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Eilar Associates, Inc.
<br />Acoustical and Environmental Consulting services
<br />size trucks, and large trucks on 4th Street during the measurement period. After a 15-minute continuous sound
<br />level measurement, there was no change in the LEQ and results were then recorded. The measured noise level
<br />and related weather conditions are shown in Table 2.
<br />MTable 2. On -Site Noise Measurement Conditions and Results Am
<br />Date
<br />Friday, April 8, 2022
<br />Time
<br />10:00 a.m. -10:15 a.m.
<br />Conditions
<br />Sunny skies, winds at 4 mph,
<br />temperature in the low 90s, with low humidity
<br />Measured Noise Level
<br />65.2 dBA LEQ
<br />3.1.3 Calculated Noise Level
<br />Noise levels were calculated for the site using the methodology described in Section 4.1 for the location,
<br />conditions, and traffic volumes counted during the noise measurements. The calculated noise levels (LEQ) were
<br />compared with the measured on -site noise level to determine if adjustments or corrections (calibration) should
<br />be applied to the traffic noise prediction model. Adjustments are intended to account for site -specific
<br />differences, such as reflection and absorption, which may be greater or lesser than accounted for in the model.
<br />The measured noise level of 65.2 dBA LEQ at approximately 30 feet north of the 4th Street centerline and
<br />approximately 45 feet east of the Mortimer Street centerline was compared to the calculated (modeled) noise
<br />level of 63.0 dBA LEQ for the same conditions and traffic flow. According to the Federal Highway
<br />Administration's Highway Traffic Noise: Analysis and Abatement Guide (see reference), a traffic noise model
<br />is considered validated if the measured and calculated noise impacts differ by three decibels or less. No
<br />adjustment was deemed necessary to model future noise levels for this location as the difference between the
<br />measured and calculated levels was found to be less than three decibels. The traffic noise model is assumed to
<br />be representative of actual traffic noise that is experienced on site. This information is shown in Table 3.
<br />Table 3. Calculated versus Measured Traffic Noise Data
<br />Location
<br />Calculated
<br />Measured
<br />Difference Correction
<br />30' north of 4th Street centerline and
<br />45' east of Mortimer Street centerline
<br />63.0 dBA LEQ
<br />65.2 dBA LEQ
<br />2.2 dB None Applied
<br />3.2 Future Noise Environment
<br />3.2.1 Railway Noise Sources
<br />The overall future noise environment at the project site will be primarily made up of traffic noise from 4th
<br />Street and 5th Street, with additional impacts from the proposed OC Streetcar located adjacent to the project
<br />site. The proposed OC Streetcar line will run along 4th Street west of Mortimer Street, and will run along
<br />Mortimer Street north of 4th Street. The centerline of the tracks is located approximately 39 feet west of the
<br />west facade of Building B. According to the Noise and Vibration Technical Report prepared for the OC
<br />Streetcar project (see reference), there will be 164 daytime and 32 nighttime streetcar operations per day. On
<br />average, there will be approximately eleven streetcar operations per hour during daytime hours and
<br />approximately four streetcar operations per hour during nighttime hours.
<br />Acoustical Analysis Report for 4th and Mortimer • Job # S220404 • July 18, 2022 Page 4
<br />Eilar Associates, Inc.
<br />Acoustical and Environmental Consulting Services
<br />Calculations were performed using the CREATE Freight Noise and Vibration Model (see reference) to
<br />determine the noise impacts from train traffic on the project site. With the current peak rail volumes detailed
<br />above, the railway noise level was calculated to be approximately 62 LDN at the west facade of Building B.
<br />Please refer to Appendix D for additional information.
<br />3.2.2 Roadway Noise Sources
<br />The future traffic volumes for surrounding roadways were not provided by the City of Santa Ana; therefore,
<br />future (year 2050) traffic volumes were calculated by applying a fairly conservative projected annual growth rate
<br />of one percent (1%) to existing volumes. In the vicinity of the project site, the traffic volumes of 4th Street
<br />and 5th Street are expected to increase to 16,816 ADT and 8,102 ADT, respectively.
<br />The same truck percentages from the current traffic volumes were used for future traffic volume modeling.
<br />For further roadway details and projected future ADT traffic volumes, please refer to Appendix C: CadnaA
<br />Analysis Data and Results.
<br />Future combined traffic and rail noise contours were calculated at ground level and show that future combined
<br />traffic and rail noise impacts to the entire project site are expected to be between approximately 64 and 72
<br />CNEL. For a graphical representation of these contours, please refer to Figure 6: Site Plan Showing Future
<br />Combined Traffic and Rail CNEL Contours and Noise Measurement Location.
<br />4.0 Methodology and Equipment
<br />4.1 Methodology
<br />4.1.1 Field Measurement
<br />Typically, a "one -hour" equivalent sound level measurement (LEQ, A -Weighted) is recorded for at least one
<br />noise -sensitive location on the site. During the on -site noise measurement, start and end times are recorded,
<br />vehicle counts are made for cars, medium trucks (double-tires/two axles), and heavy trucks (three or more
<br />axles) for the corresponding road segment(s). Supplemental sound measurements of one hour or less in
<br />duration are often made to further describe the noise environment of the site.
<br />For measurements of less than one hour in duration, the measurement time is long enough for a representative
<br />traffic volume to occur and the noise level (LEQ) to stabilize. The vehicle counts are then converted to one -
<br />hour equivalent volumes by using the appropriate multiplier. Other field data gathered includes measuring or
<br />estimating distances, angles -of -view, slopes, elevations, roadway grades, and vehicle speeds. This data is
<br />checked against the available maps and records.
<br />4.1.2 Railway Noise Calculation
<br />The evaluation of a site's exposure to railway noise requires the consideration of the distance from the site to
<br />the railroad track centerline, the number of diesel and electric trains in both directions during an average 24-
<br />hour day, the fraction of trains that operate during the night, the average number of diesel locomotives, the
<br />average length of each train, the average train speed past the site, the rail types, and whether the site is nearby
<br />crossings where train whistles or horns are sounded. Railway calculations were calculated using the CREATE
<br />Rail Noise Model, developed by Harris Miller Miller & Hanson (see reference), which uses Federal
<br />Transportation Administration (FTA) procedures. These calculations were then incorporated into a CadnaA
<br />noise model, which was calibrated.
<br />Acoustical Analysis Report for 4th and Mortimer • Job # S220404 • July 18, 2022 Page 5
<br />Eilar Associates, Inc.
<br />Acoustical and Environmental Consulting services
<br />are considered equivalent for purposes of this analysis. These metrics are used to express noise levels for both
<br />measurement and municipal regulations, for land use guidelines, and for enforcement of noise ordinances.
<br />2.1 Project Description
<br />The proposed project, 4th and Mortimer, consists of the demolition of existing onsite structures and the
<br />construction of a mixed -use development to contain 169 residential units. The provided common outdoor use
<br />areas include a ground -level courtyard, third -floor pool deck, and seventh -floor roof deck. Small private
<br />balconies are also proposed for select units. For further details, please refer to the project plans, provided as
<br />Appendix A.
<br />2.2 Project Location
<br />The project site is located at the northeast and northwest corners of 4th Street and Mortimer Street in the City
<br />of Santa Ana, California. The Assessor's Parcel Numbers (APNs) for the property are 398-325-01 and 398-
<br />330-01 through 398-330-10. The project location is shown on the Vicinity Map, Figure 1, following this report.
<br />An Assessor's Parcel Map, Satellite Aerial Photograph, and Topographic Map of this area are also provided as
<br />Figures 2 through 4, respectively.
<br />2.3 Applicable Noise Regulations
<br />The proposed project must meet the acoustical requirements of the City of Santa Ana in order to obtain
<br />approval. The City of Santa Ana Noise Element to the General Plan states that exterior noise levels at common
<br />outdoor use areas of multi -family residential properties should not exceed 65 CNEL; private outdoor use areas
<br />of multi -family properties are not required to meet noise limits. Additionally, the City of Santa Ana and State
<br />of California require interior noise levels not exceeding 45 CNEL in habitable space.
<br />The State of California also requires that nonresidential developments demonstrate compliance with the
<br />requirements of the California Green Building Standards Code (known as CALGreen). CALGreen states that,
<br />if noise level readings of 65 dBA LEQ or greater are documented at the proposed project site, the project must
<br />either (a) incorporate wall and roof/ceiling assemblies with a composite STC rating of at least 50 and exterior
<br />windows with an STC 40, or (b) provide an acoustical analysis documenting interior noise levels do not exceed
<br />50 dBA in occupied areas during any hour of operation. This report provides the performance method analysis
<br />described in Item (b).
<br />The California State Building Code Section 1206 requires that the Sound Transmission Class (STC) rating of
<br />common wall assemblies separating residential units have a minimum laboratory rating of STC 50. The same
<br />STC requirement applies for floor/ceiling assemblies, and an added requirement dictates that the Impact
<br />Insulation Class (IIC) rating of the floor/ceiling assembly is a minimum laboratory rating of IIC 50.
<br />Pertinent sections of the City of Santa Ana Noise Element to the General Plan, CALGreen, and California
<br />Building Code are provided as Appendix B.
<br />Acoustical Analysis Report for 4th and Mortimer • Job # S220404 • July 18, 2022
<br />3.0 Environmental Setting
<br />3.1 Existing Noise Environment
<br />3.1.1 Roadway Noise Sources
<br />Page 2
<br />Eilar Associates, Inc.
<br />Acoustical and Environmental Consulting Services
<br />The current primary noise sources in the vicinity of the project site are traffic noise from 4th Street and 5th
<br />Street. No other noise source is considered significant. Current traffic volumes are given based on information
<br />provided in the City of Santa Ana Traffic Census (see reference).
<br />4th Street is a two-lane, two-way Secondary Arterial running east -west along the southern boundary of the
<br />project site. The posted speed limit is 35 mph. According to The City of Santa Ana Traffic Census 2017
<br />counts, 4th Street currently carries a traffic volume of approximately 12,109 Average Daily Trips (ADT) in the
<br />vicinity of the project site.
<br />5th Street is a two-lane, two-way Secondary Arterial running east -west along the northern boundary of the
<br />project site. No speed limit was observed to be posted in the vicinity of the project site; however, based on
<br />neighboring and surrounding land use, roadway classification, professional experience, and on -site
<br />observations, a speed limit of 35 mph was assumed. According to The City of Santa Ana Traffic Census 2017
<br />counts, 5th Street currently carries a traffic volume of approximately 5,834 ADT in the vicinity of the project
<br />site.
<br />No current or future truck percentages were available for roadways in the vicinity of the project site. However,
<br />based on neighboring and surrounding land use, roadway classification, professional experience, and on -site
<br />observations, a truck percentage mix of 0.5% medium and 0.5% heavy trucks was used for 4th Street and 5th
<br />Street.
<br />Current and future (See Section 3.2) traffic volumes and vehicle mixes for roadway sections near the project
<br />site are shown in Table 1. For more information, please refer to Appendix C: CadnaA Analysis Data and
<br />Results.
<br />Table 1. Overall Roadway Traffic Information T
<br />Vehicle Mix (%)
<br />Roadway Name
<br />Speed Limit
<br />Current ADT
<br />Future ADT
<br />(mph)
<br />Medium
<br />Heavy
<br />(2017)
<br />(2050)
<br />Trucks
<br />Trucks
<br />4th Street
<br />35
<br />0.5
<br />0.5
<br />12,109
<br />16,816
<br />5th Street
<br />35
<br />0.5
<br />0.5
<br />5,834
<br />8,102
<br />Current traffic noise contours were calculated at ground level and show that traffic noise impacts to the entire
<br />project site are between approximately 63 and 70 CNEL. For a graphical representation of these contours,
<br />please refer to Figure 5: Site Plan Showing Current Traffic CNEL Contours and Noise Measurement Location.
<br />3.1.2 Measured Noise Level
<br />An on -site inspection and traffic noise measurement were made on the morning of Friday, April 8, 2022. The
<br />noise measurement was made using the methodology described in Section 4.1, at approximately 30 feet north
<br />of the 4th Street centerline and approximately 45 feet east of the Mortimer Street centerline. The noise
<br />measurement location is shown in Figures 5 and 6. Traffic volumes were recorded for automobiles, medium. -
<br />Acoustical Analysis Report for 4th and Mortimer • Job # S220404 • July 18, 2022 Page 3
<br />Figures
<br />1. Vicinity Map
<br />2. Assessor's Parcel Map
<br />3. Satellite Aerial Photograph
<br />4. Topographic Map
<br />5. Site Plan Showing Current Traffic CNEL Contours and Noise Measurement Location
<br />6. Site Plan Showing Future Combined Traffic and Rail CNEL Contours and Noise Measurement
<br />Location
<br />7. Site Plan Showing Outdoor Use Receiver and Barrier Locations
<br />8. Site Plan Showing Facade Receiver Locations
<br />Appendices
<br />A. Project Plans
<br />B. Applicable Noise Regulations
<br />C. CadnaA Analysis Data and Results
<br />D. Railway Noise Analysis and Results
<br />E. Sound Insulation Prediction Results
<br />F. Exterior -to -Interior Noise Analysis
<br />G. Recommended Products
<br />Eilar Associates, Inc.
<br />Acoustical and Environmental Consulting Services
<br />1.0 Executive Summary
<br />The proposed project, 4th and Mortimer, consists of the demolition of existing onsite structures and the
<br />construction of a mixed -use development to contain 169 residential units. The project site is located at the
<br />northeast and northwest corners of 4th Street and Mortimer Street in the City of Santa Ana, California.
<br />The current and future noise environment primarily consists of traffic noise from 4th Street and 5th Street,
<br />with some impacts from the proposed OC Streetcar in the future environment. Future combined traffic and
<br />rail noise levels at building facades are expected to range from 47 CNEL at the courtyard of Building A to 72
<br />CNEL at the south facade of Building B.
<br />The City of Santa Ana Noise Element to the General Plan states that exterior noise levels at common outdoor
<br />use areas of multi -family residential properties should not exceed 65 CNEL. Calculations show that, with a
<br />four -foot high sound barrier along the southern barrier of the Building B courtyard in place, exterior noise
<br />levels at the common outdoor use areas are expected to meet the exterior noise limit of 65 CNEL. Please refer
<br />to Figure 7 for a graphical representation of the required sound barrier location.
<br />The City of Santa Ana and the State of California require interior noise levels not exceeding 45 CNEL in
<br />habitable space. Calculations show that future noise levels on site are expected to exceed 60 CNEL at most
<br />building facades; therefore, interior noise levels may exceed 45 CNEL within units without appropriate design
<br />features in place. Calculations show that with typical exterior wall assemblies, exterior glazing with an STC
<br />rating of 28, and mechanical ventilation in all units, all interior residential space is expected to comply with City
<br />of Santa Ana and State of California noise requirements. Additionally, with proposed exterior wall construction
<br />and standard commercial glazing in place, exterior noise levels in non-residential spaces are expected to meet
<br />the noise limits of the City of San Diego Noise Element to the General Plan.
<br />Common wall and floor/ceiling assemblies recommended herein are expected to meet the minimum required
<br />ratings dictated by the State of California Building Code Section 1206 for Sound Transmission Class (STC) and
<br />Impact Insulation Class (IIC). These assemblies should be incorporated into project plans prior to building
<br />permit submittal.
<br />2.0 Introduction
<br />This acoustical analysis report is submitted to satisfy the acoustical requirements of the City of Santa Ana and
<br />the State of California. Its purpose is to assess noise impacts from nearby roadway traffic to identify project
<br />features or requirements necessary to achieve noise levels of 65 CNEL at outdoor use areas and 45 CNEL or
<br />less in interior residential space, in compliance with the noise regulations of the City of Santa Ana Noise
<br />Element to the General Plan, and noise levels of 50 dBA or less in nonresidential space in compliance with
<br />CALGreen. An evaluation of common wall and floor/ceiling assemblies is also provided.
<br />All noise level or sound level values presented herein are expressed in terms of decibels, with A -weighting to
<br />approximate the hearing sensitivity of humans. Time -averaged noise levels are expressed by the symbol LEQ
<br />for a specified duration. Unless a different time period is specified, LEQ is implied to mean a period of one
<br />hour. The Community Noise Equivalent Level (CNEL) is a calculated 24-hour weighted average, where sound
<br />levels during evening hours of 7 p.m. to 10 p.m. have an added 5 dB weighting, and sound levels during
<br />nighttime hours of 10 p.m. to 7 a.m. have an added 10 dB weighting. This is similar to the Day -Night sound
<br />level, LDN, which is a 24-hour average with an added 10 dB weighting on the same nighttime hours but no
<br />added weighting on the evening hours. Sound levels expressed in CNEL are always based on A -weighted
<br />decibels. As LDN and CNEL are generally found to be within approximately 0.5 dB or less of one another, they
<br />Acoustical Analysis Report for 4th and Mortimer • Job # S220404 • July 18, 2022 Page 1
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<br />Prepared for:
<br />LARO LLC
<br />Attention: Andrew Nelson
<br />4199 Campus Drive, Suite 200
<br />Irvine, California 92612
<br />Phone: 949-733-2000
<br />Prepared by:
<br />Eilar Associates, Inc.
<br />210 South Juniper Street, Suite 100
<br />Escondido, California 92025
<br />Phone: 760-738-5570
<br />info@eilarassociates.com
<br />Job # S220404
<br />July 18, 2022
<br />Table of Contents
<br />Page
<br />1.0
<br />Executive Summary
<br />1
<br />2.0
<br />Introduction
<br />1
<br />2.1 Project Description
<br />2.2 Project Location
<br />2.3 Applicable Noise Regulations
<br />3.0
<br />Environmental Setting
<br />3
<br />3.1 Existing Noise Environment
<br />3.2 Future Noise Environment
<br />4.0
<br />Methodology and Equipment
<br />5
<br />4.1 Methodology
<br />4.2 Measurement Equipment
<br />5.0
<br />Impacts and Mitigation
<br />8
<br />5.1 Exterior
<br />5.2 Interior
<br />6.0
<br />Conclusion
<br />16
<br />7.0
<br />Certification
<br />17
<br />8.0
<br />References
<br />18
<br />Architecture + Planning
<br />17911 Von Karman Ave.
<br />Suite 200
<br />Irvine, CA 92614
<br />ktgy.com
<br />949.851.2133
<br />KTGY Project No: 2017-0934
<br />Project Contact: Debbie Holland
<br />Email: dholland@ktgy.com
<br />Principal: Wil Wong
<br />Project Designer: D. Schoolmeester
<br />Project Director: Debbie Holland
<br />Developer
<br />ED7 OAK
<br />INVESTMENTS
<br />S
<br />4199 CAMPUS DRIVE
<br />I RVI N E, CA 92612
<br />PHONE NO. (714) 342-2502
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<br />It is the clients responsibility prior to or during construction to notify the architect in writing
<br />of any perceived errors or omissions in the plans and specifications of which a contractor
<br />thoroughly knowledgeable with the building codes and methods of construction should
<br />reasonably be aware. Written instructions addressing such perceived errors or omissions
<br />shall be received from the architect prior to the client or clients subcontractors proceeding
<br />with the work. The client will be responsible for any defects in construction if these
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<br />RENEWAL DATE
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