Slide 6 of 15
In comparing the measurement procedures of dosimetry and profiling, the major differences are in the measurement duration and the position of the microphone.
In dosimetry, S12.19 says that the measurement duration should be sufficiently long for the resulting noise exposure to be representative of the exposure associated with all the tasks performed by the employee.
In profiling which normally uses an integrating sound level meter, the duration should be sufficiently long for the resulting noise exposure to be representative of the exposure associated with each tasks performed by the employee.
In dosimetry, the position of the microphone is on the mid-top of the wearer's shoulder with the microphone oriented parallel to the shoulder plane. While the procedure in profiling would locate the microphone in what is called the hearing zone of the worker, (a hemispheric area extending from the workers ear to a distance of 12 inches) and allows for alternate positions when the worker's activities may interfere with the measurement. It also allows for measurements to be taken even if the worker is not present.