Ex. E <br />East <br />be 20Log320/3.3 = -40 dB below <br />Factor will be -28.1 dB for the muffler. The Q Factor is +6 dB, the cedar fence sound barrier <br />34.3 dBA <br />Building Factor will be -6 dB. Combining the corrected SSA values, we have . <br /> <br />(v)Combined Generator + Exhaust Noise <br />When the generator runs, both the noise through the large air vents in the wall of the generator <br />room and the noise emitted out of the muffler exhaust are combined at each noise sensitive site. <br /> <br />The generator may run when both HVAC units are operating. The right hand column shows that <br />the generator noise is so loud that there is negligible difference between the air condition units <br />running or not at any site. <br />Combined Noise <br /> <br /> Generator + Muffler = Combined + HVAC = Total <br />West62dBA 62 dBA <br /> 61 54 31.5 <br />South58 dBA 58 dBA <br /> 58 45 44.5 <br />East53dBA 53 dBA <br /> 53 34 34.5 <br />4) Discussion <br />By recalculating the community noise impact using octave band measurements for the generator, <br />a huge discrepancy in predicted noise levels has been revealed between that predicted by SSA <br />and that predicted by octave band analysis. In all three cases the City Noise Code limit of 45 <br />dBA is violated. The city also has an industrial noise limit of 60 dBA which is exceeded at the <br />west property line. <br />A) Leased Communication Equipment Room <br />What is completely left out of the SSA analysis is the impact of adding additional <br />communication equipment in the second equipment room. Although it may not change the <br />generator impact, it may well double the noise emitted by HVAC equipment because the second <br />equipment room will have to have its own set of wall mounted air conditioning units. These <br />units will be significantly closer to the west property line than the original set, and relatively the <br />same distances to the south and east properties. <br />If the distance is halved to the west property line, the sound level from the nearby AC set is 6 dB <br />louder than the noise from the first set of AC units. The equipment building corner shadowing <br />effect is reduced to about 10 dB because of the change in angles. Next is the + 5 dB effect of <br />due to the building just west of the addition bouncing sound around the corner. The result is that <br />the west property line is raised from 31 to 31 + 6 + 10 + 5 = 52 dBA. Combine this with +4 dB <br />additional noise to the south and east, and the result is that the 35 dBA limit is always broken and <br />the 45 dBA limit is violated to the west and South. <br /> <br />14 <br />