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Nov. 15 01 05:46p <br />p.1O <br />01/636 <br />Lot is not clear. There appears to be a landscaped setback area, <br />but it is not clear if this is to include any private patios or <br />that there are any decks overlcoki.ng the parking lot. it any <br />private areas exist, then the Noise Ordinance would apply. <br />The measurements suggest that the building envelope of <br />the residential structures next to Third Street and the cold City <br />Hall Parking Lot should provide 35 dBA of noise reduction. `Y'h.e <br />developer's data, suggests it could be even higher at 4G d8A. No <br />floor. plans Other than that which appears on the Exhibits were <br />examined_ This is not sufficient detail. The first floor units <br />facing Third Street take access off Third Street:. Thus, at least <br />one room on a unit has a door. Two sample cond:i.tlaus were <br />examined. The basic roam was a floor area of one hundred square <br />feet and a window area of .20 square feet with a door added can the <br />first floor. <br />The noise reduction of the structure is controlled by <br />five elements, which are the window, the ext.eTi.o:r_ wail, the doors <br />if -any, the roof and the interior treatments such as drapes, carpet <br />and furniture. The window is the weakest element of the group, so <br />it is customary tc examine the noise reduction where the window <br />noise redtacta.o.n is the variable. The noise reduction of any of the <br />panels is defined in terms of the Sound Transmission Class (STC) <br />rating, This rating system allows a uniform method of selecting <br />Products tesl.ed according to established standards. The <br />calculations are based on this rating system. The noise reduction <br />calculations are contained in Appendix 4 and were based can first <br />detezmi.ning what, if any, window rating alone would meet the 35 dBA <br />noise reduction. criteria. If it could not be achieved, thexa the <br />wall rating was modified and if that failed, the door rating. A <br />window rating of STC 40 was considered the upper practical_ limit <br />for available products. -The results show the following: <br />Sample Room Without. Door <br />>r 1!ndc_w A.1 ne . Reaches only 33 dBA- with an STC 40 window. <br />W3-n.dpw With Wall Modification. Reaches 35 dBA with an <br />STC 30 window and interior drywall Mounted on resilient <br />channels. <br />Sample ]Room With D<)or <br />Window Alone: Reaches only 25 dBA with an STC 40 window. <br />Wind-0 With Wall. Modification: Reaches 25 dBA wit b an <br />.STC 40 'Window and interior drywall Mounted on resilient <br />channels. <br />W:i.aldaw WWhA.-F—all Modification and U Waded Dorar: <br />Reaches 3.5 dBA with an STC 40 window and STC 38 door, <br />9 <br />