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<br />david br,g b associatas. incorporatad <br /> <br />1313 5th street s.e.. suite 322 · minneapolis. mn. 55414 · telephone: 612-331-4571 <br /> <br />31 August 1993 <br /> <br />MEMORANDUM <br /> <br />TO: Dan McCarthy, Advanced Circuits <br />Mike Falk, City of Roseville <br /> <br />FROM: Dave Braslau <br /> <br />RE: Sound Level Measurements near Anderson Residence on 30 August 1993 <br /> <br />A spot check was made of sound levels next to Oasis Pond and just east of the <br />Anderson residence at approximately 10:30 pm on Monday evening, 30 August <br />1993. Wind conditions at the time were calm. According to a telephone conver- <br />sation with Dan McCarthy on Tuesday, 31 August 1993, all normal equipment was <br />in operation at the time of the readings. <br /> <br />The following average readings were obtained over a time period spanning <br />several minutes which appeared to represent typical sound levels at that site. <br /> <br />Noise Metric <br />Lmax (maximum level) <br />L01 <br />L10 <br /> <br />L50 <br /> <br />L90 <br /> <br />Lmin (minimum level) <br /> <br />Measured <br />69.0 dBA <br />51. 5 dBA <br />51. 0 dBA <br />50.0 dBA <br />49.5 dBA <br />48. 5 dBA <br /> <br />MPCA Standard <br /> <br />55 dBA <br />50 dBA <br /> <br />The noise floor appeared to be caused not by equipment from Advanced Circuits <br />but from traffic on I-35W although it is approximately one half mile west of <br />the site. Sound levels from ACI were steady and did not, under the. calm wind <br />conditions, appear to be intrusive. The mitigation of levels including con- <br />struction of the cyclone enclosure, scrubber sound barrier, and replacement of <br />the fan in the smaller scrubber have reduced the overall level to 50 dBA near <br />the Anderson residence, which is the nighttime MPCA L50 standard. If all of <br />the other measures identified in the Noise Reduction Plan are implemented and <br />enforced, the facility should remain in compliance with the MPCA standards and <br />present a reduced disturbance for the adjacent neighborhood. <br /> <br />It may be <br />to ensure <br />standard. <br />ings. <br /> <br />helpful to monitor for a longer term (overnight) as was done before <br />that the ambient (continuous) levels are consistently below the MPCA <br />Please let me know if you have any questions concerning these find- <br /> <br />nois0830.mea 93014-01 <br />