Listening to The Sound of Safety
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.