TagPart 150(118)

This document outlines the Future (2021) Noise Exposure Map and Noise Compatibility Program for Seattle-Tacoma International Airport, projecting noise levels for a typical day in 2021 assuming all recommended noise abatement measures are in place. Using the FAA's Integrated Noise Model, it forecasts 419,597 annual aircraft operations — a 15.4% increase over 2016 baseline levels — and maps noise contours at 65, 70, and 75 decibel DNL thresholds. The report details the fleet mix and runway usage data used in the modeling, with Boeing 737-800s representing the largest share of daily operations.

Resolution No. 3683 is a Port of Seattle Commission resolution concluding the 2013 update to the Federal Aviation Regulation (FAR) Part 150 Noise and Land Use Compatibility Study for Seattle-Tacoma International Airport. It directs Port staff to submit updated Noise Exposure Maps to the FAA and implements a range of noise-reduction measures, including school sound insulation, preferential runway use at night, and voluntary rescheduling of nighttime short-haul flights. The resolution builds on previous Part 150 Studies from 1985, 1993, and 2000, incorporating public input and a formal environmental review process.

This exhibit from the Seattle-Tacoma International Airport 14 CFR Part 150 Study maps the existing 2013 baseline noise exposure contours around Sea-Tac Airport, showing DNL 65, 70, and 75 dBA noise zones across surrounding communities including SeaTac, Burien, Des Moines, and Tukwila. The DNL 65 dBA or greater contour covers approximately 5.9 square miles, encompassing an estimated 1,887 housing units and roughly 4,879 residents, along with 9 noise-sensitive facilities such as schools, churches, and hospitals. Notably, no housing units fall within the higher-impact DNL 70 dBA or above zones, though significant residential and commercial land uses exist within the broader 65 dBA contour area.

The City of Des Moines, Washington repealed its local Sound Code (DMMC 14.08.180–14.08.440) in response to reduced aircraft noise projections from the Port of Seattle's Part 150 Study, improved State building codes, and concerns from the development community that the code was unnecessarily burdensome. The repeal does not affect homeowners' eligibility for Port of Seattle sound insulation remediation funding. The city indicated it would continue to support residents through consumer information resources on sound protection options.

At a March 1, 2012 Des Moines, WA City Council study session, staff presented a policy discussion on whether to update the city's Sound Transmission Control (Sound Code) requirements, which govern noise-reducing construction standards for buildings near Sea-Tac Airport. The existing code, last revised in 1996, was criticized by developers and homeowners as overly burdensome, while the Port of Seattle's official 'Part 150' noise contour study won't be finalized until 2016. The Council was asked to consider options ranging from immediate regulatory relief—such as reducing sound zones, limiting requirements to windows only, or making compliance voluntary—to waiting until the 2016 study is complete before making any changes.

This document is Appendix N of the Seattle-Tacoma International Airport Part 150 Noise Compatibility Study Update, compiled by Landrum & Brown in October 2013. It contains the FAA's official approval, dated August 19, 2010, of the aviation activity forecast submitted by Sea-Tac Airport in July 2010. The FAA determined that the forecast provided adequate justification for total aircraft operations and authorized its use in the airport's Noise Compatibility Plan Update.

The Port of Seattle is seeking authorization to hire a consulting team to update Sea-Tac Airport's Part 150 Noise and Land Use Compatibility Plan, last approved by the FAA in 2002. The update is needed to reflect major changes in the airport's noise environment, including the opening of a new third runway, the shift to quieter aircraft by airlines such as Alaska and Horizon, and fewer flight operations than originally forecast. The project, estimated to cost between $500,000 and $1 million and funded 80% by FAA grants, is expected to be completed and submitted to the FAA by late 2010.