Noise Legislation
The effects of work-related noise on hearing
have been known about since the Industrial
Revolution. Evidence of the effects of noise on hearing has
been well documented in the UK’s shipbuilding industry, where it
was known as ‘boilermaker’s ear’. However, it was not until
studies were carried out in the 1950s that the relationship between
high noise levels, length of exposure time and the increased risk
of noise induced hearing loss (NIHL) was quantified. NIHL is
insidious since it happens over time and often goes unnoticed.
Although workplace legislation in the UK and
USA dates back to the 1970s, for many years ‘the military’ were
exempt from such legislation and immune from prosecution. However,
this position changed in the 1980s.
Exposure to Noise
The exact detail of the legislation differs
from country to country but fundamentally it places maximum limits
on exposure levels and the time operatives may be
exposed. This combination of level and time forms the concept
of noise dose and it is the accumulation of noise dose over time
that increases the risk of NIHL.
For example, the same daily noise dose can be
achieved by 90 dB(A) for 4 hours or 93 dB (A) for 2 hours or 87
dB(A) for 8 hours.
There is also a separate limit on the peak
noise caused by impulsive sources, such as weapon discharge or
explosives. Not only does repeated impulsive noise quickly
lead to a high noise dose, temporary shift and the risk of
permanent NIHL, it can also cause instantaneous damage to the
‘mechanical’ parts of the ear, as with a burst eardrum
Physical Agents Noise Directive
Most recently, the Physical Agents (Noise) Directive has been
imposed Europe-wide and has been implemented in the UK as the
Control of Noise at
Work Act (2005), replacing the earlier Noise at
Work Legislation (1989).
The 2005 Regulations requires employers to
take action to protect workers at levels of noise 5 dB(A) lower
than in the 1989 Regulations and now require health surveillance
(hearing checks) for those regularly exposed noise above 85
dB(A).
For more detail it is advisable to refer to
the agency tasked with enforcing the legislation, which in the UK
is the HSE, who have an informative website www.hse.gov.uk/noise