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<br />. t. <br /> <br />. , <br /> <br />[ij <br /> <br />tWin city test:,nQ <br />CDrr.~Cl(atlDn <br />~ CROM'HLL AVE.NlJ~ <br />ST .'AUl MN 55'11 <br />PHONF 61~~S J601 <br /> <br /> <br />REPORT OF: !!Q!f.!!..!.U~'_RECO~iNDATIONS <br /> <br />LABORATORY N(l, <br /> <br />4141 87-11~8 <br /> <br />DATE: July 24, 1987 <br />PACE: 3 <br /> <br />~ll,~t Pl!.OCEl:th(E: <br /> <br />On July Q I 198] I a'l abbrtviated noise survey W'.I.S CO'lC:l.lcted at the lIl~&Surell!.ent site wIth <br />the coo':'ing/heat1ng unit off. The tllonltori,lg was conducted ov.... a 15 minute r-eriod <br />us1ug 8tl1nJard procedures as Qutlinel1 by th, Minnesota Pollution Cor.trol Agency - Nolle <br />Pollutlofi ~ontrol sectIon. B1~ic~11y. a ~ype 2 sound level meter In th~ A-welghted- <br />fait response ~de was p!actd on the bo~n~ary lin~ of the property clostst t~ the nolee <br />source. The ~ourd lev61 ~~ter was plared at least four (ect above the grovnd and at <br />least 10 feet frolll l1ny other reflect tng surt scar Mensurelllents were ta:"o:.::. eW.ll::; 10 <br />.ecQnds over the 1~ mlnut~ Ferlod b~gtnnlng at 10:00 pm. <br /> <br />iJn ';uly 1 J, 1987 I two IdentlG"l 15 ~lnute surv~ys were taken ~1th the units on and off. <br />Abo, 111 octave bl!nd llleaSI\\c.JE"nts were tAken at the &curvey site and at a locat1o~1 I <br />~~:e~ from th~ unIt to deter~ine the spectral contenL of the no18~ emitted by the unIt. <br /> <br />The s/~tPf':l ",...,. C.ll1bra::cd b",ful.'e o.nd after the meaS\lremtnts. <br /> <br />I OBS~RYATIO~: <br /> <br />~redomltul~e n018e .-ll.lurcl':f.l not incl\Jtling tl,e hea~{ .lg/.ooETlg unit wcrf.l traff1c noise ,)n <br />Lt x1:1gt)/\ k,enue f.Ib?ut 100 feet fo:C9t of the lIleasureruent; poJlnt and a1 rplane nohe. <br />Scatterl'd nohe lIt,)urces luch as lllotorr.1'c1es, trucks, and loud carll loIere observed during <br />till' mor-ltoring thles. These .cattere'.! sour~e!l were Infreq<Jeflt enough to have an <br />insIgnificant effect on the LI~ and L50 values. <br /> <br />The nlgl,ttll'Ae LlO arid L50 perllbsible levels were viclated during bo::h monItoring <br />~~"iods \titl: and wlthout the unit runn1n-t>. II 4 -is rise was noted in tht. LtO and 1.50 A- <br />,.-c:1ghted lev-els when the unit was turned on. Thil:l degree of change is clearly <br />distingul,hable. <br /> <br />The current barrier surroundIng the unit 18 acoustIcally tranJparent and theref"re <br />provides littl~ or no protectIon. <br /> <br />COHCLUSIONS: <br /> <br />Even though t1'.. p-r~i8~ub1c 1.10 Ilnd L$O levels were vloIal.!d w1th the unit off, it is <br />hlg~lly p"S84.ble tl'\. dl.:ring rite later hours (I.e., after ::lidnight) thi5 level will fall <br />to within t~.e ~ ~.ll.is8i"le range. The unit rU"lntng d\.lrin~ this period ceul f e<llJily <br />bring the 1.1Q anc. :,50 levels abovl: the permissible range. <br /> <br />...... ~UA4- ""'Of.e:"',QoIr,t TCi ell."""'. ".... ~..~c A'!fO OUfII.....V.. At L.....~ .a A.... .u..iIl"tlIl'"~D''' t..., _ON. 101 N' ,....-L ....,.0-..,.. ~ 1I:iC.'."". .....0 .u,~- <br />...".... ~ ~..l'tON 011 .'f...,.........,. Co..c:...~ CHI . JII '..II.......-oM.. _&....1lOoNe 0&iA ..~T." ..........0 ............ ~ ......TT..... ......v".~ <br />