Hearing Awareness Week

How is your hearing?

This week is Hearing Awareness Week so naturally I am talking about hearing in terms of an occupational hazard.  Specifically work related hearing loss.  Of all the senses hearing is one of if not the most important so taking care of it is essential. Because once you damage it, unfortunately their isn't a lot of coming back.

If I was to ask you what causes work related hearing loss, most of you would say noise or the boss.  Certainly noise (sound and pressure) is the main cause but there are also causes that carry a lesser risk but a risk all the same. And they are vibration, ototoxic substances and for people working on phones, acoustic shock. Alone they may not do a lot of damage but a combination of any and it’s a recipe for hearing damage.

In this blog we have a quick look at each type of hazard and what your obligations under the OHS framework is.  

Noise

When we talk about ‘noise’ in the workplace, what we are really referring to in terms of OHS is exposure to ‘excessive’ levels of noise. Now every husband out there would already know that the Oxford Dictionary defines noise as any sound, especially if harsh or confused.

So what is excessive noise?

For noise to be excessive there must be a standard that is acceptable. And there is. For Australia it is set out in each of the jurisdictions Regulations. For example, Part 4.1 of the Work Health and Safety Regulation 2011 states:

Regulation 56        Meaning of exposure standard for noise

(1) In this regulation:

exposure standard for noise, in relation to a person, means—

(a) LAeq,8h of 85 dB(A); or

(b) LC,peak of 140 dB(C).

Wow Neil that’s great but what does that exactly mean?

Without getting to technical its basically saying that over the equivalent of an eight hour shift an accepted level of noise is 85 decibels measured as dB(A) and that it should never go above a peak of 140 decibels measured as dB(C).

Now the tricky thing about noise is that if you were to measure 88 dB(A), it’s not just an increase of three decibels, it’s actually doubled the exposure level. Put simply for every increase of 3 decibels, the standard time for exposure is halved (under Australian legislation).

So 85 dB(A) is okay for eight hours exposure but 88 dB(A) is only good for four hours exposure and 91 dB(A) for two hours and so on. It also works in reverse so 82 dB(A) is acceptable for 16 hours etc. Hence the eight hour equivalent.

But because it is a bit of a science (just a little…) what you need to remember is:

• 85 dB(A) is the level of acceptable exposure at work,
• this is averaged out over a work day or week so shifts longer or shorter than 8 hours is going to change that acceptable level,
• an increase in decibels is not linear (i.e., an increase of 3 decibels halves the exposure time), and
• exposure takes into account time spent away from noise levels above 85 decibels.

To give you a brief understanding of different levels of sound, normal conversations are around 50-60 decibels while 70 decibels is a noisy office environment and music festivals are usually over 100.

The Code of Practice – Managing noise and preventing hearing loss at work contains a table that demonstrates the equivalent noise exposures for each equivalent shift and is a useful guideline if you work in a noisy environment.

Vibration

It is said that exposure to prolonged hand-arm vibration (which is a hazardous manual task) can also lead to hearing loss. So when considering noise levels within your workplace, it is also important to look at what plant and equipment exposes workers to vibration.

What is the risk of hearing loss being caused by this plant?

Ototoxic Substances

This is just a fancy name for chemicals that affect the ear which include solvents, heavy metals, asphyxiants and even some medication.  So things like paints, fuels, printing material and fumes from burnt tyres along with occupations in the construction and manufacturing industry are going to expose workers to potential hearing loss as a result of these ototoxic substances.

It might make you think twice the next time you’re at the burnout masters at Summernats breathing in all those fumes.  Sure you’ve protected you and your kids ears wearing hearing protection, but it’s not just the noise you need to be protecting yourself from to prevent hearing loss. 

Acoustic Shock

This only applies to workers who work on telephones and may experience a sudden increase in sound levels or unexpected loud noises.

Your legislative responsibilities

Noise

Well it’s pretty easy to guess right? Ensure workers are not exposed to noise in excess of the exposure standard through the application of risk management i.e., eliminate the hazard and minimise the risk. 

Now if the hazard can’t be eliminated you may be required to provide personal protective equipment to protect the worker from work related hearing loss. But given noise is pressure of airways and has a little bit science behind it, you can’t just go buying any type of hearing protection and hope it will do the job. Just like dust masks provide protection for specific dust, so to hearing protection provides protection for a specific type of noise. And then there is the whole passive vs active forms of protection.

But something I find a lot of organisations don’t realise is that if they require workers to frequently wear PPE because of excessive noise, then they are legally required to provide audiometric testing for those workers within three months of the worker commencing the work and at least every 2 years (not applicable to WA jurisdiction).

And finally if you design, manufacture, import or supply plant (equipment, machinery etc), you have some specific obligations regarding the noise of said plant.  These include things like the plant must be as quiet as is reasonably practicable and all the information must be available and supplied to anyone who uses the plant.

This is information is available in the relevant OHS Regulation for your jurisdiction.

Vibration

If the plant or equipment can not be replaced, what type of dampening or absorption can be introduced to reduce the level of vibration.

Ototoxic Substance

So if workers are exposed to chemicals in a noisy environment, whether it’s the fumes, vapours or direct contact, audiometric testing even if they don’t frequently wear hearing protection should be provided to monitor the health of the workers (which is a requirement under section 19 of the WHS Act).

Resources

Australian/New Zealand Standard 1269:2005 Occupational Noise Management (suite)

Code of Practice – Managing noise and preventing hearing loss at work.

Work Health and Safety Regulation 2011 (Part 4.1)

(Victorian) Occupational Health and Safety Regulations 2007 (Part 3.2)

(West Australian) Occupational Safety and Health Regulations 1996 (Division 4)

If you require any assistance or have questions related to managing noise in your workplace please contact us today.

Neil Norman

The Safety Guru