HomeMy WebLinkAboutCT 2017-0006; ROOSEVELT TOWNHOMES; ACOUSTICAL ANALYSIS REPORT; 2017-08-28ABC Acoustics, Inc.
NOISE CONTROL EXPERTS
ACOUSTICAL ANALYSIS REPORT
ROOSEVELT TOWNHOMES VILLAGE
City of Carlsbad, California
PREPARED FOR:
Frontis Studio
830 Missouri Street, #2
San Diego. 92109
ABC Report No: 2500
August 28, 2017
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
5.3 TRAIN HORN NOISE ATTENUATIO N: ................................................................................. 9
6.0 REFERENCES CITED: ........................................................................................... 10
7.0 CERTIFICATION: ................................................................................................ 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 LOCATION AND TRAIN WHISTLE NOISE CONTOURS (3 th FLOOR) ................ 8
LIST OF TABLES
TABLE 1: CITY OF CARLSBAD LAND USE NOISE COMPATIBILITY GUIDELINES ..................... 4
LIST OF ATTACHMENTS
ATTACHMENT "A" -NOISE CALCULATION DATA
Roosevelt Townhomes Village
1.0 INTRODUCTION:
Roosevelt Townhomes Village project would construct five three-story townhomes
comprising of 5 living units and a covered over-ground parking. The project site is
located west of the Roosevelt Street in Carlsbad, California. Vicinity land uses are
primarily residential.
Noise sources of potential significance in the area include the local streets and the
Burlington Northern Santa Fe (BNSF) railroad tracks which run approximately 730
feet west 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 Frontis Studio (March 2017).
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
ABC Acoustics, Inc. Report 2500 1
Roosevelt Townhomes Village
2.0 PROJECT DESCRIPTION:
Roosevelt Townhomes Village project site is located at 2569 Roosevelt Street within the
City of Carlsbad, California. The project site is currently occupied by a single-family
home. The project would construct 5 attached/detached three-story condominium units
accommodated. The ground floor includes covered parking spaces. A Site Plan for the
project is included in Figure 2.
Noise levels impacting the project site stem primarily from traffic on Roosevelt Street
and, to a lesser degree, Laguna Street. BNSF railroads run 730 feet southwest of the site.
Although train noise is barely audible at the project site, occasional train whistles are
clearly audible. This report includes an analysis of the noise impacts relating to railroad
whistle in Section 4.1.3.
I• . [
0 hlt'IJ
0 c,..,,._, ... Pml"f
~'llnAV ' t
FIGURE Z: SITE PLAN
ABC Acoustic, Inc. Report: 2500 2
Roosevelt Townhomes Village
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.
ABC Acoustic, Inc. Report: 2500 3
Roosevelt Townhomes Village
TABLE 1: CITY OF CARLSBAD LAND USE -NOISE COMPATIBILITY GUIDELINE
Land Use Category
Re idenlial-
Single Family
Residential-
Multiple Family
Transient Lodging-
Motels, Hotel
Schools, Libraries,
Churche , Hospitals,
Nursing Homes
Auditoriums,
Concert
Sports Arena,
Outdoor
Pla)1ground~.
Parks
Golf Cour es, Ridi11g
tables, Water
Recreation, Ccmcterie
Office Buildings, Busines
Commercial and
Professional
Industrial, Manufacturing,
Utilitie , A riculturc
ABC Acoustic, Inc.
Exterior Day/Night Noise Levels
DNL or Ldn , dB
55 60 65 70 75 80
Report: 2500
INTERPRETATION
Normally Acceptable:
pccified land use i atisfactory,
based upon the a umption that
any buildings involved arc of
normal conventional cons! ruction,
without any special noise insulation
requirement
Conditionally Acceptable:
New construction or development
should be undertaken only after a
detailed analy is of the noise
reduction requirements is made
and needed noise insulation
features included in the design. -Normally Unacceptable:
New construction or development
hould generally be discouraged. If
new con truction or development
does proceed, a detailed analysi of
the noise reduction requirements
must be made and needed noise
insulation feature included in the
design. -Clcarlr Unacceptable:
ew construction or development
clearly should not be undertaken.
4
Roosevelt Townhomes Village
4.0 NOISE IMPACT ASSESSMENT:
Existing noise sources of potential significance in the vicinity of Roosevelt
Townhomes Village project are Roosevelt Street and, to a lesser degree, Laguna
Drive, and the BNSF railroad tracks.
Existing noise levels at the project site were measured during peak hours of
afternoon traffic on August 16, 2017, a typical sunny and calm Carlsbad day. On-site
cumulative hourly average noise levels (Leqh) at 40 feet from Roosevelt Street's
centerline were measured to be 53-54 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 Kja:!r (B&K) Type 2250 analyzer, a
Type 1 Sound Level Meter, per ANSI S1.4.
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:
Roosevelt Street is a two-lane, two-way local road running east of the project site.
The posted speed limit is 25 mph. According to SANDAG, the current traffic volume
along Madison Street is approximately 1,700 Average Daily Trips (ADT).
Laguna Drive is a two-lane, two-way local road running north of the project site. The
posted speed limit is 30 mph. The current traffic volume along Laguna Drive is
approximately 3,400 ADT (SANDAG).
Exterior noise levels impacting the project site from traffic along these two roadways
were calculated using the SoundPlan Computer Model. Details of noise modeling
are presented in Attachment "A". Noise contours are shown in Figure 3 below.
Traffic-related noise impacts at building fac;ade would be approximately 54 dBA
CNEL which is in total agreement with the on-site measured noise levels.
ABC Acoustic, Inc. Report: 2500 5
Roosevelt Townhomes Village
FIGURE 3: SITE LOCATION AND TRAFFIC NOISE CNEL CONTOURS
ABC Acoustic, Inc. Report: 2500 6
Roosevelt Townhomes Village
4.1.2 Railroad Noise Impacts:
The BNSF railroad tracks pass 730 feet southwest 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 t o train horn. Sound intensity of conventional
train horns with respect to distance is presented in Figure 4. Although t here are no
rail road crossings at immediate vicin ity of the project site, short-term noise impacts
due to train horn were assessed to present peak instantaneous impacts.
<
CONVENTIONAL TRAIN HORN NOISE
INTENSITY vs. DISTANCE 110..-----------~-~=-----------, 1 .s 108.5
104 .0 104 0
1001-------------i.+.-------------1
96.5 96.5
~00 ~---------~~~~~--------~
~
~~~------~~~~~~-~~--------~ ! C
69.5 -70 .,_6_,9 . ...,5 ,c;.;..--------+--+-+-+--+-------....;;:::=,;;.;;
Inaudible I
I I
Loud Voice Loud Voice
50 t--'---r----~--...-,....---'-+-'--__,_-,--
·8000 000 ·2000 0 2000 4000 6000 8000
Distance From Crossing -Feet
FIGURE 4: CONVENTIONAL TRAIN HORN NOISE
Short term noise impacts due to train horn were calculat ed at the building fa~ade.
Results of modeling is presen ted in Attachment "A" and Figure 5 below. As shown in
Figure 5, the short-t erm train horn noise level is approximately 62 dBA along the
west side of third floor.
ABC Ac oustic, Inc. Report: 2500 7
Roosevelt Townhomes Village
FIGURE 5: SITE LOCATION AND TRAIN WHISTLE NOISE CONTOURS {3th FLOOR)
4.1.3 Existing Cumulative Noise Impacts:
Noise measurements and modeling for the project resulted in a cumulative exterior
noise impact of approximately 54 dBA CNEL on the ground floor. The exterior noise
impacts are primarily vehicular and rail traffic-related. To account for train horn
noise on the 3th floor, a 2 dB penalty was added to the exterior noise level of 54 dB.
Hence, exterior noise level along the west side of 3th floor is anticipated to be 56 dBA
CNEL. To present a worst-case scenario, the entire project site was assumed to be
impacted by an exterior cumulative noise of 56 dBA CNEL.
4.2 Future Noise Environment:
Future noise levels along Roosevelt Street, Laguna Drive, and BNSF railroad tracks
are anticipated to be similar to existing levels. Future exterior noise impacts at the
project site would range between 54 and 56 dBA CNEL.
ABC Acoustic, Inc. Report: 2500 8
Roosevelt Townhomes Village
5.0 CONDITIONS OF DEVELOPMENT AND MITIGATION:
5.1 Exterior Noise Attenuation:
Exterior noise impacts at the project site would be 56 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 partially open. Hence, exterior noise of 60 dBA Ldn
would be reduced to 45 dBA Ldn inside. The proposed Six on Madison project
includes air conditioning systems which provide for closed-window conditions.
Closed-window conditions provide for an additional 5-10 dB reduction with double-
glazed windows. Therefore, an exterior noise of 60 dBA CNEL would be reduced to
35-40 dBA CNEL with windows closed. Since interior noise levels would be within
the allowable limit of 45 dBA CNEL, no additional noise abatement measures are
required.
5.3 Train Horn Noise Attenuation:
Noise impacts due to train horn are not considered significant as they are very short
term. Although not required by State or City code, train horn noise levels were
modeled to determine interior noise levels in selected habitable areas of project
during such events. Results of calculations are presented in Tables A-2 and A-5 of
Attachment "A".
As presented in Tables A-2 and A-5, interior noise levels within all habitable areas of
the project would be reduced to 45 dBA Leqh or lower during train horn occurrences
if the following optional noise abatement measures are incorporated.
1) Exterior windows and sliding doors shall have STC 24 or higher.
2) Residential entry doors shall be solid core wooden and weather-stripped
with an STC of 24 or higher.
ABC Acoustic, Inc. Report: 2500 9
Roosevelt Townhomes Village
6.0 REFERENCES CITED:
California, State of; Uniform Building Codes
2005 Section 1203 ofthe California Building Codes {CBC).
Frontis Studio
2017 Architectural Plans for Roosevelt Townhomes Village 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).
ABC Acoustic, Inc. Report: 2500 10
Roosevelt Townhomes Village
7.0 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 1398 Roosevelt Townhomes Village project.
There are many factors involved in actual acoustical performance of a structure. And
since ABC Acoustics, Inc. has no control over the construction, workmanship and
building materials performance, ABC Acoustics, Inc. is not, and could not be held
liable, for final results of any recommendations or implementation of such
recommendations presented herein.
This report was prepared by Shara T. Sanavi.
ABC Acoustics, Inc.
~Aa,o, Pr~tHION
Shara T. Sanavi
Principal
sharo@abcacoustics.com
ABC Acoustic, Inc. Report: 2500 11
Roosevelt Townhomes Village
ATTACHMENT "A"
NOISE CALCULATION DATA
ABC Acoustic, Inc. Report: 2500 12
F:\sp\Roolevell\Shffll.111
Project: Roosevelt Townhomes
Project-No. 2500
s, . 57
57 • 60
60 • 63
63 • 66
66 • 69
69 • 72
72 • 75
75 • 78
78 • 81
81 • 84
=>• 84
Map
1
Signs and symbols
-Ao.tl 1Jm
-Emlillon~""'
-Suffilee
CZ] M1ln blft!dill1
Polnt11Keo-
D Nob1nkult1lont1•~
Length scale 1:565
10 20 30 ,o
m
F:\sp\flOOH~t\Roose...e!L~p
Client: Frontis Studio
Project: Roosevelt Townhomes
Project-No. 2500
Map
2
Train 10
Result number 6
Calculation in 10 m :above ground
ProjKlftllllleet:S,IA\1'1
C,Nttd:8/21/2017
Proctt1H with Sound PLAN 7.l, Updat• l/19/2()15
Levels Leq,d
lnd8(A)
Signs and symbols
54 • 57
57 • 60
60 • 63
63 -66
66 • 69
69 • 72 72 . 75
75 -78
78 • 81
81 • 84
-Ro.d;a.llis
-Emfu..:.-ohe
-Surf.kt
[Z] Miln bulldins
CJ Hokeu,lcula!l<Jn~"•
-UneMltH'Ce
>= 84
Length scale 1:881
a s 10 20 30 ◄o
m
ABC Acoustics,_ Inc.
Project No: R2500
Receiver
R1
R2
R3
I I
SoundPLAN 7.3
Usage Fl
RA G
F2
F3
RA G
F2
F3
RA G
F2
F3
Roosevelt Townhomes
Assessed receiver levels
Traffic
Ldn Leq,d Leq,n
dB(A) dB(A) dB(A)
36.7 36.4 27.1
39.6 39.3 30.0
41 .1 40.8 31 .6
49.4 49.1 39.9
51 .6 51 .3 42.1
52.5 52.2 42.9
52.4 52.1 42.9
52.9 52.5 43.4
53.1 52.7 43.6
Table: A-1
ABC ACOUSTICS
08-22-2017 ATTACHMENT
REPORT-2500
TABLE A-2
RESULTS OF INTERIOR NOISE ANALYSIS
Location -Living Room -south side
Noise source -TRAFFIC NOISE (NBS, 1978)
Octave Band center Frequency, Hz
12 5 250 500 1000 2000 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
246 246 246 246 246 246
INTERIOR A-WEIGHTED SOUND LEVEL SPECTRUM ('CLOSED WINDOWS' CONDITIONS)
29.8 34.9 34.8 35.1 27.9 19.2
Building Facade Reflection correction -3.0 dB
Quality correction -3.0 dB
SOUND TRANSMISSION THROUGH CONSTRUCTIONS
Building Element Information
# construction STC AREA
1. STUCCO WALL 2. WINDOW (3/32" GLASS)
sq. ft.
46 76.0
24 104.0
TOTAL A-WEIGHTED SOUND LEVEL IN THE ROOM
A-Weighted sound Level
EXTERIOR INTERIOR
closed Open %
60
60
21
40
40
21 0
56 50
56
ACorr
0.0
0.0
ABC ACOUSTICS
08-23-2017
REPORT-2500
TABLE A-3
RESULTS OF INTERIOR NOISE ANALYSIS
Location -Bedroom-3rd Floor-North side
Noise Source -TRAFFIC NOISE (NBS, 1978)
ATTACHMENT
-------------------------------------------------==------------=========
12 5
Octave Band center Frequency, Hz
250 500 1000 2000 4000
Refererice 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
150 150 150 150 150 150
INTERIOR A-WEIGHTED SOUND LEVEL SPECTRUM ('CLOSED WINDOWS' CONDITIONS)
29.0 34.1 33.9 34.2 27.1 18.4
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
24
44.0
52.0
60
60
21
39
21 0 0.0
55 so 0.0
TOTAL A-WEIGHTED SOUND LEVEL IN THE ROOM 39 55
ABC ACOUSTICS
08-22-2017
REPORT-2500
TABLE A-4
RESULTS OF INTERIOR NOISE ANALYSIS
Location -Bedroom -3rd Floor -North side
Noise Source -TRA FFIC 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
93 93 93 93 93 93
INTERIOR A-WEIGHTED SOUND LEVEL SPECTRUM ('CLOSED WINDOWS' CONDITIONS)
26.5 30.4 30.2 30.5 23.4 14.6
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. WINDOW (3/32" GLASS)
46
24
44.0
13. 5
60
60
23
35
23 0 0.0
51 50 0.0
-----------------------=========================================-======= TOTAL A-WEIGHTED SOUND LEVEL IN THE ROOM 35 51 -----------------------==============--=---============================
ABC ACOUSTICS
08-23-2017
REPORT-2500
TABLE A-5
RESULTS OF INTERIOR NOISE ANALYSIS
Location -Bedroom-3rd Floor-South side
Noise Source -TRAFFIC NOISE (NBS, 1978)
ATTACHMENT
---------------------------======-==--================================== Octave Band center Frequency, Hz 125 250 500 1000 2000 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
150 150 150 150 150 150
------------------=--=====--=-========================================== INTERIOR A-WEIGHTED SOUND LEVEL SPECTRUM ('CLOSED WINDOWS' CONDITIONS)
25.5 26.2 26.1 26.4 19.3 10.5
--------------------=======--=-=--====================================== 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
24
118.0
8.0
60
60
26
31
26 0 0.0
47 50 0.0
TOTAL A-WEIGHTED SOUND LEVEL IN THE ROOM 32 47