Traffic Noise Analysis for The Westerly City of Simi Valley, California

Transcription

1 ATTACHMENT 6 Traffic Noise Analysis for The Westerly City of Simi Valley, California August 3, 2016 Prepared For: Landsea Homes 7525 Irvine Center Drive, Suite 200 Irvine, CA Prepared By: Ted Lindberg, INCE Bd. Cert. Mike Holritz, INCE Fairchild Road, Suite 230 Irvine, CA

2 TRAFFIC NOISE ANALYSIS FOR THE WESTERLY CITY OF SIMI VALLEY 1.0 INTRODUCTION The purpose of this report is to demonstrate compliance of The Westerly with the noise related Conditions of Approval placed on the project by the City of Simi Valley. The project calls for the development of multi-family homes. The project is located in the City of Simi Valley, as shown in Exhibit 1. The site plan is shown in Exhibit 2. The project will be impacted by noise from traffic on Madera Road and Los Angeles Avenue. This report specifies any mitigation measures necessary to meet the 63 CNEL exterior noise standard and the 45 CNEL interior noise standard. Site plan and grading information was obtained from the Site Plan-Base-Alt Model by Hunsaker and Associates. 2.0 CITY OF SIMI VALLEY NOISE STANDARDS The City of Simi Valley specifies outdoor and indoor noise limits for residential land uses. Both standards are based upon the CNEL index. CNEL (Community Noise Equivalent Level) is a 24- hour time-weighted annual average noise level based on the A-weighted decibel. A-weighting is a frequency correction that correlates overall sound pressure levels with the frequency response of the human ear. Time weighting refers to the fact that noise that occurs during certain noisesensitive time periods is given more significance because it occurs at these times. In the calculation of CNEL, noise occurring in the evening time period (7 p.m. to 10 p.m.) is weighted by 5 db, while noise occurring in the nighttime period (10 p.m. to 7 a.m.) is weighted by 10 db. These time periods and weighting factors are used to reflect increased sensitivity to noise while sleeping, eating, and relaxing. The City of Simi Valley traffic noise standards are contained in Chapter 8 of the General Plan. Table N-2 indicates that the City has adopted an exterior noise standard of 63 CNEL for private patio areas and balconies at multi-family residences, and an interior noise standard of 45 CNEL. 513

3 514

4 515

5 3.0 NOISE EXPOSURE The existing traffic noise levels presented in this report were determined by conducting longterm measurements near the roadways adjacent to the site. The measurement locations are shown in Exhibit hour noise measurements were made along Madera Road between 1:00 p.m. on June 27 and 1:00 p.m. on June 28, hour noise measurements were made along Los Angeles Avenue between 1:00 p.m. on June 28 and 1:00 p.m. on June 29, The noise monitor used to measure the noise levels was a Brüel & Kjær Type 2236 Sound Level Meter. The measurement system was calibrated before and after the measurements with a Brüel & Kjær Type 4231 sound level calibrator, with current calibration traceable to the National Institute of Standards and Technology. Noise measurements were performed with the microphone placed at approximately 5 above ground level. These measurements were performed at the same distance to the roadways as the proposed exterior living areas, and are used to determine the existing CNEL noise levels at the nearest exterior areas of the project. The measurement results are presented in Table

6 517

7 Table 1 HOURLY NOISE LEVELS AND RESULTING CNEL LEVELS MEASURED NOISE LEVEL HOUR MADERA ROAD LOS ANGELES AVENUE 1300 to to to to to to to to to to to to to to to to to to to to to to to to Existing CNEL = The nearest exterior residential area along Madera Road will be 97 feet from the centerline of the roadway. At this distance, observers would be exposed to existing unmitigated traffic noise levels of about 66.6 CNEL. The nearest exterior residential area along Los Angeles Avenue will be 95 feet from the centerline of the roadway. At this distance, observers would be exposed to existing unmitigated traffic noise levels of about 65.2 CNEL. 518

8 Traffic volumes are expected to increase in the future. The existing and year-2030 peak-hour traffic volumes were obtained from the Draft Westerly Residential Development Transportation Impact Study by Fehr & Peers, June Comparison of these existing and future peak-hour volumes results in the noise level increase in decibels due to traffic growth. Calculations show that for both roadways, the traffic noise levels are expected to increase by 1.5 db due to increased traffic volumes. Therefore, traffic noise levels at exterior areas are projected to be 68.1 CNEL along Madera Road, and 66.7 CNEL along Los Angeles Avenue. 4.0 EXTERIOR MITIGATION There are no private exterior living areas in the project. According to Ms. Lorri Hammer at the City Planning Department, the patios are front courtyards, and are not subject to the City s 63 CNEL exterior noise standard. Balconies are not planned for the project. Therefore, noise barriers will not be required. 5.0 INTERIOR NOISE The project must comply with the City of Simi Valley indoor noise standard of 45 CNEL. To meet the interior noise standard, the buildings must provide sufficient outdoor-to-indoor building attenuation to reduce the noise to acceptable levels. The outdoor-to-indoor noise reduction characteristics of a building are determined by combining the transmission loss of each of the building elements that make up the building. Each unique building element has a characteristic transmission loss. For residential units, the critical building elements are the roof, walls, windows, doors, attic configuration and insulation. The total noise reduction achieved is dependent upon the transmission loss of each element, and the surface area of that element in relation to the total surface area of the room. Room absorption is the final factor used in determining the total noise reduction. The nearest exterior building surface along Madera Road will be exposed to noise levels of 68.4 CNEL, and therefore, rooms along Madera Road will require at least 23.4 db noise reduction in order to meet the 45 CNEL interior noise standard. Exterior building surfaces along Los Angeles Avenue will be exposed to noise levels of 67.3 CNEL, and therefore, rooms at this location will require at least 22.3 db noise reduction in order to meet the 45 CNEL interior noise standard. Detailed engineering calculations are necessary for building attenuation requirements greater than 20 db. A future study will be needed to address the interior noise levels when complete architectural drawings are available, and prior to the issuance of building permits. 519

9 6.0 ADEQUATE VENTILATION Since the noise attenuation of a building falls to about 12 db with windows open, all buildings exposed to noise levels greater than 57 CNEL will meet the 45 CNEL interior noise standard only with windows closed. In order to assume that windows can remain closed to achieve this required attenuation, adequate ventilation with windows closed must be provided per the applicable California Building Standards Code. Adequate ventilation will be required for the units shown in Exhibit

10 521

11 APPENDIX CALCULATION SPREADSHEETS DATA USED TO DETERMINE EXTERIOR NOISE LEVELS 522

12 "The Westerly", Simi Valley Measured 97' = 66.6 CNEL WORKSHEET - CALVENO - (NO MACRO) tl Landsea Homes - Gene Strojek future db increase = 1.5 From: BarrCalc CNEL MASTER PROJECT # projected future CNEL 68.1 MH; July 2016 Date Roadway Name Madera Road Day Eve Night Equiv Vehicles Per Day 38,500 ADT to match projected CNEL Auto 75.51% 12.57% 9.34% 208.6% 97.42% Speed (mph) 45 speed per google street view MT 1.56% 0.09% 0.19% 3.7% 1.84% Grade Adj. (db) 0.00 db HT 0.64% 0.02% 0.08% 1.5% 0.74% Vehicle Noise Red (db) 0 db 77.71% 12.68% 9.61% Roadway Grade 0.0% To get other noise levels (CNEL), To get other distances (ft), This is the CNEL at 15m put in other distances (ft) put in other noise levels Soft Hard Dist. Soft Hard CNEL Soft Hard Auto ,312 Medium Truck ,837 Heavy Truck ,459 Total ,159 bldg meas 'd DX "The Westerly", Simi Valley Measured 95' = 65.2 CNEL WORKSHEET - CALVENO - (NO MACRO) tl Landsea Homes - Gene Strojek future db increase = 1.5 From: BarrCalc CNEL MASTER PROJECT # projected future CNEL 66.7 MH; July 2016 Date Roadway Name Los Angeles Avenue Day Eve Night Equiv Vehicles Per Day 27,000 ADT to match projected CNEL Auto 75.51% 12.57% 9.34% 208.6% 97.42% Speed (mph) 45 speed per google street view MT 1.56% 0.09% 0.19% 3.7% 1.84% Grade Adj. (db) 0.00 db HT 0.64% 0.02% 0.08% 1.5% 0.74% Vehicle Noise Red (db) 0 db 77.71% 12.68% 9.61% Roadway Grade 0.0% To get other noise levels (CNEL), To get other distances (ft), This is the CNEL at 15m put in other distances (ft) put in other noise levels Soft Hard Dist. Soft Hard CNEL Soft Hard Auto ,622 Medium Truck ,288 Heavy Truck ,023 Total bldg meas 'd DX