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� <br /> — __.._ �i_i��_�Q-'�-:? TH'� 15:=:ii IC.P�"F.f �.,i':.T Ci"iIP�.1F'<ltl TFiI_ I10:�(1„� ^, i _-�;:�ll ti51'c{ Fp: __ '__ <br /> � �� <br /> Mr. Henk Lewis <br /> � t� October 31 , 1989 <br /> Pape Two <br /> � � <br /> ��� Che Site pinn for the devclopment indicates tiiut the north building w111 De � <br /> y� set Dack 20 feet fran the north fence 1ine. Compensating for Lh1s Elfference <br /> �H�a in distence fran the noise source (5R 526) , the notse levels for the 6 foot <br /> N <br /> � end 12 foot elevatlons arc 72 and 73 dBA, respectively. <br /> ��d <br /> � �g ACtording to the Snohomish County Dlanning Departrnent (based on a telephone <br /> �y � <br /> � conversation on June 16, 1989 wlth Mr. Justin Osemenel, the requirement s to <br /> � y meet an interior LeQ of 45. This ob,lective wttl requlre an outslde-to- <br /> g w inatde notse red��Ction of 28 dB (73-45) fur the north, east, end Nest Taces of , <br /> �S3� tha north build(ng. This noise reductlon w111 be requlred only 1n those rooms <br /> ���a whlch are ad�acent to SR 526. Due to the s1m11arity of nolse levels nt the 6 <br /> �� foot ena 12 foot meesurement locetions, upper and lower residentiat units <br /> should receive identical noise re9uctton treetment. <br /> An outside-Lo-lnsiGe noise reduction of up to 28 AB can be achieved with <br /> C� typScal recidentlal construction (assumin9 insulated giass wlndows, solid core <br /> doorb, end a1r-tight seels). S1nce the north units are borderline in meeting <br /> , the 28 dB notse rpduction requtrement, we recomnend the folloNtng: <br /> I �� 1 . For the north walks of the rooms ad,jaCent to SR 526 in the north building, <br /> edd e second layer of 1/2 inch gypsum Doard tnslde. <br /> i �� <br /> 2. The wlndoNs fn the north face of the units ad,�acent to SR 526 should be <br /> � duel glazed with gless which is at least 3/16 1nCh thick and a minimum <br /> �� 3/4 lnch alrspace� It is recommended that theso wlndoWs not be operable <br /> Cue to potential noise leakage through operable window seels. <br /> �J 3. Sliding insulated glass doors should consist of 1/4 incn tempered glass <br /> with n 1/2 lnch elrspece, equipped with air-tight seals. <br /> 4. Pattos on Lhe second end Lh1rd fluor of the north buildtny should be <br /> canpletely enclosed using constructton similar to that 1n Recomnendations <br /> 1 , 2, and '± above. It 1s our opinion that the patlos as plenned w111 be <br /> unuaable clua to n�isa 1ev'rla frw� SR 526. <br /> IOwM qlehard�8 Oh�udlere Ine. <br /> Ca�eufln+le h oM On� i,�Pllpn <br />