1131 84TH ST SE 2018-01-02 MF Import

C:3 1 ,_ saw J sa, 1`g TV Environmental Consultants Mr. Steve Hecht p.0. nox 646 Muki)teo, WA 98275 Dear Mr. Hecht: U907640,Aee..W., Suite 230, Mountlake Tenaee. WA 96043(206) 7714 5003 December 6, 1990 ON 1p �t 1 % �eD� As you requested, TRC Environmental Consultants has evaluated traffic noise levels at your proposed building site adjacent to SR-526 in Everett, Washington. This letter describes our measurements and our perspective on traffic noise impacts on the site. Interior sound levels were measured in a residence located at 1029 84th Street, two houses west of the subject property on Tuesday and Wednesday, November 13 and 14, 1990. The so,.nd level meter was positioned in the garage of the residence to record hourly sound levels over a 24-hour period. A Larson -Davis 700-20 sound level meter equipped with a gruel 6 Kjaer 4176 microphone was used for the measurements. The sound level meter was mounted five feet above the ground on a tripod and positioned 82 feet from the center of the enearest nvironmentsinothe project area• Table und traffic lanon R15summarizes the measurements. sound Our measurements indicate that the average sound enetgy for the 24-hour period (denoted Leq(24)) was 46.8 dBA and the day -night sound level? a mn)was 51 levels Ldn is similar to Leq(24) except that night time (10 p.m. sleepinglhours10 itAisodesir desirable account fto have nor the tinterior ra rLdn nearbance ise causes 45 dBAin living spaces. Altho„gh TRC attempted to measure sound levels in a structure similar in construction type to the proposed house, the only suitable ltf availablethe for the measurem,:nt. was the garage at 1029 84th Street. sheathing egocaarage oend aluminum is constructed with 2 x 4 walls, no insulation, plywood exterior siding. "he home you propose to construct specifies interior gypsum wallboard, insulation, and 2 x 6 walls. As an added feature, all living walls facing SR-526 will bt covered with brick. To determine the additional sound attenuation provided by the construction materials you propose. TRC calculated the sound transmission loss for the garage where we took our measurements and for the home you propose. The transmission loss is a measure of the attenuation of the sound by a barrier such as a wall, u. Comprig oand is a funtion of ctave bandsc cbetween 63eand e8000chertz, the y of the on norwalla inn the hhome attenuation you propose to build would provide a minimum of 26 dB more attenuation than the garage walls where we measured. Much of the additional attenuation was attributable to the brick facing. Seattle. WA • Hartlord. CT • Denver. CO -Los Angeles. CA • SoroeneL NJ • Washington. DC A TK Company