HomeMy WebLinkAbout4.J._Noise IV. ENVIRONMENTAL IMPACT ANALYSIS
J. NOISE
INTRODUCTION
This section of the Draft EIR describes noise in the project area. Where appropriate, this section provides
project level analysis for the Phase 1 Precise Plan, and program level analysis for the remainder of
development proposed by the GateNya-,T Business Park Master Plan. A regulatory frameNyork is also
provided in this section describing applicable agencies and regulations related to noise.
Preparation of this section used data from various sources. These sources include the City of South San
Francisco General Plan Noise Element, the South San Francisco Municipal Code, the East of 101 Area
Plan, San Mateo County Comprehensive Airport Land Use Plan, and by measuring and modeling existing
and future noise levels at the project site and the surrounding land uses. Traffic information contained in
the traffic study prepared for the proposed project Nyas used to prepare the noise modeling for vehicular
sources.
No comment letters related to noise Nyere received in response to the June 16, 2008 Notice of Preparation
(NOP) or the October 22, 2008 Notice of Preparation (NOP) circulated for the project. The NOP and
comment letters are included in Appendix A of this Draft EIR.
ENVIRONMENTAL SETTING
Fundamental Concepts of Environmental Noise
Noise can be defined as unNyanted sound. It is commonly measured Nvith an instrument called a sound
level meter Nyhich senses sound Nvith a microphone and converts it into a number called a sound level.
Sound levels are expressed in units of decibels (dB).
To correlate the microphone signal to a level that corresponds to the N-,-a-,- humans perceive noise, the A-
NyBighting filter is used. A-Nyeighting de-emphasizes logy-frequency and very high-frequency sound in a
manner similar to human hearing. The use of A-Nveighting is required by most local agencies as Nyell as
other Federal and State noise regulations (e.g. Caltrans, EPA, OSHA and HUD). The abbreviation dBA is
often used N-,-hen the A-Nyeighted sound level is reported.
Because of the time-varying nature of environmental sound, there are many descriptors that are used to
quantiA- the sound level. Although one individual descriptor alone does not fulIv describe a particular
noise environment, taken together, they can more accurately represent the noise environment. There are
four descriptors that are commonly used in environmental studies;the Lm, Leq, L,)o and La„(or CNEL).
The maximum instantaneous noise level (L,,,,,) is often used to identIA- the loudness of a single event
such as a car pass-by or airplane flyover. To express the average noise level, the Leq (equivalent noise
level) is used. The Leq can be measured over any length of time but is typically reported for periods of 15
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minutes to one hour. The background noise level (or residual noise level) is the sound level during the
quietest moments. It is usually generated by steady sources such as distant freeway traffic. It can be
quantified Nvith a descriptor called the L,,o which is the sound level exceeded 90 percent of the time.
To quantiA- the noise level over a 24-hour period, the Day/Night Average Sound Level (La„ or DNL) or
Community Noise Equivalent Level (CNEL) is used. These descriptors are averages like the Leq except
they include, by definition, a ten dBA "penalty"for noises that occur during nighttime hours (10 p.m. to 7
a.m.) to account for people's sensitivity to intrusive noise during these hours. The CNEL also includes a
five dBA "penalty" during evening hours (7 p.m. to 10 p.m. to account for peoples' increased sensitivity
during these hours.'
In general, human sound perception is such that a change in sound level of 3 dB is just noticeable, a
change of 5 dB is clearly noticeable and a change of 10 dB is perceived as a doubling (or halving) of
loudness.
Existing Noise Environment
The major noise sources affecting the site are vehicular traffic on Oyster Point Boulevard, vehicular
traffic on Gateway- Boulevard, and aircraft overflights from San Francisco International Airport (SFO).
Highway- 101 and the railroad tracks that support Caltrain and freight train operations are also located to
the Nvest. The project site is currently occupied by six single story commercial buildings, including a Fed-
Ex Building and a child care facility for Genentech.
Noise measurements Nvere conducted on the project site to quantiA-the existing noise environment. These
included two 24-hour noise measurements (Location A and B) and four short-term 15—minute noise
measurements (Locations 1 through 4). The noise measurement locations are shoN-,n in Figure IV.J-1.
The short-term measurement results Nvere correlated Nvith simultaneous measurements at the long-term
monitoring locations to determine the CNEL at the short-term measurement locations. Table IV.J-1 shows
the results of the short-term measurements. Figure IV.J-2 shows the hourly plot of the measured noise
levels at long-term measurement Location A and Location B.
'American Vatiorial Standards Institute,Al SI S1.1-1994,Acoustical Terniriology, 1994.
'C.'oweliHarzdbookofErzvironnierztalAcoustics, 1994.
Gateway Business Park Alaster Plan IT:J. Voise.
Draft Eizvironnieiz tal Impact Report Page If:J--2
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Long-term Noise Measurement Results at Location A
CNEL =76 dBA
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Long-term Noise Measurement Results at Location B
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Source: Rosen Goldberg Der& Lewitz, Inc.
CHRISTOPHER A. JOSEPH & ASSOCIATES Figure IV.J-2
E:nviiroirnrneirntal IP=Iainirdng c;ind IRc;sea rc:lh Long-Term Noise Measurement
('to)of South Sari Fralzcisco October 2009
Each measurement location represents an area of the site that may be impacted adversely by noise. Long-
term measurement Location A Nvas used to determine the daily variation in traffic noise on both Ouster
Point Boulevard and Gateway Boulevard. Long-term measurement Location B Nvas shielded from traffic
noise so that it Nvould be possible to isolate noise from aircraft overflights. Short-term measurement
Locations 1 through 3 represent the noise exposure at the likely project building facades. Location 4
represents the noise environment at the proposed courtyard,near the center of the site.
Table IV.J-1
Short-Term Noise Measurement Results
Location Height Above Time A-weighted Sound Level,dBA
Ground(feet) LQ Lio Lso L90 CNEL
Ovster Point Boulevard 5 68 70 66 62 72
1 (65 feet to centerline of 11:15-30 a.m.
roadway)
24 68 71 67 64 72
Gateway Boulevard 5 61 64 60 56 65
2 (North side of site 100 12:00-15 p.m.
feet to centerline of
roadway) 24 64 66 63 61 68
Gateway Boulevard 5 58 61 57 54 62
3 (South side of site 100 12:30-45 p.m.
feet to centerline of
roadway) 24 62 66 61 58 67
Center of Site
4 (At proposed courtyard 5 1:00-15 p.m. 57 58 56 55 58
location)
`GAEL based on coniparison with residts of sinndtaneous nieasitrenients at long-term locations.
Soitrce:Rosen Goldberg Der and Levitz,bic. 2008
The project site is currently* exposed to a CNEL of up to 72 dBA which is dominated by traffic noise on
the nearby*roads. Traffic noise from Highway 101 did not appreciably*affect the noise environment at the
locations along Gateway and Oyster Point Boulevards. Noise generated by passing trains Nvas not
discernable during the measurements. Measurement locations away from local roadways (Location 4 and
B) Nvere exposed to a CNEL of between 58 and 64 dBA from combined aircraft and distant roadway
noise.
During the measurement program aircraft produced maximum noise levels of up to 88 dBA Nvith a
typical aircraft L,,,,, of about 77 dBA. The vast majoritA- of louder aircraft flyovers occurred during the
first day*of noise monitoring (see Figure IV.J-3). The finding that the number of daily*aircraft overflights
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is highly variable is not unexpected since the aircraft may take one of several flight paths (not all of which
lead directly over the site) depending on factors such as the Nvind direction. Therefore, it is assumed that
between the first and second day of the long-term noise measurements, Nveather conditions changed
sufficiently to alter the flight path of the departing aircraft. Because of this dependence of aircraft noise
on Nveather, it is appropriate to quantiA- long-term airport noise based on noise contours which are
calculated using average annual flight patterns. The latest noise contours generated by San Francisco
International Airport' area shoN-,n in the Noise Exposure Map Update — 2001. This document contains
contours for the year 2006 (which Nvas a future year when the document Nvas prepared) that show the
project site is located 2,700 feet outside the CNEL 60 dBA contour. This means the project site is
exposed to a CNEL from aircraft which is less than 60 dBA.
Noise Sensitive Land Uses in the Project Vicinity
Land uses surrounding the site are mostly limited to offices, commercial and light industrial. Noise
sensitive land uses are typically defined as residences, schools, places of Nvorship, hospitals, care centers
and hotels. The nearest noise sensitive land use is an existing hotel (Larkspur Landing) to the south that is
Nvithin 30 feet of the southern property line. Another hotel (Hilton Garden Inn)is located another 400 feet
to the south. The nearest residential land uses are located to the northwest of the site. These residences are
located along the Nvest side of US 101 and are about 1,900 feet from the project site. The existing
Genentech Child Care facility occupies 850 Gateway- on the project site. Although it is not residential or
hotel use it is considered to be a noise sensitive use which includes both indoor and outdoor areas. It is
considered in this assessment since it is expected to remain during the earliest phase of the project
construction(i.e. Phase la of the Precise Plan).
Regulatory Setting
Local Noise Guidelines
The Gateway- Business Park project is located in South San Francisco which has noise standards in its
General Plan and Municipal Code. The proposed project is subject to the noise policies of the East of 101
Area Plan and County of San Mateo Airport Land Use Plan for San Francisco International Airport.
City of South San Francisco General Plan
The Noise Element of the South San Francisco General Plan contains policy statements Nvith the goal of
achieving acceptable noise levels throughout South San Francisco. The City has guidelines for noise and
land use compatibility in the noise element. These guidelines are summarized in Table IV.J-2.
City of South San Francisco Municipal Code
Chapter 8.32.030 of the City's Noise Ordinance specifies maximum permissible sound levels to be
generated by any property Nvithin the City. The maximum alloNvable level is determined by the land use
3 Conversation with Dave C.'arborze, ,San Alateo Airport Larzd Use C oInInission; 4August2008
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category of the receiving property. These levels are summarized in Table IV.J-3. The levels shoN-,n in
Table IV.J-3 are applicable for noises that occur up to 30 minutes per hour. Higher noise levels are
alloNved, but for shorter periods of time.
Table IV.J-2
Land Use Criteria for Noise-Impacted Areas
FLand Use CNEL Range General Land Use Criteria
Residential Less than 65 Satisfacton -:no special
insulation requirements
65 to 70 Development requires analysis
of noise reduction requirements
and insulation as needed
Over 70 Development should not be
undertaken
Commercial Less than 70 Satisfactory:no special
insulation requirements
70 to 80 Development requires analysis
of noise reduction requirements
and noise insulation as needed
Over 80 Airport-related development
only: special noise insulation
should be provided
Industrial Less than 75 Satisfactory:no special
insulation requirements
75 to 85 Development requires analysis
of noise reduction requirements
and noise insulation as needed
Over 85 Airport-related development
only: special noise insulation
should be provided
Open Less than 75 Satisfactory:no special
insulation requirements
Over 75 Avoid uses invoking
concentrations of people or
animals
Source:City of Soirth Sari Francisco General Plan Noise Element,SFO Air portLarid
Use Plan
Chapter 832.050 (d)identifies a Special Provision which allows construction activities Nvith a City permit
between the hours of 8 a.m. to 8 p.m. on Nveekdays, 9 a.m. to 8 p.m. on Saturdays and 10 a.m. to 6 p.m. on
Sundays and holidays. Other hours may be authorized by obtaining a permit, provided the construction
meets at least one of the folloNving requirements:
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1. No individual piece of equipment shall produce a noise level exceeding 90 dB at a
distance of 25 feet. If the device is housed Nvithin a structure or trailer on the property*,the
measurement shall be made outside the structure at a distance as close to 25 feet from the
equipment as possible.
2. The noise level at any point outside of the property*plane of the project shall not exceed
90 dB.
Table IV.J-3
Maximum Permissible Noise Levels
Land Use Category Time Period Noise Level(dB)
R-E,R-1 and R-2 zones 10 p.m. -7 a.m. 50
or any single-family or
duplex residential in a
specific plan district 7 a.m. - 10 p.m. 60
R-3 and D-C zones or
any multiple-family 10 p.m. -7 a.m. 55
residential or mixed
residential/commercial in 7 a.m. - 10 p.m. 60
any specific plan district
C-1,P-C, Gateway and
Ovster Point Marina 10 p.m. -7 a.m. 60
specific plan districts or
any commercial use in 7 a.m. - 10 p.m. 65
any specific plan district
M-L P-1 Anti-time 70
Source:City ofSozrth San Francisco Vbtnicipal Code
East of 101 Area Plan
The East of 101 Area Plan applies to the areas of South San Francisco bounded by the City limits to the
north and south, the San Francisco Bay to the east and Highway 101 to the Nvest. The Plan's Noise
Element provides policies to ensure anticipated land uses in the plan area Nvill not be exposed to
unacceptable noise levels. For commercial development, Policy* NO-2 states that the daytime interior
hourly* average noise levels (Leq) should not exceed Leq 45 dBA and instantaneous interior noise levels
should not exceed 60 dBA. The East of 101 Area Plan indicates that office and retail buildings
located beN,-een Colma Creels and Oyster Point Boulevard are required to provide a minimum exterior-to-
interior noise attenuation of 27 dBA. This minimum attenuation is based on an aircraft noise level of L,,,,,
87 dBA which is comparable to the airplane L,,,,,values measured for this EIR.
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San Mateo County Comprehensive Airport Land Use Plan
The current San Mateo Comprehensive Airport Land Use Plan (ALUP) Nvas adopted by the San Mateo
County Airport Land Use Commission (ALUC) in December 1996. It contains the same standards that
are presented in the Land Use Criteria for Noise Impacted Areas for the City of South San Francisco
General Plan Noise Element(Table IV.J-2 of this EIR).
ENVIRONMENTAL IMPACTS
Thresholds of Significance
Appendix G of the 2007 CEQA Guidelines contains a checklist to help identIA- whether a proposed
project could result in potentially significant impacts Nvith respect to either noise or vibration. These
guidelines have been adopted as thresholds of significance. A potentially significant impact would occur
if the proposed project Nvould result in any of the folloNving:
• Exposure of persons to or generation of noise levels in excess of standards established in the local
general plan or noise ordinance, or applicable standards of other agencies.
• Exposure of persons to or generation of excessive groundborne vibration or groundborne noise
levels.
• A substantial permanent increase in ambient noise levels in the project vicinity above levels
existing Nvithout the project.
• A substantial temporary or periodic increase in ambient noise levels in the project vicinity
existing Nvithout the project.
• For a project located Nvithin an airport land use plan or, where such a plan has not been adopted,
Nvithin two miles of a public airport or public use airport, exposure of people residing or Nvorking
in the project area to excessive noise levels.
• For a project in the vicinity of a private airstrip, exposure of people residing or Nvorking in the
project area to excessive noise levels.
Neither the CEQA Guidelines nor the City s General Plan define what is considered to be a "substantial
increase." In general, an increase 3 dB is just noticeable, a change of 5 dB is clearly noticeable and a
change of 10 dB is perceived as a doubling (or halving). Therefore, the folloNving increases in noise are
considered to be significant:
• 5 dBA or greater if the future noise is Nvithin the normally acceptable range (CNEL 65 dBA or
less for residences,hotels and child care; CNEL 70 dBA or less for offices and retail).
• 3 dBA or greater if future noise level is above the normally acceptable range.
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CEQA, the City and the State do not specIA- acceptable vibration levels from construction activities. For
the purposes of this assessment, the methodology described by the Federal Transit Administration (FTA)
is used. These FTA criteria are based on the potential for annoyance and interference Nvith vibration
sensitive activities Nvhich is much more stringent than criteria for structural damage. The FTA specifies an
impact criterion of a vibration level of 80 VdB5 for residences and hotels and 83 VdB for offices. These
criteria are for "infrequent" events (i.e. transit train passbys). Although more stringent criteria are
recommended for"frequent"or"occasional"events,these are not used since construction activities Nvould
generally occur during the day-mime and Nvould not be permanent.
Impacts and Mitigations
Impact IV.J--1: The proposed project could result in exposure of persons to or generation of noise in
excess of standards established in the local generalplan or noise ordinance, or applicable standards of
other agencies. Operational noise at the site, such as that created by HVAC equipment, would exceed
the noise generation standards set forth in the City's Municipal Code.
The heating, ventilation and air-conditioning (HVAC) equipment for the project buildings Nvill likely be
located on the roof-tops of the buildings. At this time the details of the HVAC system are not knoN-,n and
therefore, precise predictions can not be made regarding the noise levels at the nearby land uses. It is
possible that HVAC noise levels could exceed the limits of the Municipal Code at adjacent noise sensitive
land uses such as the Larkspur Landing Hotel. This is considered to be a potentially significant impact;
hoNvever, implementation of Mitigation Measure IV.J-1.1 Nvould reduce this impact to a less than
significant level by requiring the project's HVAC design to include noise control measures adequate to
meet the Citv's Noise Standards.
Mitigation Measure IV.J-1.1 Operational Noise
As the proposed project moves fonvard an analysis of the noise generated by the project's mechanical
equipment should be conducted to assess the proposed equipment Nvith respect to the standards of 60 dBA
at the property* line between the hours of 10 p.m. and 7 a.m. and 65 dBA at the property line beN,-een the
hours of 7 a.m. and 10 p.m. The analysis should specIA-the noise control measures required to meet these
noise levels. Specific measures can not be specified at this time because of the lack of detailed
information on the HVAC equipment design and location. Typical measures include barriers or
enclosures around rooftop equipment. Other measures include duct silencers and acoustical louvers at the
ventilation openings. Once the noise control measures are included in the design a letter should be
submitted to the City* Building Division should require a letter from the designer stating that the project
has been designed to meet the City s Standards.
Impact IV.J--2: The proposed project could result in exposure of persons to or generation of noise in
excess of standards established in the local generalplan or noise ordinance, or applicable standards of
4 Transit Voise aizd I7bratioiz InipactAssessnieizt,Federal Transit Administration,May 2006
5 VdB—The vibration velocity level expressed in decibels re one micro-inch per second.
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other agencies. The proposed project could expose persons to traffic-related noise lei�els greater than
the upper limit of satisfactory noise lei�els for commercial land use of CNEL 70 dBA.
In the future, the proposed project buildings Nvill be exposed to a CNEL of up to 76 dBA due to traffic
along Oyster Point Boulevard and Gatevmy Boulevard. The city Nvill require that an analysis of noise
reduction requirements be conducted and noise insulation features be included, as needed, in the design.
This is considered to be a potentially significant impact; hoNvever, implementation of Mitigation Measure
IV.J-2.1 Nvill reduce this impact to a less than significant level by requiring sound-rated Nvindows and
special exterior Nvall construction as necessary to meet the East of 101 Area Plan interior noise level goal.
Mitigation Measure IV.J--2.1 Future Traffic Noise
Prior to the approval of any precise plan for the project site, an acoustical analysis shall be prepared by a
qualified acoustical consultant in order to determine the measures required to achieve acceptable interior
noise levels for the buildings included as part of the precise plan. The East of 101 Area Plan contains
interior noise level goal of Leq 45 dBA. This Nvill require a noise reduction of up to 30 dBA. This analysis
can not be made at this time because of the lack of detailed information on the glazing t-pe and exterior
facade construction. Typical measures include sound-rated Nvindows and special exterior Nvall
construction.
Impact IV.J--3: The proposed project would not cause a substantial increase in ambient noise lei�els in
the project i icinity aboi e lei�els existing without the project.
The effect of project generated traffic Nvas calculated using the Federal Highwa-T Administration's Traffic
Noise Model (TNM 2.5). Table IV.J-4 shows the calculated existing and project generated traffic noise
levels along the roadvmys in the project vicinity. It Nvas found that the greatest effect on ambient levels
Nvill occur at the existing land uses (offices and hotels) along Gatevmy and Oyster Boulevards Nvhere the
increase Nvill be up to 1.1 dBA. The nearest residential land use potentially affected by project generated
traffic is across US 101 near Sister Cities Boulevard. The noise level along this roadway- is expected to
increase by less than 1 dBA due to project generated traffic. Therefore,this is considered to be a less than
significant impact and no mitigation is required. [Cumulative traffic increases are assessed in the
Cumulative Impacts section of this report.]
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Table IV.J-4:
Traffic Noise Levels with and without Project
Roadway CNEL at 100 feet from Roadway Centerline,dBA
Existin Existin +Project Increase
Oyster Point Boulevard
US 101 to Gateway 72.6 73.4 0.8
Gateway to Veterans 71.4 72.2 0.8
Gateway Boulevard
Oyster Point to Project Access 66.8 67.6 0.7
Project Access to East Grand 65.4 66.6 1.1
Sister Cities Boulevard
Airport to West 69.1 69.3 0.1
Som°ce:Rosen Goldberg Der acid Lewitz,bic. 2009
Impact IV.J-4: The proposed project would result in substantial temporary or periodic increase in
ambient noise levels in the project i icinity.
Ambient noise levels in the project vicinity Nvill temporarily increase during the project-related demolition
and construction activities. This Nvill include the phased removal of the existing buildings which Nvill be
replaced Nvith six new office buildings and two to four parking structures. The project Nvould most likely
be constructed in six phases from 2011 to 2020. Since the construction Nvould be phased there is the
potential for construction noise to affect the buildings neighboring the project site as Nvell as the occupied
buildings on the project site (remaining existing buildings and newIN-constructed project buildings).
The noisier activities Nvould occur during the initial phases of construction which are demolition, mass
excavation, site grading and foundation Nvork. These phases typically include use of heavy diesel powered
machinery such as impact hammers, compactors, front end loaders, bacichoes, bulldozers, scrapers,
graders, trucks and concrete equipment. The later phases Nvould involve construction of the building, and
may require a crane and smaller equipment such as generators, compressors,power tools, and hand tools.
The nearest noise sensitive building adjacent to the project site is the Larkspur Landing South San
Francisco Hotel along Gateway Boulevard which is about 66 feet from the south of the southernmost
proposed parking structure. Another hotel is located farther to the south across a parking lot. The nearest
office buildings to the project site are those currently under construction along Oyster Point Boulevard
which are as close as 88 feet to the proposed project buildings.
The Genentech Child Care facility is currently occupying Building 850 on the project site. In addition to
the indoor facilities, there are outdoor play areas on the eastern and southern sides of the building.
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According to the Precise Plan 6, Building 850 Nvould remain during the demolition of the existing Building
900, the construction of the replacement building and the construction of the new parking structure. The
new parking structure Nvould be directly adjacent to the eastern play area. The southern play area is
approximately 220 feet from the proposed parking structure. Figure IV.J-3 shows the relationship
between the child care facility and the project buildings in the first phase of development.
Table IV.J-5 shows the expected noise levels from various construction equipment at the nearest land uses
when construction and demolition activities are occurring at their closest. The table does not include noise
levels from pile driving since pile driving Nvill not be required during construction. The noise levels at the
two Genentech Child Care outdoor play areas are shoN-,n in the table. Building 850 is located between the
farther (southern) play area and the proposed project buildings and, therefore, the noise levels include a
factor for the acoustical shielding provided by the building.
The noise level standards of the South San Francisco Municipal Code are not applied to construction
activities because of a Special Provision that allows construction beN,-een 8 a.m. to 8 p.m. on Nveekdays,
9 a.m. to 8 p.m. on Saturdays and 10 a.m. to 6 p.m. on Sundays and holidays.
Although the construction activities are alloNved by the Citv's code they Nvill cause a temporary, short-
term substantial increase in noise levels at the nearest land uses. For example, the existing daytime noise
level at noise near the center of the site is Leq 57 dBA (see noise measurement at Location 4). Maximum
noise levels from the nearest construction activities Nvould represent a roughly 20 to 30 dBA increase over
the existing average noise levels. The increase in average noise levels Nvill depend on the duration that the
equipment Nvill operate and the number of simultaneous activities. Construction noise Nvould be loud
enough to interfere Nvith speech communication outdoors. At the Genentech Child Care facility in 850
Gatewav, maximum construction noise levels Nvould be high enough in rooms along the exterior window
to potentially interfere Nvith sleep. This is a significant temporary noise impact and implementation of
Mitigation Measure IV.J-4.1 is required.
Since the mitigation measures Nvill reduce construction noise where feasible and minimize the potential
for disturbance, and because construction noise is exempted from noise limits by the provisions of the
South San Francisco Municipal Code, the construction noise impact at the existing office buildings and
hotels Nvould be less than significant after mitigation.
Since the construction noise Nvould significantly affect the noise sensitive use of the Genentech Child
Care facility that includes outdoor play areas and indoor areas that could be used for dad-mime sleeping,
and mitigation measures such as noise barriers Nvill be only partially effective in reducing construction
noise levels and minimizing noise induced activity interference (the construction of the upper floors
Nvould be elevated above a noise barrier) construction noise at the Genentech Child Care facility, while
temporary,is considered significant and unaiwidable after mitigation.
6 Gateway Business Park Phase I Precise Plarz 850 & 900 Gateway Boulevard, ,South Sari Francisco, CA,
Chaniberlirz Associates,June 26, 2008.
Gateway Business Park Alaster Plan IT:J. Voise.
Draft Erzvironnierz tal Impact Report Page If:J-13
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Table IV.J-5:
Construction Noise Levels at Existing Land Uses
Maximum Noise Levels(Lm.,)
for Typical Construction Activities,dBA
Construction Larkspur Nearest Office Genentech Child Care Facility
Equipment Landing South Building on
San Francisco Adjacent Eastern Outdoor Southern
Hotel Property Play Area Outdoor Play
Area
Backhoe 78 75 81 57
Compactor 81 78 84 60
Compressor 76 73 79 55
Concrete Pump Truck 79 76 82 58
Crane 79 76 82 58
Bulldozer 80 77 83 59
Dump Truck 74 71 77 53
Excavator 79 76 82 58
Front End Loader 77 74 80 56
Grader 83 80 86 62
Jackhammer 87 84 90 66
Paver 75 72 78 54
Pneumatic Tools 83 80 86 1 62
Source:Rosen Goldberg Der acid Lewitz,Inc. 2008
Mitigation Measure IV.J-4.1 Construction Generated Noise
Prepare a demolition and construction noise control plan that identifies detailed, site-specific noise
attenuation measures that Nvill be used to minimize impacts on adjacent land uses. The plan should be
prepared under the supervision of a qualified acoustical consultant or person experienced Nvith equipment
and techniques that can be used to reduce construction related noise. The plan must include but is not
limited to the folloNving:
• Implement noise attenuation measures, Nvhich shall include noise barriers or noise blankets.
Particular attention should be paid to providing a noise barrier (at least 12-feet tall) to protect
outdoor uses such as the eastern play area of the Genentech Child Care facility, if it remains
during construction.
• Provide advance notification to surrounding land uses disclosing the construction schedule,
including the various types of activities that Nvould be occurring throughout the duration of the
construction period.
• Ensure that construction equipment is properIv muffled according to industry standards.
Gateway Business Park_11aster Plan IT:J. Voise.
Draft Erzvironnierz tal Impact Report Page If:J-1 5
00)of South Sari Francisco October 2009
• Place noise-generating construction equipment and locate construction staging areas avmy from
sensitive uses,Nvhere feasible.
• Schedule high noise-producing activities beN,-een when they Nvould be least likely to interfere
Nvith the noise sensitive activities of the neighboring land uses. When near the hotels this Nvould
mean restricting construction during sleeping hours. HoNvever,near office buildings or Genentech
Child Care uses the evening hours may be preferable because the buildings are not occupied.
• In addition to the preparation of the construction noise control plan, the folloNving measures are
recommended and may be included in the plan:
• Designate an on-site construction noise complaint manager for the duration of the project.
• Post signs around the project site to inform persons of the construction hours and the name and
phone number of the person or persons to notifiT in the event of a noise related problem.
• A pre-construction meeting shall be held Nvith the job inspectors and the general contractor/on-
site project manager to confirm that noise mitigation practices (including construction hours,
neighborhood notification,posted signs,etc.) are completed.
• The project applicant shall require by contract specifications that construction staging areas along
Nvith operation of earthmoving equipment within the project site be located as far awa-T from
vibration and noise sensitive sites as possible. Contract specifications shall be included in the
construction documents, which shall be revieNved by the City prior to issuance of a grading
permit.
• The project applicant shall require by contract specifications that heavily loaded trucks should be
routed avmv from noise and vibration sensitive uses, to the extent possible. Contract
specifications shall be included on the construction documents, Nvhich shall be revieNved by the
City prior to issuance of a grading permit.
Impact IV.J-5: The proposed project could result in exposure of persons to or generation of excessive
groundborne ibration or groundborne noise lei�els.
Construction equipment could generate noticeable vibration at adjacent buildings on and off the site. The
greatest potential for vibration generation Nvould be during the excavation and foundation construction
activities. Pile driving often generates the highest vibration levels at a construction site, however, pile
driving Nvould not be required for the project. Table IV.J-6 shows the vibration levels for different
construction equipment at their closest approach to the Larkspur Landing South San Francisco Hotel and
commercial buildings both on and off the site. As the equipment moves farther away, the vibration level
drops rapidly, due to absorption from the ground through which the vibration propagates.
Construction activities Nvould result in vibration levels that are generally Nvithin the FTA's impact levels
of 80 VdB for residences and hotels and 83 VdB for offices. The vibration level from a vibrator`* roller
could slightly exceed the impact criteria(by 1 VdB),but only briefly when it is at its closest point.
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Table IV.J-6:
Vibration Levels at Nearby Receivers
Construction Maximum Vibration by Receiver,VdB
Equipment Larkspur Landing Nearest Office Nearest Commercial
South San Francisco Building on Adjacent Building on Project
Hotel Property Site(Due to Phasing)
Large Bulldozer 74 70 73
Loaded Trucks 73 69 72
Jackhammer 66 62 65
Vibratory-Roller 81 77 80
Hoe Ram 74 69 72
Caisson Drilling 74 70 73
Source:Rosen Goldberg Der acid Lewitz,Inc. 2008
Since the project yvould be constructed in phases,it is possible that onsite office buildings could be still be
occupied and, therefore, potentially affected during the construction of a project building. There is also
the potential for nearby buildings to contain vibration sensitive research equipment such as electron
microscopes. This equipment could be affected at loyver levels that those discussed above. Therefore,
groundborne vibration is considered a potentially significant impact.
Implementation of Mitigation Measure IV.J-5.1 yvould reduce the impact of groundborne vibration to a
less than significant level by minimizing the potential for vibration to interfere yvith vibration sensitive
equipment yvhich may be located nearby.
Mitigation Measure IV.J-5.1 Groundborne Vibration
Prior to the commencement of ground clearing activities, the project applicant shall conduct a
preconstruction survey to determine yvhether the construction project's activities yvould impact vibration
sensitive equipment located in adjacent buildings yvithin 100 feet of the construction activity. If it is
determined that no impact yvould occur then construction activities shall begin and no further action need
be taken. If the project applicant determines that vibration sensitive equipment has the potential to be
affected, it shall implement a construction schedule to ensure that construction activities yvould occur
during times N-,-hen vibration sensitive equipment would not be in use.
Impact IV.J--6: The proposed project could result in exposure of people residing or working at the
project site to excessive noise levels.rom a project located within an airport land use plan or, where
such a plan has not been adopted,within two miles of a public or public use airport.
The proposed project site is located yvithin tyvo miles of the San Francisco International Airport. Noise
contours prepared for the airport indicate that the project site is located 2,700 feet outside the CNEL
60 dBA contour. Therefore, the proposed office buildings yvould be exposed to an aircraft generated
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CNEL belovy 60 dBA Nyhich is considered satisfactory for commercial development by the policies of the
South San Francisco General Plan and the San Mateo County Airport Land Use Commission. The
policies of the East of 101 Area Plan indicate that office and retail buildings located in the project area are
required to provide a minimum exterior-to-interior noise attenuation of 27 dBA to reduce indoor
maximum instantaneous noise levels (L,,,,,) from aircraft to the goal of 60 dBA (Policy NO-2). Therefore,
airport noise is a less than significant impact Nyith respect to the City and County criteria but mitigation is
required to be consistent Nyith the local land use plan (East of 101 Area Plan). Implementation of
Mitigation Measure IV.J-6.1 Nyould ensure that impacts remain less than significant.
Mitigation Measure IV.J-6.1 Aircraft Noise
Prior to approval of submittal of the first building permit, an aircraft sound attenuation study must be
prepared that indicates Nyhat measures Nyill be implemented to achieve the minimum exterior-to-interior
noise attenuation of 27 dBA from aircraft overflights. The study should revievy the exterior Nyindovy/Nyall
and roof/ceiling construction and specIA-, if necessary, measures such as sound-rated Nyindovys and
acoustical treatments to the fresh air ventilation system.
Impact IV.J-7. The proposed project would not result in exposure of people residing or working at the
project site to excessive noise lei�els.rom a private airstrip.
The proposed project site is not within the vicinity of any private airstrip. Therefore no impact Nyould
occur and no mitigation measures are required.
CUMULATIVE IMPACTS
Noise level increases due to increased traffic are summarized in Table IV.J-7. In the future, cumulative
traffic Nyill increase the traffic noise levels at the commercial land uses along Gatevmv and Oyster Point
Boulevards by 2.0 to 4.7 dBA. Cumulative traffic Nyill increase the traffic noise levels at residential land
use along Sister Cities Boulevard by up to 2.5 dBA.
These cumulative traffic noise increases exceed the threshold of 3 dBA for a significant increase.
Although the project contribution is generally small, (0.8 dBA or less), the increase in traffic noise is a
significant and unai oidable cumulative impact.
LEVEL OF SIGNIFICANCE AFTER MITIGATION
Implementation of Mitigation Measures IV.J-1.1, IV.J-2.1, IV.J-5.1, and IV.J-6.1 identified in this section
Nyould adequately mitigate potential impacts related to operational noise, future traffic noise, construction
noise impacts to office uses, groundborne vibration, and aircraft noise. These impacts Nyould also be
reduced to a less than significant level. HoNyever, construction noise impacts to noise sensitive uses
(Genentech Child Care Facility), even Nyith implementation of Mitigation Measure IV.J-4.1, Nyould
remain significant and unai oidable.
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Table IV.J-7:
Cumulative Traffic Noise Increases
Traffic Noise Level(CNEL) at 100 Project
I
Roadway +Project ncrease
Feet from Centerline,dBA Existing t Future Contribution to
Future Future+ Future CNEL
Existing (2035) Project in CNEL(dBA) (dBA)
Oi-ster Point Boulevard
US 101 to Gateway 72,6 76.1 76.5 39 0.4
Gateway to Veterans 71.4 75.8 76.1 4.7 0.3
Gateway-Boulevard
Oyster Point to Project Access 66.8 68.3 689 2.0 0.5
Project Access to East Grand 65.4 67.3 68.1 2.7 0.8
Sister Cities Boulevard
Airport to West 69.1 71.6 71.6 2.5 0.1
Source:Rosen Goldberg Der acid Lewitz,Inc. 2009
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