a) Sound Measuring Equipment
1) Use an integrating sound level meter alone or in conjunction with an octave-band or ⅓ octave-band filter set or a real-time sound analyzer (octave-band or ⅓ octave-band) that complies with the following standards incorporated by reference at 35 Ill. Adm. Code 900.106:
- A) ANSI/ASA S1.4-2014/Part 1/IEC 61672:1-2013 "American National Standard Electroacoustics – Sound Level Meters – Part 1: Specifications (a nationally adopted international standard)".
- B) ANSI/ASA S1.11-2014/Part1/IEC 61260:1-2014 "Electroacoustics − Octave-Band and Fractional-Octave-Band Filters – Part 1: Specifications (a nationally adopted international standard)".
- C) ANSI/ASA S1.6-2016 "Preferred Frequencies and Filter Band Center Frequencies, for Acoustical Measurements".
- D) ANSI/ASA S1.8-2016 "Reference Values for Levels Used in Acoustics and Vibrations".
- E) IEC 61672-1:2013 "Electroacoustics Sound Level Meters – Part 1: Specifications".
- 2) Use a magnetic tape recorder, graphic level recorder or other indicating device conforming with the SAE Recommended Practice J184 "Qualifying a Sound Data Acquisition System", August 2014, incorporated by reference at 35 Ill. Adm. Code 900.106.
- 3) Calibrate sound measuring equipment traceable to the National Bureau of Standards at least once every 12 months.
- 4) For outdoor measurement, use a microphone with an attached windscreen.
b) Weather Measuring Equipment
- 1) Us an anemometer and compass or other devices to measure wind speed and direction in compliance with the manufacturer's recommended procedures.
- 2) Use a thermometer, designed to measure ambient temperature, in compliance with the manufacturer's recommended procedures.
- 3) Use a hygrometer in compliance with the manufacturer's recommended procedures to measure the relative humidity.
- 4) Use a barometer in compliance with the manufacturer's recommended procedures to measure the barometric pressure.
(Source: Amended at 42 Ill. Reg. 20487, effective November 1, 2018)