017 Building_B_Noise Report_07032018
Prepared for:
Federal Way Campus, LLC
Prepared by:
Ramboll US Corporation
Lynnwood, Washington
July 2018
Project Number:
1690002845
GREENLINE BUILDING “B”
DEVELOPMENT, FEDERAL WAY,
WASHINGTON
ENVIRONMENTAL NOISE REPORT
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Executive Summary i Ramboll
EXECUTIVE SUMMARY
Ramboll US Corporation (Ramboll) completed a study of noise-related issues surrounding
the proposed development of an approximately 214,050 square-foot warehouse called
Greenline Building “B” Development (the Project) on Weyerhaeuser Way South, south of
33rd Place S, at the Weyerhaeuser Campus in Federal Way, Washington.
Existing sound levels were measured to document the ambient noise environment at a
residential property located north of the Project. The measurement location was considered
representative of existing sound levels at several residential and commercial properties in
the Project vicinity.
Acoustically significant equipment anticipated during normal operations of the Project were
assumed to include rooftop HVAC units, Make-Up Air units, exhaust fans, an emergency
generator, and ground-level truck traffic for loading and unloading of products.
Using noise source data from previously measured equipment at similar facilities, a noise
model was prepared to estimate noise levels received at nearby residential and commercial
locations. An assessment of noise impact was based on compliance with the applicable WAC
noise limits, and on the predicted increase over existing ambient conditions.
The assessment found that operation of the proposed Project would result in acoustically
negligible increases in ambient noise at nearby residential receivers, and between no
increase and very minor increases at nearby commercial receivers. The proposed Project
would be within compliance of applicable noise limits at all nearby residential and
commercial receivers. An evaluation of the actual facility design, once submitted, should be
completed to ensure that the types and numbers of equipment to be installed at the
warehouse, as well as warehouse activities, are consistent or similar to those identified in
this report.
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Contents ii Ramboll
CONTENTS
Executive Summary .................................................................................................. i
Contents .................................................................................................................. ii
Acronyms and Abbreviations .................................................................................. iii
1. Introduction .................................................................................................... 1
1.1 Project Description .................................................................................... 1
1.2 Rationale for Noise Study ........................................................................... 1
2. Noise Terminology and Descriptors ................................................................. 2
3. Regulatory Setting ........................................................................................... 4
3.1 City of Federal Way ................................................................................... 4
3.2 Washington Administrative Code ................................................................. 4
4. Existing Environment ....................................................................................... 6
4.1 Affected Environment ................................................................................ 6
4.2 Existing Noise Environment ........................................................................ 6
5. Noise Impact Assessment .............................................................................. 10
5.1 Construction Noise Assessment .................................................................. 10
5.1.1 Construction Noise Assessment – General Mitigation Methods ............... 12
5.2 Operational Noise Assessment ................................................................... 12
5.2.1 Noise Prediction Model .................................................................... 12
5.2.2 Emission Sources ........................................................................... 13
5.2.3 Noise Sensitive Receivers ................................................................ 14
5.2.4 Noise Modeling Results – Assessment of Compliance with WAC Limits .... 14
5.2.5 Noise Modeling Results – Assessment of Increase over Existing
Conditions ..................................................................................... 14
5.2.6 Additional Considerations – Loading Docks ......................................... 14
5.2.7 Additional Considerations – Off Site Traffic ......................................... 15
5.2.8 Results Summary and Mitigation ....................................................... 15
6. Conclusions ................................................................................................... 17
APPENDICIES
Appendix A - Figures
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ENVIRONMENTAL NOISE REPORT
Contents iii Ramboll
ACRONYMS AND ABBREVIATIONS
Acoustically neutral ............... A description of equipment or material such as a wind screen
used over a sound level meter microphone that, due to its
composition, has little or no effect on the sound pressure
levels reaching the microphone
Day-night sound level (Ldn) ... A 24-hour sound level metric similar to a 24-hour Leq, except
the Ldn includes an additional 10 dBA added to sound levels
in each hour between 10 PM and 7 AM to account for
increased sensitivity to noise during times when people are
typically trying to sleep
dB ...................................... decibel, referring to a unit measured on the decibel scale
used to quantify sound levels
dBA .................................... A-weighted decibel, a system for weighting measured sound
levels to reflect the frequencies that people hear best
Distance attenuation ............. the rate at which sound levels decrease with increasing
distance from a noise source based on the dissipation of
sound energy as the sound wave increases in size (think of a
balloon getting thinner as it becomes more inflated)
Equivalent sound level (Leq) ... A sound level metric that is the level that if held constant
over the same period of time would have the same sound
energy as the actual, fluctuating sound (i.e., an energy-
average sound level)
Leq ...................................... Equivalent sound level (see above)
Ln ....................................... Statistical noise level, the level exceeded during n percent of
the measurement period, where n is a number between 0
and 100 (for example, L50 is the level exceeded 50 percent
of the time)
Noise criteria ........................ A set of definitions establishing the conditions under which a
noise impact is determined to have occurred.
Noise impact ........................ A measured or model-calculated condition in which the
absolute (i.e., total) sound level and/or a project-related
sound level increase exceed a defined noise impact criterion.
Noise metric ........................ One of a number of measures used to quantify noise (e.g.,
Leq, or Lmax)
SLM .................................... Sound level measurement
Sound level ......................... Sound pressure level (see below)
Sound power level ................ A measure of the sound energy emitted by noise source
expressed as energy per unit of time. Not to be confused
with sound pressure level.
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ENVIRONMENTAL NOISE REPORT
Contents iv Ramboll
Sound pressure level ............ Ten times the base-10 logarithm of the square of the ratio of
the mean square sound pressure, in a stated frequency band
(often weighted), and the reference mean-square sound
pressure of 20 μPa (micro pascals, a standard reference unit
of pressure), which is approximately equal to the threshold
of human hearing at 1 kilohertz. Sound pressure level is
expressed in decibels.
Type I meter ........................ A type of sound level meter defined by American National
Standards Institute as being to measure sound pressure
levels to an accuracy within 0.5 dBA
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Introduction 1 Ramboll
1. INTRODUCTION
1.1 Project Description
Federal Way Campus, LLC is proposing to develop a general commodity warehouse on 16.9
acres of land zoned CP-01 within the City of Federal Way, Washington. The proposed
Greenline Building “B” Development (the Project), will be approximately 214,050 square
feet in size and will include accessory parking for up to 245 vehicles. Commercial vehicle
ingress and egress access will occur at Weyerhaeuser Way South, near the interchange
ramps for State Route 18 (SR 18). A 50-foot wide managed forest buffer will run along the
property boundary adjacent to Weyerhaeuser Way South, where it forms the boundary of
the CP-01 zone and then widens to 100-feet adjacent to SR 18.
At the time of this analysis, the exact use of the warehouse had not been established.
However, it is anticipated that the warehouse will be used for general commodities that do
not require cold storage. Furthermore, the warehouse will not include processing or
manufacturing facilities. Equipment typical of a general commodities warehouse include
HVAC units to provide heating and cooling to office spaces; air handling equipment, such as
make-up air units (MUAs), to provide heat and ventilation to warehouse spaces; rooftop
exhaust vents; emergency generators; and access for truck deliveries and product loadout.
1.2 Rationale for Noise Study
The City of Federal Way has established submittal requirements for Process III applications.
These requirements include topographical surveys, site plans, drainage, building design, and
noise studies to support the application.
The City is also requiring a SEPA checklist be submitted as part of the application. The
checklist includes the following questions pertaining to noise:
SEPA 7(b)(1): What types of noise existing in the area that may affect your project?
SEPA 7(b)(2): What types and levels of noise would be created by or associated with the
project on a short-term or a long-term basis?
SEPA 7(b)(1): Proposed measures to reduce or control noise impacts, if any?
The following noise assessment has been prepared to respond to the requirements of the
City’s Process III application and to support SEPA checklist and threshold determination.
The noise assessment evaluates both short-term noise from construction of the Project and
long-term noise from operation of the Project. The assessment of operational noise
evaluates compliance with applicable noise limits and the potential for noise impacts due to
increases over existing sound levels.
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ENVIRONMENTAL NOISE REPORT
Noise Terminology and Descriptors 2 Ramboll
2. NOISE TERMINOLOGY AND DESCRIPTORS
Noise is sometimes defined as unwanted sound. This report makes no such distinction, and
the terms noise and sound are used more or less synonymously.
The human ear responds to a very wide range of sound intensities. The decibel scale (dB)
used to describe sound is a logarithmic rating system which accounts for the large
differences in audible sound intensities. This scale accounts for the human perception of a
doubling of loudness as an increase of 10 dB. Therefore, a 70-dB sound level will sound
about twice as loud as a 60-dB sound level. People generally cannot detect differences of 1
or 2 dB. In ideal laboratory situations, differences of 2 or 3 dB can be detected by people,
but such a change probably would not be noticed in a typical outdoor environment. A 5-dB
change would probably be clearly perceived by most people under normal listening
conditions.
On the logarithmic decibel scale used to describe noise, a doubling of sound-generating
activity (i.e., a doubling of the sound energy) causes a 3-dB increase in average sound
produced by that source, not a doubling of the loudness of the sound (which requires a 10-
dB increase). For example, if traffic along a road is causing a 60 dB sound level at some
nearby location, twice as much traffic on this same road would cause the sound level at this
same location to increase to 63 dB. Such an increase might not be discernible in a complex
acoustical environment.
When addressing the effects of noise on people, it is useful to consider the frequency
response of the human ear. Sound-measuring instruments are therefore often programmed
to “weight” measured sounds based on the way people hear. The frequency-weighting most
often used is A-weighting because it approximates the frequency response of human
hearing and is highly correlated to the effects of noise on people. Measurements from
instruments using this system are reported in "A weighted decibels" or dBA. All sound levels
in this evaluation are reported in A weighted decibels.
Relatively long, multi-source “line” sources, such as roads with continuous traffic, emit
cylindrical sound waves. Due to the cylindrical spreading of these sound waves, sound levels
from such sources decrease with each doubling of distance from the source at a rate of
about 3 dBA. Sound waves from discrete events or stationary “point” sources, such as a car
horn, spread as a sphere, and sound levels from such sources decrease 6 dBA per doubling
of the distance from the source. Conversely, moving half the distance closer to a source
increases sound levels by 3 dBA and 6 dBA for line and point sources, respectively.
For a given source, a number of factors affect the sound transmission from the source,
which in turn affect the potential for noise impacts. Important factors include distance from
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Noise Terminology and Descriptors 3 Ramboll
the source, frequency of the sound, atmospheric conditions, absorbency and roughness of
the intervening ground surface, the presence or absence of intervening obstructions (e.g.,
buildings), and the duration of the noise-producing event. The degree of impact on humans
also depends on who is listening (individual physiological and psychological factors) and on
existing sound levels (background noise).
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Regulatory Setting 4 Ramboll
3. REGULATORY SETTING
3.1 City of Federal Way
The City of Federal Way has established a noise ordinance in the Federal Way Revised Code
(FWRC) Chapter 7.10, Noise. FWRC 7.10.050(1) adopts the maximum permissible sound
level limits identified in the Chapter 173-60 of the Washington Administrative Code (WAC
173-60, see Section 3.2).
FWRC 7.10.020, Public Disturbance Noise, also identifies activities and events that are
considered by the City to cause a public disturbance. FWRC 7.10.020(8) identifies
construction noise as a public disturbance noise when it occurs between the hours of 8:00
p.m. and 7:00 a.m. on weekdays and 8:00 p.m. and 9:00 a.m. on weekends.
3.2 Washington Administrative Code
The City of Federal Way adopts the sound level limits established in WAC 173-60. WAC
173-60 identifies limits on sounds crossing property boundaries based on the Environmental
Designation for Noise Abatement (EDNA) of the sound source and the receiving properties.
EDNA classifications are typically designated based on land uses as follows:
EDNA Class A: Lands where human beings reside and sleep (e.g., residences, hospitals).
EDNA Class B: Lands involving uses requiring protection against noise interference with
speech (e.g., commercial and retail businesses, offices, public services).
EDNA Class C: Lands involving economic activities of such a nature that higher noise
levels than experienced in other areas is normally to be anticipated (e.g., industrial
property; warehouse and distribution facilities).
The applicable noise limits for EDNA source and receiver combinations are listed in Table 1.
Table 1. WAC Maximum Permissible Sound Level Limits
EDNA of
Source Property
EDNA of Receiving Property
Class A (a) Class B Class C
Class A 55 57 60
Class B 57 60 65
Class C 60 65 70
(a) The limitations for noise received in Class A EDNAs are reduced by 10 dBA during nighttime hours, defined in
the state rule as 10 p.m. to 7 a.m.
Source: WAC 173-60-40
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ENVIRONMENTAL NOISE REPORT
Regulatory Setting 5 Ramboll
The "maximum permissible" environmental noise levels may be exceeded for short periods
by a total of not more than 15 minutes in any one-hour period. The allowed short-term
increases follow: up to 5 dBA for no more than 15 minutes in any hour, or up to 10 dBA for
no more than 5 minutes of any hour, or up to 15 dBA for no more than 1.5 minutes of any
hour. These allowed short-term increases can be described in terms of noise metrics that
represent the percentage of time certain levels are exceeded. For example, the hourly L25
metric represents the sound level that is exceeded 25 percent of the time or 15 minutes in
an hour. Similarly, the L8.3 and L2.5 are the sound levels exceeded 5 and 1.5 minutes in an
hour, respectively. The maximum permissible levels are not to be exceeded by more than
15 dBA at any time, and this limit is represented by the Lmax noise metric.
The zoning for the Project site is Corporate Park (CP-1). The proposed use of the site as a
warehouse or distribution facility would result in its classification as a Class C EDNA noise
source. Residential properties in the vicinity of the Project are classified as Class A receiving
properties. Nearby office or commercial buildings are designated Class B EDNA receivers.
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Existing Environment 6 Ramboll
4. EXISTING ENVIRONMENT
4.1 Affected Environment
The Project would be located within a 16.9-acrea parcel, and the warehouse itself would
cover an approximately 214,050 square foot area (see Appendix A, Figure 3), with
additional area for parking (up to 245 vehicles) and truck loading. The warehouse would be
bordered to the south by SR 18, beyond which are residential and commercial land uses; to
the east by commercial office buildings, beyond which are residential land uses; to the north
by a currently vacant wooded lot (the proposed Weyerhaeuser Building “A” development
site), beyond which are residential land uses that border the south shore of North Lake; and
to the west by a commercial facility currently operated by Weyerhaeuser. The existing
Project site currently is densely wooded and would be cleared to make room for the
warehouse and associated parking and driveways.
The nearest residential areas to the Project are located north of the Project property on the
north side of 33rd Place South on the south shore of North Lake. Residential areas located
further from the Project site include those northeast of the Project along 38th Ave South
and other nearby roadways. South of SR 18 there are residential properties north of
S 349th Street, west of Weyerhaeuser Way South.
Commercial properties are located immediately east of the Project site in land zoned “Office
Park”, a commercial zoning type that includes an office complex and a church. Also,
commercial facilities are located immediately south of the Project site, southeast of the of
SR 18/Weyerhaeuser Way South interchange.
West of the site, between the Project limits and Interstate-5 (I-5), is property owned by
Weyerhaeuser, which includes botanical gardens, other outdoor spaces, and commercial
areas zoned “Office Park”.
4.2 Existing Noise Environment
The existing acoustic environment in the vicinity of the Project is typical of a suburban area
relatively close to major highways and/or local roadways. The main source of noise in the
Project vicinity is from traffic along I-5, SR 18, and Weyerhaeuser Way South.
A sound level measurement was taken in December 2016 to characterize the existing noise
environment in the project vicinity. The sound level measurement was conducted over a
period of four days, including both weekdays and weekend days, at a location
representative of residential properties in the vicinity of the Project, at 33636 30th
Avenue South in Federal Way. The meter at LT-1 was placed in the backyard of this
property, representing existing noise levels at outdoor residential use areas along the south
side of North Lake. Appendix A, Figure 1
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ENVIRONMENTAL NOISE REPORT
Existing Environment 7 Ramboll
The sound level measurement was taken using a Larson Davis model LxT Class I sound level
meter set to capture hourly data over the four-day period. The meter’s microphone was
placed in an acoustically-neutral wind screen positioned approximately five (5) feet above
ground. The meter was factory calibrated within the previous 12 months and was field
calibrated immediately prior to use.
The meter was located below the grade of Weyerhaeuser Way S and there was no direct line
of sight between the meter and Weyerhaeuser Way S. However, when present, traffic noise
from this road was a dominant noise source. Traffic noise from I-5, approximately 2,200
feet northwest, and SR 18, approximately 1,900 feet southeast, were observed as
continuous and steady sources of background noise. Additional noise sources included
infrequent miscellaneous residential activity and birds.
Sound level measurement data are summarized in Table 2 and depicted graphically in
Figure 2. Included in Table 2 is the range of hourly average Leq 1 and hourly Ln 2 sound
level data for daytime (7 a.m. to 10 p.m.) and nighttime (10 p.m. to 7 a.m.) periods and
the day-night sound level (Ldn 3) for each day.
1 The Leq is the level that if held constant over the same period of time would have the same sound
energy as the actual, fluctuating sound. As such, the Leq can be considered an energy-average sound
level. This metric should not be confused with an arithmetic average which tends to de-emphasize
high and low values. The Leq noise metric has been found to be highly correlated to community
response to noise, and is often the metric calculated by noise models used to assess potential impacts
and the need for mitigation.
2 The “n” in Ln is the percent of time that a sound level is exceeded and is used describe the range of
sound levels recorded during the measurement period. For example, the L8.3 level is the noise level
that is exceeded 8.3% of the time (e.g., 5 minutes in any one hour).
3 The day-night sound level, Ldn, is similar to a 24-hour Leq, Leq(24), except that a 10-decibel penalty
is added to sound levels between 10 p.m. and 7 a.m. to account for potential sleep interference.
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Existing Environment 8 Ramboll
Table 2. Ambient Noise Monitoring Summary (dBA)
Period of
Measurement
Time of
Day (a)
Range of Hourly Sound Levels (b), (c)
Ldn
Leq Range L25 L8.2 L2.5 Lmax
Weekday
Day 51-59 52-59 54-62 56-65 63-77
59 - 60
Night 50-58 49-58 51-62 53-65 59-76
Weekend
Day 52-58 50-56 53-62 59-66 67-78
59
Night 46-55 47-54 48-61 49-65 54-73
(a) "Day" refers to the hours between 7 a.m. and 10 p.m., "Night" to the hours between 10 PM and 7 AM.
(b) Contributing sound sources included traffic from Weyerhaeuser Way S, I-5, and SR 18, as well as nearby
residential activity and birds.
(c) The L2.5, L8.3, and L25 levels are defined previously in this report in the discussion of the regulatory noise
limits.
Source: Ramboll
The range of data provided in Table 2 indicates that daytime sound levels varied only
slightly between weekday and weekend day and night periods.
As indicated, the applicable WAC sound level limits are based on maximum permissible
sound levels and allowed exceedances of these limits (e.g., L25, L8.3,. etc.). This
assessment of existing conditions includes a computation of these WAC metrics for
comparison, however note that the WAC limits apply only to an assessment of compliance of
the future Project, relative to noise received at nearby residential properties.
The highest levels of noise occurred during the typical morning commute period (i.e.,
between 6 a.m. and 8 a.m.) and evening commute period (i.e., between 5 p.m. and 7
p.m.). Although Ramboll staff were not present during all measurement hours, it is likely
that traffic on Weyerhaeuser Way S was the source of the highest levels of noise received
during these peak commute periods. A full tabulation of all hourly sound level data can be
made available upon request. See Appendix A, Figure 2 for a graphical overview of
hourly sound level measurement results.
Note that the proposed Project is assumed to operate 24 hours per day, 7 days per week,
although truck traffic activity and generator testing would occur only during daytime hours.
Therefore, the lowest nighttime hourly sound level (46 dBA, Leq), measured between 4 a.m.
and 5 a.m. on Sunday, December 18, 2016, was used to represent the average existing
noise environment when assessing the potential for a worst-case increase over ambient
conditions (i.e., operation of the Project during nighttime hours). During daytime hours, the
lowest measured sound level was 51 dBA, Leq, measured between 12 p.m. and 1 p.m. on
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Existing Environment 9 Ramboll
Thursday, December 15, 2016, and was used to represent the average existing noise
environment during daytime hours.
The nighttime and daytime sound levels have been assumed to be representative of the
existing noise environment at all residential receiving properties north of the Project.
Northwest of the Project, the nearest residential properties are located adjacent to I-5 and
dominated by highway traffic noise. Existing noise levels west of I-5 have been assumed to
be 50 dBA during nighttime hours and 60 dBA during daytime hours.
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ENVIRONMENTAL NOISE REPORT
Noise Impact Assessment 10 Ramboll
5. NOISE IMPACT ASSESSMENT
5.1 Construction Noise Assessment
During construction of the proposed warehouse, there would be temporary increases in
sound levels near active construction areas of the properties due to the use of heavy
equipment on-site, as well as along area roadways used for hauling construction materials
and removing overburden (e.g., trees, earth). The increases in noise levels would depend
on the type of equipment being used and the amount of time it is in use. Expected activities
include clearing, grading, excavation, road building, paving, and building construction.
Table 3 displays typical noise levels produced by equipment that could be used during
construction of the Project. Sound levels near many types of construction equipment listed
below exceed the levels recommended for residential land uses and decrease at a rate of
about 6 dBA for each doubling of distance from the source(s). Typical construction sound
levels are given for distances of 100, 200, and 400 feet to give some idea of equipment
sound levels at varying distances.
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Noise Impact Assessment 11 Ramboll
Table 3. Typical Noise Levels From Construction Activities & Equipment (dBA)
Activity
Range of Hourly Leqs
At 100 Feet At 200 Feet At 400 Feet
Clearing 77 71 65
Grading 69-82 63-76 57-70
Paving 66-82 60-76 54-70
Erection 66-78 60-72 54-66
Types of Equipment
Range of Hourly Sound Levels
At 100 Feet At 200 Feet At 400 Feet
Bulldozer 71-90 65-84 59-78
Dump Truck 76-88 70-82 64-76
Scraper 74-87 68-81 62-75
Paver 80-82 74-76 68-70
Generators 65-76 59-70 53-64
Compressors 68-75 62-69 56-63
Source: EPA and others, compiled by Ramboll
Site development and construction of the proposed warehouse could generate relatively
high sound levels on and near the project property, particularly at residential areas to the
north and, to a lesser extent, to the south. Also, high levels of construction noise may be
audible at times at commercial facilities to the east and northwest. Primary sound sources
could include excavation and grading equipment, large haul trucks used for materials such
as concrete, and earth and tree removal. Other smaller pieces of equipment may include
generators, compressors, and pumps all with the potential to contribute to cumulative noise
emissions during construction.
As summarized above in Section 3, FWRC 7.10.020(8) states that sounds from construction
sites during nighttime hours are considered a public disturbance (nighttime hours are
defined by the City of Federal Way as between 8:00 p.m. and 7:00 a.m. on weekdays and
between 8:00 p.m. and 9:00 a.m. on weekends).
During daytime hours, when Project construction is expected to occur, construction
activities could result in elevated levels of noise from the Project site. Although daytime
construction could be perceived as intrusive at residential receivers, the temporary nature of
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Noise Impact Assessment 12 Ramboll
construction activities, and the restriction of construction to daytime hours, is expected to
minimize the potential for noise impacts. In addition, the developer would employ best
management practices to reduce construction noise.
5.1.1 Construction Noise Assessment – General Mitigation Methods
The following may help to reduce to the potential for high levels of noise from construction
equipment or activities, as may be received at existing noise-sensitive land uses, and
therefore would help to reduce the potential for perceived impact:
• Require that all equipment be fitted with properly sized mufflers, and if necessary,
engine intake silencers
• Require that all equipment be in good working order.
• Use quieter construction equipment models if available, and whenever possible use
pneumatic tools rather than diesel or gas-powered tools.
• Place portable stationary equipment as far as possible from existing residential and
noise-sensitive commercial areas, and if necessary, place temporary barriers around
stationary equipment.
• For mobile equipment, consider replacing typical pure-tone backup alarms with ambient-
sensing and/or broadband backup alarms.
5.2 Operational Noise Assessment
Operation of the proposed warehouse is expected to generate noise emissions that may be
received at nearby residential and commercial facilities. Noise from stationary equipment,
as well as from mobile sources such as trucks, are typical sources of noise at a warehouse.
The following summarizes the assessment completed to evaluate operational noise from
these sources and includes a summary of the noise model used for the assessment, details
of the expected sound sources, a review of nearby noise sensitive receiving properties, and
assessment results.
5.2.1 Noise Prediction Model
Ramboll completed noise modeling using the CadnaA noise model, based on the noise
propagation algorithms established in ISO 9613-2. CadnaA is a computerized noise
prediction model that can calculate sound levels after considering the noise reductions or
enhancements of a range of factors including distance, topography, ground surface types,
intervening structures, atmospheric absorption, and meteorological conditions. Noise
sources were based on frequency-specific measurements of representative equipment or on
estimates of equipment noise levels based on relative throughput ratings for specified
equipment. The modeling considered noise emissions from all Project-related sources and
predicted off-site sound levels at nearby receptor locations.
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Noise Impact Assessment 13 Ramboll
The Project building was modeled at an assumed height of 30 feet, and local topography
was imported from a publicly-available online source. Ground was assumed to be soft, or
acoustically “absorptive”, with the exception of paved roads and parking lots.
5.2.2 Emission Sources
Noise modeling was completed based on assumed warehouse operation. Sound level data
for typical warehouse sources were taken from Ramboll’s sound source library and included
the following (noise model source IDs indicated in parentheses):
• 6 Rooftop HVAC units for office heating and cooling (AC1 – AC6)
• 12 Rooftop Make Up Air units (MUA1 – MUA12)
• 6 Rooftop Exhaust Fans (EF1 – EF6)
• 1 Emergency Diesel Generator (G1)
• Truck routes within the site, assumed 14 trucks per hour (TR1)
Table 4 provides a tabular summary of the sound sources used for this assessment,
including the number of pieces of equipment and estimated sound levels. As a worst-case
assessment, it was assumed that all equipment and activities, including testing of the
emergency generator4, would occur continuously, 24 hours per day. An illustration of the
assumed location of warehouse equipment is found in Appendix A, Figure 4.
Table 4. Noise Source Summary (dBA)
Source Type Number of Units Sound Power Level Per Unit (dBA)
Rooftop HVAC Unit 6 86 dBA (a)
Rooftop MUA Unit 12 88 dBA (a)
Rooftop Exhaust Fan 6 90 dBA (a)
Emergency Generator 1 100 dBA (b)
Truck Route 14 per hour 104 dBA (per truck) (a)
(a) Sound power level based on sound level measurements taken by Ramboll
(b) Sound level for generator based on manufacturer specifications for 30 kW generator plus 5 dBA penalty
added to conservatively estimate potentially larger generator at the Project.
Source: Ramboll
4 Emergency use generators typically are tested during daytime hours only; therefore this assessment
presents an overly-conservative evaluation of generator testing noise during nighttime hours.
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Noise Impact Assessment 14 Ramboll
5.2.3 Noise Sensitive Receivers
Noise modeling was completed to estimate operational noise levels at receptors in the
Project vicinity. A graphical illustration of noise-sensitive receiving locations is found in
Figure 3.
5.2.4 Noise Modeling Results – Assessment of Compliance with WAC Limits
Model-calculated sound levels are presented in Table 5, and a graphical representation of
results can be found in Appendix A, Figure 5, which shows the noise contours generated
by the model.
Operation of the Project is expected to be well within the applicable WAC sound level limits
at all nearby Class A and Class B EDNA receivers.
At the nearest Class A EDNA receiver represented by R2 (see Figure 3), predicted worst-
case operating conditions would result in an hourly sound level of 38 dBA, 12-dBA below the
applicable nighttime limit of 50 dBA. Operational sound levels at all remaining Class A
EDNA receivers are predicted to be even lower.
At the nearest Class B EDNA receiver, represented by C4 (see Figure 3), predicted worst-
case operating conditions would result in an hourly sound level of 49 dBA, 16-dBA below the
applicable limit of 65 dBA (applicable during both daytime and nighttime hours). Operational
sound levels at all remaining Class B EDNA receivers are predicted to be even lower.
5.2.5 Noise Modeling Results – Assessment of Increase over Existing Conditions
At the nearest Class A EDNA receiver (R2), operation of the Project would result in noise
levels that are 1 dBA above the quietest existing nighttime hour, an acoustically negligible
increase. That is, the projected increase at R2 is unlikely to be perceptible by most people in
a controlled noise environment, and much less likely to be perceptible in a typical active
outdoor environment where there are existing sources of ambient noise (i.e., traffic on I-5
and local roads).
Note that the loudest source of Project-related noise is from the estimated 14 trucks per
hour, assumed to access the Project site during all daytime and nighttime hours. Should
the proposed warehouse operate with fewer or no trucks during nighttime hours, Project-
related sound level increases may be less than 1 dBA.
5.2.6 Additional Considerations – Loading Docks
Noise emissions from up to 14 trucks per hours would include entry, moving within a
circular path of the parking area on the east side of the warehouse, and exiting. Although
trucks would be expected to load and unload at loading docks at the warehouse, noise from
loading dock operations typically do not generate high levels of noise relative to truck
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Noise Impact Assessment 15 Ramboll
movement. Therefore, loading dock activity is not anticipate to generate emissions beyond
what has been accounted for in this assessment.
5.2.7 Additional Considerations – Off Site Traffic
Noise from traffic traveling on public roadways is exempt from WAC 173-60 for vehicles
regulated under WAC 173-62 (WAC 173-60-50(4)(a)). Therefore, noise from traffic
accessing the Project would be exempt from the WAC (and therefore from FWRC) when
traveling on public roadways. However, increases in traffic volumes on area roadways may
result in minor increases in ambient noise levels during peak Project hours.
Trucks accessing the Project are expected arrive along Weyerhaeuser Way South to/from SR
18. There are no residential or other Class A EDNA receivers along this access route.
Automobile traffic accessing the Project, including staff and visitors, would access the site
using the ingress/egress points on Weyerhaeuser Way South and Weyerhaeuser Way Road.
The number of staff required to operate and maintain the warehouse would vary depending
on specific operational requirements. Parking would be provided for up to 245 vehicles. The
staff arrival and departure schedule, and the volumes of traffic expected to arrive/depart
during peak hours, will depend on operating requirements of the Project. However, most
traffic is expected to access the site from the south, along Weyerhaeuser Way South,
to/from SR 18. The remainder are expected to access the Project from the north, either
from South 336th Street or further north. Project-related maximum hourly traffic volumes
are expected to be low and are not anticipated to generate acoustically-significant increases
in ambient noise.
5.2.8 Results Summary and Mitigation
As indicated, operation of the Project is expected to comply with WAC noise limits at all
nearby Class A and Class B EDNA receivers. The predicted worst-case increase over
existing conditions during nighttime hours is not expected to be perceptible at the nearest
Class A EDNA receiver.
Noise mitigation measures are not warranted at this time.
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Noise Impact Assessment 16 Ramboll
Table 5. Noise Modeling Results (dBA)
Receiver
A
Background: Existing
Noise Level During
Quietest Nighttime
or Daytime Hour (a)
Assessment of Noise Impact Assessment of WAC Compliance
B
Project Only Sound
Levels
C
Project plus
Background
(A + B)
D
Increase from Project
+ Background Over
Background
(C - A) (b)
E
WAC Sound
Level Limit
F
Project Only (B)
Complies with
WAC?
R1
46
(Quietest Nighttime
Hour)
37 47 0
50 (c)
Yes
R2 38 47 1 Yes
R3 38 47 1 Yes
R4 35 47 0 Yes
R5 35 47 0 Yes
R6 31 47 0 Yes
R7 35 47 0 Yes
R8 35 47 0 Yes
C1
Assessment of Noise
Increase Not
Applicable to Class B
EDNA Receivers
36
Assessment of Noise Increase Not Applicable to
Class B EDNA Receivers 65
Yes
C2 42 Yes
C3 45 Yes
C4 49 Yes
C5 44 Yes
C6 41 Yes
C7 44 Yes
(a) Existing noise level measured at 33636 30th Avenue South, used to represent existing environment at all residential noise receiver locations.
(b) Tabulated results are rounded to the nearest whole number, and apparent calculations errors are due to rounding.
(c) Represents the nighttime sound level limits, 10-dBA below the daytime limit of 60 dBA.
Source: Ramboll
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Conclusions 17 Ramboll
6. CONCLUSIONS
The proposed Project would include the development of an approximately 214,050 square
foot general commodities warehouse in Federal Way, Washington. The noise assessment
was prepared to respond to the requirements of the City’s Process III application and to
support the Project’s SEPA checklist.
Sound level measurements were taken at a residential property located north of the
proposed warehouse, on a property owned by Weyerhaeuser, and considered representative
of residential properties evaluated for this study.
Construction of the Project is expected to comply with the public disturbance nighttime
timing restrictions established within the Federal Way Revised Code. Temporary daytime
construction noise is expected to result in short-term increases in noise that may be
mitigated by simple, common sense techniques to reduce construction noise.
During operation, noise emissions for equipment common to warehouses were assumed for
the Project including rooftop HVAC units, Make-Up Air units, and exhaust fans; an
emergency generator, and; ground-level truck traffic.
A noise model was prepared to estimate operational noise at nearby residential (Class A
EDNA) and commercial (Class B EDNA) receivers. An assessment of noise impact was
based on compliance with the applicable WAC noise limits, and on the predicted increase
over existing ambient conditions at EDNA Class A receivers.
The noise study found that the proposed Project would comply with all applicable WAC limits
during both daytime and nighttime hours. Further, the Project is expected to result in
acoustically negligible increases over the existing ambient noise environment at the nearest
residential properties.
Noise mitigation measures are not recommended at this time. A detailed review of final
operating conditions should be completed to ensure that this noise study accurately and
conservatively reflects future Project operation.
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Appendix A Ramboll
APPENDIX A
Figures
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Appendix A Ramboll
Figure 1. Sound Level Measurement Location
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Appendix A Ramboll
Figure 2. Long Term Sound Level Measurement - Graphically Summary
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Appendix A Ramboll
Figure 3. Project and Noise Receptor Locations
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Appendix A Ramboll
Figure 4. Noise Source Locations
GREENLINE BUILDING “B” DEVELOPMENT, FEDERAL WAY, WASHINGTON
ENVIRONMENTAL NOISE REPORT
Appendix A Ramboll
Figure 5. Noise Model Isopleth Contours