Health surveillance in the form of Audiometric testing (hearing) is a statutory requirement for employers where employees are considered to be at risk from Noise Induced Hearing Loss.
This is applicable where a noise exposure risk assessment has identified personal exposure to noise on a daily or weekly basis that exceeds the upper action level of 85 dBA and for individuals perceived to be at a greater risk if exposed to between the lower and upper exposure action values of 80 and 85 dBA.
Occupational hearing testing or audiometric testing is a technique used to detect changes or damage in hearing ability due to a number of causes including Noise Induced Hearing Loss and therefore enables appropriate follow up remedial actions including medical referral to be carried out.
On a longer-term basis it is also the most appropriate means to validate any hearing protection programme to confirm or otherwise that the control measures are effective and that individual employees hearing ability is not deteriorating through continued exposure to noise at work.
Hearing testing involves an initial visual examination in the ear to check for abnormalities or excess wax/obstructions followed by the presenting of sounds of fixed frequencies and varying intensities to each ear in order to produce an audiogram which details the hearing threshold levels. In an ideal situation a hearing-testing programme should consist of a baseline audiogram conducted before employment begins followed by a schedule to monitor threshold levels following exposure to noise at work.
Where a workforce is already exposed to noise however the baseline audiogram is simply the first test to be carried out. The schedule of testing would then allow for a repeat test after one year followed by repeat testing every two (preferable) or three years.
As a prerequisite to the baseline examination it is also important to obtain information in the form of a questionnaire regarding the individual's current job, previous noise exposures from work activities elsewhere and hobbies and medical history including any known complaints relating to the ears or hearing.
