Abstract
As the various industrial machinery has come into being by development of industrial technology, the productivity of the basic industrial machinery has improved. However, at the same time, noise from various industrial machinery disturbs the quiet environment. There are 35 kinds of the noise emission machinery defined in the noise and vibration control act according to the horse power and the number of machinery. These were classified in 1992, and the characteristics of the noise emission machinery may be different from the past one. So we need to investigate the characteristics of the noise emitted by machinery to control it rightly. We measured sound intensity of 32 noise emission machinery to calculate the sound power levels of those and investigated the characteristics of the sound power level of those according to the frequency. We found that the forging machine, concrete pipe and pile making machine, sawing machine, etc. are noisy. The generator, the concrete pipe and pile making machine, etc. emit the low frequency noise, but the molding machine, the stone cutter, the metal cutter, etc. emit the high frequency noise.