工場騒音について (<特集>騷音特集号)

抄録

The sound pressure levels and the spectra of various noises, to which the employees were exposed in the ship-yard, iron works, mines and so on, were examined. The frequency analysis was mainly performed by the octave-band analyzer. Sometimes the unsteady noises were recorded on a magnetic recorder. From the octave-band spectrum obtained, the loudness was calculated by the procedure of Mintz and Tyzzer, and the degree of hearing damage risk was proposed in five steps; namely, harmless (-), doubtful (±), harmful (+), very harmful, and extremely harmful, according as the loudness of any octave band was below 50, 100, 200, and 400 and over 400 sones, respectively. The statistical relation between the sound pressure level and the calculated loudness level was found. The difference of the two levels was considerably varied according to the shape of the spectrum, especially at high sound pressure levels, e. g. , the calculated loudness levels of 100db noises were distributed from 110 to 115phons but those of 115db noises from 122 to 136phons.