HomeMy WebLinkAboutEx 06_Noise Study.pdf
(206) 378-0569 www.greenbusch.com
1900 W Nickerson St., #201, Seattle, WA 98119 2262 N Albina Ave., #340 Portland, OR 97227
Memorandum
DATE: December 8, 2022
TO: Julei Campos – Lynx Consulting, Inc.
FROM: Justin Morgan, INCE
RE: Comcast Kent Noise Study
INTRODUCTION
The intent of this Noise Study is to evaluate sound levels associated with the new
equipment planned for installation at the Comcast Kent site (Site) located at 18809 116 th
Avenue Southeast in Renton, Washington. This Noise Study includes a summary of
applicable noise regulations, predicted sound levels at nearby properties, and
recommended noise mitigation to achieve compliance with codified sound limits.
SUMMARY
To reduce sound emissions from the new equipment proposed at the Site, solid barriers
should replace the existing chain-link fence around the perimeter of the Site. These
barriers should range in height between 6-feet tall and 9-feet tall. Additionally, the
proposed AirSys units should operate in “quiet mode.” Predicted sound levels with the
inclusion of these barriers and AirSys units operating in “quiet mode” comply with the
Renton Municipal Code sound limits at all nearby properties.
ZONING AND REGULATORY CRITERIA
Sound levels within the City of Renton are regulated by the Renton Municipal Code (RMC)
Chapter 8.7. RMC Chapter 8-7-2 adopts by reference the maximum environmental noise
levels defined in the Washington Administrative Code (WAC) Chapter 173-60. The WAC
173-60 sound limits are based on the Environmental Designation for Noise Abatement
(EDNA) classification of the property containing the sound source and the EDNA
classifications of properties receiving the sound. RMC Chapter 8-7-4 adopts the EDNA
classifications defined in WAC 173-60-030. WAC 173-60-030 defines EDNA
classifications by land use and are as follows:
Class A EDNA - Lands where human beings reside and sleep. Typically, Class A
EDNA will be the following types of property used for human habitation :
December 8, 2022
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1900 W Nickerson St., #201, Seattle, WA 98119 2262 N Albina Ave., #340 Portland, OR 97227
o Residential
o Multiple family living accommodations
o Recreational and entertainment, (e.g., camps, parks, camping facilities, and
resorts)
o Community service, (e.g., group homes, assisted living facilities, hospitals,
health and correctional facilities)
Class B EDNA - Lands involving uses requiring protection against noise
interference with speech. Typically, Class B EDNA will be the following types of
property:
o Commercial living accommodations
o Commercial dining establishments
o Motor vehicle services
o Retail services
o Banks and office buildings
o Miscellaneous commercial services, property not used for human habitation
o Recreation and entertainment, property not used for human habitation (e.g.,
theaters, stadiums, fairgrounds, and amusement parks)
o Community services, property not used for human habitation (e.g.,
educational, religious, governmental, cultural and recreational facilities)
Class C EDNA - Lands involving economic activities of such a nature that higher
noise levels than experienced in other areas is normally to be anticipated. Persons
working in these areas are normally covered by noise control regulations of the
department of labor and industries. Uses typical of Class A EDNA are generally
not permitted within such areas. Typically, Class C EDNA will be the following
types of property:
o Storage, warehouse, and distribution facilities
o Industrial property used for the production and fabrication of durable and
nondurable goods
o Agricultural and silvicultural property used for the production of crops, wood
products, or livestock
In addition to land use, EDNA classifications also take into consideration the present,
future, and historical use of properties, as well as the use of other lands in the vicinity.
Maximum permissible sound levels are identified in WAC Chapter 173-60-040 and are
shown in Table 1.
Table 1. Maximum Permissible Sound Levels, dBA
EDNA of Sound
Source
EDNA of Receiving Property
Class A Class B Class C
Class A 55 57 60
Class B 57 60 65
Class C 60 65 70
Source: WAC Chapter 173-60-040
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1900 W Nickerson St., #201, Seattle, WA 98119 2262 N Albina Ave., #340 Portland, OR 97227
WAC Chapter 173-60-040(2)(b) includes modifications to the sound limits shown in Table
1. These modifications include a 10 dB reduction to sound levels received by Class A
EDNA properties between the hours of 10:00 PM and 7:00 AM.
Sounds that are exempt from the sound limits shown in Table 1 are listed in WAC 173-
60-050. WAC 173-60-050(4)(f) provides an exemption for sounds created by emergency
equipment and work necessary in the interests of law enforcement or for health, safety,
or welfare of the community. Because the proposed generator is an emergency generator
this exemption likely applies and sounds created by the emergency generator would be
exempt during testing, exercising, and operation during an emergency; however, this
should be confirmed with the City of Renton.
The Site is located on a currently undeveloped parcel. The Site and the parcel west of the
Site are considered Class C EDNA. The property north of the Site is a school and is
considered a Class B EDNA. Class A EDNA properties are located directly south of the
Site and to the east, across 116th Avenue Southeast. However, the parcel the Site is
located on is being subdivided and developed into single-family homes. Although the Site
remains a Class C EDNA, the single-family homes being developed around the Site will
be Class A EDNA.
The location of the Site and future EDNA classifications are illustrated in Figure 1, and
the resulting sound limits for the Site are shown in Table 2.
Figure 1. EDNA Classifications
December 8, 2022
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1900 W Nickerson St., #201, Seattle, WA 98119 2262 N Albina Ave., #340 Portland, OR 97227
Table 2. Project Sound Limits, dBA
Receiving Property EDNA of Receiving
Property
Project Sound
Limits (day/night)
North Class B 65/65
South
Class A 60/50 East
West
ACOUSTICAL MODEL
The primary tool used to predict sound levels at neighboring property lines was the 3-D
computer noise modeling software environment, Cadna/A. Cadna/A utilizes the CADNA
(Control of Accuracy and Debugging for Numerical Applications) computation engine
developed by the Pierre et Marie Curie University of Paris. The model used for this project
utilized the International Organization for Standardization 9613 Part II algorithms,
implemented in the Cadna/A software, which accounted for the effects of distance,
topography, and surface reflections on sound levels. The acoustical model is typically
accurate to within 3 dB. Some conservative assumptions were used in the model created
for this project to ensure sufficient design margin within the predicted sound levels.
Therefore, predicted sound levels can be compared to applicable criteria directly, without
consideration of additional design margin.
The locations of the equipment were determined from drawings provided by Lynx
Consulting, Inc. Topographical information and property line locations were determined
from King County Geographical Information System data. Building locations and heights
were estimated using Google Earth imagery.
ANALYSIS
The new Comcast equipment cabinet, the two Comcast battery cabinets, the 100-kilowatt
(kW) emergency generator, and the existing equipment shelter were placed in the
computer noise model at the locations shown in drawings provided by Lynx Consulting,
Inc. The new equipment cabinet includes two HVAC units installed on the south side of
the cabinet. These HVAC units are specified as AirSys UNICOOL Model
28V2B5MR410AAC units. Sound data for these units were obtained from the equipment
specifications which include sound levels from normal operations and when the units are
operating in “quiet mode.”
The two new Comcast battery cabinets on the south side of the Site each have two
temperature control units. Sound data for these units was not available at the time of this
report. A similar unit was used in this analysis to estimate sound emissions from the new
battery cabinets.
There are two existing wall-mounted HVAC units on the north side of the existing
equipment shelter. These units are Bard W36HB-A0ZZP4XXR 3-ton heat pumps. Sound
data for these units was shown in the equipment specifications.
December 8, 2022
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1900 W Nickerson St., #201, Seattle, WA 98119 2262 N Albina Ave., #340 Portland, OR 97227
Sound data used in the acoustical model for the proposed and existing units are shown
in Table 3.
Table 3. Modeled Equipment Sound Levels
Equipment Operating Mode Distance, feet Sound Level, dBA
AirSys Model
28V2B5MR410AAC1
Normal Operation 6.5 68
Quiet Mode 62
Battery Cabinet2 Normal Operation 1.5 73
Bard W36HB-
A0ZZPXXR3 Normal Operation 10 67
1. AIRSYS UNICOOL Specification Sheet Rev1.2.
2. Battery Cabinet Specification Sheet
3. Bard Wall-Mount Heat Pumps 1.5-5 Ton Capacity W18H-W60 Models 208V-460V 60hz Specification Book
A 100-kW emergency generator will also be installed on the southeast side of the Site.
Although the generator is assumed to be exempt from codified sound limits, it should only
be exercised during daytime hours to minimize potential noise effects to nearby
properties.
RESULTS
Predicted sound levels at adjacent properties from the proposed battery cabinets, the
equipment cabinet cooling units operating normally, and the HVAC units on the existing
equipment shelter are shown in Table 4.
Table 4. Predicted Unmitigated Sound Levels, dBA
Receiving Property Project Sound
Limits (day/night)
Predicted
Sound Level
Complies with Sound
Limits?
North 65/65 68
No, exceeds daytime
and nighttime limits
South
60/50
70
East 65
West 67
As shown in Table 4, predicted sound levels from the Site exceed the daytime and
nighttime sound limits at all adjacent property lines.
To reduce sound levels to within codified sound limits, the chain-link fence located on the
west, south, and east sides of the Site should be replaced with a 9-foot-tall solid barrier.
The west and east sides of the barrier should extend further north to meet the north
property line. The northern portion of the chain-link fence should be replaced with a 6-
foot-tall solid barrier. The gate does not need to be a solid barrier. The locations and
heights of the recommended solid barriers are shown in Figure 2. Additionally, the new
AirSys units should operate in “quiet mode.” The resulting sound levels with the addition
of the solid barriers and AirSys units operating in “quiet mode” are shown in Table 5.
December 8, 2022
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Comcast Kent Noise Study
(206) 378-0569 www.greenbusch.com
1900 W Nickerson St., #201, Seattle, WA 98119 2262 N Albina Ave., #340 Portland, OR 97227
Figure 2. Locations and Heights of Solid Barriers
Table 5. Predicted Mitigated Sound Levels, dBA
Receiving Property Project Sound
Limits (day/night)
Predicted
Sound Level
Complies with Sound
Limits?
North 65/65 63
Yes South
60/50
50
East 49
West 50
Predicted sound levels with the addition of the solid barriers described above and the
AirSys units operating in “quiet mode” comply with daytime and nighttime sound limits at
all nearby properties. Figure 3 illustrates predicted mitigated sound levels five feet above
grade.
December 8, 2022
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Comcast Kent Noise Study
(206) 378-0569 www.greenbusch.com
1900 W Nickerson St., #201, Seattle, WA 98119 2262 N Albina Ave., #340 Portland, OR 97227
Figure 3. Predicted Mitigated Sound Levels, dBA
CONCLUSION
Based on the information provided to our office by Lynx Consulting, Inc., sound produced
by the proposed equipment is anticipated to be within codified sound limits at all nearby
properties with the inclusion of the solid barriers described in this document and AirSys
units operating in “quiet mode.”
Respectfully submitted;
Justin Morgan, INCE
Lead Noise and Vibration Consultant