HomeMy WebLinkAboutSEA Cedar COW PL Noise Report
222 Etruria Street, Suite 100
Seattle, WA 98109
206.839.0819 P // 206.839.0824 F
August 23, 2017
Richard Cardoza
Senior Project Manager
LDC, Inc
20210 142nd Ave NE
Woodinville, WA 98072LDC, Inc
RE: SEA Cedar River COW– Property Line Noise Report
Site: 1300 Bronson Way North, Renton, WA
Dear Richard,
This report presents a noise survey performed in the immediate vicinity of the proposed Verizon
telecommunications facility at 1300 Bronson Way North in Renton, Washington. This noise
survey extends from the proposed equipment to the nearest properties. The purpose of this report
is to document the existing conditions and the impacts of the acoustical changes due to the
proposed equipment. This report contains data on the existing and predicted noise environments,
impact criteria and an evaluation of the predicted sound levels as they relate to the criteria.
Ambient Conditions
Existing ambient noise levels were measured on site with a Svantek 971 sound level meter on
August 23, 2017. The average ambient noise level was 66 dBA, due primarily to local traffic.
Code Requirements
The site is located within the City of Renton Zoning jurisdiction on CA (Commercial Arterial) zoned
property. The properties to the west, south and east are also zoned CA. The property to the
north is zoned R-10.
The proposed new equipment consists of a cell-on-wheels shelter with a mobile generator as a
power supply. The equipment is expected to run 24 hours a day.
Renton Municipal Code Chapter 8-7-2 adopts by reference Washington Administrative Code
Sections 173-60-020, 040, 050, and 090, and further identifies all commercial properties as Class
B EDNA and all residential properties as Class A EDNA
Under WAC 173-60-040, noise from equipment on a Class B EDNA property is limited as follows:
Class A EDNA Receiver: Noise is limited to 57 dBA during daytime hours. During nighttime,
defined as the hours between 10 p.m. and 7 a.m., maximum sound levels are reduced by 10 dBA
for receiving properties within Class A EDNA's. Since the equipment is expected to operate 24
hours a day, it meet the 47 dBA nighttime limit at the residential receiving properties.
Class B EDNA Receiver: Noise is limited to 60 dBA 24 hours a day. Since the equipment is
expected to operate 24 hours a day, it must meet the 60 dBA limit at the commercial receiving
properties.
RECEIVED
08/29/2017
amorganroth
PLANNING DIVISION
SEA Cedar River COW Page 2
Predicted Equipment Sound Levels
24-Hour Operation Equipment
The proposed shelter will have two Marvair 24ACA-4CII air-conditioning units mounted on the
east end of the shelter. The air conditioning units each have a sound level of 70 dBA at 5 feet
and operate on a lead/lag cycle. The generator is a MQ Whisperwatt DCA-70 series which has
a sound level of 65 dBA at 23 feet.
Methods established by ARI Standard 275-2010 and ASHRAE were used in predicting equipment
noise levels to the receiving properties. Application factors such as location, height, and reflective
surfaces are accounted for in the calculations.
Cell-on-wheels shelter:
The shelter will be located at grade surrounded by a chain link fence. The nearest occupied
residential property is approximately 150 feet north of the equipment. The nearest receiving
commercial property is located approximately 75 feet east of the equipment. The following table
presents the predicted sound level at the nearest receiving properties:
Table 1: Predicted Noise Levels: Proposed Equipment Shelter
Line Application Factor N E
1 Sound Pressure Level at 5 ft (dBA), Lp1 70 70
2 Distance Factor (DF)
Inverse-Square Law (Free Field): DF = 20*log (d1/d2)
-30
(150 ft)
-24
(75 ft)
3 New Equipment Sound Pressure Level at Receiver, Lpr
(Add lines 1 and 2) 40 46
As shown in Table 1, the cell-on-wheels shelter will meet the 60 dBA limit at the commercial
receiving property and the 47 dBA nighttime code limit at the residential receiving property.
Generator:
The generator will be located to the south of the shelter. The nearest occupied residential property
is approximately 160 feet north of the generator. The nearest receiving commercial property is
located approximately 80 feet east of the generator. The following table presents the predicted
sound level at the nearest receiving properties:
Table 2: Predicted Noise Levels: Proposed Generator
Line Application Factor N E
1 Sound Pressure Level at 23 ft (dBA), Lp1 65 65
2 Noise reduction – intervening shelter -3
3 Distance Factor (DF)
Inverse-Square Law (Free Field): DF = 20*log (d1/d2)
-16
(160 ft)
-11
(75 ft)
4 New Equipment Sound Pressure Level at Receiver, Lpr
(Add lines 1 and 2) 46 54
As shown in Table 1, the proposed generator will meet the 60 dBA limit at the commercial
receiving property and the 47 dBA nighttime code limit at the residential receiving property.
SEA Cedar River COW Page 3
This report has been prepared for the titled project or named part thereof and should not be used in whole or part and relied upon
for any other project without the written authorization of SSA Acoustics, LLP. SSA Acoustics, LLP a ccepts no responsibility or
liability for the consequences of this document if it is used for a purpose other than that for which it was commissioned. P ersons
wishing to use or rely upon this report for other purposes must seek written authority to do so from the owner of this report and/or
SSA Acoustics, LLP and agree to indemnify SSA Acoustics, LLP for any and all resulting loss or damage. SSA Acoustics, LLP
accepts no responsibility or liability for this document to any other party other than the person by whom it was commissioned. The
findings and opinions expressed are relevant to the dates of the works and should not be relied upon to represent conditions at
substantially later dates. Opinions included therein are based on information gathered duri ng the study and from our experience.
If additional information becomes available which may affect our comments, conclusions or recommendations SSA Acoustics, LLP
reserves the right to review the information, reassess any new potential concerns and modify our opinions accordingly.
Please contact us if you have questions or need further information.
Sincerely,
SSA Acoustics, LLP
Alan Burt, P.E.
ACOUSTICAL CONSULTANT
PARTNER