ORDINANCE NO. 13,696

AN ORDINANCE to amend the Municipal Code of Des Moines, 1991, adopted by Ordinance No. 11,651, passed April 15, 1991, as heretofore amended, by repealing subsection (c) of Section 16-145 thereof and by adding and enacting a new subsection (d) to Section 16-150, regarding the calibration of sound meters.

BE IT ORDAINED by the City Council of the City of Des Moines, Iowa:

Section 1. That the Municipal Code of Des Moines, 1991, adopted by Ordinance No. 11,651, passed April 15, 1991, as amended by Ordinance No. 11,801 passed April 20, 1992, as amended by Ordinance No. 13,013 passed March 28, 1994, be and is hereby amended by repealing subsection (c) of Section 16-145 thereof and by adding and enacting a new subsection (d) to Section 16-150, regarding the calibration of sound meters, as follows:

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16-150. POWERS AND DUTIES OF THE NOISE CONTROL DIVISION; ENFORCEMENT.

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(d) The measurement of sound or noise shall be made with a sound level meter meeting the standards prescribed by the American National Standards Institute or its successor body. The instrument shall be maintained in calibration and good working order. Octave band corrections may be employed in meeting the response specification. A calibration check shall be made of the meter before and after any measurement used for enforcement purposes. If multiple meters are used by a city department, the meters used by that department shall be validated to a common calibration device for the department to reduce potential variability. Measurements recorded shall be taken so as to provide a proper representation of the noise source. The microphone during measurement shall be positioned so as not to create any unnatural enhancement or diminution of the measured noise. A windscreen for the microphone shall be used when required. Traffic, aircraft and other transportation noise sources and other background noises shall not be considered in taking measurements except where such background noise interferes with the primary noise being measured.

Sec. 2. This ordinance shall be in full force and effect from and after its passage and publication as provided by law.

FORM APPROVED:

Roger K. Brown

Assistant City Attorney