Ill. Admin. Code tit. 35, § 901.122
The Combustion Turbine Power Generation Facility located at 1559 Gifford Road in Elgin, Illinois must not cause or allow the emission of sound from any property-line noise source located on that property that exceeds any allowable octave band sound pressure level specified in the following table, when measured at any point within the receiving Class A or Class B land.
| Octave Band Center Frequency (Hertz) | Allowable Octave Band Sound Pressure Levels (dB) of Sound Emitted to any Receiving Class A or Class B Land from Ameren Elgin Facility | |
| Class A Land | Class B Land | |
| 31.5 | 80 | 80 |
| 63 | 74 | 79 |
| 125 | 69 | 74 |
| 250 | 64 | 69 |
| 500 | 58 | 63 |
| 1000 | 58 | 58 |
| 2000 | 58 | 58 |
| 4000 | 50 | 50 |
| 8000 | 40 | 45 |
(Source: Amended at 42 Ill. Reg. 20453, effective November 1, 2018)