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Home My WebLink AboutSDP 93-09; AVIARA PA 25 & 26 NORTH; PRELIMINARY EXTERIOR NOISE ANALYSIS; 1991-02-22• • PRELIMINARY EXTERIOR NOISE ANALYSIS FOR PLANNING AREA 26 NORTH CITY OF CARLSBAD Report# 91-37 February 22, 1991 Prepared For: Hillman Properties West, Inc. 2011 Palomar Airport Road Suite 206 Carlsbad, CA 92009 Prepared By: Vincent Mestre, P.E. MikeHolritz MESTRE GREVE ASSOCIATES 280 Newport Center Drive Suite 230 Newport Beach, CA 92660-7528 (714)760-0891 • • SUMMARY MINIMUM REQUIREMENTS TO MEET CITY OF CARLSBAD STANDARDS Report #91-37 February 22, 1991 EXTERIOR NOISE LEVELS Mestre Greve Associates Report# 91-37 Page l The project must comply with the City's 60 CNEL exterior noise standard. Without mitigation, first floor exterior observers would experience a worst case traffic noise level of 59.6 CNEL at Lot 3. All first floor outdoor living areas in the project will meet the 60 CNEL exterior noise standard without exterior mitigation. The data used in the noise analysis arc shown in the Appendix. If second story balconies arc planned facin1 AI1a Road, balcony barriers will be needed for some homes, The rcqyired balcony barrier locations and heiibts can be addressed in a furure srudy when precise mdioi plans and architectural drawin1s become available, • INTERIOR NOISE LEVELS Residential buildings achieve outdoor to indoor noise reductions of at least 20 dB assuming windows arc closed. Assuming buildings are _located at least 20 feet behind lot edges, all first and second floor exterior building surfaces in the project will be exposed to noise levels less than 65 CNEL, and will therefore require less than 20 dB noise reduction to meet the 45 CNEL interior noise standard. Therefore, all buildings in the project will meet the 45 CNEL interior noise standard without building upgrades. MECHANICAL VENTILATION REQUIREMENTS Since the noise attenuation of a building falls to about 15 dB with windows open, any buildings exposed to noise levels greater than 60 CNEL will meet the 45 CNEL interior noise standard only with windows closed, therefore requiring mechanical ventilation. Since all first floor exterior building surfaces in the project will be exposed to noise levels less than 60 CNEL, single story homes in the project will not require mechanical ventilation. If two-stozy homes arc planned alon ~ Ale;a Road, mechanical ventilation will be reguired for any two-stozy homes on those lots listed in Table S2. Table S2 PRELIMINARY MECHANICAL VENTILATION REQUIREMENTS LOTNUMBER 2 through 4 7 through 9 • • PRELIMINARY EXTERIOR NOISE ANALYSIS FOR AVIARA PLANNING AREA 26 NORTH CITY OF CARLSBAD 1.0 INTRODUCTION Mestre Greve Associates Report# 91-37 Page 2 The purpose of this report is to show compliance of Planning Area 26 North 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 homes. This report incorporates the 60 CNEL exterior noise standard adopted by the City of Carlsbad. The project is located in the City of Carlsbad, east of Interstate 5, as shown in Exhibit 1. The project site will be 'impacted by traffic noise from Alga Road. Due to substantial shielding from surrounding topography, the project site will not be impacted by traffic noise from Interstate 5. The project is not impacted by railroad or aircraft noise. This study determines the need for any mitigation measures to meet the 60 CNEL exterior noise standard, and addresses the 45 CNEL interior noise standard required by the City of Carlsbad. 2.0 NOISE CRITERIA The predominant rating scale now used in California for land-use compatibility assessment is the Community Noise Equivalent Level (CNEL). CNEL 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 car. Time weighting refers to the fact that noise that occurs during cenain sensitive time periods is penalized for occurring at these times. The evening time period (7 PM to 10 PM) penalizes noises by 5 dB, while nighttime (10 PM to 7 AM) noises arc penalized by 10 dB. These time periods and penalties were selected to reflect peoples sensitivity to noise as a function of activity. The City of Carlsbad requires that outdoor living areas not exceed a noise level of 60 CNEL for a six-foot-tall observer located five feet within the property line. In addition, interior noise levels may not exceed 45 CNEL. The site plan for the project (Exhibit 2) was prepared by P &.D Technologies (''Tentative Map for Aviara Planning Arca 26 North, Phase II; December 6, 1990"). 3.0 METHODOLOGY The noise levels projected in the next section of this report were computed using the Highway Noise Model published by the Federal Highway Administration (''FHW A 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. CNEL contours are found by iterating over many distances until the distance to 60,-65, and 70 CNEL contours arc reached. OCEANSIDE VISTA CARL PA 2 6 --,ii-+---1~1.& NORTH Exhibit 1 -Vicinity Map MESTRE GREVE ASSOCIATES 3: m ti) ~ m a ,, m < !Tl > ti) ti) 8 ~ ti) ~ il< =--· C" -· -N l V'.J -· -~ ~ -~ ::, I N ' \ ~ 1 "'\ \ '-\ \ \ \ • IJ I 1_, . '\~~ '~i~\, •• \,· l .. \: ,. .-~\ ') ',) .,/~\J\t \ \ \\ \_.:. . \~ .. . . • .• 'l\ -~·tt•~:--~.'\.._ '• ~~• \\~-~ . t" . . \ . I \. ··• • ' ~ \ •-I • \ \ • • -' y ._ .. :· .,_..,lit'~ .• .. /~.'-.··· \ ~ \ r\-i \ 1 r l (• _K:.; ( .. i_°'.. I" ~~---=-• '\_\ \ I .:/..· //,1 -..,-. \ l L. I J/lf ~~ t~'. \\l)i(··(, ~~ ,D \ ·.\\~ • .1 [3 :\,\ .. •. \'\ ~ )I~ _· ·:\( . .. ,. /' .. ; -' ' : • /)'" :·- ... \ { (\ f, I ) • ·. \ . ,. I . . \ ·\I / .:,(··. : •. I . \ \ . .. ·. I ! \\\ \ ·i ·-• -i~ i \ . :·1 \ 1,J .. · .{1~ :\ \ ... .. ;,\i \ \; \ I • . ... 1-W I . .: 6 :· I , •• \ \ \ ! . . ' .. ) \ \ 1· _\ . :.:•"'"\. ~~ .• . .::0 (Ir • ~-.t:')~. :f.:• _\~~ \ Ii ,-·1· ~!]{ .' ,l,6"%Trrn-._ .·.: ~ ~, ..• ~J;! . . ·1 'f ~-' -.:-. -I.,{ d!rj~r,-..,._ ,; ;,l'lj I '/ ~·-· ~f.-• ·'f; -~ I ,, ~ .. -I f.T""':;~~ (!j ,() \,_.., ./ I Q) • · 1 ~~~ , .. ; to· .• ~ ( ~-(" \~' ·' l '" + ~I \ - • 4.0 ROADWAY NOISE • Mestre Greve Associates Report# 91-37 Page 3 The future traffic volume for Alga Road was obtained from our contour analysis prepared for the Carlsbad Noise Element, (Mestre Greve Associates, April 26, 1990). The future average daily traffic volume for Alga Road between Poinsettia Lane and Batiquitos Drive is 25,400. A vehicle speed of 40 miles ~r hour was utilized. Traffic mixes for each of the time periods used in the CNEL calculation are presented in Table 1. These traffic distribution estimates arc based upon traffic surveys, and arc considered typical for arterials in Southern California. Table 1 TRAFFIC DISTRIBUTION PER TIME OF DAY IN PERCENT OF ADT VEHICLE TYPE Automobile Medium Truck Heavy Truck 0\. Y EVENING NIGHT 75.51 1.56 0.64 12.57 0.09 0.02 9.34 0.19 0.08 Using the assumptions presented above, the future noise levels were computed. The results are reported here in Table 2 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 2 do not take into account the effects of intervening topography that may affect the roadway noise exposure. Topographic effects are included in subsequent analyses to determine the acrual noise exposure on the project site. 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. Table 2 DISTANCE TO NOISE CONTOURS FOR FUTURE TRAFFIC CONDITIONS ROADWAY SEGMENT DISTANCE TO CNEL CONTOUR (FT) -70--65--60- Alga Road 45 97 209 Due to shielding by the roadway edge, first floor exterior observers along Alga Road will experience a !I13,Ximum traffic noise level of 59.6 CNEL at Lot 3. This shielding effect is shown pictorially in Exhibit 3. If second story balconies are planned facing Alga Road, these exterior living areas will not be shielded by the roadway edge, and would experience a worst case traffic noise level of 64.4 CNEL at Lot 3. 205.0_._ _______ ....... _ __.~ .vtESTRE GREVE ASSOCIATES -··z .. ~ --··-··-··-··-··-··-··-··-··-··-··-··-··-··-··-··-··-··-··-·· 220.5 1 inch horizontal = 25 feet 1 inch venical = 12.5 feet Exhibit 3 N Graphic Representation of Roadway Shielding at Lot 3 ~ • S.O EXTERIOR NOISE MITIGATION Mestre Greve Associates Report# 91-37 Page 4 Since the first floor exterior living areas along Alga Road will be exposed to noise levels of less than 60 CNEL, all first floor exterior living areas in the project will meet the exterior noise standard without noise barriers. If second stoo: balconies are planned facioi Al&a Road, balcony barriers wjll be needed for some homes, The rcgyired balcony bauier locations and heiibts can be addressed in a furure study when precise mdini plans and architectural drawinis become available, 6. 0 INTERIOR NOISE MITIGATION The project must comply with the City of Carlsbad indoor noise standard. With standard construction practices in California, residential buildings achieve outdoor to indoor noise reductions of at least 20 dB assuming windows arc closed. All first and second floor exterior building surf aces in the project will be exposed to noise levels less than 65 CNEL, and will therefore require less than 20 dB noise reduction to meet the 45 CNEL interior noise standard. Therefore, all buildings in the project will meet the 45 CNEL interior noise standard without building upgrades. 7. 0 MECHANICAL VENTILATION REQUIREMENTS Since the noise attenuation of a building falls to about 15 dB with windows open, any buildings exposed to noise levels greater than 60 CNEL will meet the 45 CNEL interior noise standard only with windows closed, therefore requiring mechanical ventilation. Since all first floor exterior building surfaces in the project will be exposed to noise levels less than 60 CNEL, any single story homes in the project will not require mechanical ventilation. If two-story homes arc planned for the prQject, mechanical ventiration wm be ~uired for the cwo-stozy homes on those Lots listed below in Table 4 and shown in Exhibit 4, Table 4 MECHANICAL VENTILATION REQUIREMENTS FOR PLANNING AREA 26 NORTH LOTNUMBER 2 through 4 7 through 9 • • l I TWO-STORY HOMES REQUIRING MECHANICAL VENTILATION Q , .. Exhibit 4 -Mechanical Ventilation Requirements (Two-Story Buildings Only) MESTRE GREVE ASSOCIATES Lot 2 3 4 7 8 9 10 • APPENDIX • Mestre Greve Associates Rcpon # 91-37 Page 5 DATA USED IN NOISE ANALYSIS ALONG ALGA ROAD Road Dist. To Dist. To DtsL To Pad Observer Elevation To Observer Elevation Height 219.8 160 205.5 6 220.5 51 220.5 100 205 6 222.1 51 222.1 100 204 6 222.9 51 222.9 120 195 6 223.7 51 223.7 120 196.5 6 227 51 227' 120 196.5 6 227 51 227 195 196.5 6