18 Morgan Suite 200
Irvine, CA 92618
www.mobilenet.net
Report Date: 11/21/2023
Noise Study Analysis
SITE – SCL CULVER 13 • 4604 Sepulveda Blvd. Culver City, CA 90232
Prepared For - Crown Castle
200 Spectrum Center Drive. Irvine, CA - 92618
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Executive Summary
Crown Castle has contracted MobileNet Services to evaluate the output acoustical noise levels of a proposed small cell site and its compliancy with those of the limits set forth by the municipality of Culver City, CA. Crown Castle proposes to install a single canister type antenna with accompanying remote radio units mounted on a wooden utility pole in the public right-of-way near 4604 Sepulveda Blvd. Culver City, CA 90232. Noise from the proposed operation of this site will comply with the City’s appropriate noise limits/regulations.
Site Name: SCL CULVER 13
Latitude: 34.001845°
Longitude: -118.404724°
Structure Type: Wooden Utility Pole
Address: 4604 Sepulveda Blvd. Culver City, CA 90232
Current Municipal Standards
The City of Culver City establishes guidelines pertaining to limits on maximum noise levels in the General Plan Noise Element Document. Table N.3 Interior and Exterior Noise Standards, shown below, defines Community Noise Equivalent Levels (CNEL) for different categories of land use. The proposed location of the site places it in an area zoned for commercial usage.
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Table 1: Culver City General Plan Noise Element – Interior and Exterior Noise Standards
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Fundamentals and Calculation Methodology
The amplitude of pressure waves generated by a sound source determines the loudness of that source. Sound pressure amplitude is measured in micro-Pascals (mPa). One mPa is approximately one hundred billionth (0.00000000001) of normal atmospheric pressure. Sound pressure amplitudes for different kinds of noise environments can range from less than 100 to 100,000,000 mPa. Because of this huge range of values, sound is rarely expressed in terms of mPa.
Instead, a logarithmic scale is used to describe sound pressure level (SPL ) in terms of decibels (dB ). The threshold of hearing for young people is about 0 dB, which corresponds to 20 mPa.
However, the decibel scale alone does not adequately characterize how humans perceive noise.
Human hearing is limited in the range of audible frequencies as well as in the way it perceives the SPL in that range.
In general, people are most sensitive to the frequency range of 1,000–8,000 Hz and perceive sounds within that range better than sounds of the same amplitude in higher or lower frequencies. To approximate the response of the human ear, sound levels of individual frequency bands are weighted, depending on the human sensitivity to those frequencies. Then, an “A -weighted” sound level (expresse d in units of dBA) can be computed based on this information.
The A-weighting network approximates the frequency response of the average young ear when listening to most ordinary sounds. This frequency response (shown below) as defined by the International Standard IEC 61672:2003 is incorporated into most calibrated field test equipment used to measure noise level.
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The table below describes typical A-weighted noise levels for various noise sources.
Manufacturers of a variety of equipment such as but not limited to HVAC systems, power g enerators and telecommunication devices will usually test their product s to determine the noise level at a particular known set distance. From this information provided by the manufacturers we can determine the corresponding sound pressure level at any distance such as nearby buildings and or property lines with the following formula:
𝑆𝑃𝐿2 = 𝑆𝑃𝐿 1 − 20log (𝑟2 𝑟1⁄ ), … (1)
where 𝑆𝑃𝐿1 is the noise level at distance 𝑟1 and 𝑆𝑃𝐿 2 is the noise level at distance 𝑟2.
Because decibels are logarithmic units, SPL cannot be added or subtracted through ordinary arithmetic. Under the decibel scale, a doubling of sound energy corresponds to a 3-dB increase. In other words, when two identical sources are each producing sound of the same loudness, the resulting sound level at a given distance would be 3 dB higher than one source under the same conditions. Mathematically we can also calculate the addition of multiple sources by the following formula:
𝑆𝑃𝐿Total = 10log[ 10𝑆𝑃𝐿1 10⁄ + 10𝑆𝑃𝐿2 10⁄ + 10𝑆𝑃𝐿3 10⁄ … + 10𝑆𝑃𝐿𝑁 10⁄ ], … (2)
where 𝑆𝑃𝐿1 and 𝑆𝑃𝐿𝑁 are the separate sound pressure level, and 𝑁 is the total number of individual noise sources.
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Proposed Equipment
Based on the information provided by Crown Castle the carrier plans to install a single canister type antenna with accompanying remote radio units mounted atop a streetlight pole in the public right-of-way adjacent to a Commercial (General Corridor) classified zone of Culver City. The nearest property line to the noise source is approximately 7.0 feet to the North.
Study Results
Per the manufacturers’ specification sheet, the maximum noise level is as follows:
Equipment Maximum Noise Level
(dBA)
Reference Distance
(meters)
Ericsson Radio 8843 B2/B66A 28 1
Ericsson Radio 8863 B77D 28 1
It is assumed that there are no other stationary noise sources nearby. Since the canister antenna is a passive unit and does not emit any audible noise. Therefore, the maximum calculated noise level for the combined continuous operation of the two installed remote radio unit s is 23.3 dBA. This is below the City’s most restrictive Exterior A- Weighted Noise Level of 65 dBA for the exterior of a commercial designated zoned areas of Culver City.
Conclusion
From the analysis above and all provided information it is believed that the operation of the Crown Castle small cell, located at 4604 Sepulveda Blvd. Culver City, CA 90232 will comply with that City’s requirements for limiting the emission of noise levels.