HomeMy WebLinkAboutPUD 2018-0008; THREE ON CHERRY; ACOUSTICAL ANALYSIS REPORT; 2018-08-27'
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ABC Acoustics, Inc.
NOISE CONTROL EXPERTS
ACOUSTICAL ANALYSIS REPORT
THREE ON CHERRY
City of Carlsbad, California
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AUG 31 2018
CITY OF CARL.S3 "!J
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PREPARED FOR:
DI Donato Associates
3939 First Avenue, Suite 100
San Diego, CA 92103
ABC Report No: 2552
August 27, 2018
TABLE OF CONTENTS
1.0 INTRODUCTION: ...................................................................................................... 1
2.0 PROJECT DESCRIPTION: ............................................................................................ 2
3.0 APPLICABLE STANDARDS: ........................................................................................ 3
3.1 EXTERIOR NOISE STANDARDS: .............................................................................................. 3
3.2 EXTERIOR-TO-INTERIOR NOISE STANDARDS: ............................................................................ 3
3.3 INTERIOR NOISE LIMITS: ...................................................................................................... 3
4.0 NOISE IMPACT ASSESSMENT: ................................................................................... 5
4.1 EXISTING NOISE COMPUTER MODELING: ................................................................................ 5
4.1.1 Vehicular Traffic Noise Modeling: .......................................................................... 5
4.1.2 Railroad Noise Impacts: ......................................................................................... 7
4.1.3 Existing Cumulative Noise Impacts: ....................................................................... 8
4.2 FUTURE NOISE ENVIRONMENT: ............................................................................................ 8
5.0 CONDITIONS OF DEVELOPMENT AND MITIGATION: ................................................. 9
5.1 EXTERIOR NOISE ATTENUATION: ........................................................................................... 9
5.2 INTERIOR NOISE ATTENUATION: ............................................................................................ 9
6.0 CERTIFICATION: ..................................................................................................... 10
7.0 REFERENCES CITED: ................................................................................................ 11
LIST OF FIGURES
FIGURE 1: VICINITY MAP ............................................................................................................ 1
FIGURE 2: SITE PLAN .................................................................................................................. 2
FIGURE 3: SITE LOCATION AND TRAFFIC NOISE CNEL CONTOURS ............................................ 6
FIGURE 4: CONVENTIONAL TRAIN HORN NOISE .......... : ............................................................. 7
FIGURE 5: SITE PLAN TRAIN WHISTLE NOISE CNEL CONTOURS ................................................. 8
TABLE 1: CITY OF CARLSBAD LAND USE NOISE COMPATIBILITY GUIDELINES ........................... 4
LIST OF ATTACHMENTS
ATTACHMENT "A" -NOISE CALCULATION DATA
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Three on Cherry, Carlsbad -Acoustics
1.0 INTRODUCTION:
Three on Cherry project would construct a new 2-story condominium residential
building comprising of 3 living units and a covered over-ground parking. The project
site is located along Cherry Avenue in Carlsbad, California. Vicinity land uses are
primarily residential.
Noise sources of potential significance in the area include Carlsbad Boulevard,
Cherry Avenue and the Burlington Northern Santa Fe (BNSF) railroad tracks which
run approximately 1000 feet east of the site (Figure 1). The City of Carlsbad has
requested an Acoustical Analysis Report to assess compliance of the project with the
City's exterior and interior noise standards. This Acoustical Analysis Report addresses
the cumulative exterior and interior noise levels impacting the project. It is based on
vehicular traffic information provided by the City of Carlsbad and noise
measurements conducted at the project site by ABC Acoustics. It also makes use of
the architectural plans prepared for the project by Di Donato Associates (February
2018).
The following sections of this report include a description of the project, a discussion
of the applicable standards, results of acoustical analysis and the need for acoustical
treatment measures to ensure compliance with interior acoustics of 45 dBA Ldn or
lower, as required by the City of Carlsbad.
FIGURE 1: VICINITY MAP
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Three on Cherry, Carlsbad -Acoustics
2.0 PROJECT DESCRIPTION:
Three on Cherry project site is located at 160 Cherry Avenue within the City of Carlsbad,
California. The project site is currently occupied by a single-story home. The project
would construct 3 attached two-story condominium units. The ground floor includes
parking spaces, and bedrooms. A Site Plan for the project is included in Figure 2.
Noise levels impacting the project site stem primarily from traffic on Carlsbad Boulevard
and, to a lesser degree, Cherry Avenue. BNSF railroad tracks run 1000 feet east of the
site. Although train noise is barely audible at the project site, occasional train whistles
are audible. This report includes an analysis of the noise impacts relating to railroad
whistle in Section 4.1.2.
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FIGURE 2: SITE PLAN
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Three on Cherry, Carlsbad -Acoustics
3.0 APPLICABLE STANDARDS:
3.1 Exterior Noise Standards:
The City of Carlsbad has established a set of community noise standards which identify
compatible outdoor and indoor noise levels for various types of land uses (Table 1). As
presented in Table 1, multi-family residential development is normally acceptable within
an exterior noise environment of 65 dBA Ldn or lower. If the exterior noise levels exceed
the normally acceptable levels, measures should be examined to reduce such impacts to
below a level of significance at the project site.
3.2 Exterior-to-Interior Noise Standards:
If exterior noise levels cannot be reduced to acceptable levels by practical means,
specific design and construction techniques must be incorporated to reduce the interior
noise levels. The maximum interior noise limit for residential land uses within the City of
Carlsbad is 45 dB-A Ldn.
Units of noise are expressed as decibels (dB) and the "A"-weighted noise scale is used
because it closely approximates the perception of loudness by humans. Ldn (Day-Night
Community Noise Level) is the energy-averaged time-weighted annual noise level over a
24-hour period. Time-weighting technique applies a penalty to the actual hourly noise
levels during certain periods of evening and/or nighttime hours. Ldn applies a 10 dB-A
penalty to the nighttime hours of 10 pm to the following 7 am. This penalty was selected
to reflect people's sensitivity to noise as a function of activity.
Community Noise Equivalent Level (CNEL) is similar to Ldn except it has an additional 5
dB penalty applied to the evening hours of 7 pm to 10 pm. Ldn and CNEL are often used
interchangeably.
3.3 Interior Noise Limits:
The City of Carlsbad, per California Code of Regulations, Title 24, requires all new
multi-unit residential projects located within an exterior noise environment
exceeding 60 dBA CNEL to conduct an interior acoustical analysis. The interior
Acoustical Analysis Report must address the interior noise impacts at the project site
and, if necessary, recommend sound attenuation measures to reduce such impacts
at all habitable areas to 45 dBA CNEL or lower.
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Three on Cherry, Carlsbad -Acoustics
TABLE 1: CITY OF CARLSBAD LAND USE -NOISE COMPATIBILITY GUIDELINE
Land Use Category
Residential-
Single Family
Residential-
Multiple Family
Transimt l.odging-
Motels, Hotels
Schools, Libraries.
Oturches, Hospitals,
Nursin Homes
Auditoriwns,
Concert
Sports Arena,
Outdoor
Playgrounds,
Parks
Golf Coones, Riding
Stables, Water
Recreation, Cemeteries
Office Buildings, Business
Commercial and
Professional
Industrial, Manufacturing,
Utilities, A riculture
ABC Acoustic, Inc.
Exterior Day/Night Noise Levels
DNL or Ldn , dB
55 60 65 70 75 80
Report: 2552
INTERPRETATION
Normally Acceptable:
Specified land use is satisfactory,
based upoo the aiaumption that
any buildings involved are of
normal conventional construction,
without any special noise insulation
requirements
Conditionally Acceptable:
New construction or development
should be undertaken only after a
detailed analysis of the noise
reduction requirements is made
and needed noise insulation
features included in the design. -Normally Unacceptable:
New construction or development
should generally be discouraged. If
new construction or development
does proceed. a detailed analysis of
the noise reduction requirementJ
must be made and needed noise
insulation fealures included in the
design. -Clearly Unacceptable:
New construction or development
clearly should not be undertaken.
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4.0 NOISE IMPACT ASSESSMENT:
Existing noise sources of potential significance in the vicinity of Three on Cherry
project are Carlsbad Boulevard and, to a lesser degree, Cherry Avenue and the BNSF
railroad tracks.
Existing noise levels at the project site were measured during peak hours of
afternoon traffic on July 23, 2018, a typical sunny and calm Carlsbad day. On-site
cumulative hourly average noise levels (Leqh) at 40 feet from Cherry Avenue's
centerline were measured to be 55-57 dBA. Hourly average noise levels during peak
hours of traffic are often equivalent to the Ldn at that location. Noise
measurements were conducted using a Bruel and Kj~r (B&K) Type 2250 analyzer, a
Type 1 Sound Level Meter, per ANSI Sl.4.
4.1 Existing Noise Computer Modeling:
Noise levels impacting the project site were also calculated using the SoundPlan
Computer Model along with traffic information provided by SANDAG and available
train noise data.
4.1.1 Vehicular Traffic Noise Modeling:
Carlsbad Boulevard is a four-lane, two-way major road running west of the project
site. The posted speed limit is 30 mph. According to SANDAG Series 13, the current
traffic volume along Carlsbad Boulevard is approximately 12,700 Average Daily Trips
(ADT).
Cherry Avenue is a two-lane, two-way local road running east of the project site. The
posted speed limit is 25 mph. The current traffic volume along Cherry Avenue is
approximately 3,100 ADT (SANDAG).
Exterior noise levels impacting the project site from traffic along these two roadways
were calculated and a noise contour map was generated. Details of noise modeling
are presented in Attachment "A". Noise contours are shown in Figure 3 below.
Traffic-related noise impacts at building fa~ade would be approximately 56 dBA
CNEL which is in agreement with the on-site measured noise levels.
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Three on Cherry, Carlsbad -Acoustics
FIGURE 3: SITE LOCATION AND TRAFFIC NOISE CNEL CONTOURS
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Three on Cherry, Carlsbad -Acoustics
4.1.2 Railroad Noise Impacts:
The BNSF railroad tracks pass 1000 feet north east of the project site. These
tracks are utilized by the Amtrak as well as the Coaster and the BNSF Cargo
trains. Train locomotive noise impacts are not significant at the project site due
to shielding effect of the existing development within the intervening
topography. The only noise of potential significance is due to train horn. Sound
intensity of conventional train horns with respect to distance is presented in
Figure 4. Although there are no railroad crossings at immediate vicinity of the
project site, short-term noise impacts due to occasional train horn were assessed
to present peak instantaneous impacts.
CONVENTIONAL TRAIN HORN NOISE
INTENSITY vs. DISTANCE
110,,----------~~l""T"".-rr.r-------------, 1
104,0 104.0
96.5 96.5 C
l oo ~--------~~~~~--------~
~
l ~r ------~~~-~~~~-------~ ! .5 70 69.5
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Loud Vok:e
69.5
Loud Voice
50 r------,i-----,.--...,..-------....... -------------....L..4
-8000 -4000 ·2000 0 2000 4000 6000 8000
Distance From Crosalng • Feet
FIGURE 4: CONVENTIONAL TRAIN HORN NOISE
Short term noise impacts due to train horn were calculated at the building fa~ade.
Results of modeling is presented in Attachment "A" and Figure 5 below. As shown in
Figure 5, the short-term train horn noise level is approximately 53 dBA along the
south-east side of third floor. Train horn noise is 2 decibels lower along the ground
ABC Acoustic, Inc. Report: 2552 7
Three on Cherry, Carlsbad -Acoustics
floor or 51 dBA. Since train horn noise level is very short term, it does not contribute
to the overall noise of 57 dBA CNEL impacting the site from vehicular traffic sources.
80 · 83
83 • 86
-
86 · 89
>• 89 FIGURE 5: SITE PLAN TRAIN WHISTLE NOISE CNEL CONTOURS
4.1.3 Existing Cumulative Noise Impacts:
Noise measurements and modeling for the project resulted in a cumulative exterior
noise impact of approximately 57 dBA CNEL on the ground floor. To account for the
short-term train horn noise on the 3rd floor, a 2-dB penalty was added to the exterior
noise level. To present a worst-case scenario, the entire project site was assumed to
be impacted by an exterior cumulative noise of 59 dBA CNEL.
4.2 Future Noise Environment:
Future noise levels along Carlsbad Boulevard, Cherry Avenue, and BNSF railroad
tracks are anticipated to be similar to existing levels. Future exterior noise impacts
at the project site would range between 57 and 59 dBA CNEL.
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5.0 CONDITIONS OF DEVELOPMENT AND MITIGATION:
5.1 Exterior Noise Attenuation:
Exterior noise impacts at the project site would be 59 dBA CNEL or lower. Since
exterior noise impacts would not be significant, no exterior noise attenuation
measures are recommended.
5.2 Interior Noise Attenuation:
Since exterior noise impacts at building fa~ade do not exceed the allowable limit of
60 dBA Ldn, no interior noise attenuation is required.
California light-frame residential structures provide for 15 dB exterior-to-interior
noise reduction with windows open. Hence, exterior noise of 59 dBA Ldn would be
reduced to 44 dBA Ldn inside. The proposed Three on Cherry project includes air
conditioning for all units which provides for closed-window conditions. Closed-
window conditions provide for an additional 5-10 dB reduction with double-glazed
windows. Therefore, an exterior noise of 59 dBA CNEL would be reduced to 34-39
dBA CNEL with windows closed. Interior noise levels at the project site were
calculated at selected cross sections. Results of interior noise calculations are C presented in Tables A-3 to A-5 of Attachment "A".
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Interior noise levels within all habitable areas of the project would be in compliance
considering the following project features:
1) All habitable areas of Three on Cherry project shall be equipped with
mechanical ventilation to provide for fresh air, in compliance with CBC and
California Mechanical Codes (CMC) Chapter 4.
2) Exterior windows and sliding doors shall have STC 23 or higher.
3) Residential entry doors shall be solid core wooden and weather-stripped
with an STC of 23 or higher.
The above noise treatment measures, if incorporated, would reduce the interior
noise impacts at the proposed project site to levels acceptable by the City of
Carlsbad.
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Three on Cherry, carlsbad -Acoustics
6.0 CERTIFICATION:
The findings and recommendations presented in this acoustical analysis report are
based on available information at the time of analysis. They represent a true and
factual analysis of the scope of work relating to potential acoustical issues associated
with the subject Three on Cherry project.
There are many factors involved in actual acoustical performance of a structure.
Since ABC Acoustics, Inc. has no control over the construction, workmanship and
building material's performance, ABC Acoustics, Inc. is not and could not be held
liable for final results or any damages which may occur as a result of implementing
the recommendations presented herein.
This report was prepared by Sharo T. Sanavi.
ABC Acoustics, Inc.
Sharo T. Sanavi
Principal
sharo@abcacoustics.com
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7 .O REFERENCES CITED:
California, State of; Uniform Building Codes
2005 Section 1203 of the California Building Codes (CBC).
Di Donato Associates
2018 Architectural Plans for Three on Cherry project
Carlsbad, City of
2011 General Plan, Noise Element.
U.S. Department of Health, Education, and Welfare
1975 Compendium of Materials for Noise Control.
U.S. Department of Transportation, Federal Highway Administration
1978 Highway Traffic Noise Prediction Model (FHWA-RD-77-108).
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Three on Cherry, Carlsbad -Acoustics
ATTACHMENT "A"
NOISE CALCULATION DATA
ABC Acoustic, Inc. Report: 2552 12
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Project: Three on Cherry, Carlsbad
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Map
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Result number 2
calculation in 1.5 m above ground
Project qinffr: Sail Atter
Created: 7/26/2018
Processed wtth SoundPLAN 7.3, Update 3/19/2015
Levels Ldn
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-45 · 48
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51 · 54
54 • 57 11111111 57 . 60
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Receivers
Table A-1
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• Project No: R2552
R1 G
F2
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F4
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Assessed receiver levels
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11467639.6 3668055.1 17.45
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11467649.7 3668061 .2 18.58
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Table: A-2
58.3 57.1 49.8
58.7 57.4 50.3
59.1 57.6 50.7
58.8 57.5 50.4
57.8 56.8 49.0
58.0 57.1 49.3
58.1 57.2 49.3
58.9 57.7 50.4
ABC ACOUSTICS
08-27-2018
REPORT-2552
TABLE A-3
RESULTS OF INTERIOR NOISE ANALYSIS
Location -Bedroom-First Floor-south
Noise source -TRAFFIC NOISE (NBS, 1978)
Octave Band center Frequency, Hz
125 250 500 1000 2000
ATTACHMENT
4000
Reference Exterior A-Weighted sound Level spectrum (re. total of 100 dB)
86.0 90.7 93.5 95.8 92.7 87.0
Room sound Absorption in sabins
135 135 135 135 135 135
INTERIOR A-WEIGHTED SOUND LEVEL SPECTRUM ('CLOSED WINDOWS' CONDITIONS)
27.8 32.2 32.1 32.4 25.2 16.5
Building Facade Reflection correction -3.0 dB
Quality correction -3.0 dB
#
SOUND TRANSMISSION THROUGH CONSTRUCTIONS
Building Element Information
construction STC AREA
sq.ft.
A-Weighted sound Level
EXTERIOR INTERIOR
closed open%
ACorr
1. STUCCO WALL
2. WINDOW (3/32" GLASS)
46
23
78.0
38.0
59
59
23
39
23 0 0.0
55 50 0.0
TOTAL A-WEIGHTED SOUND LEVEL IN THE ROOM 39 55
ABC ACOUSTICS
08-27-2018 REPORT-2552
TABLE A-4
RESULTS OF INTERIOR NOISE ANALYSIS
Location -Living room-second floor-south
Noise Source -TRAFFIC NOISE (NBS, 1978)
octave Band center Frequency, Hz
125 250 500 1000 2000
ATTACHMENT
4000
Reference Exterior A-Weighted sound Level Spectrum (re. total of 100 dB)
86.0 90.7 93.5 95.8 92.7 87.0
Room sound Absorption in sabins
82 82 82 82 82 82
INTERIOR A-WEIGHTED SOUND LEVEL SPECTRUM ('CLOSED WINDOWS' CONDITIONS)
29.3 33.4 33.2 33.5 26.4 17.6
Building Facade Reflection correction -3.0 dB
Quality Correction -3.0 dB
#
SOUND TRANSMISSION THROUGH CONSTRUCTIONS
Building Element Information
construction STC AREA
sq.ft.
A-Weighted sound Level
EXTERIOR INTERIOR
closed open%
ACorr
1. STUCCO WALL
2. sliding glass door
46
23
87.0
30.0
59
59
25
40
25 0 0.0
55 50 0.0
TOTAL A-WEIGHTED SOUND LEVEL IN THE ROOM 40 55
ABC ACOUSTICS
08-27-2018
REPORT-2552
TABLE A-5
RESULTS OF INTERIOR NOISE ANALYSIS
Location -Master bedroom-Third Floor-south
Noise source -TRAFFIC NOISE (NBS, 1978)
Octave Band center Frequency, Hz
125 250 500 1000 2000
ATTACHMENT
4000
Reference Exterior A-Weighted sound Level Spectrum (re. total of 100 dB)
86.0 90.7 93.5 95.8 92.7 87.0
Room sound Absorption in sabins
186 186 186 186 186 186
INTERIOR A-WEIGHTED SOUND LEVEL SPECTRUM ('CLOSED WINDOWS' CONDITIONS)
25.9 29.7 29.5 29.8 22.7 13.9
Building Facade Reflection correction -3.0 dB
Quality correction -3.0 dB
#
SOUND TRANSMISSION THROUGH CONSTRUCTIONS
Building Element Information
construction STC AREA
sq.ft.
A-Weighted sound Level
EXTERIOR INTERIOR
closed Open%
ACorr
1. STUCCO WALL
2. WINDOW (3/32" GLASS)
46 101.4
23 29.0
59
59
23
36
23 0 0.0
51 50 0.0
TOTAL A-WEIGHTED SOUND LEVEL IN THE ROOM 36 51
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