Noise at Work Assessments: Dosimeter’s or Sound Level Meter’s? Which is the best?

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Noise at Work Assessments: Dosimeter’s or Sound Level Meter’s? Which is the best?

   In many industries the noise levels can be deafening, especially when employees operate high-powered tools and machinery, work in nightclubs and pubs with loud music or stand close to vehicles (helicopters/aeroplanes) taking off and landing. Prolonged exposure to dangerous noise levels can lead to temporary or permanent hearing loss. Under the Noise at Work Act (2005) employees hearing needs to be protected. Noise levels therefore need to be measured and assessed, so what is the best method to do this by?

Getting accurate data is important when undertaking a noise at work assessment, to do this, you want an instrument you can rely on to get you the best data, but is this a Dosimeter? Or a sound level meter?

We take a look at the advantages and disadvantages of both methods here, in relation to NAW assessments we have recently carried out.

A strong advantage of the dosimeter (as seen on the left) is that it is securely fastened to an employee at the start of the shift and left to run for the duration of their workload. Dosimeter’s are great when assessing roles that it may be dangerous or impractical for the assessor to be, For example a recent assessment undertaken by HA acoustics included assessing hearing protection used by technical crew and baggage handlers at an airport. The dosimeters came in handy here as it was impractical for the assessor to get as close to the aircraft during take-off as required by the technical crew.

The dosimeter records the daily noise exposure and highlights periods of intense noises. However, it relies on the employee keeping a daily record of their actions, so the high noise peaks can be related back to the task they were undertaking. This method relies on the use of the employee keeping good records, which in some instances can be tricky, for example for people on heavy moveable machinery, such as forklifts. Dosimeters should also only be used by reliable employees as the results could be tampered with, by creating higher noise levels than usual.


Sound level meters, are often preferred as the assessor can ensure that the noise measurements are appropriate and of a good quality as they take the measurements. A sample measurements are taken 10-15cm’s away from the employees left and right ears whilst they are working. These measurements can then be calculated to determine a person’s daily exposure level. If an impulsive sound is occurring, such as cutting metal sheet then longer measurement times maybe required to ensure all data is gathered.  Settings on a sound level meter can also be adjusted during the survey according to the different noise levels within a factory / warehouse, for example in a recently assessed food manufacturer’s the levels, where potatoes were being washed, and onions cleaned were far louder than the production line or packaging area of the company. Different range levels were therefore needed, to ensure good measurement data.


Here at HA, we will tailor the type of Noise at Work assessment required for your industry, and can use both dosimeters and sound level meters at once, depending on the variation of job roles within your company. Our reports are tailored to meet your companies and HSE’s needs. So contact us now.


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