Section 901.106  Prominent Discrete Tones

a)         A person must not cause or allow the emission of any prominent discrete tone from any property-line noise source located on any Class A, B or C land to any receiving Class A, B or C land, when measured at any point within the receiving land.  One-third octave band sound pressure levels must be measured at least 25 feet from the property-line noise source.

b)         Subsection (a) does not apply to prominent discrete tones having a one-third octave band sound pressure level 10 or more dB below the allowable octave band sound pressure level specified in Sections 901.102 through 901.104 for the octave band that contains the one-third octave band.  In the application of this subsection, the applicable numeric standard for sound emitted from any existing property-line noise source to receiving Class A land, for both daytime and nighttime operations, is found in Section 901.102(a).

(Source:  Amended at 42 Ill. Reg. 20453, effective November 1, 2018)