HomeMy WebLinkAbout10.UP25-0003 Noise StudyEnvironmental Noise Assessment
Elsey Verizon Cellular Facility
Butte County, California
BAC Job #2025-040
Prepared For:
Complete Wireless Consulting
Attn: Alliyah Muhammad
2009 V Street
Sacramento, CA 95818
Prepared By:
Bollard Acoustical Consultants, Inc.
Dario Gotchet, Principal
Institute of Noise Control Engineering (INCE), Elected Member
May 5, 2025
Bollard Acoustical Consultants, Inc. | P.O. Box 7968, Auburn, CA. 95604 | Phone: (530) 537-2328 | bacnoise.com
Bollard Acoustical Consultants, Inc.
Environmental Noise Assessment
Elsey Verizon Cellular Facility – Butte County, California
Page 1
Introduction
The Elsey Verizon Wireless Unmanned Telecommunications Facility (project) proposes the
installation of cellular equipment within a lease area located off Coal Canyon Road in Butte
County, California (APN: 041-140-023). The outdoor equipment cabinets and an emergency
standby diesel generator have been identified as the primary noise sources associated with the
project. The project site location with aerial imagery is shown in Figure 1. The studied site
drawings are dated April 10, 2025.
Bollard Acoustical Consultants, Inc. has been contracted by Complete Wireless Consulting, Inc.
to complete an environmental noise assessment regarding the proposed project cellular
equipment operations. Specifically, the following assessment addresses daily noise production
and exposure associated with operation of the project emergency generator and outdoor
equipment cabinets.
Please refer to Appendix A for definitions of acoustical terminology used in this report. Appendix
B illustrates common noise levels associated with various sources.
Criteria for Acceptable Noise Exposure
Butte County Code of Ordinances
41A-7 Exterior noise standards.
a) The following noise standards, unless otherwise specifically indicated in this chapter, shall
apply to all noise sensitive exterior areas within Butte County.
Table 1
Butte County Code of Ordinances – Exterior Noise Level Standards
Noise Descriptor
Day (7am – 7pm) Evening (7pm – 10 pm) Night (10 pm – 7 am)
Designation
Urban
Non-
Urban Urban
Non-
Urban Urban
Non-
Urban
Hourly Average (Leq) 55 50 50 45 45 40
Maximum (Lmax) 70 60 60 55 55 50
Source: Butte County Code of Ordinances, Section 41A-7
b) It is unlawful for any person at any location within the County to create any noise which
causes noise levels on an affected property, when measured in the designated exterior
location, to exceed the noise standards specified above.
c) Each of the noise limits specified in subdivision (a) of this section shall be reduced by five
(5) dBA for recurring impulsive noise, simple or pure tone noise, or for noises consisting
of speech or music.
Bollard Acoustical Consultants, Inc.
Environmental Noise Assessment
Elsey Verizon Cellular Facility – Butte County, California
Page 2
d) Noise level standards, which are up to five (5) dBA less than those specified above, based
upon determination of existing low ambient noise levels in the vicinity of the project site
may be imposed.
e) In urban areas, the exterior noise level standard shall be applied to the property line of the
receiving property. In non-urban areas, the exterior noise level standard shall be applied
at a point one hundred (100) feet away from the residence or at the property line if the
residence is closer than one hundred (100) feet. The above standards shall be measured
only on property containing a noise sensitive land use.
41A-8 Interior noise standards.
a) The following noise standards, unless otherwise specifically indicated in this chapter, shall
apply to all noise-sensitive interior areas within Butte County.
Table 2
Butte County Code of Ordinances – Interior Noise Level Standards
Noise Level Descriptor
Daytime
(7am – 7pm)
Evening
(7pm – 10 pm)
Nighttime
(10 pm – 7 am)
Hourly Average (Leq) 45 40 35
Maximum (Lmax) 60 55 50
Source: Butte County Code of Ordinances, Section 41A-8
b) It is unlawful for any person at any location within the County to create any noise which
causes the noise levels on an affected property, when measured in the designated interior
noise-sensitive area, to exceed the noise standards specified above.
c) Each of the noise limits specified in subdivision (a) of this section shall be reduced by five
(5) dBA for recurring impulsive noise, simple or pure tone noise, or for noises consisting
of speech or music.
41A-9 Exemptions.
The following activities shall be exempted from the provisions of this chapter:
e) Any mechanical device, apparatus, or equipment related to or connected with emergency
activities or emergency work;
Exemptions to the Code of Ordinances Noise Regulations
Section 41A-9 of the Butte County Code of Ordinances provides exemptions to the noise
regulations contained in Section 41A-7 and 41A-8. Specifically, Section 41A-9(e) states that
activities associated with “any mechanical device, apparatus or equipment related to or connected
with emergency activities or emergency work” shall be exempt from compliance with Section 41A-
7 and 41A-8 noise level limits. Section 41A-4 defines “emergency work” as “the use of any
machinery, equipment, vehicle, manpower or other activity to protect, maintain, provide or restore
Bollard Acoustical Consultants, Inc.
Environmental Noise Assessment
Elsey Verizon Cellular Facility – Butte County, California
Page 3
safe conditions in the community or for citizenry, or work by private or public utilities when
restoring utility service.
Because the project cellular equipment would operate using County power, the specific purpose
of the generator proposed as part of this project is to provide power to the system during an
emergency power outage, thereby allowing the system to provide vital communications during the
power outage.
Noise Standards Applied to the Project
Equipment Cabinets
Noise would be generated by this project in two ways. The first is the ongoing operation of the
cellular equipment cabinets’ cooling systems. These systems utilize fans to circulate cooling air
through the electric circuitry. During warmer periods, the cooling requirements will be greater, and
the fans will run continuously. During cooler periods, however, the heat transfer requirements are
diminished, and the fans will run intermittently as needed. Because the fan operation is a normal
aspect of the project, and because the fans could run continuously during warm nighttime hours
(i.e., more than 30 minutes per hour), project equipment cabinet noise was assessed relative to
the County’s hourly average (Leq) noise level standards presented in Tables 1 and 2. Satisfaction
with the City’s nighttime noise level criteria would ensure compliance with the County’s less
restrictive daytime noise level standard.
Emergency Generator
The function of the emergency generator is to provide ongoing communications support during
emergencies resulting in power outages. As a result, the emergency generator would operate
only during routine testing and emergency power outages.
With respect to testing, the emergency generator would be tested during daytime hours only,
twice per month, for a duration not exceeding 15 minutes during each test. The purpose of this
routine testing is to ensure that the generator will be properly lubricated and in good working order
in the event of an emergency resulting in a power outage.
Aside from the routine daytime testing described above, the proposed emergency generator
would only operate during nighttime hours during emergencies resulting in power outages.
Section 41A-9 of the Code of Ordinances exempts noise from the project generator while it’s
performing emergency work. As a result, noise from project generator operations during
emergencies (daytime and nighttime) would be exempt from applicable County noise level criteria.
However, Section 41A-9 does not clearly specify whether the exemption would also apply to
periodic monthly routine daytime testing of the project generator, which sole purpose is to ensure
good working order of the generator during emergencies. The County’s daytime hourly average
(Leq) noise level criteria are presented in Tables 1 and 2.
Legend
Figure 10150300
Scale (Feet)
Proposed Verizon Cellular Equipment Lease Area
Elsey Verizon Cellular Facility
Butte County, California
Proposed Cellular Facility Lease Area
& Nearest Noise-Sensitive Use
Noise-Sensitive Receiver (Residence)
1
#
Bollard Acoustical Consultants, Inc.
Environmental Noise Assessment
Elsey Verizon Cellular Facility – Butte County, California
Page 5
Project Noise Generation
As discussed previously, there are two project noise sources which are considered in this
evaluation: the equipment cabinet cooling systems and the emergency diesel generator. The
evaluation of potential noise impacts associated with the operation of each noise source is
evaluated separately as follows:
Equipment Cabinet Noise Source and Reference Noise Levels
The project proposes the installation of two (2) equipment cabinets within the equipment lease
area shown in Figure 1. Based on a review of the project site plans, the cabinets assumed for the
project are as follows: one (1) Commscope CMC-85-36 power/battery cabinet and one (1)
miscellaneous cabinet cooled by a McLean Model T-20 air conditioner. The cabinet reference
noise levels are provided in Table 3. The manufacturer’s noise level data specification sheets for
the proposed equipment cabinets are provided as Appendix C.
Table 3
Reference Noise Level Data of Proposed Equipment Cabinets
Equipment
Number of
Cabinets
Reference Noise
Level (dB)
Reference
Distance (ft)
Commscope CMC-85-36 1 60 5
McLean T-20 1 66 5
Note: Manufacturer specification sheets provided as Appendix C.
Generator Noise Source and Reference Noise Level
The project also proposes the installation of an emergency standby diesel generator within the
lease area to maintain cellular service during emergency power outages. According to the project
site plans (Sheet A-4.2), the generator proposed for installation at this site is a Kohler Model
30REOZK. According to the manufacturer sound level data sheets, provided as Appendix D, the
reference sound pressure levels for proposed generator are 79 dB at 23 feet when equipped with
a weather enclosure, and 65 dB at 23 feet when equipped with a sound enclosure. For this
analysis, it is assumed that the project generator will be equipped with the manufacturer’s sound
enclosure, resulting in a reference sound pressure level of 65 dB at 23 feet.
Predicted Facility Equipment Noise Levels at the Nearest Noise-Sensitive Use
The closest off-parcel noise-sensitive use has been identified as a residence, shown as receiver
1 in Figure 1. Assuming standard spherical spreading loss (-6 dB per doubling of distance),
project-equipment noise level exposure at the closest residence was calculated and the results
of those calculations are presented in Table 4.
According to the Butte County GIS online parcel viewer, the closest noise-sensitive use
(residence – receiver 1) is located on a parcel that is agriculturally zoned (AG-20). Butte County
defines agricultural zoning as a “non-urban” designation. For “non-urban” areas, the County’s
exterior noise limits are applied at a point 100 feet away from the noise-sensitive use (i.e.,
residence).
Bollard Acoustical Consultants, Inc.
Environmental Noise Assessment
Elsey Verizon Cellular Facility – Butte County, California
Page 6
Table 4
Project Equipment Noise Exposure at the Nearest Noise-Sensitive Use
Receiver1
Distance from
Lease Area2
Predicted Equipment Noise Level, Leq (dB)
Cabinets Generator
1 – Residence 700 24 35
1 Receiver location is shown in Figure 1.
2 Distance scaled from lease area to a point 100’ from residence using provided site plans and Google Earth.
Source: BAC 2025
As shown in Table 4, project equipment cabinet noise level exposure is predicted to be 24 dB Leq
at the nearest noise-sensitive use (residence – receiver 1), which would satisfy the Butte County
Code of Ordinances 40 dB Leq exterior nighttime noise level limit for noise-sensitive non-urban
areas. In addition, based on the predicted exterior noise level presented in Table 4, project
equipment cabinet noise levels within the closest residence is expected to be well below the
County’s 35 dB Leq interior nighttime noise level limit for noise-sensitive non-urban areas. As a
result, consideration of project equipment cabinet noise mitigation measures would not be
warranted for the project.
As mentioned previously, Butte County Code of Ordinances Section 41A-9(e) exempts noise from
project generator operation while it’s performing emergency work. Thus, project generator
operation during emergencies would be exempt from applicable County daytime and nighttime
noise level criteria. However, should County planning staff determine that noise associated with
periodic routine daytime testing of the project generator is not exempt pursuant to Section 41A-
9(e), project generator noise would be subject to compliance with the County’s 50 dB Leq exterior
daytime noise level limit for noise-sensitive non-urban areas (Table 1). As indicated in Table 4,
project emergency generator noise level exposure is predicted to comply with the County’s 50 dB
Leq exterior daytime noise level limit at the nearest noise-sensitive use (residence – receiver 1).
Further, based on the predicted exterior noise level presented in Table 4, project generator noise
levels within the closest residence are expected to be well below the County’s 45 dB Leq interior
daytime noise level limit for noise-sensitive non-urban areas. As a result, consideration of project
emergency generator noise mitigation measures would not be warranted for the project.
Conclusions
Based on the analysis and results presented in this report, project-related equipment noise
exposure is expected to satisfy the applicable Butte County noise level criteria at the nearest
noise-sensitive uses. As a result, no further consideration of equipment noise mitigation measures
would be warranted for this project.
This concludes our environmental noise assessment for the proposed Elsey Verizon Cellular
Facility in Butte County, California. Please contact BAC at (530) 537-2328 or
dariog@bacnoise.com with any questions or requests for additional information.
Appendix A
Acoustical Terminology
Acoustics The science of sound.
Ambient The distinctive acoustical characteristics of a given space consisting of all noise sources
Noise audible at that location. In many cases, the term ambient is used to describe an existing
or pre-project condition such as the setting in an environmental noise study.
Attenuation The reduction of an acoustic signal.
A-Weighting A frequency-response adjustment of a sound level meter that conditions the output signalto approximate human response.
Decibel or dB Fundamental unit of sound, A Bell is defined as the logarithm of the ratio of the soundpressure squared over the reference pressure squared. A Decibel is one-tenth of a Bell.
CNEL Community Noise Equivalent Level. Defined as the 24-hour average noise level with
noise occurring during evening hours (7 - 10 p.m.) weighted by a factor of three andnighttime hours weighted by a factor of 10 prior to averaging.
Frequency The measure of the rapidity of alterations of a periodic signal, expressed in cycles persecond or hertz.
Ldn Day/Night Average Sound Level. Similar to CNEL but with no evening weighting.
Leq Equivalent or energy-averaged sound level.
Lmax The highest root-mean-square (RMS) sound level measured over a given period of time.
Loudness A subjective term for the sensation of the magnitude of sound.
Masking The amount (or the process) by which the threshold of audibility is for one sound is raised
by the presence of another (masking) sound.
Noise Unwanted sound.
Peak Noise The level corresponding to the highest (not RMS) sound pressure measured over a given
period of time. This term is often confused with the Maximum level, which is the highest
RMS level.
RT6060 The time it takes reverberant sound to decay by 60 dB once the source has beenremoved.
Sabin The unit of sound absorption. One square foot of material absorbing 100% of incident
sound has an absorption of 1 sabin.
SEL A rating, in decibels, of a discrete event, such as an aircraft flyover or train passby, that compresses the total sound energy of the event into a 1-s time period.
Threshold The lowest sound that can be perceived by the human auditory system, generally
of Hearing considered to be 0 dB for persons with perfect hearing.
Threshold Approximately 120 dB above the threshold of hearing.
of Pain
Appendix C-1
Appendix D-1
Generator Sound Level Data
Appendix D-2
Generator Sound Level Data