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WSB Engineering Carwash Noise Impact Assessment <br />David Braslau Associates, Inc. Page 8 <br /> <br />4.0 SOUND LEVEL MODELING <br />4.1. Carwash Sound Sources <br />It was anticipated that a similar carwash establishment to the one proposed in St. Anthony could <br />be used as a basis for sound level modeling, but permission to take these readings was not <br />granted. Therefore, sound level monitoring of another carwash (Eddiez Southdale Car Wash, <br />2816 W. 66th St., Minneapolis (Edina), MN 55423) with typical design was performed to capture <br />representative levels. <br /> <br />Source octave band spectra adjusted to 50 feet for the three primary noise sources associated with <br />the carwash are presented in Figure 4.1. The washing and dryer levels were measured at different <br />distances and the vacuum level was measured at 10 feet. Source elevation for the dryer exit was <br />8 feet and 6 feet for the washing entrance and vacuums. Precise elevations are not critical <br />compared with distances from sources to receivers. <br />4.2. Model Geometry <br />Assumed geometry for computer noise predictions is shown in Figure 4.2. One receptor is <br />located on each balcony of Kenzington Condominiums for all five floors, to show how sound <br />might be distributed across the building façade. Four first floor receptors are assumed for the <br />Walker Methodist residence and one receptor 25 feet from each of the closest homes. The <br />carwash building walls are also assumed to provide barriers to sound levels. <br /> <br />74