Health impacts of noise
The risks from noise are pretty much entirely focused around the health of individuals so naturally the health side of things features heavily in the regulations and what they are trying to achieve.
The two issues involved in the whole noise exposure gubbins are hearing losses (referred to as noise induced hearing loss, NIHL) and tinnitus. Back in the good old days of the three day working week and men standing around fires in old oil drums on strike outside a factory, NIHL was what we called Industrial Deafness. Tinnitus meanwhile is the sensation of noise in your ears which isn't really there. Both are covered in more detail in the page on the effects of noise on hearing.
In practice, when the noise regulations say that an employer needs to have a programme of health surveillance in place for employees, what they are talking about is audiometry, or hearing tests as normal people call them. The 'hear noise press button' thing that people probably had at school, minus the free lollipop. You can do these yourself or get someone in to do it. Unless you have the full set up in-house, it's easier to just get someone in.
The requirement is that if you have anyone who is routinely exposed to noise levels averaging over 85dB(A) then the employer needs to implement a programme of health surveillance.
Audiometry is an ongoing programme rather than a one-shot jobby so is something which will need to be set up and maintained as long as you have high noise areas in your work. The links over there to the left will give you a shed-load of information on audiometry, how to set it up, how often to do it, the murky world of medical confidentiality which it takes you into, and so on. Have fun.