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Home My WebLink AboutCT 89-35; VISTA SAN MALO; ENVIRONMENTAL STUDY ANALYSIS; 1990-01-08• cAc Environmental Study Ana1ysis and Report for Vista San Malo 4 Detached Single Family Houses project (Job Number 8923 B) Located S. E. corner of Las Flores Dr./Tuttle Street in the city of Carlsbad, County of San Diego, California Assessors Paree 1 Number: 155-1 60-12 Prepared for LVM Design Mr. LYNN MAUDLIN Architect l 857 Tule Crt, Carlsbad CA 92000 Tel:(619)438-2110 by cAc Callforn1a Acoustical Consultants 16998 Dominican Dr. San Diego, CA 92128 Tel:(619) 592-9-592 Dec. 1 6 , 1 989 Revised: Jan 8, 1 990 CD • • Summary This report contains measurements and analysis pertaining to the present and future (2009) exterior CNEL effecting the site of the development project, 4 detached single family houses, named: Vista San Malo. located on the South side of the Las Flores Dr., SW. from the Tuttle Street, in the city of Carlsbad California. APN 155 .. • 160··· l 2. Job No.8923B. The present and predicted future noise, is originating from 1. The 8 lane traffic on lnterst.5, presently 115,000 ADT CNEL 78 dB(A)* 2. The Las Flores exit.off ramp.stop sign" 3,200 ADT CNEL 66 dB(A)** 3. Las Flores Dr. 100 Ft.W of the ramp " . 6,000 ADT CNEL 67.5 Present, maximum combined CNEL = <68 dB(A) (see report for detail and explemation) Future highest combined CNEL ., at mark 4 = 69.S dB(A) *., ** * Sf nee the site is in the general direction of the main growing pattern of the San Diego County, our future noise calculation is based on the most conserYative, data projection with the "worst" possible combination of 1.7 x present ADT, 2% HT.and 90/ 10% day/night traffic distribution. Present environmental noise regulation in the City of Carlsbad request that the noise level 5' ins•ide the property line, at 6' observation height should not exceed an Leq( h) 60 dB(A). Furthermore at the building site at the upper level of the highest window should also no more than 60 dB(A) Leq( h) environmental noise residue. In concurrence with the noise ordinance requests of the City of Carlsbad Noise mitigation measures in essence will be achieved by a 8' high cement brick, or cement brick/plexiglass combination fence sound barrier wall at the N.side ( Las Flores side ) of the No. 1 unit. This noise barrier wall should continue an additional 1 o· toward S.E. alongside the property line at the Tuttle street. It should continue for an additional 30' in the same direction, but only 7' high and finally another 30' as a 6' high barrier fence; thus shading the No.2 (and partly the other two as we 11) Building's exposed side(s) as we 11. At all other point of the project, regular I "stucco 2x4 with R-· 11 insul.-1· 1 /2" Gypsum inside type walls and normal single glass windows will prov1de sufficient structural noise insulatton to keep the interior under 45 dB(A) w1th the predicted future exterior noise exposure. 0 • 1 . INTRODUCTION The purpose of this report is to investigate and ensure the project's comp11ance with the app11cab1e environmental noise regulations of City of Carlsbad, San Diego County and the State of California: Thus, no higher, than 60 dB(A) (CNEL) within the project site at any outside recreational areas, and no more than CNEL 45 dB(A) inside of a residence building at an habitable areas. In addition and more specifically the present environmental noise regulation in the C1ty of Carlsbad requests, that the noise level 5' inside the property line, at 6' observat1on height ( 1.82 m, instead of the standard 1.50 m. !) should not exceed an Leq(h) 60 dB(A). Furthermore at the building site at the upper level of the highest window should also no more than 60 dB(A) Leq(h) environmental noise residue. 2. DATA AND APPROACH The first steep is to establish and evaluate the present and the predicted future exterior noise level exposing the project. The latest available CALTRANS and SANDAG data was used, compared and adjusted with our on-location measurements. Based on this, plus several different demographic and area growth pattern etc. was considered to project an - as realistic as possible -future no1se level around the project. ·r raffic noise was measured 2 times on site, both at peak traffic times: Dec. 7,89, Thusday 12 noon to 1 PM (lunch hour), and Dec. 8, Fr1day 5-6 PM. The Friday noise Leq(h) was 1-2 dB(A) higher at every measured locations, therefore we use the Friday (rush hour) readings here, as f o11ows: A Interstate 5, (W.sjde of the Hwy; ) on the edge of a terrace about. 25' above the Hwy surface level and approx. 50' distance from the closest S.bound lane Leq (20 min.) 78 dB(A)*(approx.600 Ft.from the closest point of the site) ( this is only a reference data.) 3. PRESENT ENVIRONMENTAL NOISE Some typical no1se exposed po1nts on the parameter of the site: See Blueprint "SP" red marks for measurement locations. 1. Interstate 5. at the closest point of the project Lequ0 min) 64.7 dB(A) 2. Tuttle Street South side Leqc10 min.) 65 dB(A) 3. The Las Flores exit.off ramp.(stop sign.) Leqc 1ominJ 66 dB(A) 4 On Las Flores Dr. , 100 Ft.W. from No.2. Leqc 1omin.) 68.5 dB(A) Measuring distances :Mark 1. 600 Ft, Mark 2 & 3: 50ft from the stated noise source· 0 -- 1 nstruments : Bruel & Kjaer ( B&K) 2218 with automatic Leq computing feature, No. 1613 , and B&K 2232. C serial No. 1178693) ASTM class A type precision instruments. Both with wind screen and compensattng ring. The proper calibration was checked with the standard (matching) B&K calibrator. 4. PREDICTED FUTURE NOISE LEVELS (up to 2010). The dominant environmental noise here is traffic noise. The future noise then could be calculated as the logarithmical function of the predicted growth of the number of vech1cles. The prediction is a 70-100% growth in the number of vechicles in 20 years here, at this section of I. 5. When the Hwy traffic grows, the traffic on the immediate service and paral lei streets nearby w111 grow proportionately. But, since this section of the 1.5 -and w1th it the immediate surronding streets -are already close to a saturated level, the resulting noise wil I not grow at the usua I 3dB rate, per each doub Ii ng of the number of vechicles, because of the adherent, necessary slow down of the speed, Consequently a 1. 7 increase on the present noise level dB(A) figures wi 11 yield a realistic future CNEL number. Calculation with the FHWA model RD-77-108 (with 10% night traffic and 2% HTr.) indicates similar results. Thus, Future Noise levels on different points around the site. (see mark No. 1-9 on blue print SP.) These are adjusted CNEL figures,taking the shading effect of the buildings in to consideration also. At Mark No.1 = CNEL 66.5, at Mark No.4 = CNEL 69.7 at Mark No.7 = CNEL 59 at Mark 2 = 66.7 Mark 5 = 57 Mark 8 = 58 5. ANALYSIS AND CONCLUSION Mark 3 = 67.5 Mark 6 = 62.1 Mark 9 = 57 As we can see from the above compiled future noise data, the area with relatively strongest noise exposure is the N.side of BuiJding 1. (mark 4 on Blue print SP): Here, at the dotted line a min. a· high sound barrier wall would be needed to assure an under 60 db(A) CNEL in the Northen part of the property s· inside of the property 1 ine at 6' height observation point. This wall could be of solid cement blocks, or bricks or a combination of 5ft high solid masonary/brick/cement block wall and an additional 3 Ft high 1 /2" tick plexiglass combination on the top of it. • • This wall/barrier should start at the N.W. side ( Las Flores side ) of the No. 1 unit and should continue an additional 1 o· toward 5.E. alongside the propertry line at the Tuttle street. It should continue for an additional 30' in the same direction, but only 7' high and finally another 30' as a 6' high barrier fence; thus shading the No.2 (and partly the other two as we11) Building's exposed side(s) as well. With the sound attenuation of the above barrier(s} [(oCl=-4-1 0dB(A). depend1ng on u,e t11ght and locat1on) and tt1e considerable attenuating (shading) effect of the surronding bui ld1ngs, at a11 point of th1s project the regular structural and insulation elements .. exter1or walls .. w1ndows etc. w111 be sufffc1ent to keep the interior noise 1eve1 under the 45 dB(A) 1eve1. Concerning the special request of the City of Carlsbad to keep the exterior noise level at the second floor top window level not higher than 60 dB(A), our analysis shows, that tt1e closest and most exposed second floor window at the height of 15· wi 11 be at Building No. 1. at 67 Ft distance from the traffic noise at Las Flores Dr. With the attanuation effect of the 8' high noise barrier and at the distance the resulting Leq(h) w111 be somewhere 61-63 dB (depending on the actual future number of Heavy Trucks that w1 ll go by 1n twenty years !) Any further mitigation here, to achieve a "guaranteed" below 6Q_lllLlevel. here, would necessitate a minimum 11 • high barrier wall, therefore, for this minor and rather theoretical environmental convenience should be considered highly unpractical and cost-prohibitive. At building No.2 the second floor top window level distance is 1 oo· from the noise, thus the noise exposure here will be not above the 60 dB(A) CNEL. At the other two buildings the noise/distance relation is better, therefore no further invest1gation is necessary there. As a fo11ow-up, of this Environmental study, when blueprints with all details of the interior layouts will be available, we shall provide a standard cAc • Acoustical Analysis and Report· with exact details of the proper insulation and interior noise control in the effected rooms of all the 4 buildings in this project. Frank Rosnay chief consultant cAc • ·-1-~I-: • ~-r.--} ;----t--1-I.· /t~ -. . + ••• , LI: m j . . . ! -· • 1 ,,.1•.-~ • -··i -"i • • ~--: •• . . .... .. +e--t--t-1 -f---,-+-------:----;---.=:-i::::#.f=-,h,~---:-- 1 ---+=-=_=_rl-_ ·.....,,-~--,'--i-~r_ . I i . -I·-- . -'-· --! ! - I I ---1 i--i1 I I I e,. __ J -, , I ·--t -· I I t_ I -r:,...J,1--1 ·-., ·--. I ; : .. I It =i -I i :_-_ 1 ~, :-~~1 : ----i--.--,-• I ! ! . I l- 1 I 1 i/., ··J··-I . I ' . I- I I -I I i I .H;.ft: : .I ! 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