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Home My WebLink AboutCT 99-13; Steiner Property; Tentative Map (CT) (21)3 EXTERIOR NOISE ANALYSIS FOR THE STEINER PROPERTY CITY OF CARLSBAD Report #99-118 June 28,1999 Prepared for: WESTERN PACIFIC HOUSING 2385 Camino Vida Roble, Suite 107 Carlsbad, CA 92009 Prepared By: Fred Greve, P.E. Keith Utsler MESTRE GREVE ASSOCIATES 280 Newport Center Drive Suite 230 Newport Beach, CA 92660-7528 Phone (949) 760-0891 Fax (949) 760-1928 Mestre Greve Associates Report #99-118 Page Iof6 SUMMARY EXTERIOR NOISE ANALYSIS FOR THE STEINER PROPERTY CITY OF CARLSBAD EXTERIOR NOISE MITIGATION The City of Carlsbad has adopted an exterior noise standard of 60 CNEL. For the exterior living areas which are exposed to noise levels greater than 60 CNEL, some form of noise mitigation is required. An effective method of reducing the traffic noise to acceptable levels is with a noise barrier. The project site is located adjacent to Poinsettia Lane and El Camino Real. Representative cross-sections along Poinsettia Lane and El Camino Real (see Appendix 1A for analysis data) were analyzed utilizing the FHWA Model to determine the necessary noise barrier locations and heights. Exterior living areas adjacent to Poinsettia Lane and El Camino Real will be exposed to worst case noise levels of 64.3 CNEL at Lots 4 through 9. Therefore, in order to meet the 60 CNEL exterior noise standard, a noise barrier will be required for exterior living areas adjacent to Poinsettia Lane and El Camino Real. The required noise barrier locations and heights to meet the 60 CNEL exterior noise standard are listed in Table SI, and are shown in Exhibit SI. TABLE SI REQUIRED EXTERIOR LIVING AREA NOISE BARRIER LOCATIONS AND HEIGHTS POINSETTIA LANE REQUIRED LOT BARRIER HEIGHT* 4 through 9 5.5 * indicates height at pad elevation The noise barriers may consist of a wall, a berm, or a combination of the two. The noise barriers must have a surface density of at least 3.5 pounds per square foot, and shall have no openings or gaps. The wall may be constructed of stud and stucco, 3/8 inch plate glass, 5/8 inch plexiglass, any masonry material, or a combination of these materials. Second Floor Exterior Noise Mitigation According to the City of Carlsbad Noise Element, any balconies greater than six feet deep are considered exterior living areas, and must meet the 65 CNEL exterior noise standard. A detailed analysis will be required for the second floor exterior living areas when detailed architectural plans become available, and prior to issuance of a building permit 8ASKA PARCEL tAPN 216-^(60-57) <"<X=>3^ TO C4MN0 KM. (WE PtRT Of UfKOVBI LOHF SJBOioSKlM.6 MESTRE GREVE ASSOCIATES EXHIBIT SI NOISE BARRIER HEIGHTS & LOCATIONS Mestre Greve Associates Report #99-118 Page 2 of 6 INTERIOR NOISE MITIGATION Detailed engineering calculations which demonstrate the noise reduction levels are necessary for residential building attenuation requirements of greater than 20 dB. A detailed indoor noise analysis is required to determine the building upgrades for the homes adjacent to Poinsettia Lane and El Camino Real when detailed architectural plans become available, and prior to issuance of building permit Mestre Greve Associates Report #99-118 Page 3 of 6 EXTERIOR NOISE ANALYSIS FOR THE STEINER PROPERTY CITY OF CARLSBAD 1.0 INTRODUCTION The purpose of this report is to assess compliance of The Steiner Property with the noise related conditions of approval placed on the project by the City of Carlsbad. The project calls for the development of single-family residences. This report addresses the future noise levels at the project site in relation to the 60 CNEL exterior standard adopted by the City of Carlsbad. Site plan and grading information was obtained from Hunsaker and Associates Carlsbad, Inc. dated May 5,1999. The project is located in the City of Carlsbad, as shown in Exhibit 1. The primary noise source in the project area is traffic noise from Poinsettia Lane and El Camino Real. This study identifies any mitigation measures necessary to meet the 60 CNEL exterior standard. 2.0 CITY OF CARLSBAD NOISE STANDARDS The City of Carlsbad specifies outdoor and indoor noise limits for residential land uses. Both standards are based upon the CNEL index. CNEL or 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 occurring during certain noise-sensitive time periods is given more significance because it occurs at these times. In the calculation process, noise occurring in the evening time period (7 p.m. to 10 p.m.) is increased by 5 dB, while noise occurring in the nighttime period (10 p.m. to 7 a.m.) is increased by 10 dB. These time periods and increases were selected to reflect increased sensitivity to noise while sleeping, eating and relaxing. The City of Carlsbad has adopted an exterior noise standard of 60 CNEL for a five-foot-tall observer located five feet within the property line. In addition, the City has decided upon an interior noise standard of 45 CNEL. This analysis assesses the noise levels within the project with respect to the 60 CNEL exterior standard. 3.0 METHODOLOGY The traffic noise levels projected in this report were computed using the Highway Noise Model published by the Federal Highway Administration ("FHWA Highway Traffic Noise Prediction Model", FHWA-RD-77-108, December 1978). The FHWA Model uses traffic volume, vehicle mix, vehicle speed, and roadway geometry to compute the "equivalent noise level". A computer code has been written which computes equivalent noise levels for each of the time periods used in CNEL. Weighting these noise levels and summing them results in the CNEL for the traffic projections used. TO cumn ffM. me PMT or vmova LOT uacaaoH MFSIRF. GREVE ASSOCIATES EXHIBIT 2 NOISE BARRIER HEIGHTS & LOCATIONS Mestre Greve Associates Report #99-118 Page 4 of 6 4.0 ROADWAY NOISE EXPOSURE The future traffic information for Poinsettia Lane and El Camino Real was obtained from the City of Carlsbad Transportation Department on September 29, 1997. Table 1 presents the traffic volumes, vehicle speeds, and roadway grades used in the CNEL calculations. Table 2 presents the traffic distribution used in the calculations. Arterial traffic distribution estimates are based upon traffic surveys conducted in Southern California. TABLE 1 Future Traffic Volumes, Speeds and Roadway Grades Roadway Traffic Volume (ADT) Speed Grade Poinsettia Lane El Camino Real 14,100 42,200 50 <2% 50 <2% TABLE2 Traffic Distribution per Time of Day in Percent of ADT Vehicle Type Day Evening Night Automobile Medium Truck Heavy Truck 75.51 1.56 0.64 12.57 0.09 0.02 9.34 0.19 0.08 TheFHWA model used these assumptions to compute the future noise levels at the project site. Table 3 reports the modeling results in terms of distances to the 60, 65, and 70 CNEL contours. These represent the distances from the centerline of the roadway to the contour value shown. Note that the values given in Table 3 do not take into account the effect of intervening topography that may affect the roadway noise exposure. Topographic effects are included in a subsequent section of this report. In addition, these projections do not include any future vehicle noise reduction assumptions to take into account the effects of legislation requiring quieter vehicles in the future. TABLES Distance to Noise Contours for Future Traffic Conditions Distance to CNEL Contour (ft.) Roadway -70- -65- -60- Poinsettia Lane 44 96 206 El Camino Real 92 199 428 Mestre Greve Associates Report #99-118 Page 5 of 6 5.0 EXTERIOR NOISE MITIGATION The City of Carlsbad has adopted an exterior noise standard of 60 CNEL. For the exterior living areas which are exposed to noise levels greater than 60 CNEL, some form of noise mitigation is required. An effective method of reducing the traffic noise to acceptable levels is with a noise barrier. The project site is located adjacent to Poinsettia Lane and El Camino Real. Representative cross-sections along Poinsettia Lane and El Camino Real (see Appendix 1A for analysis data) were analyzed utilizing the FHWA Model to determine the necessary noise barrier locations and heights. Exterior living areas adjacent to Poinsettia Lane and El Camino Real will be exposed to worst case noise levels of 64.3 CNEL at Lots 4 through 9. Therefore, in order to meet the 60 CNEL exterior noise standard, a noise barrier will be required for exterior living areas adjacent to Poinsettia Lane and El Camino Real. The required noise barrier locations and heights to meet the 60 CNEL exterior noise standard are listed in Table 4, and are shown in Exhibit 2. TABLE 4 REQUIRED EXTERIOR LIVING AREA NOISE BARRIER LOCATIONS AND HEIGHTS POINSETTIA LANE REQUIRED LOT BARRIER HEIGHT* 4 through 9 5.5 * indicates height at pad elevation The noise barriers may consist of a wall, a berm, or a combination of the two. The noise barriers must have a surface density of at least 3.5 pounds per square foot, and shall have no openings or gaps. The wall may be constructed of stud and stucco, 3/8 inch plate glass, 5/8 inch plexiglass, any masonry material, or a combination of these materials. Second Floor Exterior Noise Mitigation According to the City of Carlsbad Noise Element, any balconies greater than six feet deep are considered exterior living areas, and must meet the 65 CNEL exterior noise standard. A detailed analysis will be required for the second floor exterior living areas when detailed architectural plans become available, and prior to issuance of a building permit 6.0 INTERIOR NOISE MITIGATION Detailed engineering calculations which demonstrate the noise reduction levels are necessary for residential building attenuation requirements of greater than 20 dB. A detailed indoor noise analysis is required to determine the building upgrades for the homes adjacent to Poinsettia Lane and El Camino Real when detailed architectural plans become available, and prior to issuance of building permit. 6 0 MESTRE GREVE ASSOCIATES EXHIBIT 1 VICINITY MAP c Mestre Greve Associates Report #99-118 Page 6 of 6 APPENDIX 1A DATA USED TO DETERMINE FIRST FLOOR NOISE LEVELS DESIGN DATA - REAR YARD AREA WITH A 5 FT. OBSERVER POINSETTIA LANE Lot 4 5 6 7 8 9 Road Elevation 270.0 268.6 267.6 267.0 266.4 265.2 Distance To Wall 102 102 102 102 102 102 Base Of Wall 279.0 278.5 277.6 276.2 275.0 273.0 Distance To Observer 107 107 107 107 107 107 Pad Elevation 279.0 278.5 277.6 276.2 275.0 273.0 ELCAMINOREAL Lot Road Elevation Distance To Wall Base Of Wall Distance To Observer Pad Elevation 3 4 285.0 279.0 500 410 290.0 279.0 540 415 277.5 279.0