HomeMy WebLinkAboutCT 16-02; OCEAN; 2501 STATE STREET NOISE ANALYSIS; 2016-08-25Michael Baker
INTERNATIONAL
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Introduction
MEMORANDUM
Jan Jansson, MFJN, LLC
Achilles Malisos, Michael Baker International
Alesia Hsiao, Michael Baker International
August 25, 2016
2501 State Street Noise Analysis
We Make a Difference
EC-IVED
SEP O 8 2016
\.., ~MRLSBAD
-.:,',.G DIVISION
The project proposes the residential development of 15 condominiums and two townhomes on a
0.49-acre site in the northwestern portion of the City of Carlsbad (City); refer to Exhibit 1, Site
Plan. The project site is located at 2501 State Street, approximately 0.45 miles north of Carlsbad
Village Drive and 0.54 miles west of the Interstate 5 (1-5) freeway.
The site is currently developed with a commercial use and surface parking and is located adjacent
to commercial uses to the west, multi-family residences across State Street to the north, proposed
live-work units and affordable residential units to the east, and Army and Navy Academy athletic
facilities across Carlsbad Boulevard to the south. The Burlington Northern and Santa Fe (BNSF)
Railway is located approximately 215 feet to the west. This railroad is part of the Los Angeles-
San Diego-San Luis Obispo (LOSSAN) Rail Corridor. Currently, Amtrak operates several daily
passenger trains between San Diego and Los Angeles. Freight trains also utilize this railway.
The purpose of the noise analysis is to determine the noise environment as it relates to train noise
and vibration impacts at the site compared with the applicable standards.
City of Carlsbad Noise Standards
The Noise Element of the City of Carlsbad General Plan (General Plan) identifies and defines
existing and future environmental noise levels from noise sources within or adjacent to the City,
and establishes goals, policies, and standards to minimize noise generation and mitigate impacts,
especially on noise sensitive uses such as homes and schools. The Noise Guidelines Manual
(September 1995) contains the procedures necessary to ensure that the General Plan policies
and standards are consistently and effectively applied during the City's review of the proposed
project. The City has adopted local guidelines to evaluate land use compatibility based on noise
emanating from all sources; refer to Table 1, Land Use Compatibility for Community Noise
Environments.
MBAKERINTL.COM 14725 Alton Parkway I Irvine, CA 92618
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Source: Withee MalcolmAldli1ects, LLP; July 29, 2016.
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NOTTO SCALE ~ 2501 STATE STREET NOISE ANALYSIS
b!lfSMfH:Ma .t, Site Plan
INTIINATI ONA L ::-:0811-:='°6.~~::-;1~::-:13:-7 --------------------------------------------
Exhibit 1
Table 1
Land Use Compatibility for Community Noise Environments
Residential -Single-Family 50-60 55-70 70-75 75-85
Residential -Multiple Family 50-65 60-70 70-75 75-85
Transient Lodging -Motels, Hotels 50-65 60-70 70-80 80 -85
Schools, libraries, Churches, Hospitals, Nursing Homes 50-70 60-70 70-80 80-85
Auditoriums, Concert NA 50-70 65-85 NA
Sports Arena, Outdoor NA 50-75 70 -85 NA
Playgrounds, Par1c:s 50-70 NA 67.5-75 72.5-85
Golf Courses, Riding Stables, Water Recreation, 50-75 NA 70-80 80-85 Cemeteries
Office Buildings, Business Commercial and Professional 50-70 67.5-77.5 75 -85 NA
General Industrial, Manufacturing, Utilities, Agriculture 50-75 70-80 75-85 NA
NA: Not A icable
Normally Acceptable -Specified land use is satisfactO!)', based upon the assumption that any buildings involved are of normal conventional
construction, without any special noise insulation requirements.
Conditionally Acceotable -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.
Nocmally Unacceptable -New construction or development should generally be discouraged. If new construction or development does
proceed, a detailed analysis of the noise reduction requirements must be made and needed noise insulation features included in the design.
Di r -New construction or devel nt should not be undertaken.
Table 2. Allowable Noise Exposure indicates acceptable limits of noise for various land uses for
both exterior and interior environments from transportation sources while providing standards that
development shall attain through noise attenuation measures. In addition, the Noise Element
contains Policy 5-P.8, Noise Guidelines Manual, which would update the Noise Guidelines
Manual to ensure consistency with General Plan standards and policies, and contemporary
practices.
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Table 2
Allowable Noise Exposure
Residential 60
Motels, Hotels 65
Hospitals, Residential Care, Facilities, Schools, 65 Libraries, Museums, Churches, Day Care Facilities
Playgrounds, Parks, Recreation Uses 65
Commercial and Office Uses 65
Industrial Uses 70
Notes:
...
45
45
45
50
50
65
1. Development proposed within the McClellan-Palomar Airport Area of Influence shall also be subject to the
noise compatibility policies contained in the ALUCP.
2. For non-residential uses, where an outdoor activity area is not proposed, the standard does not apply.
Where the location of outdoor activity areas is unknown, the exterior noise level standard shall be applied
to the 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
com 'bili icies contained in the ALUCP.
Methodology
SoundPLAN Model
Three dimensional acoustical modeling was conducted for the project using the SoundPLAN
model. The SoundPLAN noise modeling software specializes in computer simulations of
acoustical situations and encompasses traffic noise, occupational noise indoors and outdoors,
general industrial noise, and aircraft noise. SoundPLAN is a unique modeling and presentation
tool that allows users to optimize noise control measures and to visualize the effects of noise
propagation through an extensive graphical user interface. Some of the program features include:
• The traceable propagation models included in SoundPLAN are based upon consistent
sets of empirical data. These models allow for noise predictions within a certain level of
accuracy. Although the physics of sound propagation are always the same, the source
and propagation parameters can change dramatically. The various models in SoundPLAN
allow the user to modify these parameters to match the acoustic environment being
analyzed.
• Versatile definition of the sources input (frequency spectrum, time schedule, or idle
pattern, directivity, mitigation factors, etc.).
• Numerous control features for the verification of input geometry and source data.
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• Graphic tools for the visualization and presentation of the input and output data, the
acoustical hot-spots (i.e., the nature of the problem), the conflicts (i.e. comparisons with
governing regulations), and the benefits of various noise mitigation measures.
• Noise control optimization features (including estimates of cost versus benefit ratios).
On-Site Noise Levels
Train noise levels modeled for the project site are based on actual measured levels at the rail
alignment as well as the various number and types of trains that utilize the railroad. As depicted
in Table 3, Rail Operations, 50 trains currently pass by the project site each day. These trains
primarily include the Amtrak Pacific Surfliner and the North County Transit District (NCTD)
COASTER. By 2030, rail operations are assumed to increase due to overall growth and the
addition of Metrolink Commuter Service, resulting in a total of 98 trains per day. Additionally, the
model also assumes that a second track will be added in the future based on planned
infrastructure upgrades.
Amtrak Pacific Surfliner
Metrolink Commuter Service
COASTER
Fre· ht
Total Trains
Source: Wieland Acoustics, 2013.
Table 3
Rail Operations
22
0
22
6
50
36 64%
14
40 82%
8 33%
98 96%
A noise contour map of the sound levels and propagation path of the future train operations is
depicted in Exhibit 2, Future Noise Levels. As indicated in Exhibit 2, the estimated first floor
exterior noise level would range from below 45 to 70 dBA. Future train noise levels for the upper
levels increase slightly and future upper floor train noise levels would similarly range from below
45 to 70 dBA.
The project would be subject to the City's stationary source noise standards; refer to Table 1. As
described above, the highest on-site outdoor noise levels of 70 dBA would exceed the City's
"normally acceptable" limit of 65 dBA for multi-family residential uses. 70 to 75 dBA is the
"normally unacceptable" limit. The City's Noise and Land Use Compatibility standards indicate
that new developments within the normally unacceptable limit require a detailed analysis of the
noise reduction requirements and noise insulation features should be included in the design.
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Souri:e: Google Earth 2016.
Levels in dB(A)
> 80
75 -80
70 -75
65 -70
60 -65
55 -60
50 -55
45 -50
<=45
NOTTO SCALE ~ 2501 STATE STREET NOISE ANALYSIS
•MMlitt\mMM ~ Future Noise Levels
IMTl•N ATI ON AL Oll/1_;:l •=:,JN-153-13-7 --------------------------------------------
Exhibit 2
Additionally, the City's Noise Guidelines Manual states that potential developments within this
category shall not be approved without the following findings:
• The developer of the project has proved to the satisfaction of the Planning Commission or
Design Review Board that it is not feasible to comply with the standard.
• The Planning Commission or Design Review Board must find that there are specifically
identified overriding social and economic considerations which warrant approval of the
development even though it does not meet the noise standard.
• All purchasers of the impacted property shall be notified in writing prior to purchase, and
by deed disclosure in writing, that the property they are purchasing is noise impacted and
does not meet Carlsbad noise standards for residential property.
Using a standard outdoor to indoor attenuation rate of 20 dBA (based on standard construction
material and windows), residential interior noise levels would range from 55 to 60 dBA. As a
result, the proposed project would require upgraded windows to ensure that interior noise levels
do not exceed 45 dBA. Assuming 70 dBA as the highest exterior noise level (refer to Exhibit 2).
the windows would require a Sound Transmission Class (STC) rating of up to 34 to reduce interior
noise levels to below 45 dBA. Exhibit 3, Minimum Recommended STC Ratings for Windows and
Exterior Doors, depicts the locations and requirements of the upgraded windows for all floors
along the southern and eastern portions of the proposed development.
Deck Treatments
Exterior noise levels experienced along the southern and eastern portions of the proposed
development would be above the City's 65 dBA exterior standard. As depicted in Exhibit 1, the
units located along the southern and eastern portions of the proposed development would have
decks that face the railroad. As such, these exterior deck areas could be exposed to rail noise
levels above the City's 65 dBA threshold. Therefore, it is recommended that decks along the
southern and eastern portions of the proposed development incorporate noise attenuating deck
or patio treatments, including a barrier that is at least 42 inches high as measured from the floor.
Acceptable materials for the construction of the barrier shall have a weight of 2.5 pounds per
square foot of surface area. The barrier may be composed of the following: masonry block, stucco
veneer over wood framing (or foam core), glass, Plexiglass or Lexan (1/4 inch think) and may be
constructed out of a combination of the above listed materials.
On-Site Vibration
Vibration levels would be experienced at the project site due to operations on the nearby BNSF
railroad. The City of Carlsbad does not provide any guidelines or standards for acceptable
vibration levels. Therefore, criteria specified by U.S. Department of Transportation (DOT) and the
Federal Transit Administration (FT A) have been considered in this analysis. Specifically, the
following DOT/FT A report has been considered: Transit Noise and Vibration Impact Assessment,
Agency Report Number: FT A-VA-90-1003-06, May 2006. The impact criteria provided by the FT A
for ground-borne vibration and ground-borne noise at residential buildings are depicted in Table
~. Vibration Impact Criteria.
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Sourt:e: Withee Malcolm Architects, LLP; July 29, 2016.
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NOTTO SCALE ~ 2501 STATE STREET NOISE ANALYSIS
•h@MiN:Mti .t, Minimum Recommended STC Ratings for Windows and Exterior Doors
INTIUIATIONAL =08/1~l•J=NlS3=lJ:::-l -------------------------------------
Exhibit 3
Based on information and vibration data obtained as part of previous studies along the LOSSAN
Rail Corridor, there are between 30 and 70 passenger trains per day and less than 30 freight
trains per day going past the project site. This means that passenger trains should be assessed
relative to the "occasional events" criteria of 75 VdB for ground-borne vibration and 38 dBA for
ground-borne noise. Freight trains should be assessed relative to the "infrequent events" criteria
of 80 VdB for ground-borne vibration and 43 dBA for ground-borne noise. Ground-borne vibration
and noise levels below these thresholds would not be considered significant impacts.
Frequent
Events1
72Vd8
Occasional
Events2
75Vd8
Table4
Vibration Impact Criteria
Infrequent
Events3
80Vd8
Frequent
Events1
35dBA
VdB = vibration decibels; dBA = A-w . hted decibels
Notes:
1. 'Frequent Events' is defined as more than 70 vibration events of the same source per day.
Occasional
Events2
38dBA
2. 'Occasional Events' is defined as between 30 and 70 vibration events of the same source per day.
3. 'In uent Events' is defined as fewer than 30 vibration events of the same kind r da .
Infrequent
Events3
43dBA
Source: U.S. Department of Transportation (DOT)/Federal Transit Administration (FTA), Transit Noise and Vibration Impact Assessment,
A R rt Number: FTA-VA-90-1003--06 Ma 2006.
Based on noise and vibration studies for other projects along the same railroad line (including 25
vibration measurements of various passenger and freight trains, at various distances from the
tracks),1 it is estimated that the ground-borne vibration levels at the proposed residential buildings
would be 68 VdB for passenger trains and 73 VdB for freight trains. This is based on a building
setback of approximately 215 feet from the center of the railroad tracks, as indicated on the project
plans.
Vibration monitoring indicates that the peak frequency of the ground-borne vibration is low
frequency (i.e., less than 30 hertz [hz), as defined by FT A), which is typical for most surface track.
Under these conditions, FT A indicates that ground-borne noise levels would be approximately 50
dB tower than ground-borne vibration levels. This results in estimated ground-borne noise levels
of 18 dBA for passenger trains and 23 dBA for freight trains.
For passenger trains, the estimated ground-borne vibration level of 68 VdB is 7 VdB below the
applicable "occasional events" criterion of 75 VdB; the estimate ground-borne noise level of 18
dBA is 20 dBA below the applicable "occasional events" criterion of 38 dBA.
For freight trains, the estimate ground-borne vibration level of 73 VdB is 7 VdB below the
applicable "infrequent events" criterion of 80 VdB; the estimated ground-borne noise level of 23
dBA is 20 dBA below the applicable "infrequent events" criterion of 43 dBA.
1 Weiland Acoustics, Train Vibration Analysis for 2531-2589 State Street in Carlsbad, CA, November 5, 2013.
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As a result of the preliminary analysis discussed above, it is anticipated that the proposed project
will not be subject to a significant vibration impact, as defined by the FT A, as a result of operations
on the nearby railroad.
Conclusions
Noise levels from the nearby railway would result in ground floor exterior noise levels between 40
and 67 dBA and upper floor noise levels up to 70 dBA. To ensure that building interiors comply
with the City's 45 dBA limit, all exterior windows of units located along the southern and eastern
portions of the proposed development would be required to have a minimum STC rating of 34 for
windows and entry doors facing the railroad. In addition, any upper floor decks along the southern
and eastern portions of the proposed development would include a barrier that is at least 42
inches high as measured from the floor with specified treatments as described below. According
to the City's Noise Guidelines Manual, the proposed project would require approval from the
Planning Commission or Design Review Board, and specific overriding social and economic
considerations for the project must be identified. Future property owners and/or tenants must be
notified in writing that the exterior noise levels are within the City's "normally unacceptable" range.
Additionally, the proposed project would not be subject to a significant vibration impact from
operations on the nearby railroad.
Recommendations
1 Sound-rated windows and entry doors with a minimum STC rating of 34 shall be
installed on all floors of residential units located along the southern and eastern
portions of the proposed development facing the railroad (refer to Exhibit 3). Prior
to the issuance of building permits, the plans specifying the 34 STC rating shall
be submitted to and approved by the City of Carlsbad Planning Director.
2 Outdoor deck areas along the southern and eastern portions of the proposed
development that face the railroad (as depicted in Exhibit 3) shall incorporate
noise attenuating treatments. These outdoor deck activity areas shall include a
barrier that is at least 42 inches high as measured from the floor. Acceptable
materials for the construction of the barrier shall have a weight of 2.5 pounds per
square foot of surface area. The barrier may be composed of the following:
masonry block, stucco veneer over wood framing (or foam core), glass, Plexiglass
or Lexan (1/4 inch think) and may be constructed out of a combination of the above
listed materials.
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