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� � <br /> v���=o„ uv���i�ss <br /> SEAQ Glenwood <br /> o Construct the noise barrier of a solid material that wili meet the following transmission <br /> loss requirements: <br /> Table 2 <br /> Transmission Loss Re uirements 2.5 Ibsls ft <br /> Frequency <br /> Hz 63 125 250 500 1000 2000 4000 <br /> TL dB 13 16 21 25 21 24 33 <br /> Materials that have a surface mass oF 2.5 Ibs/sq ft will meet these requirements. The <br /> following are common barrier materials that meet the mass and transmission loss <br /> reGuirements: <br /> • 3/4-inch exterior grade plywood <br /> • 16-gauge sheet metal <br /> o Line the inside of the noise barrier between 1 foot and 5 feet above grade with sound <br /> absorbing material that has a minimum NRC rating of 0.50. Weather-resistant malerials <br /> that meet this requirement include 2-inch thick Cluash rigid foam board, QFR or 2-�nc;i <br /> thick Quilted Fiberglass Absorber(QFA-i 1 Silicone-coated-fiberg/ass-cloth facec�. Both <br /> products are available from Doug Bixel, (425) 646-9703. <br /> o A detail oF the barrier construction is presented in Figure 2 below. <br /> ,.�:�i�� n <br />