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A common question that often gets asked is, should I use a noise dosimeter or a sound level meter (SLM) to determine noise exposure? US occupational noise exposure regulation 29 CFR 1910.95 says “where circumstances such as high worker mobility, significant variations in sound level, or a significant component of impulse noise make area monitoring generally inappropriate, the employer shall use representative personal sampling to comply with the monitoring requirements of this paragraph unless the employer can show that area sampling produces equivalent results”.
And although ‘late to the dosimeter party’ global standards like ISO 9612 Determination of occupational noise exposure also now recognise the use of dosimeters. However, standards invariably tend to lag technology by a number of years and modern dosimeters now have a very similar capability to that of a hand-held SLM including audio recording and octave band frequency analysis. A case in point is theANSI S1.25 (R2017) [TT1] [NH2] standard for noise dosimeters which has only just gone through a revision after 10 years, the 2007 version pre-dating the introduction of badge-style devices where the microphone is close coupled to the body of the instrument rather than on a cable (which represented an obvious point of potential failure).
Finally, should a noise dosimeter be type 1 or 2 accuracy? The ANSI standard specifies type 2 but according to the parallel IEC 61252 standard, an accuracy grade is no longer specified but if pressed, you could say that they meet type 2 when the relevant functionality is viewed as a SLM.
OK that’s the nerdy bit, here’s the practical stuff.
Finally, remember why you are taking the measurements in the first place. It’s more than compliance and avoiding getting cited, it’s all about people’s health and wellbeing. Making an objective risk assessment and getting the provision of control methods including hearing protection right can also lead to better productivity.