Everyone knows that certain occupations require exposure to loud noises but just because you’re not told to wear ear protection where you work, that doesn’t mean you're safe.

Damage to your hearing can happen in two main ways. The first is by sudden trauma from a burst of short but extremely high volume sound. So, a gunshot, firework, drum beat or explosions right next to your ear would cause that kind of problem and doubtless noise-induced hearing loss (NiHL). However, it’s just as easy to suffer a slower version of NiHL over time with continued and prolonged exposure to lower level noise, and it’s this one that’s perhaps the greater problem. When the volume is lower, you might not realise that you're doing so much damage.

Now, before we go on and reveal some of the noisiest places to work, we need to understand something about the oft talked of decibel. In acoustics, 0db is essentially the threshold of human hearing. That level of noise is something we cannot hear. Our ears can cope with short exposures of over 120db but instant death of hearing cells occurs at 180db. That said, anywhere from 85db and above is going to cause NiHL over longer periods time.

That’s not quite the end of the story, though. The trick is that decibels are measured on a logarithmic scale, so the relationship between the figures isn’t the linear one that you would expect. 40db is not twice as loud 20db. Instead, it’s set such that the sound level is doubled every time you go up just 3db. So, in fact, 40db is closer to seven times louder than 20db.

Working in a bottle plant - 88db

The constant clinking of glass against glass and the whir of the machinery make working in a bottle plant one of the most dangerous factory jobs as far as your hearing goes. At 88db, it exceeds the safe levels the Government sets and requires employees to wear protection of some kind. A measurement of 88db isn’t particularly excessive as a one off but don’t be fooled into thinking you can remove your ear plugs just because it doesn’t sound that loud. Safe exposure without protection is 4 hours at a time - only half the working day.

Motorcycle courier - 90db

Riding a motorcycle at 50mph exposes the driver’s ears to 90db of noise under the helmet. The safe limit at that level is around 2.5-3 hours at a time. Doing a job around the city is not such a problem what with travelling at lower speeds but, the minute you get out onto the open road, the clock is ticking. More than anything else, it’s an important message to get across to motorbike riders in general. And the worst thing you can do on top of that is try to listen to music at the same time. In order to compete, you’d have to have your headphones pumped up beyond the noise of the bike jacking up the decibels and shortening your safe exposure time.

Flying an offshore helicopter - 97db

Ok, probably not a job most people have and, fortunately, you can’t imagine those pilots taking off their ear protection for a second. Lucky really because the safe exposure time to 97db is just 30 minutes.

Travelling on a tube train listening to an iPod - 100dB

Ok, so not strictly work but an important part of getting there. Travelling on the Tube listening to your media player is something that thousands of Londoners do every day, twice a day. What they don’t realise is that most of them are doing permanent damage to their hearing. The noise of the tube is high enough but, in order to listen clearly to your music, you need to pump it up even higher on your player. At 100db, the safe exposure is just 15 minutes. So, if you’re taking a Tube journey longer than that, it’s time to invest in some noise isolating or cancelling headphones.

Lawnmower - 107db

It’s a great way to earn cash throughout the year but do it day in day out and you’d better be wearing ear protection. A power mower - one which you’d probably be using if this was your line of work - comes in at a hefty 107db sound level. Your ears can stand about 4 minutes of that before the damage kicks in. The moral? If you can afford a power mower, don’t scrimp on the ear plugs.

Staff in a nightclub - 110db

While the bouncers are probably safe outside, barmen and women and other staff inside nightclubs are facing 110db of noise for long, long shifts in the loudest of venues. Small wonder why we as punters walk out with our ears ringing after a night in one ourselves. The safe exposure is a matter of minutes if this is something you’re doing all the time. If you’re working in one and your employers haven’t addressed the issue, it’s time to bring it up.

Rock musicians - 110db

Loud rock gigs are as noisy as the nightclubs and just because, they’re on stage, it doesn’t make the band members immune to it. In fact, worse still, they’ll generally have a monitor pointing right up at them so that they can hear what they’re playing. Most of the time, that speaker is going to have to be even louder than the others so that it’s clear.

Airport ground staff - 140db

There’s simply no way you can work in this job without hearing protection. Standing even 100ft away from a jet engine exposes you to 140db of sound. It won’t kill you but you’ll lose your hearing very quickly if you don’t pay attention to the safety regulations.

Shooting range marshals - 140db

Gun shots are dangerous for their short sharp exposures but working around them all day brings a whole new problem. A constant peppering of your ears requires the highest levels of hearing protection. If you work in one of these places, you’re either going to need custom moulded ear plugs or a heavy duty set of on-ear protectors. Foam squash fits are not as good at doing the job.

For more on how to look after your ears and some recommended headphones that'll help do the job for you, check out Etymotic and the ER 4 MicroPro series.