27.56.090 NOISE.

Sound levels shall be measured with a sound level meter and associated octave band filter manufactured according to standards prescribed by the American Standards Association, Inc., New York, N.Y. Measurements shall be made using the flat network of the sound level meter. Impulsive type noises shall be subject to the performance standards hereinafter prescribed provided that such noises shall be capable of being accurately measured with such equipment. Noises capable of being measured, for the purpose of this title, shall be those noises which cause rapid fluctuation of the needle of the sound level meter with a variation of no more than plus or minus two decibels. Noises incapable of being so measured, such as those of an irregular and intermittent nature, shall be controlled so as not to become a nuisance to adjacent uses.

At no point either on the boundary of a residence district or a commercial district or at one hundred twenty-five feet from the nearest property line of a plant or operation, whichever distance is greater, shall the sound pressure level of an individual operation or plant (other than the operation of motor vehicles and other transportation facilities) exceed the decibel levels at the designated octave bands shown hereafter for the districts indicated.