Test method for evaluating the NIOSH Noise Mapper application in a hemi-anechoic chamber

The Noise Mapper Application currently under development by the National Institute for Occupational Safety and Health (NIOSH) can be used to identify areas in the workplace where workers may be exposed to hazardous noise. The application is intended to empower workers to measure sound levels in their workplace, make informed decisions about noise exposure, and prevent occupational hearing loss. To evaluate the maps generated by the app, a single sound source or multiple sources were used to generate steady state sound fields within the NIOSH Hemi-anechoic Chamber (HAC). A sound level meter (Larson Davis, Model LxT1) was used to measure A-weighed equivalent continuous sound levels on a grid with a spacing of 1.5 m (5 ft). The NIOSH Noise Mapper Application was then used to generate sound level contour plots with a grid spacing of 3.0 m (10 ft). The accuracy of the map was evaluated by comparing the predicted sound levels with the measured sound levels. The results show the app can estimate the sound levels to within 1.5 dB(A) of the measured values when half of the measured points were used to generate the contour plot. The test method used to evaluate the NIOSH Noise Mapper Application and the results of the comparison will be discussed in this paper.