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01 Case Study

1918 Eighth

1918 Eighth Avenue is a 36-story office tower located in downtown Seattle, WA. The building was constructed in 2009 and was LEED BD+C: Core & Shell certified at the Gold level in 2010. In December 2018, the property achieved LEED v4.1 Operations and Maintenance: Existing Buildings certification at the Platinum level.

LEED for Existing Buildings: Operations and Maintenance v4.1 Platinum certified


The building received an Energy score of 90 out of 100. An ASHRAE Level I audit was completed during the performance period that identified several Energy Conservation Measures under consideration by property management.

Energy score of 90 out of 100


The building received a Water score of 81 out of 100, which can be attributed to water efficient strategies implemented during the LEED Core & Shell project. The property reduced irrigation water use by 50% and indoor water use by 30% compared to the LEED baseline.

Water score of 81 out of 100


The building has a comprehensive recycling and composting program in place. A waste audit was performed during the performance period which identified a 37% recycling rate.

Waste score of 78 out of 100


The building achieved a Transportation score of 85 out of 100 due to the majority of occupants using alternative means of transportation, such as public transportation and walking.

Transportation score of 85 out of 100

Human Experience

An IAQ audit was conducted, which determined an average indoor CO2 level of 712.4 ppm and the highest TVOC reading of 45 micrograms/m3.

Additionally, an occupant satisfaction survey was administered. Together, the IAQ audit and survey results achieved a Human Experience score of 87 out of 100.

Human Experience score of 87 out of 100

Additional Credits

The project contributed financial support to the Great Peninsula Conservancy, a nonprofit land trust dedicated to protecting the natural habitats of the Great Peninsula region of West Puget Sound.

As part of the building’s green cleaning policy, 46% of the janitorial equipment purchased met LEED sustainability requirements.

An Integrated Pest Management Plan was implemented, which resulted in the use of only non-toxic pesticides.

Additional Credits score of 3 out of 10


Total Arc Score


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