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Listening to The Sound of Safety

Published: 02nd Mar 2016

Our ability to listen to and discern different types and levels of sound can be the key to not only our safety, but also our happiness.

Our ears can detect many sounds, from the slightest whisper to the most terrific explosion. As one of the five human senses, hearing can play a crucial role in our personal safety, both during work and in our everyday lives. An equipment operator, for example, can detect a fault in their equipment simply through the noise it makes. When crossing a road, we can hear a vehicle coming around a corner before we see it. We can identify many things about a person simply by hearing that person speak, such as the sex of the person, the language being spoken, even emotion can often be read from a person’s tone of voice.

Many advances in technology now mean that damage to hearing can be partially alleviated through surgery or the use of hearing aids, but if you think that means that it’s not important to look after your hearing, think again.

Defining noise

So why should we be so concerned about noise? Firstly, let us consider noise and what it is. In it’s physical form noise is a change in air pressure. These changes in air pressure travel through the air as waves. While noise can come from many different sources, such as moving machinery parts, it usually involves vibrating surfaces. The ears can detect these changes in pressure. As the pressure waves reach the ear and hit the ear drum, the ear deciphers the information and sends the appropriate signals to our brain, telling us whether it is loud or quiet, constant or changing.

If parts of our ear such as the auditory nerves or ear drum are damaged or do not function correctly, this causes our brain to misinterpret the information. In some cases, ear damage can be sufficient to prevent any signals being sent to the brain at all, usually in the case of total deafness, or sending an incorrect signal such as ringing in the ear, in the case of Tinnitus. This usually irreversible damage to hearing is referred to in industry as Noise Induced Hearing Loss, or NIHL.

Misconceptions of noise

A common misconception with the hazard of noise is that your ears must be exposed to the noise for a long duration before damage occurs. This is simply not the case. While long periods of noise hazard exposure can indeed cause damage, a loud enough sudden noise (such as an explosion), can be enough to cause permanent damage to the ear. At the same time, not detecting noise can be just as dangerous. If we are wearing some kind of hearing protection this may shut out noise to a point where we struggle to hear anything. This means we cannot detect the presence of moving machinery, for example. This moving equipment such as an excavator or bulldozer could be working out of our area of vision, and because we cannot hear its approach we do not realise we are in its path, resulting in a collision that would highly likely prove to be fatal.

This scenario of totally removing noise also makes it difficult for workers to communicate. People are forced to remove their hearing protection so they can communicate face-to-face with colleagues, or hear communications over a radio system. This practice means our hearing protection is rendered useless, providing no benefit at all. So what should we consider when assessing noise protection requirements for our jobsite?

Assessing protection

Firstly, can we eliminate the noise hazard? If we can totally eliminate the noise, then it will pose no risks, in theory. As mentioned previously in the moving machinery and communication scenarios, however, this could be counter-productive. In these cases, we need to limit the exposure to the noise hazard by creating a safe place or safe person. Job sharing or job rotation could be one way of achieving this. Rather than exposing one person to the hazard for a full shift, we could rotate that job or task with other workers. This would mean each worker would have some exposure to the noise hazard, rather than one worker having it all.

Another good practice would be having a regular maintenance and inspection regime of equipment and machinery. Remember, the source of noise is usually a vibrating surface. This vibration could be caused by loose nuts and bolts, worn or damaged parts, or even equipment being run at the maximum of its capabilities. Keeping equipment in good working order and not pushing it to its limits will not only improve the longevity of the equipment, but has the bonus of reducing noise levels in the workplace.

Other ways of reducing noise levels could be to isolate equipment or add soft insulation/padding to it where appropriate. Isolating the equipment in a building or structure, or keeping it away from the workforce, will reduce the impact on their hearing health. Adding soft materials to the outside of vibrating surfaces can absorb some of the vibration produced, hence reducing the noise levels.

Hearing protection

We can also issue our workforce with hearing protection. This comes in many shapes, sizes and types. A properly conducted risk assessment is key to deciding what is appropriate for your staff. This is partly because of the workforce itself, as every human being is slightly different. This means everyone’s head is a different size and shape, which impacts upon what kind of hearing protection they can use. Some people’s ears are too large for full ear covering, headphone style PPE. Others are too small, struggling to fit sponge-type insertion plugs properly into their ear. In addition, the hearing protection itself can become uncomfortable over long periods of time, rubbing on exposed skin and causing irritation, especially in hot work areas where the worker is likely to sweat. Sponge-type plugs tend to be single use only, meaning if they are dropped onto the floor or become overly damp with sweat they will have to be thrown away, resulting in the worker using more than one pair per shift. Not only is this irritating for the worker, but can also become inhibitive to operations in time and cost, as staff constantly leave the work area for fresh ear plugs, and more and more have to be procured.

Other issues can include the thickness of a person’s hair, which can prevent a good seal between the hearing protection and the head. Workers who need to wear glasses will also have issues when trying to wear certain types of hearing protection. So when considering what hearing protection to use, it is a good idea to have fitting sessions with employees to ensure everyone is issued with protection appropriate to each individual in the workforce.

Hearing protection may also not be compatible with other personal protective equipment; for example, it is difficult to wear full ear headphones simultaneously with certain types of respiratory protective equipment (RPE), such as a full-face mask. This can lead to confusion and frustration, as the workforce do not know which is more important to use. Again, a suitable risk assessment will allow you to decide what is appropriate.

If you are unsure of the requirements that suit your workplace, do not be afraid to seek expert advice. You could speak to manufacturers of PPE in this instance. They would be able to advise you on what equipment is compatible with what they sell. Safety consultants are also a good source of information not only on suitability, but also for any legal requirements you may have to consider. Certain kinds of hearing protection may have to cut out a minimum level of noise, for example, or must be used by law in certain circumstances (task being undertaken/equipment being used). The employer is legally required to provide employees with PPE, free of charge, and train them in its use if necessary. Even though ear defenders and ear plugs are relatively simple to use, the same applies here. Easy ways to do this could be to include use of PPE in a site induction, or when a person changes job role or location, which necessitates a change in PPE to be used.

Noise monitoring

When faced with everything we have spoken about so far, another good practice would be to conduct noise monitoring. By using noise meters we can measure the level of noise within given work areas. This could be a constant exercise, using fixed monitors, or could be done periodically using hand-held equipment, such as dosimeters. This will allow us to put a figure on the level of noise to which our workforce is being exposed. Usually, this would be measured in the unit of Decibels (dB). You need to be careful with any increases in decibel level, as they are measured on a logarithmic scale. This means there is a substantial increase in the damage potential of the sound, even though the measured increase is relatively small. As an example, a conversation between persons may be around 65dB. Should these individuals start to argue and shout, the noise could increase to around 80db. While a 15dB increase may not seem significant, in reality the noise level has increased 45 times.

By conducting noise testing, the results will again allow us to help identify if our current controls are adequate, or if they need to be more robust. For example, we may work in an area where the average noise level is 90dB, but our current noise PPE only protects the workforce from levels up to 85dB. As mentioned earlier, there may also be a legal requirement in terms of the dB level workers can be exposed to. Oman health and safety legislation (Oman Royal Decree 286/2008 Chapter 2, Article 16 Fourthly: Noise, Table 3), for example, states that workers can be exposed daily to a maximum of 85dB in an eight hour shift. If the noise level is higher the exposure time is reduced; for example, a level of 105dB has a maximum daily exposure period of 30 minutes. UK legislation Control of Noise Regulations 2005 - Regulation 4 states that the daily exposure limit value is 87dB, but there are lower and upper action values of 80db and 85dB, respectively. So it is important to learn what regulations are appropriate to your workforce and site. Not only will this mean you are legally compliant, but it will also allow you to understand the appropriate exposure levels for your workers.

While it is all well and good quoting these numbers, here are some comparative examples of noise level, to allow you an idea of just how loud or quiet certain readings are. Normal breathing comes in at 10dB, it is barely audible, whereas the sound of thunder from a lighting strike can be as high as 120dB. Being 25 metres from an aircraft taking off would register a sound of 150 dB. At levels this high, the sound can cause the permanent damage we spoke about earlier, in this case, rupturing the ear drum.

Conducting ear health surveillance of your employees is also a good indicator of showing if your noise hazard controls are effective. This could be a separate examination of worker health, or could be done as part of a full workplace medical. Other health conditions, such as stress, headaches and irritability may also be signs that workplace noise is adversely affecting the wellbeing of your staff and employees. Otolaryngologists (ear, nose and throat doctors) and Audiologists are specialists in their area, and just like safety consultants, may be able to offer ideas and methods that you may not have thought of to help protect the health of your workforce.

Understanding sound

By understanding sound and the potential damage it can cause, we can protect our workforce from conditions such as NIHL. Always try to remember, PPE should be the last measure we resort to. Remember PPE is the least effective level of the hierarchy of controls (elimination, substitution, isolation, engineering/administration, PPE). It will not remove the hazard by eliminating the noise, and will only be effective provided that a competent person has fully analysed and assessed all of your workplace noise risks, and put the other additional controls in place. If in doubt obtain the services of a noise safety specialist or someone fully trained in workplace noise risk assessment methods and techniques. Try to remove the noise at source if possible, or at the very least, reduce the noise level. Develop and implement workplace noise reduction programmes, such as rigorous maintenance and inspection regimes, job-rotation, and workforce training in the dangers posed by excessive noise. General medical and ear health monitoring will help to identify any biological, psychosocial or physical indicators of audiological damage as a result of excessive noise.

Too often there is a big focus on the prevention of accidents and incidents, while the occupational health of workers is forgotten about. Along with MSDs (Musculoskeletal Disorders), WRULDs (Work Related Upper Limb Disorders), and chronic (long term) disorders such as mesothelioma (caused by inhalation of asbestos fibres) or melanoma (skin cancer), Noise-Induced Hearing Loss is a risk to all we must educate ourselves, peers and others about. According to the HSE (UK Health and Safety Executive) Statistics for 2104/2015 around 15,000 workers annually develop or suffer from some sort of NIHL. This contributes to a staggering loss to economies, with two thirds of the estimated cost to the United Kingdom economy coming from work related ill-health, as opposed to injuries. Two thirds of £14.3bn (www.hse.gov.uk/statistics/at-a-glance.pdf) is a huge sum of money, no matter what industry you are involved in. Also as mentioned in the HSE’s at-a-glance statistics: “The largest single cost is non-financial value given to the impact on quality and loss of life.”

By ensuring we take noise safety seriously, we can help to prevent our workplace from adding to these staggering statistics. Not only will this provide benefits in terms of a healthy, happy and productive workforce, we can ensure that the impacts and costs to our company, and the wider economy as a whole, are kept as low as reasonably practicable. Remember, protecting people generally has the added benefits of also protecting our assets, the environment, and our business reputation as a whole. Having both a safe and profitable business is a win for everyone involved.

Published: 2nd Mar 2016 in Health and Safety Middle East

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HSE professional, holding Technician status with the Institute of Occupational Safety & Health (TechIOSH). James is an approved NEBOSH and IOSH Trainer, and specialises in Materials Handling Equipment Training, for which he is a qualified instructor through ITSSAR (International Trading Standards Scheme and Register), and RTITB (Road Transport Industry Training Board).