If you work in a noisy environment, or spend a lot of time in noisy places such as nightclubs, you should protect your hearing NOW to prevent it from becoming permanantly damage.

Have you ever experienced the following?

• Ringing in your ears (tinnitus) after being exposed to loud noises?
• A 'dullness' of hearing after being exposed to loud noises?

These are tell-tale signs that some damage is being done to your inner ear. To begin with, your hearing should return to normal (unless it's an extremely loud sound - e.g. an explosion or the firing of a 12 bore shotgun). But if you keep exposing yourself to these levels of noise, then the damage becomes permanent... each further exposure having a cumulative effect.

People with a noise-induced hearing loss will find:

• Watching television and films at the cinema difficult
• Conversations in background noise (e.g. pubs, restaurants, in the street etc.) are extremely hard to follow.
• People seem to speak loud enough but mumble. Speech just doesn't have the same clarity as it used to (but they often mistake this for the way people talk 'nowadays').

There are two factors involved in damaging your hearing by noise:

• how loud the sound is
• how long you spend in it.

In the workplace there are laws to say how loud and how long is "safe". These are shown in the table below:

Noise Level	Safe Exposure Time	Action to be taken
85dB(A)	...	Your employer should make noise protection available and should advise you to wear it.
90dB(A)	8 hours in a day	It is mandatory to wear noise-protection.
93dB(A)	4 hours in a day
96dB(A)	2 hours in a day
99dB(A)	1 hour in a day
102dB(A)	30 minutes in a day
105dB(A)	15 minutes in a day
For every extra 3dB, half the exposure time
Sudden sounds of 140dB(peak) (e.g. blasts)	...	Noise protection mandatory

Although these laws don't apply to noise exposure in the home or leisure (e.g. nightclubs), they should still be considered as a guide to what's considered safe for your hearing. We'll come back to noises in leisure later.

These noise levels are specified in dB(A), which doesn't mean anything unless you can measure the level of sound. For that, you need a sound level meter, which most of us don't have access to. So how do we know when a sound might be too loud?

Here's a rough guide to help you estimate the noise level.

To use the table:

1. Ask yourself how close you need to be to a person in order for you to hear them and them to hear you.
2. What type of voice are you using to hold that conversation? Are you shouting? Is it just in a normal voice?
3. Use the lookup table to estimate the approximate noise level.
4. You can now use the table above (i.e. safe noise exposure times) to see whether or not you need hearing protection.

	Distance away from each other to be heard
	4 feet apart	2 feet apart	close to your ear
In a normal voice	< 81dB(A)	-	-
In a raised voice	87db(A)	-	-
In a very loud voice	93dB(A)	-	-
By shouting	99dB(A)	105dB(A)	-
Impossible			> 110db(A)

Here's an example:

1. Say you're standing 4 feet away from them and having to shout to be heard. The noise level will be approximately 99dB(A).
2. Now using the table above we can calculate the safe listening time as being 1 hour a day. And you should be using noise-protection.

Here are some common loud sounds we may be exposed to in our leisure time:

• Power-tools, e.g. drills
• Motorcycles (if you're a motorcyclist)
• Discos and nightclubs
• Car stereos
• Certain musical settings, e.g. drumming
• Personal stereos

Say, for example, you spend every Friday in a night club for a total of 3 hours. Often night clubs have noise levels in excess of 100dB(A) (they're not currently regulated). You should only really be spending 30 minutes in there without protection. (Work out how loud it is for yourself by using the distance-for-conversation method.)

Remember: if you find your ears ringing and a dullness of hearing after being exposed to loud noises, you must consider noise-protection.

	It's safer and less expensive to use noise protection NOW than lose your hearing later on. A hearing instrument will never be as good as our own natural hearing.

Whatever your industry or hobby there's a form of noise protection to suit you:

• Ear defenders/muffs - these look like headphone and provide the greatest reduction of loud sounds. There's a range of prices and styles. They can even be fitted into helmets. Easily visible (so your supervisor can see you're wearing it) and comfortable, but possibly too large for enclosed spaces and could be uncomfortable in hot environments. Ideal for mucky environments as there's no risk of putting muck in your ears.
• Pre-formed plastic ear plugs - good, if they fit you but not so good if you have narrow or twisty ear canals. Re-usable and washable. Risk of dirt getting into your ears if you put them in in a messy environment.
• Soft, disposable ear plugs - these are usually made from foam. You roll them up into a thin tube, insert them into your ear canal, then allow the foam to swell back to its original size, so it fits snugly to the shape of your ear. Can be purchased bulk cheaply, and disposed of after each use.
• Custom built ear plugs - these are moulded to the shape of your ear from a soft silicon material, so they're comfortable and fit, even if you have awkward ears!

The noise-protection mentioned so far simply cut out sound by blocking your ears. It can therefore make conversations difficult.

We now come on to noise-protection that is selective in what sounds it cuts out.

• Filtered ear plugs - these have a valve so that they allow normal levels of sound to come in (e.g. when your environment goes quiet) but when a loud noise comes along the valve shuts, cutting out the loud sounds.
• Speech-enhancing ear plugs - these ear plugs have a filter that allows some speech to come through while keeping out the non-speech loud sounds.
• Musician's ear plugs - most ear plugs distort the sounds in some way, making it hard to balance the bass with the treble etc. These ear plugs ensure that the balance is kept by reducing sound equally at every frequency.
• Electronic ear plugs - shooters will find these ideal because they amplify quiet sounds (so they can pick up the slightest movement) but restrict loud sounds (e.g. when they're firing a shotgun). Can be built into ear-muffs or a custom earmould.
• Stage performers'/racing drivers' ear plugs - not only do these cut out noise, but they incorporate a radio receiver to pick up instructions. Can also be used by factory workers so they can listen to the radio.

Noise protection that's properly fitted will reduce sounds entering your ears by between about 15dB and 40dB (depending on the type of noise protection you use).

So if you're exposed to noise of about 105dB(A), which has a safe exposure time of about 15 minutes, and you wear ear defenders that give a 15dB reduction, then your noise exposure will only be 90dB(A), which has a safe exposure time of 8 hours a day. You've given yourself over 7 hours of extra exposure!

Cotton wool is useless as noise protection, even when coated in vaseline. Because of its composition it allows sound to pass right through it, even though you may feel blocked up. If you are currently using cotton wool then you should find a more suitable form of noise-protection (see above for examples).

	If you need noise protection or advice on noise protection suitable for your work or leisure, please contact us.

Next subject: Other Products & Services