If you’re an employer and work in an industry where staff could be exposed to excessive noise, then you’ll need to be aware of the Government guidelines that govern this aspect of safety in the workplace. But what exactly is the legislation? How is it measured and why are the figures 80 dB, 85 dB and 87 dB so pivotal for noise studies? To find out more, read on for a comprehensive guide on what you need to know.
Why is noise exposure harmful?
In order to understand why excessive noise is harmful, it’s important to know how sound is measured and how the process of hearing works.
How sound is measured
Sound is measured in decibels (dB), with 0 representing total silence, 80 dB equivalent to heavy traffic or a noisy restaurant, 100 dB the sound level of a low-flying jet and 140 dB the threshold of pain. It’s important to note that the decibel scale is logarithmic, with every increase of 3 dB representing a doubling of the sound level and 10 dB being discerned as double the volume. When it comes to hearing, sound is expressed as A-weighted decibels, or dBA. This represents the loudness of sounds perceived by the human ear, and the scale takes into consideration the fact that we don’t hear low audio frequencies, so it’s adjusted for this sensitivity. You’ll also see C-weighted scales referred to – these represent peak sounds of above 100 dB. When it comes to noise-induced hearing loss, dBA and dBC are the units we need to refer to.
How do we hear?
Hearing itself is an incredibly complex process. Sound waves are directed from the outer ear to the middle ear as vibrations. These vibrations are then amplified in the middle ear and passed on to the inner ear, where the vibrations cause tiny sensory cells in the cochlea to move, which in turn generates an electrical signal. This signal travels to the auditory cortex, where it’s interpreted into sound. When our ears are exposed to excessive noise, the tiny hair cells and membranes of the cochlea can become damaged, and eventually die. Once the inner ear and auditory nerve are compromised, hearing loss is usually permanent, so it’s really important to protect the hearing of employees working in potentially noisy environments.
How noise affects mental health and wellbeing
Hearing loss and tinnitus aren’t the only health issues associated with exposure to excessive noise. Studies have shown that it’s a leading cause of stress for workers, and can lead to a number of medical ailments including cardiovascular disease, hypertension, a compromised immune system and can also seriously impact mental health. So it’s a really important aspect of health and safety in the workplace.
What’s a dangerous noise level?
When it comes to noise levels that can impair hearing, it’s not just the dBA level we need to look at, but also the length of exposure. Exposure to 85 dBA for a period of longer than 8 hours can lead to permanent hearing impairment; while a short blast at 120 dBA can immediately cause hearing loss.
Noise exposure legislation
It’s incredibly important to have legislation guiding limits for occupational noise exposure. In fact, this protects the employer as much as the employee, as there’s no ambiguity over what’s a dangerous noise level and what needs to be done to protect the hearing of employees.
The latest directive
The Control of Noise at Work Regulations 2005 is based on European Union directives and aims to bring all member states into alignment when it comes to protecting employees from the health risks of excessive noise exposure. The full act came into force in 2006 for UK industries, and was implemented for the music and entertainment sectors in 2008. The new act replaced the 1989 noise regulations, setting out lower maximum levels of noise exposure for workers and more stringent rules for employers to follow.
The main stipulations of the Control of Noise at Work Regulations 2005 are as follows, and you’ll see why the decibel levels stated in the first paragraph are so pivotal to the Act:
1. Exposure limit values
The exposure limit value is set at 87dB(A) for daily and weekly exposure; and a peak sound pressure of 140 dB(C). Noise levels must not exceed this upper limit.
2. Action level values
This is expressed as a lower and upper value:
- The lower exposure action value is daily or weekly exposure to 80 dB(A) and a peak sound pressure of 135 dB(C).
- The upper exposure action level is set at 85 dB(A) for daily or weekly exposure; with the C-weighted peak sound pressure set at 135 dB(C).
What happens if these values are met or exceeded?
The Act sets out the following stipulations when these noise levels are met or exceeded:
- At daily or weekly exposure to the lower exposure value of 80 dB(A), employers must carry out a risk assessment, putting in place appropriate information, training and health surveillance. Hearing protection must also be made available upon request to employees.
- If workers are exposed to the upper exposure value of 85 dB(A), hearing protection is mandatory and employers must take measures to mitigate noise exposure. This can include engineering upgrades (where faulty machinery is creating excessive noise) and the creation of hearing protection zones.
How can you make sure sound is properly monitored?
Noise levels must be assessed using a sound meter and microphone that meets the standard set by the international electrotechnical commission. This is IEC 61672-1:2013, Class 1. If you work in a business that exposes workers to excessive noise then you’ll need the professional services of an Acoustic Consultant. Using the latest professional calibrated tools and software, Acoustic Consultants can capture, assess and evaluate noise exposure, making sure that your workplace meets legislative regulations and guiding any mitigating measures that need to be put in place.
If you need guidance on protecting your workforce, then why not get in touch today? We specialise in providing a tailored approach for clients, including noise assessments and surveys. Email us at hello@auricl.com or you call theLondon office on 020 7859 4530; for the Reading office dial 0118 207 7324.