106-5. Noise Study.pdfEnvironmental Consulting Services 18488 Prospect Road — Suite 1, Saratoga, CA 95070
Phone: (408) 257-1045 stanshel.19%@_toast.net FAX: (408) 257-7235
August 13, 2010
Mr. Yun-Dian Zou
O-Mei Academy
10070 Imperial Avenue
Cupertino, CA 95014
RE: Noise Impact and Mitigation Study for Conditional Use Permit Application for O-Mei Academy,
10070 Imperial Avenue, Cupertino
Dear Mr. Zou,
In response to your request I have evaluated the potential noise impacts that could be produced at
nearby sensitive receptors by the proposed use of the building at 10070 Imperial Avenue in Cupertino for an
elementary school learning center. This report discusses the present environment, the proposed project
and activities, and the associated operational noise impacts on nearby receptors, and compliance with the
Cupertino Noise Ordinance.
To summarize the conclusions of this report, the proposed changes to the use of the project site,
building and new activities would be expected to meet the City Noise Ordinance and not produce any
significant noise incidents on the site.
Project Description [11] [2]
The O-Mei Academy proposes to provide a year-round elementary school experience for
approximately 30 kids on the subject site of approximately 16,900 square feet. O-Mei Academy proposes
to operate a new Cupertino elementary school, using the existing 5600 square foot building at the subject
address in Cupertino and the existing outdoor paved area for play activities behind the building.
The property is in a Light Industrial planning zone, with the Occupancy code to be changed from B/F-
1 to A-3, B, E applying to school activities. Paved parking for 7 vehicles would be provided in front along
the street and for 15 vehicles in back. The site has a 6-7 foot wood fence on the east and south property
lines.
The facility would accommodate a group of 30 kids initially with a staff of 3, on class schedule of 8:30
am to 6:30 pm Monday through Friday. No evening, holiday or weekend activities are planned for site.
Inside activities would include normal school educational, creative and play activities using three
classrooms and also several other rooms for special activities. The outdoor paved play area behind the
building would allow a number of types of play activities for school kids. Daily outdoor play periods for all
kids at the same time would be 15 minutes in the mid -afternoon and 30 minutes at the end of the day during
the parent pickup period. In the summer there would also be a 15-minute play period in the mid -morning
period. There would be at least one staff person on duty for every 10 kids.
Sensitive Receptor Locations
The project area is a mixed residential and commercial neighborhood along Imperial Avenue at
Granada Avenue in west Cupertino. The nearest sensitive receptor locations for noise generated by the
Academy are several 2-3 story apartment buildings south of the site on Imperial and several single family
residences across Imperial at the Granada intersection. Other types of uses near the site on Imperial
Avenue are commercial and are not considered sensitive to O-Mei Academy activities. A small park and an
infrequently -used rail line are adjacent to the site to the east. Vehicle access to the project would be from
Imperial Avenue, as at present.
Environmental Consulting Services Saratoga
O-Mei Academy Project Noise Study -- Cupertino
Page 2 of 4
This study investigates the extent to which adjacent receptors could be impacted by noise from
planned O-Mei Academy activities. The existing noise environment and potential noise impacts from the
proposed project are discussed in the following sections.
Ambient Noise Levels and Noise Sources in the Area
The primary source of ambient noise near the project site is traffic on Imperial Avenue, a local street
bounding the project site on the west side. Typical vehicle passby noise levels are in the 60-70 dBA range
at a distance of 25 feet. Trucks, buses, motorcycles, and poorly -muffled vehicles produce peak noise levels
5 to 15 dBA higher on passby. Noise is contributed to a lesser extent by sporadic vehicles on Granada
Avenue. Large and small aircraft and helicopter overflights create infrequent noise incidents of 55 to 65
dBA. Background ambient noise levels are established by arterial traffic on Stevens Creek Boulevard one
block north and high volume and high speed traffic on the 1-85 freeway two blocks east. An auto repair
facility across imperial Avenue generates a small amount of intermittent noise from power tools and
pneumatic devices during the workday. Other than typical sporadic neighborhood yard care and garbage
pickup activities, there are no other notable noise sources in the project area.
Field noise measurements were made during the morning of August 6, 2010 with a CEL-440
Precision Noise Meter and Analyzer, calibrated with a B & K Model 4230 Sound Level Calibrator.
Measurement locations were chosen to represent the site and key receptor locations, as described below:
Location 1 — middle of O-Mei Academy play yard behind building.
• Location 2 — at the corner of residential property across the Imperial Avenue/Granada Avenue
intersection from the site (25 feet from traffic)
• Location 3 — at the side of the multi -story residential property south of the project, 75 feet from
Imperial Avenue and 70 feet from the south O-Mei property line.
Noise levels were measured and are reported using percentile noise descriptors, as follows: L90
(the background noise level exceeded 90 % of the time), L50 (the median noise level exceeded 50% of the
time), L1 (the peak level exceeded 1 % of the time), and Leq (the average energy -equivalent noise level).
Measured noise levels are presented in Exhibit 1 below. The DNLILdn noise levels were computed as the
long-term average of the Leq using the daily traffic distribution in the area, with standard weighted penalties
for the nighttime hours, and modeled with an enhanced version of the National Cooperative Highway
Research Board traffic noise model [4].
EXHIBIT 1
EXISTING NOISE LEVELS (dBA)
Proposed O-Mei Academy project, Imperial Avenue, Cupertino
Location
L90
L50
Leq
Ll
Ldn
1. middle of play yard in back of
site
46
48
50
58
51
2. across intersection from site
47
50
56
67
59
3, residences south of site
46
48
51
60
54
Traffic is the dominant noise source near the project site, so noise levels at any location depend upon
volume, speed and distance to the nearest traffic, and the Exhibit 1 monitored levels indicate those
relationships. Location 1 is behind the O-Mei building and shielded from direct traffic noise, so noise levels
are set by indirect traffic noise on nearby streets. Location 2 is close to both Imperial and Granada traffic,
which sets the noise level, even though vehicle volume and speeds are low. Location 3 at the adjacent
residential buildings is 70 feet from the Imperial/Granada intersection, but has direct noise from both streets.
At all locations the L90 background noise level is a result of the moderate -volume traffic on Stevens Creek
Boulevard one block north and 1-85 two blocks east. During morning and evening periods, when
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O-Mei Academy Project Noise Study — Cupertino Page 3 of 4
temperatures are lower and humidity higher, noise is transmitted more efficiently, and noise levels from 1-85
can be higher by 5-10 dB.
Relevant Cupertino Noise Ordinance Limits [3]
Section 10.48.040 of the Cupertino Noise Ordinance applies to this project, which limits noise during
daytime hours (7 am to 8 pm) produced by sources adjacent to a residential property to 60 dBA, or by
sources adjacent to commercial property to 65 dBA. Note that there are no activities during night time
periods associated with the project, when City noise limits are more restrictive. in addition, brief daytime
noise incidents on the site would be allowed somewhat higher noise levels by Ordinance section 10.48.050.
For example, noise incidents that last less than 15 minutes during any two hour period are allowed to be 5
dB higher than the long-term general limits.
Potential O-Mel Academy Noise Impacts
Outdoor play activities behind building
All potentially noisy activities associated with the project would be in the play yard behind the building
and adjacent to the parking lot area. Indoor school activities would not be expected to be noticeable at any
nearby locations. The potential noise impacts from outdoor activities are described in the following
paragraphs:
Kids have one or two outdoor play periods of 15-30 minutes each day. During school hours there
could be approximately 30 school kids at a time playing outside, including a 30 minute period starting at 6
pm when parents pickup the kids that do no walk to school. Outdoor kids' activities would include games
with balls, such as basketball, kickball, tetherball and other outdoor games that can be played on a hard
surface. Balls bouncing on the paved surface can create intermittent noise levels of 55-60 at 75 feet. Some
of the noise generated would be from sporadic voices of kids playing and also staff directions, creating brief
noise levels of 45 to 55 dBA at 75 feet. However, the only nearby receptors with a direct sound path from
the play yard are upper floor windows at the residential buildings to the south, of which the closest are about
75 feet away. So a few of the upper floor windows could be exposed to sporadic sounds of 45-60 dBA,
similar to noise from cars coming in the residential driveway between the project and the residences. For
this reason, the play yard noise would not be disturbing, even with the residential windows open. With the
property line wood fence, ground level noise at nearby receptors would be less than 55 dBA, which is near
the L50 ambient noise level and would not be noticeable. Properties across Imperial are farther away and
would have similar noise levels as those adjacent at ground level. The anticipated noise levels for key
locations are summarized in Exhibit 2. None of the anticipated noises would exceed the Noise Ordinance
standards, since brief incidents are allowed.
EXHIBIT 2
POTENTIAL RECEPTOR NOISE LEVELS (dBA)
O-Mel Academy — Imperial Avenue, Cupertino
Location
Max Noise
Levels
1. residences south of property -- closest upper
45-60
windows facing project
2. residences south of property — ground level
40-54
facing project
3. residences across Imperial Avenue
40-55
Activities inside the building
Potential noise impacts from O-Mei Academy activities inside the building, such as reading, art,
music, and other classroom -type activities would be negligible because of noise attenuation by the walls
and windows of the building, as well as distance.
Environmental Consulting Services Saratoga
O-Mei Academy Project Noise Study — Cupertino
Conclusions and Summary
Page 4 of 4
Overall ambient noise levels in the project area now depend primarily on traffic noise, and this will
continue to be the dominant noise source in the area in the foreseeable future. The primary noticeable
noise would be intermittent and brief voice incidents and ball bouncing. With the type of activities planned,
the small number of kids, the distances involved, and property -line fence protection, the planned O-Mei
Academy activities would be within the City noise ordinance limits, and would not be expected to create any
noise impacts at adjacent receptor areas.
If I may be of further assistance on this project, please do not hesitate to contact me.
Respectfully submitted,
H. Stanton Shelly
Acoustical Consultant
Board Certified Member (1982)
Institute of Noise Control Engineering
REFERENCES
1. Project Drawings: OMEI LEARNING CENTER, Conditional Use Permit, 5 sheets; Arun Shah and
Associates, Fremont, CA; July 8, 2010.
2. Operational information sheet and facility activity description for O-Mei Academy, July 2010.
3. Noise Ordinance, Municipal Code Section 10.48, Noise levels for residential and commercial zones;
City of Cupertino; 199
4. Highway Noise - A Design Guide for Highway Engineers, National Cooperative Highway Research
Program Report 117, Highway Research Board, National Academy of Sciences, Washington, D.C.,
1971 (model enhanced and field validated by ECS).
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