Building type:




Project Status:


Gross Area:

209000 Sqft


LEED v3 EBOM (Existing Buildings) Gold

Climatic zone:



Thumbnail GSA Federal Center South Building 1202 / 0 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 1 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 2 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 3 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 4 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 5 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 6 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 7 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 8 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 10 © Benjamin Benschneider
Thumbnail GSA Federal Center South Building 1202 / 11 © ZGF Architects LLP


Using a Design-Build delivery model to get ARRA funds committed as quickly as possible, the Sellen Construction and ZGF Architects LLP team developed an integrated design and construction solution that fuses programmatic, functional and aesthetic objectives with a new standard for high-performance, cost-effective and sustainable workplace environments. The project was planned and designed in under 18 weeks in order to guarantee the performance-based contract that met GSA’s construction budget, energy performance goals and an aggressive design and construction schedule starting with a design competition at the beginning of 2010 and resulting in a completed building before the end of 2012.

The “oxbow” design solution provides an ideal workplace environment for the USACE emblematic of their mission of “Building Strong.” The building’s form—reflecting the natural oxbows past and present in the course of the adjacent Duwamish Waterway—is functional and flexible to accommodate the USACE’s nearly constantly changing team-based work. The diagrid structure extending around the building meets GSA’s security requirements for progressive collapse, ensuring the building will remain standing should one of the column elements be compromised. The exterior stainless steel shingle cladding emphasizes “Building Strong” and complements the nearby historic 1930s Albert Kahn-designed 1201 building. The dramatic, daylit wood-clad atrium—the “commons”—features timber reclaimed from the former warehouse that stood on the site and serves as the social heart of the building.



Hybrid ventilation

Ventilation + Heat recovery

Innovative cooling system

Passive Solar

High efficient façade

Rainwater harvesting

Reclaimed materials

On-site renewables

Daylighting maximised

No light pollution

Outdoor view maximised


Setting a new standard for high-performance office buildings, Federal Center South Building 1202 has met its energy goal in the first year of operation. The building is operating in the top 1% of similar-sized office buildings across the nation with an ENERGY STAR® score of 98. The project has established energy performance nearly 40% better than ASHRAE 90.1, with an EUI of 25.7 kBTU/SF/year and earned LEED-Platinum certification in the fall of 2014.

Conventional building systems have been replaced with efficient hydronic heating and cooling, and a healthier, more energy-efficient 100% outside air underfloor air distribution system. To enable these systems to perform at an optimal capacity within the project budget, an ultra-efficient building envelope - offering a high level of insulation, while transmitting ample daylight - reduces the magnitude of heating and cooling demand and optimizes the use of daylight within.

Energy and water introduced into the building are leveraged to their highest possible use. Conditioned air is delivered to the workspace via air handling units and exhausted passively through the atrium to high-efficiency heat recovery systems. Available daylight, controlled for glare and unwanted heat gain with a varying degree of frit across the atrium skylight to respond to sun exposure, is directed to the office floor plates from two sides, to offset the maximum possible amount of electric lighting.

High-efficiency boilers, cooling towers and heat pumps generate the required heating and cooling. The equipment efficiencies are high per current best practices, with the difference being that design integration has resulted in systems substantially smaller than would conventionally be required. Electric lighting design is a simple, repetitive task/ambient design that achieves a building-wide lighting power density of approximately 0.72 W/SF or lower.

Daily and seasonal patterns of sun, wind and light create a highly variable range of exterior conditions that the building attenuates to maintain internal comfort. The design capitalizes on these cyclic patterns to create thermal energy when available and store it for use when required. A thermal storage tank containing Phase Change Material (PCM) – a solution with a high heat of fusion that melts and solidifies at 55⁰F, a temperature that is often achieved in Seattle’s mild climate, absorbing or releasing heat as it does so. Together, these two systems – one seasonal in nature and the other diurnal – reduce the amplitude of cyclical climate variation, and enable the building and its occupants to work with the natural world instead of against it.

With the most efficient energy being energy that is not required, the integrated design is developed to avoid the need for on-site renewable generation to meet the required energy goals. Life-cycle cost analysis of a solar domestic hot water system and supplemental photovoltaic system were both outside the range of acceptable return.

Orientation and massing optimize daylight while reducing solar heat gain. The U-shaped form of the office bar creates daylight access on both sides of the floor plate, providing natural light to over 90% of the building to enhance energy performance and human comfort.

Exterior orientation-specific sun-shading elements, clerestory glazing, and internal adjustable window coverings control heat gain and glare while providing uninterrupted view to the outdoors, as well as time of day and weather condition awareness. The ribbon system is design with vertical blades across the entire perimeter. The system is augmented with horizontal sunshades tuned to the orientation starting with zero on the north and transitioning to one, two and three as the façade transitions around the oxbow from east to south. Peak cooling loads are targeted for a 30% reduction in the perimeter zone, resulting in a 10% reduction in the central plant cooling capacity.

On-site drainage run-off is treated within stormwater surface ponds, rain gardens and wet ponds. The runoff is collected around the perimeter of the site and directed to the western-most pond, mimicking natural site drainage patterns, and leveraging low-impact development techniques. The rainwater reuse system captures water from the roof and stores it in a 25,000-gallon cistern to be used for toilets, irrigation, a rooftop cooling tower and water features in the “commons.” These systems provide required water quality treatment. A series of exterior rain gardens were designed to drain and treat a 95th percentile rain event entirely on-site eliminating the need for a connection to the City’s stormwater system.
An estimated 430,000 gallons of rainwater will be harvested annually – providing a 79% reduction in potable water use for toilet flushing and a reduction of irrigation demand by an additional 14%. Potable domestic water use is reduced by 58% through efficient fixtures, low-water landscape and rainwater reuse.

In response to the ARRA funding requirement to reuse portions of the existing warehouse that previously stood on the site in the design of the new 1202 building, approximately 200,000 board feet of salvageable structural timber and 100,000 board feet of decking (92%)was reclaimed to form the building’s foundation, structural system, and the interior cladding of the “commons.”


Energy consumption:

N/A (N/A )

Consumption type:

Annual carbon footprint:

N/A (N/A )

Climate zone:


Min. temperature =


Max temperature =


RH =



No product info available



U.S. General Services Administration (Tenant: U.S. Army Corps of Engineers)



ZGF Architects LLP


Acoustical consultant:

The Greenbusch Group

Building services engineer:

WSP Flack + Kurtz/University Mechanical , Lane Coburn & Associates, LLC/Sequoyah Electric, LLC

Lighting consultant:

WSP Flack+Kurtz

Specialist consultant:

SiteWorksop LLC , Lane Coburn & Associates, LLC , Studio SC , Lerch Bates , Rolf Jensen & Associates , Tuazon Engineering , Hart Crowser & Associates, Inc , WSP Flack+ Kurtz

Structural Engineer:

KPFF Consulting Engineers

Sustainability consultant:

Built Ecology



Sellen Construction



Thumbnail Taekwang Green Office

Subang, West Java, Indonesia | 2014

Taekwang Green Office

PT. Indonesia Environment Consultant

Offices | LEED v3 BD+C (New Construction)

Thumbnail TNT Centre

Hoofddorp, The Netherlands | 2011

TNT Centre

Paul De Ruiter Architects | Paul de Ruiter Architects

Offices | LEED v2.2 NC

Thumbnail VeluxLab

Milan, Italy | 2013




Thumbnail La Serenissima Office Building

Via Filippo Turati, 25, 20121 Milano, Italia | 2012

La Serenissima Office Building

Park Associati (Filippo Pagliani, Michele Rossi) | Park Associati

Offices | LEED v3 BD+C (Core & Shell)

Thumbnail Energy Park - Building 03

Via Energy Park, 20871 Torri Bianche MB, Italy | 2009

Energy Park - Building 03

Garretti Associati | Garretti Associati Srl

Offices | LEED v2.0 CS

Thumbnail Bullitt Center

Seattle, WA, USA | 2012

Bullitt Center

The Miller Hull Partnership | Bullitt Center Foundation


Thumbnail Ardeko

Boulogne-Billancourt, France | 2013


Baumschlager Eberle

Offices | LEED v3 BD+C (Core & Shell)

Thumbnail Isozaki Tower

Milano, Italia | 2013

Isozaki Tower

Arata Isozaki and Andrea Maffei | Manens-Tifs

Offices | LEED v3 BD+C (Core & Shell)

Thumbnail IBN Institute

Wageningen, The Netherlands | 1998

IBN Institute

Behnisch Architekten


Thumbnail Genzyme Center

Cambridge, MA, USA | 2004

Genzyme Center

Behnisch Architekten

Offices | LEED v2.2 NC

Thumbnail Foundry

London N1 7RU, UK | 2012


Cullinan Studio

Offices | BREEAM 2008 UK Offices

Thumbnail One Angel Square

Manchester, Manchester, UK | 2012

One Angel Square


Offices | BREEAM 2008 UK Offices

Thumbnail Brussels Environment

Brussels, Belgium | 2014

Brussels Environment

cepezed architects

Offices | BREEAM International New Construction 2013

Thumbnail Pearl River Tower

Guangzhou, Guangdong, China | 2013

Pearl River Tower

Skidmore, Owings & Merrill LLP

Offices | LEED v3 BD+C (Core & Shell)

Thumbnail Geelen Counterflow

6081 Haelen, Netherlands | 2015

Geelen Counterflow


Offices | BREEAM New Construction 2011 (UK)

Thumbnail 1200 Intrepid

Philadelphia, PA, USA | 2016

1200 Intrepid

BIG Bjarke Ingels Group

Offices | LEED v3 BD+C (Core & Shell)

Thumbnail Goito58

Rome, Italy | 2012


Chapman Taylor

Offices | LEED v3 BD+C (Core & Shell) | BREEAM 2015 International In-Use

Thumbnail One Carter Lane

1 Carter Ln, London EC4V 5ER, UK | 2015

One Carter Lane

Studio Ben Allen | Cundall .

Offices | BREEAM 2014 UK Refurbishment and Fit-Out | ITACA New and Existing Interiors v1


Via Umberto Forti, 1, 56121 Montacchiello PI, Italia | 2016

"Umberto Forti" Headquarters

ATIproject S.r.l.

Offices | LEED v4 BD+C (New Construction)

Thumbnail Prysmian HQ

Milan, Metropolitan City of Milan, Italy | 2017

Prysmian HQ

Maurizio Varratta Architects | DEGW .

Offices | LEED v3 BD+C (New Construction)

Thumbnail Engie Headquarters

Via Chiese, 72, 20126 Milano MI, Italia | 2018

Engie Headquarters

Park Associati (Filippo Pagliani, Michele Rossi) | Park Associati

Offices | LEED v4 BD+C (Core & Shell)

Thumbnail Diamond Tower - Porta Nuova Varesine

Viale della Liberazione, 20124 Milano MI, Italia | 2017

Diamond Tower - Porta Nuova Varesine

Proger s.p.a | GreeningLab Specialist in Green Building

Offices | LEED v3 ID+C (Commercial Interiors)

Thumbnail Edificio Uffici - Bernina

Via Bernina, 12, 20159 Milano MI, Italia | 2012

Edificio Uffici - Bernina

RED s.c.r.l. | GreeningLab Specialist in Green Building

Offices | LEED v3 BD+C (Core & Shell)

Thumbnail NOI Techpark

Via Alessandro Volta, 13, 39100 Bolzano BZ, Italia | 2017

NOI Techpark

Chapman Taylor

Offices | LEED v4 ND (Neighborhood Development)