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1 <br />1 <br />1 <br />1 <br />1 <br />� 1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />1 <br />Table 2-4 illustrates the further noise reduction that would be <br />associated with various building types and assuming various <br />window conditions. Note that a conventional building with open <br />windows would further reduce noise levels by approximately 10 <br />dBA. Thus, residences which might be impacted by 55 Ldn levels <br />typically would have a noise level of 45 Ldn on the interior <br />without any special acoustical treatment. <br />TABLE 2-4 <br />NOISE REDUCTION PROVIDED BY A BUILDING <br />Noise Reduction <br />Due to Building <br />Building Type Window Condition Structure (dBA) <br />All <br />Light Frame <br />Masonry <br />open 10* <br />Ordinary Sash <br />Closed 20 <br />With Storm Windows 25 <br />Single Glazed 25 <br />Double Glazed 35 <br />*Approximate noise reduction of exterior all having various open - <br />window areas. <br />Percent of Exterior Wall Approximate <br />Having Open Windows Noise Reduction <br />1% 17 dBA <br />2% 14 dBA <br />4% 11 dBA <br />8% 8 dBA <br />16% 5 dBA <br />32% 2 dBA <br />50% 0 dBA <br />The analysis determined that no area, other than a portion of the <br />Airport property, would be exposed to 65 Ldn or greater in any of <br />the scenarios. Therefore, according to FAA Order 5050.4, <br />Airport Environmental Handbook, and under MC's guidelines, no <br />further analysis needs to be prepared, and it may be assumed that <br />there would be no significant noise impact. <br />Source: Fundamentals and Abatement of Highway Traffic <br />Noise - U.S. Department of Transportation <br />2-10. <br />1 <br />