Noise at Work regulations

Coming into effect from 6th April 2006, the new Noise at Work strict follow EU legislation.
From April 2006 in the UK, the level at which employers must provide hearing protection and hearing protection zones is now 85 decibels (daily or weekly average exposure) and the level at which employers must assess the risk to workers' health and provide them with information and training is now 80 decibels.
There is also an exposure limit value of 87 decibels, taking account of any reduction in exposure provided by hearing protection, above which workers must not be exposed.

The new Noise at Work regluation (full text)