AgdaPkt 2017-09-11 Closed and Joint SA PFA

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TA. - Page 97 LSA ASSOCIATES, INC. ROCKETSHIP REDWOOD CITY ELEMENTARY SCHOOL PROJECT SEPTEMBER 2016 INITIAL STUDY/MITIGATED NEGATIVE DECLARATION departing from the project site, especially during the demolition and site preparation phase of construction. The second type of short-term noise impact is related to the noise generated by heavy equipment operating on the project site. Construction is performed in discrete steps,each of which has its own mix of equipment and,consequently,its own noise characteristics. These various sequential phases would change the character of the noise generated on the site and,therefore,the noise levels surrounding the site as construction progresses. Despite the variety in the type and size of construction equipment, similarities in the dominant noise sources and patterns of operation allow construction-related noise ranges to be categorized by work phase. Table 5 lists typical construction equipment noise levels recommended for noise impact assessments,based on a distance of 50 feet between the equipment and a noise receptor. Demolition and construction activities at the Table 5: Typical Construction Equipment project site are expected to require the use of Maximum Noise Levels,Lmax earthmovers such as bulldozers and scrapers, Suggested loaders and graders,water trucks,and haul Range of Maximum Sound trucks. As shown in Table 5,the typical Maximum Levels for Sound Levels Analysis maximum noise level generated by each Type of Equipment dBA at 50 feet dBA at 50 feet bulldozer on the project site is assumed to be Pile Drivers 81 to 96 93 85 dBA Lmax102 at 50 feet from the operating Rock Drills 83 to 99 96 earthmover. The maximum noise level Jackhammers 75 to 85 82 generated by hydraulic backhoes is approxi- Pneumatic Tools 78 to 88 85 mately 86 dBA L,,,ax at 50 feet. The Pumps 74 to 84 80 Scrapers 83 to 91 87 maximum noise level generated by haul Haul Trucks 83 to 94 88 trucks is approximately 88 dBA Lmax at 50 Cranes 79 to 86 82 feet from these vehicles operating at full Portable Generators 71 to 87 80 power.Pile drivers would not be used for Rollers 75 to 82 80 construction of this project. Dozers 77 to 90 85 Tractors 77 to 82 80 Front-End Loaders 77 to 90 86 Each doubling of the sound sources with Hydraulic Backhoe 81 to 90 86 equal strength would increase the noise level Hydraulic Excavators 81 to 90 86 by 3 dBA.Assuming each piece of construe- Graders 79 to 89 86 tion equipment operates at some distance Air Compressors 76 to 89 86 apart from the other equipment,the worst- Trucks 81 to 87 86 case combined noise level at the nearest uses Source: Bolt,Beranek&Newman,1987.Noise Control for to the site during this phase of construction Buildings and Manufacturing Plants. would be 91 dBA Lmax at 50 feet from the operating equipment. The nearest existing sensitive receivers in the vicinity of the project site are the residences located approximately 400 feet south of the project site.At this distance,construction- related noise levels from the use of heavy construction equipment would be expected to attenuate to approximately 73 dBA L,,,ax,which is well below the City's 110 dBA noise ordinance threshold. Therefore,the project would not result in a significant noise impact related to construction noise. 102L.is the maximum A-weighted sound levels measured on a sound level meter,during a designated time interval,using fast time averaging. P:1RWC1401B Rocketship Sch-I\PRODUCrSUS-MND1Public\Ra ketship Public Review 09-29-16.docx(09/29/16)PUBLIC REVIEW DRAFT 73 ATTY/RESO.0084/CC RESO ADOPTING CEQA-ROCKETSHIP CHARTER SCHOOL APPEAL REV:09-05-17 VR Page 81 of 124