Hearing Protection

Workplace Noise Assessments: Protecting workers from preventable hearing loss

workplace noise assessmentsIf you have to raise your voice to be heard at a distance of one metre then it’s likely that workplace noise has reached hazardous levels and a noise assessment should be conducted.

Given noise-induced hearing loss is entirely preventable, any evidence of it in workers is unacceptable, according to Dr Barry Chesson, a certified occupational hygienist with more than 40 years experience.

“If there are signs of hearing loss occurring in a workplace then that means things are absolutely wrong. That should never happen,” said Chesson.

Hazardous levels are those that exceed the Australian work exposure standards for either the total amount of noise exposure a person experiences in an eight hour day (>85dB) or the single exposure from a sudden, loud noise (>140dB).

When asked about noise assessment processes, Chesson said the key is to always find out which particular individuals are being exposed and their personal exposure levels.

“We’ll come in and talk to people, have a look at the plans and designs, identify noisy sources and consult with supervisors, managers and employees to establish the nature of the work and the patterns of noise exposure,” he said.

“We have devices called noise dosimeters which accompany the person as they go about their job. The other type of assessment is fixed position sampling which determines what level of noise exists at certain locations or from a particular piece of equipment.”

“But ultimately it is the exposure which people have in the course of their normal work day which determines risk.”

The assessment of personal noise exposure, called a noise dose or time-weighted noise average, takes into account three factors: the noise level of the source, the frequency of contact with the source and the length of time of each contact.

“Quite often people have some sort of knowledge about the noise level but forget about duration and frequency,” said Chesson, adding that a softer noise source with a high frequency of contact for long periods is more dangerous than a very loud noise source with no people in the area.

Chesson identified three management options for noise: engineering methods which eliminate or control the source, administrative controls and PPE.

“As a hygienist we like to see organisations using the Hierarchy of Control and working their way down the list to use the most effective controls first,” he said.

“PPE is the last line of defence but still features as a first line of defence in many organisations.”

Furthermore, he said some people fall for the trap of deciding that the best form of hearing protection is Class 5 without considering the exposure patterns and if it’s the right choice.

“Overprotection is just as bad as under protection. In overprotection cases the hearing protection is much less comfortable because it’s heavy duty which reduces compliance and people may not hear important information or signals as well.”

As part of ensuring that hearing protection is effective, a lot of big firms are incorporating PPE fit testing programs into their occupational health policies, according to Chesson.

“Particularly in the case of earplugs, if you don’t insert them correctly or they’re the wrong size then you can go out there and you’re not protected,” he said.

“Fit testing gives people the confidence that when they apply hearing protection it’s actually doing the job for them.”

Chesson suggested that if an organisation is looking to employ an occupational hygienist to do a noise assessment and set up a control program or audit a pre-existing one then they should look for someone who is certified by the Australian Institute of Occupational Hygienists.