COMMISSION 
AGENDA MEMORANDUM                        Item No.          7c 
BRIEFING ITEM                             Date of Meeting      January 22, 2019 
DATE:     January 15, 2019 
TO:        Stephen P. Metruck, Executive Director 
FROM:    Arlyn Purcell, Director Aviation Environment and Sustainability 
Stan Shepherd, Manager Airport Noise Programs 
SUBJECT:  Sea-Tac Sound Mitigation Briefing 
EXECUTIVE SUMMARY 
As part of the Port's long-termcommitment to communities surrounding the airport, the Port
offers sound insulation for eligible single-family homes, apartments, condominiums, places of
worship, and schools located within the current Federal Aviation Administration (FAA)
approved Airport Noise Compatibility Program (Part 150) noise remedy boundary. Sound
insulation projects provide renovations at no cost to homeowners and include new windows,
exterior doors, storm doors and ventilation to meet the FAA standard of a 45 decibel (dB)
interior noise level. Approximately 80 percent of eligible costs are funded by FAA Airport
Improvement Program (AIP) grants. Owners are required to sign an avigation easement in
exchange for the improvements. The program began in 1985 and, to date, has insulated
approximately 9,400 homes, 8 Highline School District Schools, 5 condominium complexes (246
units), and 14 buildings on the Highline College campus. In addition to sound insulation, the
Port acquired 5 mobile home parks (359 home units), 69 homes north of the third runway 
impacted by airport noise and 1,400 single family homes associated with the third runway
construction project. 
Part 150 Study 
The Part 150 Noise Compatibility Study process is designed to identify noise incompatibilities
surrounding an airport, and to recommend measures to both correct existing incompatibilities
and to prevent future incompatibilities. For Part 150 Study purposes, noise incompatibilities are
defined as residences or public use noise-sensitive facilities and must be located within the 65
Day-Night Average Sound Level (DNL) noise contour and meet a stringent noise audit. 
Seattle-Tacoma International Airport's first Part 150 Noise Compatibility Study was completed 
in 1985. A total of three study updates were completed in 1992, 2002, and 2014. The current
noise remedy boundary was an outcome of the 2014 study update. 


Template revised April 12, 2018.

COMMISSION AGENDA  Briefing Item No. 7c                                  Page 2 of 3 
Meeting Date: January 22, 2019 
Single Family Home Sound Insulation 
The Airport Noise Office identified approximately 150 single-family homes located within the
noise remedy boundary as potentially eligible for voluntary sound insulation. All homeowners
were contacted, and the noise office received 49 completed applications. Acoustical testing
was completed on 41 single family homes in July 2018. Of those 41 single-family homes, 36
qualified for the program with an average interior DNL noise level of 45 dB or greater. 
Construction is anticipated to begin in the first quarter of 2019. 
Condominium Sound Insulation 
The Airport Noise Office has identified three condominium complexes (approximately 240
units) located within the noise remedy boundary as potentially eligible for voluntary sound
insulation. The Port is currently  procuring a consulting firm to administer the program by
providing project design and construction management.  Once the consultant firm is selected 
(anticipated in the first quarter 2019), a schedule detailing homeowner outreach, acoustic
testing, architectural design, cost estimation, construction, and closeout will be completed. 
Apartment Sound Insulation 
There are approximately 18 buildings (877 units) located within the noise remedy boundary
that are potentially eligible for sound insulation. A pilot project consisting of  one apartment
complex to be determined by Port Noise staff would begin construction in 2022 at an estimated
cost of $2.3 million. 
Places of Worship Sound Insulation 
There are approximately seven places of worship located within the noise remedy boundary
that are potentially eligible for sound insulation. A pilot project consisting of  one place of
worship to be determined by Port Noise staff would begin construction in 2023 at an estimated
cost of $1.1 million. 
Voluntary Purchase of Avigation Easements on Parcels with Mobile Homes 
Since mobile homes cannot be adequately sound insulated, it was recommended through the
Part 150 to offer avigation easements to owners. The avigation easement protects the airport
from future noise related litigation. It has been estimated that 88 mobile homes on private land
parcels are eligible to participate at a potential cost of $462,000. Project is estimated to begin
in 2021. 
Voluntary Acquisition of Residential Structures Located in the South Approach Transition
Zone (ATZ) for the Third Runway 
An ATZ is a defined area that extends 2,500 feet past the runway protection zone and was a
product of the third runway supplemental Environmental Impact Study and the Part 150 as an
eligible area for acquisition of  residential parcels for noise compatibility purposes.   The

Template revised September 22, 2016.

COMMISSION AGENDA  Briefing Item No. 7c                                  Page 3 of 3 
Meeting Date: January 22, 2019 
structures would be removed and the parcels converted to airport compatible land. Sixteen
single-family homes and six apartment buildings have been identified as potentially eligible for
the program. Project is estimated to begin in 2022. 

Highline School District Sound Insulation 
The Highline School District has a 2002 Memorandum of Agreement (MOA) with the Port and
the FAA to sound insulate 15 noise-impacted schools at a total cost of $100 million.  As of
December 2018, seven schools in the Highline School District remain to be sound insulated. In
2017, the Highline School District passed a bond for the reconstruction of Des Moines
Elementary and Highline High School, both of which fall under the MOA. Construction, including
insulation work, is currently underway at Des Moines Elementary. Highline High School will
commence construction in mid-2019. 
ATTACHMENTS TO THIS BRIEFING 
(1)   Presentation slides 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
July 10, 2018  Commission authorized $5,107,000 for procurement of a firm to provide 
consulting services for condominium complex noise remediation. 
October 11, 2016  Commission authorized $14,535,000 for Single Family Sound Insulation. 
October 22, 2013  Commission adopted Resolution No. 3683 concluding the Federal
Aviation Regulation (FAR) Part 150 Noise and Land Use Compatibility Study Update for
Seattle-Tacoma International Airport 
October 8, 2013 Resolution No. 3683 concluding the Federal Aviation Regulation (FAR) Part
150 Noise and Land Use Study Update for Seattle-Tacoma International Airport  was
introduced. 







Template revised September 22, 2016.