Noise can be a problem in the plastics industry. There are a number of machines used that can cause large amounts of noise such as granulators, shredders and agglomerators.
Short duration exposure to high noise levels can cause temporary hearing loss, but longer exposures can result in permanent damage. Permanent hearing loss is usually a gradual process and people who are exposed often don’t know their hearing is being damaged until some hearing loss has happened. Some effects of being exposed to noise can be quicker, such as developing tinnitus. Tinnitus can be debilitating for sufferers. It can be a permanent ringing or whooshing sound in the ears that can get worse when it’s quiet, such as when you are going to sleep.
This demonstration shows what it’s like to suffer noise-induced hearing loss.
The law says that employers must control the risk of hearing damage from noise at work. If you cannot eliminate noise, you must reduce it as low as possible at source. There are noise exposure limits that must not be exceeded.
The noise exposure limits are based on the combined amount of noise a person is exposed to, usually in an 8hr working day. The first stage is to work out what the likely noise exposure levels are in your workplace for workers based on the range of jobs they do. HSE has produced noise calculators that can help you work out for your workplace what the likely exposure levels are.
If noise is an issue within your workplace you will then need to work out what your action plan will be to tackle this. The best way of reducing noise in the workplace is to reduce it at source. The plastics products case study provides good practice advice on how you can reduce noise in plastic manufacturing workplaces.
If noise levels are still above the exposure levels after you have done all you can to reduce the noise at source, you need to provide hearing protection and make sure operators use it. Hearing protection will only provide the right level of protection if it is worn properly and for the whole time that users are exposed to high noise levels.
Hearing protection should reduce the sound level reaching the ear to at least below 85 dB. However, you should not try to reduce the level at the ear to below 70 dB, as this can cause difficulty with communication and operators may not hear warning signals.
In general, hearing protection should have a SNR (Single Number Rating) of around 20. SNR is the measure of protection that describes how many decibels of sound the hearing protection will stop. If you have noise survey results for your workshop, then a calculator on the HSE noise website can help you check if your hearing protection gives the right level of protection.
You need to offer your operators a choice of hearing protection. They are far more likely to use it if they are comfortable and can still communicate. You should involve your workers in deciding which type of hearing protection to provide. If they are involved in choosing it they are more likely to wear it.
When you are deciding which hearing protectors to buy, ask yourself if cheap, basic earplugs will provide the most cost effective form of protection. If each employee is wearing several pairs per day, it may be more cost effective to invest in repeated use protection.
Think about hearing protection that offers additional benefits such as:
As well as providing hearing protection for employees you also need to train them how to use it properly, how it is intended to be used, where to get replacements from and how to keep it clean and store it (if it’s not disposable).
Health surveillance (hearing checks) must be provided for all employees who are regularly exposed above the upper exposure action values (daily or weekly exposure of 85dB or peak sound pressure of 135dB) or are at risk, for example already suffer from hearing loss.