Ex. E <br />East <br />To the east of the generator room SSA made no calculation or prediction for noise impact. <br />sition of the generator room <br /> 6 dB building <br />factor due to the cedar fence sound barrier instead of the -15 dB building factor used to the west. <br />The net result would be a prediction of 80 17 (noise control) 6 <br />(building factor) = 38 dBA. <br />SSA Error: There is a distance error with the SSA report. The distance between the HVAC <br />units along the east wall of the church and the closest residential property line to the east is seen <br />to be when viewed on google Maps. B <br />Amazon Creek. There is no explanation in the SSA report why the hiking trail was selected as <br />the nearest noise sensitive property, if it was selected at all. This increased distance between the <br />noise source and noise receiving property line results in an approximate additional 5 dB <br />attenuation due to distance for noise to the east. <br />In the above East calculation the distance between the generator room vents and the property <br />-20 Log (340/23) = -23.4 <br />dB. The net result for the easterly property lines would be 80 23.4 dB (distance) 17 (noise <br />control) -6 (building factor) = 33.6 dBA. <br />ii) Basic Generator Room Calculation <br /> <br />Using the same information provided by SSA, the procedure below is a recalculation of the <br />above problem using a different approach to make the assessment. The results of this <br />assessment are similar to those in the above SSA analysis, which seems to support the SSA <br />assessment. This version of the assessment is presented here to illustrate what happens when <br />using single number representations in equipment noise calculations: Similar results are <br />developed, regardless of which method is used. <br />However, the results dramatically change when the octave analysis version of equipment noise <br />calculations are used as demonstrated in the next (iii) section. In the following analysis, only the <br />narrative discussing the sequence of calculations and the results are provided. The actual <br />calculations were left out because they provide no new information. <br />The The generator is <br />placed inside a room with 400 sqft of absorption inside. Reverberant sound level builds up to 98 <br />dBA inside room. The direct sound level on surface of room is 91 dBA. Add the two together <br />and resulting noise level at the interior surface of the room is 99 dBA. <br />Cooling air is circulated through the room, 3400 scfm through two 15 sqft louvers in order to <br />keep the air flow through the louvers in the range of 250 fpm. One cool air inlet louver and one <br />warm air outlet louver are needed. The louvers referenced are ALV-MV-8 systems. Their <br />attenuation is 15 dB at 1k, less for lower frequencies and more for higher frequencies. Assume <br />9 <br />