In spring 2015, following a noise survey undertaken by another company, this client asked me to retest noise levels and noise exposures in their packing hall. The company had been given a noise report which concluded that the employees were exposed to noise above 85 dB(A) and that hearing protection must be worn. The company could not understand why noise exposures were so high
when the packing hall was very quiet. If noise exposures really were that high, they needed to know where the noise was coming from and what they could do about it. This information was not in the original report.
I visited the site. The background noise level with the radio playing was around 70 dB(A). It was quiet! I decided to shadow operators for a cycle on each type of workstation. I used a recently calibrated sound level meter which I held by the operator’s ear. I noted the sound level for each task they performed.
This is an example of what was found and reported;
Photograph of the sheet steel hopper which resonated as the cartridges were dropped in giving a peak noise of 100 dB(A)
Taping machine peaks 90 dB(A)
Time history graph of sample 46
I was able to identify the main noise sources, such as the taping machine and feed impacts. Using the Cirrus sound level meter software I could ascertain what the noise exposure would have been without the identified noise sources. Using HSE exposure “points” I estimated full shift exposures from the measurements taken. These were similar to the results from the previous survey. This time we knew why and could plan to reduce noise at source.
The planned reduction for the examples above involved lining the hoppers and moving the automated taping machine away from the operator.
My proactive client was pleased to have found the sources of high noise levels and was even more pleased that he could do something about it. Having a proactive client who wanted to reduce risk before using protection pleased me.