COMMISSION 
AGENDA MEMORANDUM                        Item No.          8e 
ACTION ITEM                            Date of Meeting       April 27, 2021 
DATE:     April 19, 2021 
TO:        Stephen P. Metruck, Executive Director 
FROM:    Eileen Francisco, Acting Director, AV Facilities & Capital Programs 
Wayne Grotheer, Director Aviation Project Management 
SUBJECT:  S. 188th St. Tunnel Lighting (C801157) 
Amount of this request:               $4,610,000 
Total estimated project cost:         $24,500,000 
ACTION REQUESTED 
Request commission authorization for the Executive Director to (1) complete design, (2)
execute a professional services agreement for design services, and (3) enter into a reimbursable
agreement with the Federal Aviation Administration for the S. 188th St. Tunnel Lighting project
at  Seattle-Tacoma  International  Airport  (SEA).  The  amount  being  requested  under  this
authorization is $4,610,000 for a total authorization of $4,900,000 and a total estimated project
cost of $24,500,000. 
EXECUTIVE SUMMARY 
The S. 188th St. tunnel structure is located beneath Runway 34R. It was originally constructed
in 1960.  Based upon an existing easement, SEA owns the tunnel structure and the City of
SeaTac owns the S. 188th St. roadway. This project has assessed the tunnel for current code
requirements. Based on the findings of that assessment, many of the existing systems are
deficient. This project will address the structure, lighting, and other systems to ensure the
tunnel is brought to a satisfactory level of service.
JUSTIFICATION 
The life safety systems in the tunnel are original to its construction.  These systems include
ventilation,  back-up  power,  and fire detection. Most  of which  are  currently   missing  or
inoperable.  Tunnel lighting, the sole exception, was partially replaced in the 1990s, however
many of the light fixtures have failed and replacement parts are no longer available. This
project will replace or restore these systems to reduce life safety risk, improve lighting, driver 
and pedestrian safety and improve energy efficiency. 


Template revised January 10, 2019.

COMMISSION AGENDA  Action Item No. _8e_                                Page 2 of 5 
Meeting Date: April 27, 2021 
Diversity in Contracting 
The project team is  working  with the Diversity in Contracting Department to determine
participation opportunities and will set appropriate aspirational goals for women and minority
business enterprises (WMBE) participation in the design and construction contracts. 
DETAILS 
The tunnel is periodically inspected by Port of Seattle engineering in accordance with the
Washington State Department of Transportation's Bridge and Tunnel inspections. The
inspection performed in 2018 daylighted concerns over the age and condition of multiple
tunnel systems. This and other elements initiated the process to first address the lighting
system. 
SEA later decided to expand the scope to further assess all the existing life safety systems. SEA 
engaged a design consultant to assess the condition of the lighting and life safety systems. The
consultant produced a list of recommendations and those recommended for immediate action 
formed the basis of the scope of work. 
The City of SeaTac (City) will also be performing a pavement overlay of S. 188th St., including the
section of pavement located within the tunnel, during the summer of 2021. SEA and City staffs
are currently coordinating on that scope of work to ensure the objectives of both agencies can
be achieved. 
One of the projects proposed in the Sustainable Airport Master Plan Near-Term Projects
environmental review effort is the extension of Taxiway A/B.  This proposed project would
include the extension of the tunnel structure to the east as the Taxiway is extended to the
south over S. 188th St. Currently, the following scope has been identified to be included with the 
proposed extension of Taxiway A/B, and is not included in this project:  smoke control, fire
suppression, egress pathway improvements, airfield grading and drainage, hydrant stand pipes,
seismic retrofitting, and structural improvements to support additional airfield loading.  Both
project teams will continue to coordinate as each project progresses. 
The project team identified a Federal Aviation Administration fiber line that may or may not be
impacted  from  construction.  Authorization  to  enter  a  reimbursable  agreement  is  a
precautionary measure in case it is determined that such an agreement would be necessary for
design reviews or construction impacts. 
Scope of Work 
Scope of work for this project includes structural (crack sealing/spall repair), civil (sidewalk,
signage),  electrical  (lighting,  power,  emergency  power),  mechanical  (ventilation,  fire
protection),  communication  and  special  system  (fire  detection/alarm,  carbon  monoxide
monitoring, security, egress/traffic management) improvements. 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. _8e_                                Page 3 of 5 
Meeting Date: April 27, 2021 
Schedule 
Design start                                       2021 Quarter 3 
Commission construction authorization          2022 Quarter 4 
Construction start                                2023 Quarter 2 
In-use date                                       2024 Quarter 2 
Cost Breakdown                                     This Request           Total Project 
Design                                                  $4,900,000             $4,900,000 
Construction                                                     $0            $19,600,000 
Total                                                         $4,900,000             $24,500,000 
ALTERNATIVES AND IMPLICATIONS CONSIDERED 
Alternative 1  Defer scope to later projects or no action. 
Cost Implications: $0 
Pros: 
(1)   No cost incurred immediately. 
Cons: 
(1)   Ignores critical life safety system deficiencies putting the public at risk. 
This is not the recommended alternative. 
Alternative 2  Replace existing lighting and backup power generation in the tunnel. 
Cost Implications: $6,200,000 
Pros: 
(1)   Addresses lighting deficiency. 
(2)   Lower capital investment by the Port. 
Cons: 
(1)   Not all critical life safety deficiencies are addressed. 
(2)   Power  system  improvements  may  not  be  sufficient  to  support  other  life  safety
systems when remedied. 
This is not the recommended alternative. 
Alternative 3  Bring lighting and life safety systems up to a satisfactory level of service. 
Cost Implications: $24,500,000 
Pros: 
(1)   Addresses critical life safety system deficiencies as quickly as possible. 

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. _8e_                                Page 4 of 5 
Meeting Date: April 27, 2021 
Cons: 
(1)   Larger capital investment by the Port. 
(2)   Future projects may impact improvements. 
This is the recommended alternative. 
FINANCIAL IMPLICATIONS 
Cost Estimate/Authorization Summary              Capital        Expense           Total 
COST ESTIMATE 
Original estimate                                 $6,200,000               $0      $6,200,000 
Current change                                $18,300,000              $0    $18,300,000 
Revised estimate                              $24,500,000              $0    $24,500,000 
AUTHORIZATION 
Previous authorizations                            $290,000               $0        $290,000 
Current request for authorization                $4,610,000               $0      $4,610,000 
Total authorizations, including this request       $4,900,000               $0      $4,900,000 
Remaining amount to be authorized           $19,600,000             $0    $19,600,000 
Annual Budget Status and Source of Funds 
This project, CIP C801157, was included in the 2021-2025 capital budget and plan of finance
with a budget of $6,200,000. A budget increase of $18,300,000 was transferred from the
Aeronautical Reserve CIP (C800753) resulting in zero net change to the Aviation capital budget.
The funding source will be the Airport Development Fund (ADF) and revenue bonds. This
project has been submitted to the airlines for the Majority-in-Interest ballot due on April 26,
2021. 
Financial Analysis and Summary 
Project cost for analysis              $24,500,000 
Business Unit (BU)                  Airfield Movement Area 
Effect on business performance     NOI after depreciation will increase due to inclusion of
(NOI after depreciation)             capital (and operating) costs in airline rate base 
IRR/NPV (if relevant)                N/A 
CPE Impact                       $.08 in 2024 
Future Revenues and Expenses (Total cost of ownership) 
According to the existing easement agreements the City of SeaTac is responsible for the ongoing
operating and maintenance cost of the roadway, sidewalks and pedestrian barrier. The
Port is responsible for the tunnel structure and all the systems within the tunnel. There will be
an increase in the operation, preventative maintenance and unplanned maintenance costs for

Template revised June 27, 2019 (Diversity in Contracting).

COMMISSION AGENDA  Action Item No. _8e_                                Page 5 of 5 
Meeting Date: April 27, 2021 
the tunnel. Most of which will be due to reestablishing systems that were original to the
construction of the tunnel and are no longer functioning. The remaining consideration would be
for additional components used to control and monitor equipment as advances in technology
has added this capability. 
ATTACHMENTS TO THIS REQUEST 
(1)   Presentation slides 
PREVIOUS COMMISSION ACTIONS OR BRIEFINGS 
None 














Template revised June 27, 2019 (Diversity in Contracting).