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Home My WebLink AboutRS_Apron E _Noise Study Report_190606_v1.pdf 222 Etruria Street, Suite 100 Seattle, WA 98109 206.839.0819 ph // 206.839.0824 fx Noise Study Report Boeing Renton Apron E – Phase I Submitted to: Debbie Jung Emily George KPFF Boeing Renton Apron E - Phase I Page 2 Document Information FILE: Noise Study Report - Boeing Renton Apron E - Phase I PROJECT #: 19-7174 PREPARED BY: Alan Burt, P.E. SIGNED: DATE: June 10, 2019 This report has been prepared for the titled project or named part thereof and should not be used in whole or part and relied upon for any other project without the written authorization of SSA Acoustics, LLP. SSA Acoustics, LLP accepts no responsibility or liability for the consequences of this document if it is used for a purpose other than that for which it was commissioned. Persons wishing to use or rely upon this report for other purposes must seek written authority to do so from the owner of this report and/or SSA Acoustics, LLP and agree to indemnify SSA Acoustics, LLP for any and all resulting loss or damage. SSA Acoustics, LLP accepts no responsibility or liability for this document to any other party other than the person by whom it was commissioned. The findings and opinions expressed are relevant to the dates of the works and should not be relied upon to represent conditions at substantia lly later dates. Opinions included therein are based on information gathered during the study and from our experience. If additional information becomes available which may affect our comments, conclusions or recommendations SSA Acoustics, LLP reserves the right to review the information, reassess any new potential concerns and modify our opinions accordingly. Boeing Renton Apron E - Phase I Page 3 I. Introduction The following report documents the results of the evaluation of noise levels from the proposed aircraft stalls to the residential properties east of the proposed site and Renton Memorial Stadium to the south. The evaluation and analysis are based on noise data, proposed site design, and noise level criteria appropriate for the project. II. DESIGN CRITERIA ZONING & CODE REQUIREMENTS According to the City of Renton, the project site and nearest surrounding properties are currently zoned as follows: Property Zoning Project Site UC East (Residential Properties) R-8 South (Renton Stadium) UC According to Renton Municipal Code, UC properties are within “Commercial” zoning districts, and R-8 properties are within “Residential” zoning districts. City of Renton adopts WAC Sections 173- 60-020, 173-60-040, 173-60-050, and 173-60-090 for maximum environmental noise levels. WAC 173-60 defines commercial use properties as Class B EDNA and residential use properties as Class A EDNA. WAC 173-60 limits noise from a Class B EDNA (Commercial) property as follows: Class B EDNA (Commercial) Receiver: Noise is limited to 60 dBA during daytime hours. Class A EDNA (Residential) Receiver: Noise is limited to 57 dBA during daytime hours. During nighttime, defined as the hours between 10 p.m. and 7 a.m., exterior sound level limits are reduced by 10 dBA where the receiving property lies within a residential district of the City. At any hour of the day or night the applicable noise limitations above may be exceeded for any receiving property by no more than: (i) 5 dBA for a total of 15 minutes in any one-hour period; or (ii) 10 dBA for a total of 5 minutes in any one-hour period; or (iii) 15 dBA for a total of 1.5 minutes in any one-hour period. Under WAC 173-60-050, sounds created by aircraft engine testing and maintenance not related to flight operations are exempt between 7:00 AM and 10:00 PM. The current run-up test schedule consists of high-power runs allowed between 8 AM and 5 PM and medium-power runs until 6 PM. Engine run-up testing is exempt from the code limits as the run-up testing will occur only during daytime hours. The following provides an evaluation of the run-up noise levels compared to code limits and existing sound levels and mitigation measures intended to reduce the impact of noise levels to the surrounding properties. Run-up testing will vary in duration and extent throughout the day. To minimize the impact during testing, noise levels should not exceed ambient by more than 10 dBA. Boeing Renton Apron E - Phase I Page 4 The following figure shows a zoning map of the project site and surrounding properties: Figure 1: Proposed Site and Surround Properties (City of Renton GIS) AMBIENT CONDITIONS Existing ambient noise levels were measured on site with Svantek 971 noise monitors between 3/13 – 3/16, 2019. Measurements were conducted at locations representative of the residential properties. The weather during the measurements was clear and the roads were dry. Hourly average LEQ noise levels during daytime hours (between 7 AM – 10 PM) were between 57 – 63 dBA. Boeing Renton Apron E - Phase I Page 5 IV. PROJECT SITE The following figure presents the site plan with the proposed stalls and nearby buildings. Figure 2: Project Site Boeing Renton Apron E - Phase I Page 6 IV. PREDICTED NOISE LEVELS 737 Engine Run-Up Testing Noise Levels: The current run-up test schedule consists of high-power runs allowed between 8 AM and 5 PM and medium-power runs until 6 PM. Typical run-up tests last for about 35 – 40 minutes. During the tests, the engines are at idle approximately 2/3 of the time (about 25 minutes) with engines at full power for 1/3 of the time (two different runs for 5 minutes or less). One engine is tested at a time. The following are noise levels from measurements of 737 engine run-up, provided in a previous study. Noise levels were measured at 50 feet from the engines. Table 1: 737 Engine Noise Levels – Measured 50 feet from engine1 Octave Band Center Frequency (Hz) Engine Power RPM dBA 63 125 250 500 1000 2000 4000 8000 100% 4300 105 112 112 107 102 98 95 92 93 86% 3700 100 102 103 101 97 94 91 90 91 50% 2200 88 81 81 80 81 79 78 84 82 1. Source data obtained from Renton Apron C ground runup stall noise study. Noise data is for 737 Max engines. Predicted Noise Levels Noise levels were calculated based on noise reduction over distance and noise reduction from the barrier or intervening buildings. The following table presents the predicted noise levels from engine run-up testing at the receiving properties. East Receiving Properties The proposed aircraft location in the easternmost stall is approximately 400 feet to the nearest residential zoned property to the east. A solid steel sound wall is proposed along the east and north sides of the stalls to block noise to the properties to the east as shown in figure 1. The proposed noise wall will be 25 feet tall. The following are the predicted noise level at the east receiving property: Table 2 - Predicted Noise Levels – East Receiving Properties (Residential) 737 Engine Sound Level Receiver Distance (feet) Distance Reduction1 Barrier Reduction2 Lp,r 100% Power 105 dBA @ 50’ 400 -20 -15 70 dBA 86% Power 100 dBA @ 50’ 400 -20 -15 65 dBA 50% Power 86 dBA @ 50’ 400 -20 -15 51 dBA Table Notes: 1. Distance Factor = 20*log(Dr/Ds) – 10*log(Q) 2. Barrier reduction from proposed noise barrier According to the predicted noise levels, run-up engine noise will be within or slightly above existing noise levels up to 86% power, and about 10 dBA above existing levels at 100% power. This meets the recommended level increase above ambient levels to reduce the noise impact. Note that without the sound wall, noise levels from the testing would be 66 – 85 dBA, which would be significantly above existing levels. Boeing Renton Apron E - Phase I Page 7 South Receiving Property (Renton Memorial Stadium) The proposed aircraft locations in the stalls are each approximately 650 feet to the south property. The paint hanger and will act as a noise barrier to the south property. Table 3 - Predicted Noise Levels – South Receiving Property (Commercial) 737 Engine Sound Level Distance (feet) Distance Reduction1 Barrier Reduction2 Lp,r 100% Power 105 dBA @ 50’ 650 -25 -20 60 dBA 86% Power 100 dBA @ 50’ 650 -25 -20 55 dBA 50% Power 86 dBA @ 50’ 650 -25 -20 41 dBA Table Notes: 1. Distance Factor = 20*log(Dr/Ds) – 10*log(Q) 2. Barrier reduction from intervening building According to the predicted noise levels, run-up engine noise will be within current background levels. Note that the distances between the engines and the sound wall and the receiving properties are such that reflected sound energy from the sound wall will not increase noise levels from the engines. V. SUMMARY This concludes the noise evaluation for the proposed 737 run-up stalls at the Boeing Renton Apron E. Please contact us if you have questions or need further information.