8220 5TH AVE W 2016-01-01 MF Import

Mr. David L. Bigelow June 21 , 1989 Page Two According to the Snohomish County Planning Department (based on a telephone conversation on June 16, 1989, with Mr. Justin Osemene), the requirement is to meet an interior Leq of 45. This objective will require an outside-to-inside noise reduction of 25 d8 (70-45) for the north, east and west faces of units 1 through 4, and 21 dB (66-45) for the north faces of units 5 through 11 . An outside-to-inside noise reduction of up to 25 d8 can be achieved with typical residential construction (ass�ning insulated glass windows, solid core 'I � doors and air-tight weather serls) . Since units 1 through 4 are borderline in i II meeting the 25 d8 noise reduction requirement, we recartnend the following: I1 . For the north wall of unit 1 (which contains no windows) , add a second layer of 1/2 inch gypsum board inside. 2. The windows in the east and west faces of units 1 through 4 should contain i glass which is at least 3/16 inch thick and a minimum 3/4 inch airspace. The vinyl window frames should be packed with insulation and caulked in place to provide an air tight seal . � 3. Sliding insulated glass doors, if zny, should consist of 1/4 inch glass �� with a 1/2 inch airspace, equipped with air-tight seals. `� ; �3 No special construction is recon��tnd�d for units 5-11 . �� Y� , i � � I I i iowne. Richards & Chaudiere. Inc. . r-�..�., .. .-.. , . . . ..