Today, no legitimate reason exists for
any worker to incur an occupational hearing
loss. Implementation of an hearing loss
prevention program (HLPP) must hinge
on the fact that occupational noise induced
hearing loss (NIHL) is 100 percent
preventable.
The National Institute for Occupational
Safety and Health says (NIOSH), says the
key to developing and implementing an effective
program lies in a commitment by
both management and workers to prevent
hearing loss. This can be facilitated by integrating
the HLPP into the company’s overall
health and safety program. This will give
the prevention of hearing loss the same
weight as the prevention of other work-related
illnesses and injuries, thus indicating
to workers and management that occupational
hearing loss must be taken seriously.
Other factors that facilitate an effective HLPP include encouraging workers to carry
over their good hearing conservation practices
to off-the-job situations; using simple,
clearly-defined procedures; making compliance
with the HLPP a condition of employment;
and incorporating safety requirements
into written company policy.
For occupational hearing loss prevention,
NIOSH defines engineering control as “any
modification or replacement of equipment,
or related physical change at the noise
source or along the transmission path (with
the exception of hearing protectors) that reduces
the noise level at the employee’s ear.”
Typical mechanisms for engineering
noise controls include reducing noise at the
source (installing a muffler), altering the
noise path (building an acoustic enclosure
or barrier), reducing reverberation (covering
walls with sound-absorbing materials),
and reducing equipment vibration (installing vibration mounts).
Engineering controls should be the first
order of protection from excessive noise exposure.
When the noise can be reduced or
eliminated through engineering controls, the
danger to hearing is also reduced or eliminated.
Where periodic noise monitoring is
conducted, the feasibility of employing engineering
controls should be reevaluated,
with priority given to noise sources that affect
the greatest number of workers. Any reduction
in noise level (even if it is only a
few decibels) serves to make the noise hazard
more manageable, reduces the risk of
hearing loss, improves communication, and
lowers annoyance and related extra-auditory
problems associated with high noise levels.
Furthermore, when the noise can be
reduced to acceptable levels through engineering
controls, employers may
forego some of the additional difficulties and expenses related to providing hearing
protectors, education and motivation
programs, and program evaluation.
To reduce noise in an existing facility, it
is generally necessary to retrofit engineering
controls. Development of these controls
should involve engineers, safety and industrial
hygiene personnel, and the workers
who operate, service, and maintain the
equipment. Development of special noise control measures must be predicated on a
thorough assessment of the noise source and
individual worker exposure.
Consideration should be given to the relative
contribution of each noise source to the
overall sound levels. Various noise control
options should be evaluated on the basis of
their effectiveness, cost, technical feasibility,
and implications for equipment use, service,
and maintenance. Other potential complications of new noise control measures (such as
effects on lighting, heat production, ventilation
and ergonomics) should be considered.
Engineering controls must always consider
the proper maintenance of equipment.
In addition, the function and purpose of any
planned or existing engineering controls
should be fully discussed with the workers
so that they support the controls and do not
inadvertently interfere with them.
Management should also consider noise
reduction when planning for new or remodeled
facilities. Engineering controls can be
most effective when they are incorporated
into the design and purchase of equipment
from the start. In addition, the cost of incorporating
engineering controls during the design
phase is generally much lower than
retrofitting them at a later date.
The ultimate noise level can be substantially
reduced by substituting more soundabsorbent
materials, modifying equipment
structure or mechanical processes, and
isolating sources within the equipment.
A “buy-quiet” policy for new equipment
acquisitions should be adopted by management.
This process includes selecting products
or operations to be targeted for noise
reduction through new purchases, setting
criteria for new equipment noise levels, requesting
noise level specifications from
manufacturers, and including these noise
level data in bid evaluation. Again, input
from workers should be incorporated into
the buying process.
When engineering controls are inadequate,
supplemental administrative controls
may be utilized to help limit exposures. Administrative
controls are defined as changes
in the work schedule or operations that reduce
worker noise exposures. For example,
sometimes workers can be scheduled so that
their time in a noisy environment is minimized.
When extremely noisy operations are
unavoidable, the number of workers permitted
to work in such an environment
should be minimized. In all cases, the application
of administrative controls should not
result in exposing more workers to noise.
Finally, a quiet, clean, and conveniently located
lunch and break area should be provided
to give workers periodic relief from
workplace noise.
Whenever hazardous noise exists
in the workplace, measures should be taken to reduce noise levels as
much as possible to protect exposed workers and to monitor the
effectiveness of these intervention processes.
