforce wear • The need to hear traffic, radios and difficulties in communicating • Attitude – viewing PPE as an imposition without adequate consultation • Incorrect fitting (e.g. foam plugs) • Use of PPE as the sole control measure without a comprehensive noise control programme • Inadequate protector provision
Thinking beyond PPE
Companies must become aware that issuing PPE is not a simple or reliable solution. Inadequate protection • Less than 50% of companies had selected PPE based on the attenuation actually required; consequently, about half of these had specified PPE that over-protected • There was ignorance of the need to provide a choice of PPE in a number of cases Adequate protection • Hearing protection was effective for most workers in the 40% of companies who used PPE within a comprehensive noise control programme (noise control measures and ‘Buy Quiet’ policy) • PPE was most effective in companies who combined training with appropriate supervision and employee cooperation
Unnecessary protection
• Making whole buildings or sites hearing protection zones when only limited areas are noisy • Requiring the use of PPE everywhere rather than assessing the actual risk
PPE field performance issues
Earmuffs – The standard HSE recommendation has been to de-rate the manufacturers’ attenuation data by 4dB to account for ‘real world’ performance. The laboratory testing, however, showed an additional 6dB loss after a simulated month of normal use, primarily caused by stretching of the headband which is invisible to the user. This means that nearly a third of the earmuff users seen would have been under-protected. Damage to earmuff seals is more obvious, but removing an eighth of the seal showed a drop in attenuation of only 2dB. The effectiveness of the seal is also compromised by glasses, goggles and dust masks. The less bulky versions reduce the attenuation by around 2dB, the bulkier versions by up to 10dB. Moreover, wearing earmuffs over clothing (e.g. hoods in cold weather), reduced the performance by 14 – 21dB.
Earplugs – Proper fitting is the key factor. Just over 50% of the compressed foam earplug users seen had not inserted the plugs properly and most of them were ignorant of the correct fitting procedure. Simulated tests showed that the attenuation could fall to as low as 9dB if not properly fitted. Users generally preferred push-in plugs (foam or flange), as they are easier to fit and were usually inserted deeper into the ear canal. Banded ear canal caps gave negligible protection under band pressure – they have to be inserted into the ear canal entrance. While custom moulded earplugs were generally considered by companies and users to be the best available, not all users found them comfortable. While not included in the laboratory testing for the report, previously published information has indicated that the attenuation can fall by up to 6dB over the first hour of use due to temperature effects changing the shape of the ear canal.
Hearing conservation programme – best practice
The following is a pragmatic guide to the key features that should be included in order to minimise the risks to staff and potential future claims.
1 Noise control programme The HSE research showed that hearing protection was most effective in those companies where it was implemented as part of a comprehensive noise control programme. This is largely due to the cultural and management attitude engendered by the process – an unwillingness simply to try to offload responsibility (in the form of PPE) onto the workforce. In addition, PPE cannot be used for long term risk management unless you can prove that noise control is not practical. Consequently, companies must assess the costs and benefits associated with implementing an effective control programme based on the best of current technology. This requires a noise control audit. This is an engineering evaluation of the noise control options, costs and benefits carried out either as part of a Noise Management Assessment, or as an add-on to an existing assessment where the competent person does not possess the required specialist engineering expertise. In many cases, low cost engineering noise control techniques are available that can provide the bonus of a potential pay-back due to reduced costs. PPE cannot be used for long term risk management unless you can prove that noise control is not practical. Despite the regulatory requirement to reduce noise levels as far as reasonably practical, the following are the three key target noise levels which trigger particular benefits: <95dB(A) – PPE programmes can be made to work reliably <85dB(A) – PPE becomes only advisory; no Health Surveillance; reduced training and management <80dB(A) – complete deregulation Where PPE can be made advisory or unnecessary, there are substantial direct and indirect cost savings. Depending on the type of protection used and the conditions, typical cost savings on PPE can be £30 – £200 per head, per annum, with additional savings relating to improved communications, reduced management resources and absenteeism. Moreover, a simple, well policed ‘Buy Quiet’ purchasing policy is probably the most cost effective long term noise control measure that a company can take. It is important, however, that you do not allow your suppliers to spend your money on control measures that are not best practice. Do not allow your suppliers to spend your money on control measures that are not best practice.
2 Management practices The findings in the HSE report highlight a few key management practices that should be in place in order to make hearing conservation programmes as effective as practical. These are:
• Assessment – report quality is a big issue; most reports are not of ‘merchantable’ quality. You must be able to identify personnel at risk and the assessment must include a specific programme of action
• Hearing conservation programmes should be implemented as part of a comprehensive noise control and management programme and efforts should be focused on higher risk areas and activities
• Do not issue edicts making whole sites or departments mandatory hearing protection zones when a significant proportion of the workforce is not at risk. This is poor management and can also be counter-productive, as workers tend not to take the risks seriously, knowing that there is no risk in some of the areas where they are required to wear PPE
• Where health surveillance (audiometry) is required, do not skimp on the process. Allow for a little more time over and above the minimum to discuss hearing damage, PPE selection and fitting. This is an opportunity for one-on-one education and motivation
• Managers and supervisors must set an example and companies must have a procedure in place to police the use of PPE – including enforcement and disciplinary procedures
3 Training and motivation Personal motivation, company culture and supervision are key factors in operating a successful programme. Motivation is particularly important for remote workers where direct supervision is not practical. Much education on the why and how of PPE has little effect as it is dull and lacks impact. The best approach is to use brief, graphic material that workers will remember and to apply this to home life situations (such as DIY or noisy hobbies) to avoid accusations of ‘imposition’. Link this to the free issue of earplugs for home use plus other positive incentives. Supervisors and managers must also be trained in their responsibilities. Training should also be given in correct use and communication while wearing PPE. Users will often remove a protector and lean close in order to hear speech. This is unnecessary: when you don protectors, you hear your own voice more clearly and tend to speak too quietly. If you shout at the same volume as you would while not wearing PPE, other people will be able to hear your speech (and warning signals) better with PPE than without in high noise areas.
4 Choice of protectors Offering a choice of suitable protectors in noise hazard areas is a mandatory requirement. Suitability is based on three criteria: field attenuation of the protectors; physical suitability for the circumstances; comfort or wear rate.
Attenuation
There are a number of broad PPE categories based on area noise levels as follows:
• 80-85 – Hearing protection advised. Low performance protectors must be available – beware of over-protection
• 85-95 – Hearing protection mandatory. Most protectors from reputable suppliers provide adequate or over-protection
• 95-105 – High risk. Only high quality protectors, very carefully controlled and used, can provide sufficient protection
• 105 plus – Very high risk. Adequate protection cannot be guaranteed without very stringent controls and checks
Use the UK HSE website calculator to estimate the protection provided by PPE at www.hse.gov.uk/noise/calculator.htm. Suitability is based on a calculated effective noise level inside the PPE with a rating of ‘good’ or ‘acceptable’ as shown in the following table. Note that you should make an allowance for de-rating the protector performance according to the new research and the wear-rate trade-off.
Physical Suitability
The following are the main physical factors that govern the selection of suitable PPE: safety glasses, hard hats, other safety equipment, clothing, earrings,turbans, hairstyle, temperature, dust, hygiene, confined spaces, fitting difficulties (plugs) and physical factors (size of ears, skin disorders). All of these will factor into your choice of suitable ear protection.
Wear rate
If you consistently achieved a 99% PPE wear rate in noise hazard areas, you would feel that you had an effective hearing conservation programme in operation. At a 99% wear rate, however, (doffing protectors for a cumulative total of only five minutes over an eight hour shift), the maximum real-world attenuation is approximately 17dB for earmuffs and 10dB for earplugs as shown in the graphic. If staff only wear PPE for seven out of eight hours, then protection is limited to around 7dB for earplugs and 9dB for earmuffs – no matter what the theoretical performance.
Consequently, comfort, motivation and supervision are the paramount factors that determine the wear rate and therefore the protection that is achieved in practice. A very effective, but often overlooked, option to improve the performance of hearing conservation programmes is to encourage the use of different protectors at different times during the day. Reference: HSE Research Report RR720; Real World use and performance of hearing protection. www.hse.gov.uk/research/rrhtm/rr720.htm
Published: 01st Jan 2012 in Health and Safety International
