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38 <br /> 1 Thank you very much for your consideration of this statement of some of the omissions, <br /> 2 inconsistencies, and inaccuracies in the Binks SUP application. <br /> 3 <br /> 4 <br /> 5 Respectfully Submitted, <br /> 6 May 27, 2014 <br /> 7 <br /> 8 John G. Petranka <br /> 9 2531 Falls Drive <br /> 10 Chapel Hill, NC 27514 <br /> 11 <br /> 12 919-383-7855 <br /> 13 919-667-6112 (cell) <br /> 14 john.petranka(a7gmail.com <br /> 15 <br /> 16 Appendix I <br /> 17 <br /> 18 Calculation of Noise Produced by a Group of Three Inverters. Assuming that each 1500 <br /> 19 kW inverter group consists of three Advanced Energy Solaron 500 inverters, the noise level <br /> 20 generated by adding all three can be calculated as shown below (source: The Engineering <br /> 21 Toolbox: Adding Decibels. http://www.engineeringtoolbox.com/adding-decibel-d 63.html ) <br /> 22 <br /> 23 The resulting sound pressure level when adding equal sound pressures is calculated by the <br /> 24 formula: <br /> 25 Lpt = Lps + 20 log (n), where: <br /> 26 Lpt = total sound pressure level (dB) <br /> 27 Lps = sound pressure level from each single source (= 68 dB at a distance of one meter for <br /> 28 each inverter in the group of three) <br /> 29 n = number of sources (= three 500 kW units per 1500 kW station) <br /> 30 <br /> 31 Substituting: Lpt= 68 dB + 20 x log (3) <br /> 32 Lpt= 68 dB + 20 x (.47712) = 68dB + 9.54 dB <br /> 33 <br /> 34 <br /> 35 So, Lpt = 77.54 dB at 1 meter <br /> 36 <br /> 37 <br /> 38 Appendix II: Sound Level Measurements <br /> 39 <br /> 40 Background Sound Averaging ca. 32 dB. Periodic increases are attributable to songs of <br /> 41 nearby birds. <br /> 42 <br /> 43 Location of Sound Measurement. Corner of Cascade Dr. (to Sally's right) and Falls Dr. <br /> 44 (intersecting on the left). Proposed 20 acre development is property along Cascade Dr. <br /> 45 behind zoning sign. <br /> 46 <br /> 47 <br /> 48 John Petranka— My name is John Petranka, and I have been duly sworn. My wife and I have <br /> 49 lived in the Falls of New Hope Neighborhood for almost 23 years. We live at 2531 Falls Drive, <br /> 50 which is right on the corner of Falls and Cascade and directly across the street from the <br /> 51 proposed development. We chose to live in our neighborhood intentionally. We specifically <br />