A forging factory in the neighborhood of a residential area. Two forging machines weighing 88 tons are hammering steel heated to 1,200 degrees Celsius to produce mechanical parts. The noise emitted during the forging process is close to breaking the eardrums, and the vibrations are equivalent to a seismic intensity of 4. At the same time, the plant was required to meet the prefectural standards for noise and vibration in the neighborhood, and to provide sound and vibration proofing to enable operation even at night. The pillars on the north and south sides of the building are hollow air intake shafts, and inside are silencers that effectively cancel out the frequency characteristics of the hammer noise of the forging machine. The two forging machines have a double-structure foundation made of hard styrofoam to prevent vibration. The noise measurement after the completion of construction was 33 dB against the performance guarantee value of 45 dB at the noise evaluation point in the neighborhood, and the vibration measurement was 51.2 dB against the regulation value of 55 dB at the shortest distance in the village.

Japan | Niigata

Shinkenchiku November 2011 issue 124P