HomeMy WebLinkAboutSDP 2019-0015; JEFFERSON STREET APARTMENTS; ACOUSTICAL ANALYSIS REPORT; 2020-06-01E
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Environmental Planning
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Jefferson Luxury Apartments
Acoustical Analysis Report
June 2020
Prepared for:
Bejan Arfaa, Architect
2900 Fourth Ave. Suite 110
San Diego, CA 92103
Prepared by:
HELIX Environmental Planning, Inc.
7578 El Cajon Boulevard
La Mesa, CA 91942
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Jefferson Luxury Apartments
Acoustical Analysis Report
Prepared for:
Bejan Arfaa, Architect
2900 Fourth Ave. Suite 110
San Diego, CA 92103
Prepared by:
HELIX Environmental Planning, Inc.
7578 El Cajon Boulevard
La Mesa, CA 91942
June 2020
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TABLE OF CONTENTS
Section
ES EXECUTIVE SUMMARY ..................................................................................................................... 1
1.0 INTRODUCTION ................................................................................................................................ !
2.0
3.0
4.0
5.0
6.0
A
B
1.1
1.2
1.3
1.4
1.5
1.6
Purpose of the Project ........................................................................................................ 1
Project Location .................................................................................................................. 1
Project Description ............................................................................................................. 1
Noise and Sound Level Descriptors and Terminology ........................................................ 1
1.4.1 Descriptors ............................................................................................................. !
1.4.2 Terminology ........................................................................................................... 1
Noise-Sensitive Land Uses .................................................................................................. 3
Regulatory Framework ....................................................................................................... 3
1.6.1 California Noise Control Act ................................................................................... 3
1.6.2 California Noise Insulation Standards [California's Title 24 Noise Standards, Cal.
Adm. Code Title 24, Chap. 2-35] ............................................................................ 3
1.6.3 City of Carlsbad General Plan Noise Element ........................................................ 3
ENVIRONMENTAL SETTING .............................................................................................................. 5
2.1
2.2
Surrounding Land Uses ....................................................................................................... 5
Existing Noise Environment ................................................................................................ 5
2.2.1 Ambient Noise Survey ............................................................................................ 5
METHODOLOGY AND ASSUMPTIONS .............................................................................................. 6
3.1 Methodology ....................................................................................................................... 6
3.1.1 Ambient Noise Survey ............................................................................................ 6
3.1.2 Noise Modeling Software ...................................................................................... 6
3.2 Assumptions ........................................................................................................................ 6
3.2.1 Vehicular Traffic ..................................................................................................... 6
NOISE IMPACTS ................................................................................................................................ 7
4.1
4.2
4.3
Guidelines for the Determination of Significance ............................................................... 7
Exterior Noise Exposure ...................................................................................................... 7
Interior Noise Exposure ...................................................................................................... 9
LIST OF PREPARERS ........................................................................................................................ 12
REFERENCES ................................................................................................................................... 13
LIST OF APPENDICES
Exterior to Interior Analysis Methodology
Exterior to Interior Analysis Data Sheets for Corner Units
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LIST OF FIGURES
Title Follows Page
Regional Location ............................................................................................................................. 2
Aerial Photograph ............................................................................................................................ 2
Site Plan ........................................................................................................................................... 2
4 Ground Level Contours and Receivers ............................................................................................. 8
1
2
3
4
5
6
7
LIST OF TABLES
Allowable Transportation Noise Exposure ....................................................................................... 4
Performance Standards for Non-Transportation Sources (as Measured at Property Lines of
Sources/Sensitive Uses) ................................................................................................................... 4
Noise Measurement Results ............................................................................................................ 5
Recorded Traffic Volume and Vehicle Mix for Measurement ......................................................... 5
Existing and Projected Area Traffic Volumes ................................................................................... 7
Exterior Traffic Noise Levels ............................................................................................................. 8
Calculation of Interior Noise for Each Analyzed Residential Room ............................................... 10
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ACRONYMS AND ABBREVIATIONS
ADT
ANSI
CAD
CadnaA
Caltrans
City
CNEL
dB
dBA
Hz
(I-)
kHz
mPa
NSLU
SANDAG
SPL
STC
TFIC
TNM
USDOT
average daily traffic
American National Standards Institute
Computer Aided Design
Computer Aided Noise Abatement
California Department ofTransportation
City of Carlsbad
Community Noise Equivalent Level
decibel
A-weighted decibels
Hertz
Interstate
kilohertz
Day-Night level
equivalent sound level
micro-Pascals
noise-sensitive land use
San Diego Association of Governments
sound pressure level
Sound Transmission Class
Transportation Forecast Information Center
Traffic Noise Model
U.S. Department of Transportation
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
EXECUTIVE SUMMARY
This report presents an assessment of potential noise impacts associated with the proposed Jefferson
Luxury Apartments project (project).
The project site is located at 3039 Jefferson Street between Carlsbad Village Drive and Oak Avenue in
the city of Carlsbad, California. The project proposes the construction and operation of a mixed-use
multi-family residential development. The project would include 11 residential units and two
commercial spaces in a single building.
Exterior noise levels from vehicular traffic would exceed the City's 65 Community Noise Equivalent Level
(CNEL) threshold for some of the project's exterior use areas. Mitigation measure NOl-1 requires a 5-
foot sound wall to protect the 4th floor decks facing Jefferson Street and the Interstate (1-5) freeway
from vehicular traffic noise.
Because noise levels at the building fa~ades were modeled above 60 CNEL, interior noise levels may not
comply with the City's interior noise standard of 45 CNEL. Mitigation Measure NOl-2, which requires
windows with dual glazing providing a minimum Sound Transmission Class (STC} 25 test rating, would
ensure that interior noise levels do not exceed 45 CNEL.
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
1.0
1.1
INTRODUCTION
PURPOSE OF THE PROJECT
This report analyzes potential noise impacts associated with the proposed Jefferson Luxury Apartments
project (project). The analysis includes a description of existing conditions in the project vicinity, an
assessment of potential future transportation noise at the site, and the requirements for exterior to
interior noise control to meet the City of Carlsbad (City) and State of California Title 24 noise control
requirements .
1.2 PROJECT LOCATION
The project site is located at 3039 Jefferson Street between Carlsbad Village Drive and Oak Avenue in
the city of Carlsbad, California. See Figure 1, Regional Location, and Figure 2, Aerial Photograph .
1.3 PROJECT DESCRIPTION
The project proposes the construction and operation of a mixed-use multi-family residential
development. The project would include 11 residential units and two commercial spaces in a single
building. See Figure 3, Site Plan .
1.4 NOISE AND SOUND LEVEL DESCRIPTORS AND TERMINOLOGY
1.4.1 Descriptors
All noise level or sound level values presented herein are expressed in terms of decibels (dB), with
A-weighting (dBA) to approximate the hearing sensitivity of humans. Time-averaged noise levels are
expressed by the symbol LEO, with a specified duration. The Community Noise Equivalent Level (CNEL) is
a 24-hour average, where noise levels during the evening hours of 7:00 p.m. to 10:00 p.m. have an
added 5 dBA weighting, and sound levels during the nighttime hours of 10:00 p.m. to 7:00 a.m. have an
added 10 dBA weighting. This is similar to the Day-Night sound level (LoN), which is a 24-hour average
with an added 10 dBA weighting on the same nighttime hours but no added weighting on the evening
hours. Sound levels expressed in CNEL are always based on dBA. These metrics are used to express noise
levels for both measurement and municipal regulations, as well as for land use guidelines and
enforcement of noise ordinances.
Sound Transmission Class (STC) is expressed as a single number, which approximates or best represents
the sound reduction for a single unit area, in decibels, from one side of a common partition to the other .
1.4.2 Terminology
1.4.2.1 Sound, Noise, and Acoustics
Sound can be described as the mechanical energy of a vibrating object transmitted by pressure waves
through a liquid or gaseous medium (e.g., air) to a hearing organ, such as a human ear. Noise is defined
as loud, unexpected, or annoying sound.
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
In the science of acoustics, the fundamental model consists of a sound (or noise) source, a receiver, and
the propagation path between the two. The loudness of the noise source and obstructions or
atmospheric factors affecting the propagation path to the receiver determines the sound level and
characteristics of the noise perceived by the receiver. The field of acoustics deals primarily with the
propagation and control of sound.
1.4.2.2 Frequency
Continuous sound can be described by frequency (pitch) and amplitude (loudness). A low-frequency
sound is perceived as low in pitch. Frequency is expressed in terms of cycles per second, or Hertz (Hz)
(e.g., a frequency of 250 cycles per second is referred to as 250 Hz). High frequencies are sometimes
more conveniently expressed in kilohertz (kHz), or thousands of Hertz. The audible frequency range for
humans is generally between 20 Hz and 20,000 Hz .
1.4.2.3 Sound Pressure Levels and Decibels
The amplitude of pressure waves generated by a sound source determines the loudness of that source.
Sound pressure amplitude is measured in micro-Pascals (mPa). One mPa is approximately one hundred
billionth (0.00000000001) of normal atmospheric pressure. Sound pressure amplitudes for different
kinds of noise environments can range from less than 100 to 100,000,000 mPa. Because of this wide
range of values, sound is rarely expressed in terms of mPa. Instead, a logarithmic scale is used to
describe sound pressure level (SPL) in terms of dBA. The threshold of hearing for the human ear is about
0 dBA, which corresponds to 20 mPa.
1.4.2.4 Addition of Decibels
Because decibels are logarithmic units, SPL cannot be added or subtracted through standard arithmetic .
Under the decibel scale, a doubling of sound energy corresponds to a 3 dBA increase. In other words,
when two identical sources are each producing sound of the same loudness, the resulting sound level at
a given distance would be 3 dBA higher than from one source under the same conditions. For example,
if one automobile produces an SPL of 70 dB when it passes an observer, two cars passing simultaneously
would not produce 140 dBA-rather, they would combine to produce 73 dBA. Under the decibel scale,
three sources of equal loudness together produce a sound level 5 dBA louder than one source.
Under controlled conditions in an acoustical laboratory, the trained, healthy human ear is able to
discern 1-dBA changes in sound levels, when exposed to steady, single-frequency ("pure-tone") signals
in the mid-frequency (1,000 Hz-8,000 Hz) range. In typical noisy environments, changes in noise of 1 to
2 dBA are generally not perceptible. It is widely accepted, however, that people begin to detect sound
level increases of 3 dB in typical noisy environments. Further, a 5 dBA increase is generally perceived as
a distinctly noticeable increase, and a 10 dBA increase is generally perceived as a doubling of loudness.
No known studies have directly correlated the ability of a healthy human ear to discern specific levels of
change in traffic noise over a 24-hour period. Many ordinances, however, specify a change of 3 CNEL as
the significant impact threshold. This is based on the concept of a doubling in noise energy resulting in a
3 dBA change in noise, which is the amount of change in noise necessary for the increase to be
perceptible to the average healthy human ear.
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Source: Base Map Layers (SanGIS, 2016)
Regional Location
Figure 1
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Aerial Photograph
Figure 2
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
1.5 NOISE-SENSITIVE LAND USES
Noise-sensitive land uses (NSLUs) are land uses that may be subject to stress and/or interference from
excessive noise, including residences, hospitals, schools, hotels, resorts, libraries, sensitive wildlife
habitat, or similar facilities where quiet is an important attribute of the environment. Noise receptors
are individual locations that may be affected by noise. The project's future residents would be
considered NSLUs .
1.6 REGULATORY FRAMEWORK
1.6.1 California Noise Control Act
The California Noise Control Act is a section within the California Health and Safety Code that describes
excessive noise as a serious hazard to public health and welfare and that exposure to certain levels of
noise can result in physiological, psychological, and economic damage. It also finds that there is a
continuous and increasing bombardment of noise in the urban, suburban, and rural areas. The California
Noise Control Act declares that the State of California has a responsibility to protect the health and
welfare of its citizens by the control, prevention, and abatement of noise. It is the policy of the State to
provide an environment for all Californians free from noise that jeopardizes their health or welfare.
1.6.2 California Noise Insulation Standards [California's Title 24 Noise
Standards, Cal. Adm. Code Title 24, Chap. 2-35)
In 1974, the California Commission on Housing and Community Development adopted noise insulation
standards for multi-family residential buildings (Title 24, Part 2, California Code of Regulations). Title 24
establishes standards for interior room noise (attributable to outside noise sources). The regulations
also specify that acoustical studies must be prepared whenever a residential building or structure is
proposed to be located near an existing or adopted freeway route, expressway, parkway, major street,
thoroughfare, rail line, rapid transit line, or industrial noise source, and where such noise source or
sources create an exterior CNEL (or LoN) of 60 dBA or greater. Such acoustical analysis must demonstrate
that the residence has been designed to limit intruding noise to an interior CNEL (or LoN) of 45 dBA
or less.
1.6.3 City of Carlsbad General Plan Noise Element
Table 5-2 of the City's General Plan Noise Element (City 2015; recreated herein as Table 1, Allowable
Transportation Noise Exposure) indicates acceptable limits of noise for various land uses for both
exterior and interior environments from transportation sources. Development shall attain these
standards through noise attenuation measures. These limits are based on guidelines provided by the
California Office of Planning and Research .
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Jefferson Luxury Apartment s Acoustical Analysis Report I June 2020
Table 1
ALLOWABLE TRANSPORTATION NOISE EXPOSURE1
Land Use Outdoor Activity Interior Spaces
Areas2•3 (CNEL) (CNEL)
Residential 604 45
Motels, Hotels 65 45
Hospitals, Residential Care
Facilities, Schools,
Libraries, Museums, 65 45
Churches, Day Care
Facilities
Playgrounds, Parks, 65 50 Recreation Uses
Commercial and Office
Uses 65 50
Industrial Uses 70 65
1. Development proposed within the McClellan-Palomar Airport Area of
Influence shal l also be subject to the noise compatibility policies
contained in the ALUCP.
2. For non-residential uses, w here an outdoor activity area is not
proposed, t he standard does not apply. Where the location of outdoor
activity areas is unknown, the exterior noise level standard shall be
applied to t he property line of the receiving use.
3. Where it is not possible to reduce noise in outdoor activity areas to the
allowable maximum, levels up to 5 dB higher may be allowed provided
that available exterior noise level reduction measures have been
implemented and interior noise levels are in compliance with this
table.
4. An exterior noise exposure level of 65 dBA CNEL is allowable for
residential uses in a mixed-use project and for residential uses within
the McClellan-Palomar Airport Area of Influence, pursuant to the noise
compatibility policies contained in t he ALUCP.
Table 5-3 of the City's General Plan Noise Element (City 2015; recreated herein as Table 2, Performance
Standards for Non-transportation Sources [as Measured at Property Lines of Source/Sensitive Use])
provides standards for noise from non-transportation noise sources such as, but not limited to,
industrial facilities, automotive servicing, car washes, equipment yards, nightclubs, hotels, and shopping
centers. These standards apply to t he noise sources themselves, as measured at the edge of the
property line; noise cau sed by motor vehicles traveling to and from the site is exempt from this
standard.
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Table 2
PERFORMANCE STANDARDS FOR NON-TRANSPORTATION SOURCES (AS MEASURED
AT PROPERTY LINES OF SOURCES/SENSITIVE USES)
Noise Level Descriptor Daytime Nighttime
(7:00 a.m. to 10:00 p.m.) (10:00 p.m. to 7:00 a.m.)
Hourly LEo, dB 55 45
Maximum Level, dB 75 65
Each of the noise levels specified above shall be lowered by 5 dB for simple tone noises,
noises consisting primarily of speech or music, or for recurring impulsive noises.
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
2.0
2.1
ENVIRONMENTAL SETTING
SURROUNDING LAND USES
The project site is within a mixed-use area that includes commercial and residential land uses near a
central commercial corridor with close access to the Interstate (I-) 5 freeway.
2.2 EXISTING NOISE ENVIRONMENT
The primary existing noise sources are roadways adjacent to and nearby the project site, including
Jefferson Street, Carlsbad Village Drive, and the 1-5 freeway. No significant additional offsite noise
sources were noted.
2.2.1 Ambient Noise Survey
An ambient noise survey was conducted for the project on Wednesday June 3, 2020. The measurement
was taken adjacent to the site next to Jefferson Street. The noise meter was positioned next to the
sidewalk on the subject property in a planted area near the southern site border. This measurement was
taken to measure traffic noise from Jefferson Street and other nearby roadways, as well as other
ambient noise sources. Traffic counts were recorded for automobiles, medium-size trucks
(double-tires/two axles), and heavy trucks (three or more axles). The measured noise levels and related
environmental conditions are shown in Table 3, Noise Measurement Results. Traffic counts for the timed
measurement and the one-hour equivalent volume are shown in Table 4, Recorded Traffic Volume and
Vehicle Mix.
Date:
Conditions:
Time:
Location:
Measured Noise Level:
Table 3
NOISE MEASUREMENT RESULTS
Measurement 1 -Traffic
Wednesday June 3, 2020
Temperature: 78°F. Wind Speed: 2 mph. Normal humidity. Sunny.
11:35 a.m. -11:50 a.m.
10 feet north of site transformer at southeastern property corner
adjacent Jefferson Street sidewalk.
58.6 dBA Leo
Notes: Small ambient noise source nearby, automotive traffic only (no light or
heavy trucks) on Jefferson Street.
Table 4
RECORDED TRAFFIC VOLUME AND VEHICLE MIX FOR MEASUREMENT
Roadway Traffic
15-minute Count Jefferson Street One-hour Equivalent
1 Medium Trucks (double tires/two axles)
2 Heavy Trucks (three or more axles)
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3.0
3.1
3.1.1
METHODOLOGY AND ASSUMPTIONS
METHODOLOGY
Ambient Noise Survey
The following equipment was used to measure existing noise levels at the project site:
• Larson Davis 831 Noise Meter
• Larson Davis Model CA250 Calibrator
• Windscreen and tripod for the sound level meter
The sound level meter was field-calibrated immediately prior to the noise measurements to ensure
accuracy. All sound level measurements conducted and presented in this report were made with a
sound level meter that conforms to the American National Standards Institute (ANSI) specifications for
sound level meters (ANSI Sl.4-1983 R2006). All instruments were maintained with National Institute of
Standards and Technology traceable calibration per the manufacturers' standards .
3.1.2 Noise Modeling Software
Modeling of the exterior noise environment for this report was accomplished using two computer noise
models: Computer Aided Noise Abatement (CadnaA) version 2020 and Traffic Noise Model (TNM)
version 2.5. CadnaA is a model-based computer program developed by DataKustik for predicting noise
impacts in a wide variety of conditions. CadnaA assists in the calculation, presentation, assessment, and
mitigation of noise exposure. It allows for the input of project-related information, such as noise source
data, barriers, structures, and topography to create a detailed CadnaA model, and uses the most up-to-
date calculation standards to predict outdoor noise impacts. CadnaA traffic noise prediction is based on
the data and methodology used in the TNM. The TNM was released in February 2004 by the U.S.
Department of Transportation (USDOT) and calculates the daytime average hourly LEu from
three-dimensional model inputs and traffic data {California Department of Transportation [Caltrans]
2004). The TNM used in this analysis was developed from Computer Aided Design (CAD) plans provided
by the project architect. Input variables included road alignment, elevation, lane configuration, area
topography, existing and planned noise control features, projected traffic volumes, estimated truck
composition percentages, and vehicle speeds.
The one-hour LEu noise level is calculated utilizing peak-hour traffic; peak-hour traffic volumes can be
estimated based on the assumption that 10 percent of the average daily traffic would occur during a
peak hour. The model-calculated one-hour Lrn noise output is the equivalent to the CNEL (Caltrans
2013).
3.2 ASSUMPTIONS
3.2.1 Vehicular Traffic
Traffic data for roadways in the project vicinity are based on the San Diego Association of Governments
(SAN DAG) Transportation Forecast Information Center (TFIC; SAN DAG 2020). The TFIC provides both the
older Series 12 and more recent Series 13 traffic forecasts for San Diego County. The Series 13 forecast
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
shows a significant reduction in the traffic volumes for the streets around the project site; therefore, the
Series 12 forecast, which was used in the City planning documents, was used for year 2035 traffic
volumes for this ana lysis.
The existing (year 2020) and projected (year 2035) average daily traffic (ADT) volumes are shown in
Table 5, Existing and Projected Area Traffic Volumes, below.
4.0
4.1
Table 5
EXISTING AND PROJECTED AREA TRAFFIC VOLUMES
Roadway/Segment
Carlsbad Village Drive
East of Jefferson Street
West of Jefferson Street
Jefferson Street
Sout h of Carlsbad Village Drive
North of Carlsbad Village Drive
1-5 Freeway
Northbound
Southbound
ADT = average daily traffic
Source: SANDAG 2020
NOISE IMPACTS
ADT
Year 2020 Year 2035
19,900 19,700
18,500 22,200
800 1,600
5,100 5,200
87,700 97,300
82,200 96,800
GUIDELINES FOR THE DETERMINATION OF SIGNIFICANCE
Impacts would be significant if the project would expose proposed multi-family residential outdoor
activity use areas to noise levels exceeding 65 CNEL or interior use areas to noise levels exceeding
45 CNEL; or if the project would expose commercial outdoor activity use areas to noise levels exceeding
65 CNEL or interior use areas to noise levels exceeding 50 CNEL.
4.2 EXTERIOR NOISE EXPOSURE
Traffic noise levels in year 2035 conditions vary at the site depending on the building elevation. The site
is shielded from a direct view of the 1-5 freeway to the east at the lower levels. Only at the upper (4th)
floor would a direct view of 1-5 exist. The modeled exterior noise levels from year 2035 traffic volumes at
t he project's various receiver locations are shown in Table 6, Exterior Traffic Noise Levels. The ground
level noise levels, as well as the receiver locations, are shown on Figure 4, Ground Level Contours and
Receivers.
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
Table 6
EXTERIOR TRAFFIC NOISE LEVELS
Noise Level (CNEL)
Receiver Location Ground 1st 2nd 3rd 4th 4th Floor
Level Floor Floor Floor Floor Mitigated
Northwest Corner
Rl (facing Carlsbad Village 61.8 61.5 62.0 62.8 64.4 64.4
Drive)
R2 North Central (facing 62.4 62.1 62.6 63.1 64.7 64.7 Carlsbad Village Drive)
Northeast Corner
R3 (facing Carlsbad Village 63.5 63.5 63.9 64.4 66.0 65.1
Drive)
R4 Northeast Corner 63.2 63.2 63.5 64.1 65.8 64.7 (facing Jefferson Street)
RS Southeast Corner 62.7 62.4 62.9 63.4 64.9 64.1 (facing Jefferson Street)
R6 Southeast Corner 59.7 59.2 (facing Oak Street) 60.1 61.0 63.7 63.6
R7 South Central (facing 60.1 59.6 60.4 61.2 63.4 63.5 Oak Street)
R8 Southwest Corner 54.4 53.8 53.9 54.9 60.0 60.5
Southwest edge
R9 (opposite Jefferson 54.7 54.0 54.7 56.5 60.2 61.0
Street)
As seen in Table 6, all exterior areas (deck space) is in compliance with the General Plan 65 CNEL limit
except the 4th floor decks facing Jefferson Street and the 1-5 freeway, where noise levels may be as high
as 66 CNEL. Impacts to exterior use areas may therefore be significant without mitigation at these
locations. If desired, mitigation measure NOl-1 would reduce impacts to less than significant levels.
NOl-1 On-Site Noise Barriers for Transportation Noise: Noise levels at the proposed 4th floor
decks facing Jefferson Street and the 1-5 freeway may be exposed to noise levels in excess of
65 CNEL. Noise may be reduced to less than 65 CNEL with edge-of-deck on-site noise
barriers (walls).
The noise barrier for the exterior use areas exceeding 65 CNEL shall be a 5-foot high wall
along the outer edge of the deck space.
The noise attenuation wall must be solid. It can be constructed of masonry, wood, plastic,
fiberglass, steel, or a combination of those materials, as long as there are no cracks or gaps,
through or below the wall. Any seams or cracks must be filled or caulked. If wood is used, it
can be tongue and groove and must be at least one-inch total thickness or have a density of
at least 3½ pounds per square foot. Where architectural or aesthetic factors allow, glass or
clear plastic ¾ of an inch thick or thicker may be used on the upper portion, if it is desirable
to preserve a view. Sheet metal of 18 gauge (minimum) may be used, if it meets the other
criteria and is properly supported and stiffened so that it does not rattle or create noise
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~ Project Boundary
8 Noise Receiver
Noise Contours
45dBA
50dBA
55 dBA
60dBA
--65dBA
--70dBA
o~E---3-~~E---3-~~100 Feet t
HELIX
EnviT011m611lal Planning
Source: Aerial (SanGIS, 2017)
Ground Level Contours and Receivers
Figure 4
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
itself from vibration or wind. Any door(s) or gate(s) must be designed with overlapping
closures on the bottom and sides and meet the minimum specifications of the wall materials
described above. The gate(s) may be of one-inch thick or better wood, solid-sheet metal of
at least 18-gauge metal, or an exterior-grade solid-core steel door with prefabricated
doorjambs .
As shown in Table 6, with the noise walls installed, on-site noise levels would be at or below 65 CNEL,
and impacts would be less than significant.
4.3 INTERIOR NOISE EXPOSURE
As shown in Table 6, exterior building fai;:ade noise levels may exceed 60 CNEL at the proposed
residences. Traditional architectural materials are normally able to reduce exterior-to-interior noise by
up to 15 dBA. Therefore, interior noise levels may exceed the 45 CNEL habitable space interior noise
standard, resulting in a potentially significant impact.
The methodology for the determination of interior noise levels from exterior noise levels is discussed in
Appendix A, Exterior to Interior Analysis Methodology.
Planning is based on the loudest exterior noise level of 66 CNEL and looks at habitable interior room
noise levels for the different impacted room types. The 2016 California Building Code specifically notes
planning is required only for habitable spaces (normally assumed to include bedrooms, living rooms,
food preparation and eating areas, etc.). Further, it should be noted that the ASTM International
standards for testing require that no noise measurement shall be taken at less than one meter from a
hard-reflecting surface. This precludes verification planning results or measurements within most
hallways, closest, and bathrooms. The aforementioned spaces are normally not occupied for extended
time periods and normally have limited exterior wall exposure. As such they are typically not included in
a habitable space exterior to interior analysis .
The analysis is based on the typical 4-inch stud wall design with an interior 5/8 Type "X" Gypsum board
inner surface, wood sheathing, and 7 /8-inch exterior stucco providing an approximate STC 46 rated
exterior wall.
• 0.875-inch cement plaster
• 0.5-inch shear wall
• 2-inch x 4-inch studs
• 0.625-inch Type "X" gypsum drywall
The analyzed rooms and associated specifications are as follows:
1. 4th Floor (northwest corner) Unit 17 Living/Dining
Room Size: 15' -0" X 17' -04"
Window(s): (1) 5-0,4-0
Door: (1) 6-0, 6-8
2. 4th Floor (northwest corner) Unit 17 Master Bedroom
Room Size: 11' -09" X 12' -08"
Door: (1) 6-0,7-0
HELIX Environmenllll Planning
9
Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
3. 4th Floor (northeast corner) Unit 13 Master Bedroom
Room Size: 14'-09" X 12'-11"
Window(s): (1) 6-0,2-6
Sliding Door: (1) 6-0,7-0
4. 4th Floor (northeast corner) Unit 13 Living/Dining
Room Size: 15' -0" X 18' -09"
Glass Door: (1) 10-0, 7-0
5. 4th Floor (southeast corner) Unit 14 Living/Dining
Room Size: 20' -06" X 28' -06"
Glass Door: (1) 10-0, 7-0
6. 4th Floor (southeast corner) Unit 14 Master Bedroom
Room Size: 12' -10" X 13' -0"
Window(s): (1) 5-0,4-0
Sliding Door: (1) 6-0,7-0
7. 4th Floor (southwest corner) Unit 16 Bedroom
Room Size: 12' -0" X 12' -0"
Window(s): (1) 5-0,4-0
Sliding Door: (1) 6-0, 7-0
8. 4th Floor (southwest corner) Unit 16 Living/Dining
Room Size: 15"-00" X 24'-00"
Glass Door: (1) 10-0, 7-0
Table 7, Calculation of Interior Noise for Each Analyzed Residential Room, provides the unit-by-unit
analysis for t he loudest noise level for the various residential rooms with STC 25 windows.
Table 7
CALCULATION OF INTERIOR NOISE FOR EACH ANALYZED RESIDENTIAL ROOM
Exterior CNEL Windows
Analyzed Room Wall or STC25
Wall/Wall Interior 45 CNEL or Less
Unit 17 Living/Dining Room 66/54.7 37.7 Yes
Unit 17 Master Bedroom 66 40.3 Yes
Unit 13 Master Bedroom 66 42.3 Yes
Unit 13 Living/Dining Room 66 38.8 Yes
Unit 14 Living/Dining Room 66 35.7 Yes
Unit 14 Mast er Bedroom 66/66 43.2 Yes
Unit 16 Bedroom 66/54.4 41.8 Yes
Unit 16 Living/Dining Room 66 40.3 Yes
HELIX Envirollmentat Plannfng 10
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
As shown in Table 7, interior noise levels at all analyzed rooms would be below the 45 CNEL limit with
STC 25 windows. Typical "worst-case" analysis data calculation sheets are provided for the four 4th floor
corner units in Appendix B .
Implementation of mitigation measure NOl-2 would ensure that interior noise levels would be below 45
CNEL and that the potential impacts are reduced to less than significant levels.
NOl-2 Exterior-to-Interior Noise Level Limit: Windows with dual glazing providing a minimum STC
25 rating by laboratory test shall be provided for all residential units. Inclusion of glazing
providing a minimum STC 25 test rating will reduce interior noise levels to less than 45 CNEL
for habitable living spaces in compliance with City and State standards .
Appropriate means of air circulation and provision of fresh air shall be provided to allow
windows to remain closed for extended intervals of time so that acceptable interior noise
levels can be maintained. The mechanical ventilation system shall meet the criteria of the
International Building Code (Chapter 12, Section 1203.3 of the 2001 California
Building Code).
Exterior noise at the ground floor commercial uses is less than 65 CNEL. With a 15 CNEL assumed
minimum reduction, interior noise will be less than SO CNEL limit. No further analysis is required .
HELIX Enllironmental Planning
11
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
5.0 LIST OF PREPARERS
Charles Terry, Principal Acoustician
Hunter Stapp, Noise Analyst
HELIX Envimnmental Pfann/1111
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Jefferson Luxury Apartments Acoustical Analysis Report I June 2020
6.0 REFERENCES
California Department of Transportation (Caltrans). 2013. Technical Noise Supplement for the Traffic
Noise Analysis Protocol (TeNS). September.
2004. Traffic Noise Model (TNM) .
City of Carlsbad. 2015. General Plan Noise Element. September .
San Diego Association of Governments (SAN DAG). 2020. Transportation Forecast Information Center .
Available from: http://tfic.sandag.org/.
HELIX Environmental Plannlng
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Appendix A
Exterior to Interior Analysis
Methodology
HELIX Environmental Planning, Inc.
7578 El Cajon Boulevard
La Mesa, CA 91942
619.462.1515 tel
619.462.0552 fax
www.helixepi.com
METHODOLOGY FOR EXTERIOR-TO-INTERIOR NOISE ANALYSIS
HELIX
Environmental Planning
The California Building Code, California Department of Transportation (Caltrans), local municipalities,
and other agencies (such as Housing and Urban Development) may require an acoustical analysis for
interior usable spaces that have high levels of ext erior noise. This analysis must demonstrate that
building features and/or mitigation will provide interior noise levels within the agency-specified
maximum noise limits. To compute this exterior-to-interior noise level decrease, the following
information about the interior space is required:
• Number of unique assemblies in the wall (doors, window/wall mount air conditioners, sliding
glass doors, windows, roof, etc.)
• Size, number of units, and sound transmission data for each assembly type
• Length of sound impacted wall(s)
• Depth of sound impacted room
• Height of room to be analyzed
• Exterior noise level at wall(s) (and roof if applicable) assemblies of sound impacted room
Octave Exterior Noise per Wall(s)
Typically, the exterior noise is provided as dBA, CNEL, or LoN-These data must be converted to un-
weighted octave data. To make this conversion, the calculated noise exposure is converted to octave
band sound pressure levels (SPL) by t he addition of the following octave data curves shown in Ta ble 1,
CNEL or dBA to Octave SPL Conversion for Specific Noise Sources, for different noise sources.
Table 1
CNEL OR dBA TO OCTAVE SPL CONVERSION FOR SPECIFIC TRANSPORTATION NOISE SOURCES
Band 125 Hz 250Hz 500 Hz 1000 Hz 2000 Hz 4000 Hz
Traffic -16.7 -11.2 -8.7 -4.7 -4.7 -10.7
Aircraft -15.3 -6.8 -4.3 -6.3 -9.3 -15.3
Heavy Trucks -11.1 -6.6 -5.1 -6.1 -9.1 -15.1
Train -6.6 -13.1 -6.7 -6.5 -7.3 -10.5
Hz=Hertz
Composite Sound Transmission per Octave per Wall(s) Assembly
The composite unit (typically 1-square foot) STC rating is ca lculated from the individual exterior wall
assemblies by the following formulae:
"tn = 1/lQ Tln/10
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Methodology for Exterior to Interior Analysis
"Cavg = (S1 "Cn + S2 "Cn ... Sn "Cn) / S
TLc = 10 log10 ( 1 / "Cavg}
NR = TLc -10 log10 (S)
Room Absorption
Page 2 of 2
Each analyzed room has a unique noise absorption level that reduces the overall interior noise. The
reduction in room noise due to absorption is calculated by the following methodology:
ABS = 10 log10 (A)
Octave Room Noise Level
Noise Level= XP -NR -ABS -AW
Explanation of Abbreviations
XP -Octave Wall Noise Exposure
"Cn -Component Transmission Coefficient
•avg -Average Transmission Coefficient All Components
TLn -Component Sound Transmission Loss
TLc -Combined Sound Transmission Loss
Sn -Area of Components
S -Total Area
NR -Component Noise Reduction
A -Absorption (Sabins)
ABS -Noise Reduction Due to Room Absorption
AW -Octave A -weighting
HELIX
Envtronmental Plannrng
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Appendix B
Exterior to Interior Analysis Data
Sheets for Corner Units
EXTERIOR TO INTEwt~viROJSE1'R'~UCTION ANALYSIS
Project Name: Jefferson Multi-Family Wall 1 of 2
Room Name: Living Room I Room Type : Moderate
125 Hz 250 Hz fil!QJ:g l!ili! 2KHz 4KHz
Reverberation Time (sec} : 1.2 1.2 1.2 1.2 1.0 1.0 · Moderately Reflective Room
Room Absorption (Sabins} : 83 83 83 83 104 104
Noise Level 125 Hz 250 Hz fil!QJ:g 1KHz illi! 4KHz
Source 1: Traffic 66.0 CNEL 49.3 54.8 57.3 61 .3 61.3 55.3 : Traffic Spectrum
Source 2: <NIA> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Source 3: <NIA> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
!Source 4: <NIA> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Overall: 66.0 CNEL 49.3 54.8 57.3 61.3 61.3 55.3 : Effechv~ ~_?ise Spectrum
Assembly Type Open Width Height 9rt Total Area 125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
STC 56 Double Stud 7-lnch Wall with 2-layers 5/8 Type '"X"" lnsul N 15 8 1 100.0 30 41 49 54 58 55
Window, Insulated Dual-Glazed STC 25 N 5 4 1 20.0 14 21 24 22 30 29
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 00 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
Room Depth: 17.3 ft Overall Area: 120 ft'
Volume: 2076 ft'
Number of Impacted Walls: 2
125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
49.3 54.8 57.3 61.3 61.3 55.3 : Exterior Wall Noise Exposure
21.3 28.6 31.7 29.8 37.7 36.7 : Transmission Loss
Windows Closed
I
0.5 7.8 10.9 9.0 17.0 15.9 . Noise Reduction
Interior Noise Level: 37.7 CNEL 19.2 19.2 19.2 19.2 20.2 20.2 : Absorption
29.6 27.8 27.2 331 24.2 19.2 : Noise Level
36.5 CNEL WINDOWS OPEN
125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
49.3 54.8 57.3 61.3 61.3 55.3 : Exterior Wall Noise Exposure
21.3 28.6 31.7 29.8 37.7 36.7 · Transmission Loss
0.5 78 10.9 9.0 17.0 15.9 : Noise Reduction
19.2 19.2 19.2 19.2 20.2 20.2 : Absorption
29.6 27.8 27.2 33.1 24.2 19.2 : Noise Level
~6.5 CNEL WINDOWS CLOSED
7578 El Ca1on Boulevard, La Mesa. CA 91941 6/1612020
EXTERIOR TO INTERIOR NOISE REDUCTION ANALYSIS
Project Name: Jefferson Multi-Family
0
Room Name: Living Room
Assembll,'. Tl,'.pe
STC 56 Double Stud 7-lnch Wall with 2-layers 518 Type "X" lnsul
Window Insulated Dual-Glazed STC 25
<NIA>
<NIA>
<NIA>
<NIA>
<NIA>
<NIA>
<NIA>
<NIA>
<NIA>
<NIA>
Source 1: Traffic
Source 2: <N/A>
Isource 3: <N/A>
Source 4: <NIA>
Overall:
Open Width
N 17.3
N 5
N 0
N 0
N 0
N 0
N 0
N 0
N 0
N 0
N 0
N 0
Wall 2 of 2
Noise Level 125 Hz 250 Hz 500 Hz 1KHz
61.0 CNEL 44.3 49.8 52.3 56.3
0.0 CNEL 0.0 0.0 0.0 0.0
0.0 CNEL 0.0 0.0 0.0 0.0
0.0 CNEL 0.0 0.0 0.0 0.0
61.0 CNEL 44.3 49.8 52.3 56.3
Height 9!i'. Total Area 125 Hz 250 Hz 500 Hz 1KHz
8 1 118.4 30 41 49 54
4 1 20.0 14 21 24 22
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
Overall Area: 138.4 ft'
125 Hz 250 Hz 500 Hz 1KHz
44.3 49.8 52.3 563
21.8 29.2 32.3 30.4
0.4 7.7 10.9 9.0
19.2 19.2 19.2 19.2
24.7 22.9 22.2 28.1
31.5 CNEL WINDOWS OPEN
125 Hz 250 Hz 500 Hz 1KHz
44.3 49.8 52.3 56.3
21.8 29.2 32.3 30.4
0.4 7.7 10.9 9.0
19.2 19.2 19.2 19.2
24.7 22.9 22.2 28.1
31.5 CN~ WINDOWS CLOSED
~ 4KHz
56.3 50.3 : Traffic Spectrum
0.0 0.0
0.0 0.0
0.0 0.0
56.3 50.3 : Effective Noise Spectru_m
2KHz 4KHz
58 55
30 29
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
2KHz 4KHz
56.3 50.3 : Exterior Wall Noise Exposure
38.4 37.3 : Transmission loss
16.9 15.9 : Noise Reduction
20.2 20.2 : Absorption
19.2 14.2 : Noise Level
2KHz ~
56.3 50.3 · Exterior Wall Noise Exposure
38.4 37.3 : Transmission Loss
16.9 15.9 . Noise Reduction
20.2 20.2 : Absorption
19.2 142 ; Noise Level
EXTERIOR TO INTERttffl'NOJS!'1Rf!DU'CTION ANALYSIS
Project Name: Jefferson Multi-Family Wall 1 of 2
Room Name: Bedroom Unit 14 I Room Type : Moderate
fill!! 250 Hz 500 Hz 1KHz 2KHz 4KHz
Reverberation Time (sec) : 1.2 1.2 1.2 1.2 1.0 1.0 : Moderately Reflective Room
Room Absorption (Sabins) : 50 50 50 50 63 63
Noise Level 125 Hz ~ 500 Hz 1KHz 2KHz 4KHz
Source 1: Traffic 66.0 CNEL 49.3 54.8 57.3 61.3 61.3 55.3 : Traffic Spectrum
Source 2: <N/A> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Source 3: <N/A> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Source 4: <N/A> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Overall: 66.0 CNEL 49.3 54.8 57.3 61.3 61.3 55.3 : Effective Noise Spectrum
Assemb~ Ti1pe Open Width Height 91Y Total Area 125 Hz 250 Hz 500 Hz jJStl! 2KHz 4KHz
STC 56 Double Stud 7-lnch Wall with 2-layers 5/8 Type "X" lnsul N 12 5 8 1 59.2 30 41 49 54 58 55
Window, Insulated Dual-Glazed STC 25 N 6 6.8 1 40.8 14 21 24 22 30 29
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
Room Depth: 12.5 ft Overall Area: 100 ft'
Volume: 1250 ft'
Number of Impacted Walls: 2
125 Hz 250 Hz 500 Hz 1KHz 2KHz ~
49.3 54.8 57.3 61.3 61.3 55.3 : Exterior Wall Noise Exposure
17.7 24.8 27.9 25.9 33.9 32.9 : Transmission Loss
Windows Closed
I
0.0 4.8 7.9 5.9 13.9 12.9 : Noise Reduction
Interior Noise Level: 43.2 CNEL 17.0 17.0 17.0 17.0 18.0 18.0 : Absorption
32.3 33.0 32.4 38.4 29.5 24.5 : Noise Level
41.3 CNEL 'MNDOWS OPEN
125 Hz 250 Hz 500 Hz 1KHz £!S!:g 4KHz
49.3 54.8 57.3 61.3 61.3 55.3 : Exterior Wall Noise Exposure
17.7 24.8 27.9 25.9 33.9 32.9 : Transmission Loss
0.0 4.8 7.9 5.9 13.9 12.9 : Noise Reduction
17.0 17.0 17.0 17.0 18.0 18.0 : Absorption
32.3 33.0 32.4 38.4 29.5 24.5 : Noise Level
41.3 CNEL 'MNDOWS CLOSED
7578 El Cajon Boulevard, La Mesa, CA 91941 6/1612020
EXTERIOR TO INTERlMWOTS!'1REDUCTION ANALYSIS
Project Name: Jefferson Multi-Family Wall 1 of 1
Room Name: Living Room Unit 16 I Room Type : Moderate
125 Hz 250 Hz 500 Hz ~ 2KHz 4KHz
Reverberation Time (sec) : 1.2 1.2 1.2 1.2 1.0 1.0 : Moderately Reflective Room
Room Absorption (Sabins) : 99 99 99 99 124 124
Noise Level 125 Hz 250 Hz 500 Hz 1KHz ~ 4KHz
Source 1: Traffic 66.0 CNEL 49.3 54.8 57.3 61 .3 61.3 55.3 : Traffic Spectrum
Source 2: <NIA> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Source 3: <N/A> 0.0 CNEL 00 0.0 0.0 0.0 0.0 0.0
Source 4: <NIA> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Overall: 66.0 CNEL 49.3 54.8 57.3 61.3 61.3 55.3 : Effective Noise Spectrum
Assembll,'. TJi'.l!e Oeen Width Height 9!Y. Total Area 125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
STC 56 Double Stud 7-lnch Wall with 2-layers 5/8 Type "X" lnsul N 14.8 8 1 50.4 30 41 49 54 58 55
Window. Insulated Dual-Glazed STC 25 N 10 6.8 1 68.0 14 21 24 22 30 29
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
Room Depth: 20.9 ft Overall Area: 118.4 ft'
Volume: 2475 ft3
Number of Impacted Walls:
125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
49.3 54.8 57.3 61.3 61 .3 553 : Exterior Wall Noise Exposure
16.3 23.4 26.4 24.4 32.4 31.4 : Transmiss10n Loss
Windows Closed
I
0.0 2.6 5.7 3.7 117 10.7 : Noise Reduction
Interior Noise Level: 40.3 CNEL 20.0 20.0 20.0 20.0 20.9 20.9 : Absorption
29.4 32.2 31.7 37.7 28.7 23 7 · Noise Level
40.3 CNEL WINDOWS OPEN
125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
49.3 54.8 57.3 61.3 61.3 55.3 : Exterior Wall Noise Exposure
16.3 23.4 26.4 24.4 32.4 31.4 : Transmission Loss
0.0 2.6 5.7 3.7 11.7 10.7 : Noise Reduction
20.0 20.0 20.0 20.0 20.9 20.9 : Absorption
29.4 32.2 31 .7 37.7 28.7 23.7 : Noise Level
~0.3 CNEL WINDOWS CLOSED
7578 El Cajon Boulevard, La Mesa, CA 91941 6116/2020
EXTERIOR TO INTER!t)R1ft'OJSe'1~TION ANALYSIS
Project Name: Jefferson Multi-Family Wall 1 of 2
Room Name: Bedroom Unit 13 I Room Type : Moderate
lli.l:!! lli.!:!! ill.!:!! 1!9:1! 2KHz 4KHz
Reverberation Time (sec) : 1.2 1.2 1.2 1.2 1.0 1.0 : Moderately Reflective Room
Room Absorption (Sabins) : 61 61 61 61 76 76
Noise Level 125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
Source 1: Traffic 66.0 CNEL 49.3 54.8 57.3 61.3 61.3 55.3 : Traffic Spectrum
Source 2: <N/A> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Source 3: <N/A> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Source 4: <N/A> 0.0 CNEL 0.0 0.0 0.0 0.0 0.0 0.0
Overall: 66.0 CNEL 49.3 54.8 57.3 61.3 61.3 55.3 : Effective Noise Spectrum
Assemb!:L Tir:l!e Ol!en ~ Height Q!y_ Total Area 125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
STC 56 Double Stud 7-lnch Wall with 2-layers 5/8 Type ··x" lnsul N 14 8 8 1 98.4 30 41 49 54 58 55
Window. Insulated Dual-Glazed STC 25 N 5 4 1 20.0 14 21 24 22 30 29
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<NIA> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
<N/A> N 0 0 0 0.0 0 0 0 0 0 0
Room Depth: 12.9 ft Overall Area: 118.4 ft'
Volume: 1527 ft'
Number of Impacted Walls: 2
125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
49.3 54.8 57.3 61.3 61.3 55.3 : Exterior Wal1 Noise Exposure
CNEJ I
21.2 28.5 31.7 29.7 37.7 36.7 : Transmission Loss
Windows Closed 0.5 7.8 10.9 9.0 17.0 15.9 : Noise Reduction
Interior Noise Level: 42.3 17.9 17.9 17.9 17.9 18.8 18.8 : Absorption
31.0 29.2 28.5 34.5 25.5 20.5 · Noise Level
37.8 CNEL WINDOWS OPEN
125 Hz 250 Hz 500 Hz 1KHz 2KHz 4KHz
49.3 54.8 57.3 61.3 61.3 55.3 ; Exterior Wall Noise Exposure
21.2 28.5 31.7 29.7 37.7 36.7 . Transmission Loss
0.5 78 10.9 9.0 17.0 15.9 : Noise Reduction
17.9 17.9 17.9 17.9 18.8 18.8 : Absorption
31.0 29.2 28.5 34.5 25.5 20.5 : Noise Level
37.8 CNEL WINDOWS CLOSED
7578 El Cajon Boulevard, La Mesa, CA 91941 6116/2020
EXTERIOR TO INTERIOR NOISE REDUCTION ANALYSIS
Project Name: Jefferson Multi-Family
0
Room Name: Bedroom Unit 17
Assembl:t T:t11e
STC 56 Double Stud 7-lnch Wall with 2-layers 5/8 Type "X" lnsul
Window. Insulated Dual-Glazed STC 25
<N/A>
<N/A>
<N/A>
<N/A>
<N/A>
<N/A>
<N/A>
<N/A>
<N/A>
<N/A>
Source 1: Traffic
Source 2: <N/A>
Source 3: <N/A>
I source 4: <N/A>
Overall:
O11en Width
N 12 9
N 6
N 0
N 0
N 0
N 0
N 0
N 0
N 0
N 0
N 0
N 0
Wall 2 of 2
Noise Level ll§.1!! 250 Hz 500 Hz 1KHz
66.0 CNEL 49.3 54.8 57.3 61 .3
0.0 CNEL 0.0 0.0 0.0 0.0
0.0 CNEL 0.0 0.0 0.0 0.0
0.0 CNEL 0.0 0.0 0.0 0.0
66.0 CNEL 49.3 54.8 57.3 61.3
Height 9!ll. Total Area 125 Hz ~ ~ 1KHz
8 1 62.4 30 41 49 54
6 .8 1 40.8 14 21 24 22
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 00 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
0 0 0.0 0 0 0 0
Overall Area: 103.2 ft2
125 Hz ~ 500 Hz 1KHz
49.3 54.8 57.3 61.3
17.9 25.0 28.0 26.0
0.0 48 7.9 5.9
17.9 17.9 17.9 17.9
31.4 32.1 31.6 376
40.5 CNEL WINDOWS OPEN
ll§.1!! 250 Hz 500 Hz 1KHz
49.3 54.8 57.3 61.3
17.9 25.0 28.0 260
0.0 4.8 7.9 5.9
17.9 17.9 17.9 17.9
31.4 32.1 31.6 37.6
40.5 CNEL WINDOWS CLOSED
2KHz 4KHz
61.3 55.3 : Traffic Spectrum
0.0 0.0
0.0 0.0
0.0 0.0
61.3 55.3 : Effective Noise Spectrum
2KHz 4KHz
58 55
30 29
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
2KHz 4KHz
61.3 55.3 : Exterior Wall Noise Exposure
34.0 33.0 : Transmission Loss
13.9 12.9 . Noise Reduction
18.8 18.8 : Absorption
28.6 23.6 : Noise Level
2KHz 4KHz
61.3 55.3 : Exterior Wall Noise Exposure
34.0 33.0 : Transmission Loss
13.9 12.9 · Noise Reduction
18.8 18.8 : Absorption
28.6 23.6 : Noise Level