As an employer operating in an industry where your staff is constantly exposed to excessive noise, you need to have a clear understanding of the Government guidelines governing this facet of workplace safety. You might be wondering what this legislation is all about, how it is measured, and why the figures 80 dB, 85 dB, and 87 dB are so instrumental in noise studies. Keep reading to find out more.
Why is noise exposure harmful?
To fully appreciate the risk that exposure to excessive noise poses, you first need to understand how sound is measured and how the hearing process works.
How is sound measured?
We measure the intensity of sound in units known as decibels, with 0 representing total silence. For perspective, 80 dB is equivalent to the noise caused by heavy traffic or that experienced in a busy noisy restaurant, 100 dB is the noise level of a low-flying jet, and 140 dB is the threshold of pain. But you should note that the decibel scale is logarithmic – an increase of 3 dB represents a doubling of the sound level, and a 10 dB increase is usually perceived as double the volume. In regards to the process of hearing, sound is expressed as A-weighted decibels or dBA. This measures the loudness of sounds perceived by the human ear. The dBA scale takes into account the fact that the human ear doesn’t detect low audio frequencies, thus it is adjusted to cater to this fact. There are also C-weighted scales, representing peak sounds above 100 dB. dBA and dBC are the units referred to when discussing noise-induced hearing loss.
How do we hear?
As with other processes in the human body, hearing is an extremely complicated process. Sound waves from external sources enter the outer ear and into the middle ear as vibrations. The middle ear is responsible for amplifying these vibrations and passing them onto the inner ear, where they cause the movement of tiny sensory cells in the cochlea. This movement in turn leads to the production of electrical signals that travel to the auditory cortex and are interpreted into sound. The problem arises when we are exposed to excessive noise since the excessive vibration can cause the tiny hair cells and membranes of the cochlea to get damaged and eventually die. It is important to note that when the inner ear and auditory nerve becomes damaged, hearing loss is permanent. Thus, it is crucial that you take measures to safeguard the hearing of employees working in noisy environments.
How does noise affect mental health and wellbeing?
Tinnitus and hearing loss are just but a few of the potential issues linked with exposure to excessive noise. According to various studies, excessive noise is a leading cause of stress among workers and can contribute to a range of medical conditions including hypertension, cardiovascular disease, a compromised immune system, and can have a significant impact on one’s mental health. Thus, this should be a serious consideration when it comes to health and safety in the working place.
What is a harmful noise level?
In regards to noise levels that can potentially cause impaired hearing, there is a lot more to consider than just the dBA level. You also need to take a look at the length of exposure. With that being said, being exposed to 85 dBA for a period exceeding 8 hours can cause permanent hearing impairment. Even worse, a short blast of 120 dBA can cause instant hearing loss.
Noise exposure legislation
It goes without saying that there needs to be legislation that curbs the amount of noise that workers can be exposed to. What you may not realize is that this legislation protects you, the employer, as much as it does the employee since it leaves no ambiguity over what noise level is potentially dangerous. It also stipulates what should be done to protect the hearing of employees.