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HomeMy WebLinkAbout22-102032-UP Site Noise Study-5-4-22 (206) 378-0569 (855) 476-2874 www.greenbusch.com 1900 W Nickerson St., #201, Seattle, WA 98119  209 Oxford Rd, Franklin, OH 45005  2262 N Albina Ave., #340 Portland, OR 97227 Memorandum DATE: April 9, 2022 TO: Lindsay Crawford, AIA – Bassetti Architects FROM: Drew Savas, INCE Ashley Masoner RE: Illahee Middle School Replacement – Site Noise Study Lindsay: This memorandum compares the measured sound levels at Illahee Middle School (36001 1st Avenue South, Federal Way, WA) with Washington Administrative Code (WAC) 246- 366-030(3), which provides exterior sound limits for new schools and additions to existing schools. SUMMARY School is assumed to be in session between 8 A.M. and 2:30 P.M., therefore sound levels measured during the hours of 8 A.M. to 3 P.M. are compared with the hourly WAC exterior sound limits. Two sound meters were set up on opposite ends of the campus: one meter was located on the roof of Building 1 (referred to as Location 1) and one on the roof of Building 6 (referred to as Location 2). Site noise levels measured at Location 1 were below WAC exterior limits during school hours. Site noise levels measured at Location 2 occasionally exceed WAC exterior limits during school hours; while measured exceedances of the WAC LEQ exterior limit at Location 2 could be attributed to nearby active rooftop equipment, the exceedance of the LMAX exterior limits cannot be attributed to the rooftop equipment. Therefore, building envelope sound reduction must be considered during design to ensure WAC interior sound limits are not exceeded. MEASUREMENTS Weather Conditions Existing noise levels were documented between 5:00 P.M. on Tuesday, February 22,2022 and 8:00 A.M. on Thursday, February, 24, 2022. Weather conditions varied throughout the data collection period, including wind speeds of up to 12 miles per hour. The temperature ranged from 23 to 36 degrees Fahrenheit and there was no precipitation. April 9, 2022 Page 2 Illahee Middle School Replacement – Site Noise Study (206) 378-0569 (855) 476-2874 www.greenbusch.com 1900 W Nickerson St., #201, Seattle, WA 98119  209 Oxford Rd, Franklin, OH 45005  2262 N Albina Ave., #340 Portland, OR 97227 Location Equipment was deployed at two locations near the future school façade. The first location, Location 1, was on the roof of Building 1 near the northwest end. The second location, Location 2, was on the roof of Building 6 at northeast corner which is near the closest roadway (First Avenue South). See Figure 1. Equipment Two Svantek 971 Type 1 (as defined by ANSI) sound level meters were used for the measurements. Field calibrations were performed before and verified after the measurement period. All equipment was laboratory calibrated within one year of the measurement date. Figure 1. Measurement Locations April 9, 2022 Page 3 Illahee Middle School Replacement – Site Noise Study (206) 378-0569 (855) 476-2874 www.greenbusch.com 1900 W Nickerson St., #201, Seattle, WA 98119  209 Oxford Rd, Franklin, OH 45005  2262 N Albina Ave., #340 Portland, OR 97227 Figure 2. Location 1 Equipment Figure 3. Location 2 Equipment REGULATORY CRITERIA WAC 246-366-030(3) includes the following requirement. However, it should be noted that the time-weighting for LMAX is not defined in this section of the WAC, “slow” (LASMAX), “fast” (LAFMAX), and “impulse” (LAIMAX) are possible time weightings, where slow results is the lowest sound level and impulse the highest, for short -duration events of louder duration (dog bark, birdsong, motorcycle passby, etc.). The only reference to time weighting is in WAC 173-58-080, which states a slow response shall be used for vehicle exhaust systems. While not directly related to WAC 246-366-030, it serves as the only available guidance on what time weighting may have been intended. Noise from any source at a proposed site for a new school, an addition to an existing school, or a portable classroom shall not exceed an hourly average of 55 dBA (LEQ 60 minutes) and shall not exceed an hourly maximum (LMAX) of 75 dBA during the time of day the school is in session; except sites exceeding these sound levels are acceptable if a plan for sound reduction is included in the new construction proposal and the plan for sound reduction is approved by the health officer. April 9, 2022 Page 4 Illahee Middle School Replacement – Site Noise Study (206) 378-0569 (855) 476-2874 www.greenbusch.com 1900 W Nickerson St., #201, Seattle, WA 98119  209 Oxford Rd, Franklin, OH 45005  2262 N Albina Ave., #340 Portland, OR 97227 These exterior limits are intended to ensure that interior sound levels comply with WAC 246-366-110(2): In new construction, the actual background noise at any student location within the classroom shall not exceed 45 dBA (LEQ,x) and 70 dB (LEQ,x) (unweighted scale) where x is thirty seconds or more. The health officer shall determine compliance with this section when the ventilation system and the ventilation system's noise generating components, e.g., condenser, heat pump, etc., are in operation. In summary, the combination of environmental noise (sounds from outside) and interior background noise (sounds from building mechanical) cannot exceed 45 dBA LEQ,30sec within a classroom. RESULTS As shown in Table 1 and Figure 4, the hourly sound levels measured during school hours at Location 1 comply with the WAC limits of LEQ 55 dBA and LMAX 75 dBA, including both “fast” and “slow” LMAX time weightings. However, at Location 2, the WAC limit of LEQ 55 dBA was exceeded during the 8 A.M., 12 P.M., and 1 P.M. hour, as shown in Table 1 and Figure 5. Additionally, the hourly LASMAX sound level exceeded the WAC limit of LMAX 75 dBA during the 1 P.M. Furthermore, the hourly LAFMAX sound level during the 8 A.M., 9 A.M., 12 P.M., and 1 P.M. hour at Location 2 exceeded the WAC limit of LMAX 75 dBA. Table 1. Measured Hourly Sound Levels during School Hours, Min-Max, dBA Location Date [Time] LAEQ (WAC Limit) LASMAX (WAC Limit) LAFMAX (WAC Limit) Location 1 February 23, 2022 [8 A.M. – 3 P.M.] 46-52 (Limit 55) 61-66 (Limit 75) 64-71 (Limit 75) Location 2 February 23, 2022 [8 A.M. – 3 P.M.] 54-59 (Limit 55) 63-77 (Limit 75) 66-81 (Limit 75) April 9, 2022 Page 5 Illahee Middle School Replacement – Site Noise Study (206) 378-0569 (855) 476-2874 www.greenbusch.com 1900 W Nickerson St., #201, Seattle, WA 98119  209 Oxford Rd, Franklin, OH 45005  2262 N Albina Ave., #340 Portland, OR 97227 Figure 4. Location 1 Measured Hourly Sound Levels during School Hours Figure 5. Location 2 Measured Hourly Sound Levels during School Hours CONCLUSION The WAC 246-366-030(3) acoustical requirements are being met at Location 1, but not at Location 2. These elevated noise levels will need to be addressed in the façade design to accommodate classroom interior sound levels outlined in WAC 246-366-110(2).