How often should audiometric tests be repeated / redone?
The HSE via their L108 bible are suitably vague on this, stating that the first two years should be annual but then they are a little woolly after that, other than to say 'regular' and 'no more than three years'. There is however a well-established standard practice for the testing frequency.
Standard audiometric testing schedule
Year 1 (the first hearing test for an individual).
You do their first hearing test to get the baseline - this is the initial test which is compared to the expected standards for their age but which is also then used for the comparison in future tests to identify changes. If you have never done tests before this will be the first year of your screening programme, otherwise will be the first time a new employee is examined after they start working for you.
Year 2 (the second hearing test for an individual)
This hearing test is done one year after the first test. This test is compared to both the expected results for their age and gender but also to the previous year's audiometric test result to ensure the hearing is not deteriorating.
From now on the audiometry re-test frequency depends on the category of result:
Category 1 - Every three years
Category 2 - Every two years
Category 3 - Every year
Category 4 - Every year
This is not explicitly law as such but is what people like insurers and the HSE expect to see and is the one which forms the basis of our standard recommendations for future testing in our reports and scheduled re-test reminders.
Variations in frequency of screening hearing tests
As the schedule above is not specified in law, employers do have some room for altering it, providing it is not putting people at risk. In practice, this usually means larger employers follow the schedule above as they are expected to put more resources to meeting it, while smaller ones do sometimes vary it a bit to balance the risk against their costs - that old 'reasonably practicable' judgement.
Example alternative audiometric test schedule for a smaller employer
The standard to follow is the same as the one above, but there is the possibility of altering it slightly if the employer wishes to, usually because numbers to be tested in a year are getting very low. For example, if an employer has 100 employees and does a series of hearing tests, it is reasonable that after the second year they may have:
75 employees who are Category 1
15 employees who are Category 2
6 employees who are Category 3
4 employees who are Category 4
This would mean that in the Cat 3 and 4 year they only have ten employees who need testing. Most service providers charge by the day which can make doing just ten tests quite expensive. One alternative pattern I have seen in use therefore was:
Year 1: Everyone
Year 2: Everyone
Then all Cat 2, 3 and 4 people and new people in 18 months
Then everyone again 18 months after that
In this pattern the Cat 2 people are done slightly early, and the Cat 3 and 4 people slightly late, but not drastically so, and bundled together makes it more cost-effective and eliminates one visit and keeps everyone much more tightly grouped into manageable batches. This route seems pretty sensible for smaller employers.
Expiring results - don't let them get too old!
One thing to bear in mind is that audiometric test results do have an expiry date, beyond which the natural changes due to age are such that the older results are no longer viable for use as comparisons. This limit is three years so don't let the re-test frequency go beyond that or you have to start all over again at Year 1.
Audiometry for new starters
There is a separate FAQ page just covering new starters in more detail.
There is usually a difference between the very large employers with an in-house occupational health department, and smaller employers. In all my years doing audiometry, pretty much all bar the very largest employers just bundle new starters into whatever is the next batch of tests coming due.
If hearing protection is in place and noise awareness training provided this seems a perfectly reasonable approach and is a good balance of risk against cost - you aren't going to make someone deaf in the relatively short period until the next audiometry session is due.