Noise monitoring:
1.1 Area noise monitoring: Contractors should measure noise levels
in areas under their control, using sound level meter and place hazard warning signs
at the entrance to areas with noise level 80 dBA or more, requiring employees to
wear hearing protectors when entering or working in such areas, or doing a task
where a noise level of 80 dBA or more is generated.
1.2 Personal exposure monitoring: Measure exposure of representative
employees, working in areas with noise level 80 dBA or more, to noise using noise
dosimeter, and identify employee groups who are exposed to noise at or above 85
dBA Time Weighted Average (TWA) for 8 hour shift.
Audiometric Testing: Employees ability to hear sound at various frequencies is assessed
by a qualified health professional using an audiometer in a quiet booth, and result
is recorded in the form of a graph called audiogram. Elements of audiometric testing
include Baseline audiometric testing, annual audiometric testing and follow up.
3.1 Baseline audiogram is the first audiogram. It serves as a reference
audiogram for an employee against which his/ her future audiograms are compared.
It is provided as part of pre-employment medical examination or within 6 months
of exposure at or above 8-hour TWA of 85 dBA.
3.2 Annual Audiogram should be conducted every year for employees
exposed to noise at or above 8-hour TWA of 85 dBA. It is done to detect early effect
of noise on hearing called Standard Threshold Shift (STS).
3.3 Follow up: Employees showing STS must be informed in writing
with a copy to their supervisor. Affected employee’s supervisor must review
hearing protection with the employee, train the employee in use and care of hearing
protectors, and ensure that affected employee’s exposure to noise with hearing
protectors does not exceed 8-hour TWA of 85 dB.