Architecture Firm:
Ruffcorn Mott Hinthorne Stine
Completion Date:
November 2007
Project Format (not yet built / built):
Built
Project Size (sf / site acreage):
169,603 s.f./0.81 acres
Project Location:
909 Fifth Avenue, Seattle, WA
Interior Designer:
Craig Norman/DH Design/Ruffcorn Mott Hinthorne Stine
General Contractor:
Turner Construction
Landscape Designer:
Phillips Farevaag Smallenberg
Lighting Consultant:
Flack & Kurtz
Structural Engineer:
Magnusson Klemencic Associates
Mechanical Engineer:
Hermanson
Electrical Engineer:
Gerber Engineering
Commissioning Agent:
Flack & Kurtz
Air Quality Consultant:
Ecotope
Civil Engineer:
Magnusson Klemencic Associates
Other:
Brightworks, Sustainability Consultant
Owner:
Beacon Capital/Kennedy Wilson
Sustainable Sites:
This full block downtown Seattle site is bounded by 4th and 5th Avenues and Madison and Marion Streets. The south half of the site is occupied by the 41-story Union Bank of California Tower completed in 1973 and is connected to a 2 story retail/office structure with roof plaza located on the northwest quadrant. A drive-up bank teller station formerly occupied the northeast quadrant. A seven-level parking garage exists below the east half of the property. The previous north plaza area consisted of over 30,000 s.f. of concrete impervious surfaces.
Fifth and Madison is a new 24-story, 126-unit condominium tower with ground level retail. The new tower is located on the northeast corner of the site, along 5th Avenue and Madison Street in order to maximize access to light and air between the new tower and the existing office tower. The roof area not occupied by the new tower was redeveloped into a public urban plaza that is predominantly native/adaptive landscaped and accessible from both 5th Avenue and the adjacent existing office tower.
The development team regarded the property as an opportunity to integrate sustainable practices into the rehabilitation and operation of an entire city block including the re-positioning in the marketplace of the existing 1973 41-story office tower, the creation of a sustainable 24-story housing project in the urban core, and a connecting public landscaped plaza. Altogether, the property is projected to be the first LEED-Gold full city block in downtown Seattle.
The primary objective for the Owner in further developing the property was to utilize and strengthen the existing infrastructure on the north half of the site to take advantage of the underutilized plaza to create a public green space between the existing tower and the new residential tower. The influence on the design solution manifested itself in two ways.
First, the placement of the new tower was dictated by the location and capacity of the existing concrete garage structural system in order to avoid disrupting automobile circulation, and to minimize the impact on existing parking stalls. New perimeter columns were located to bear on the existing garage perimeter walls, while new interior moment frame columns were aligned with existing garage columns and shear walls.
Secondly, there was an approximately seven foot grade differential between the existing roof plaza in the northwest quadrant and the 5th Avenue frontage. One of the design challenges was to unify the public space while negotiating that grade change. The design solution was to create a sloping plane from 5th Avenue up to the roof plaza that in effect made the grade differential disappear and created an interstitial space where the irrigation cistern is located.
The public plaza includes a water feature that starts at the west parapet above 4th Avenue and cascades in a series of steps to 5th Avenue. The plaza incorporates native and adaptive landscaping and increases the amount of landscaped area by over 200%.
The existing parking garage capacity exceeded the current minimum parking requirements for office space such that the office parking allotment was reduced to the current zoning code minimum while the resulting spaces were dedicated to fulfill the needs of the residential tower. Therefore, the amount of useable area on the property was increased by almost 170,000 square feet without adding any parking.
The development strategy for the property has significantly increased the effective lifespan of the existing 1973 development.
Toward Zero Energy:
The design concept was to create a crystalline tall, skinny tower with floor-to-ceiling glass to maximize views and daylight penetration into the building. The design team strategized from the beginning on how to balance the exterior shell elements and ASHRAE comfort recommendations while maximizing energy efficiency and minimizing the size and complexity of the mechanical system. The mechanical design-build engineer recommended the use of a relatively new hybrid system that combines the efficiency and economy of a heat pump unit with that of a fan coil system. This hybrid unit is a small, water-cooled air conditioner with a hydronic coil for heating. All individual units are connected to a single circulation loop. In cooling mode, the hybrid unit uses its compressor to provide direct expansion cooling and rejects its heat through its water-cooled condenser attached to the circulation loop. During heating, the compressor does not operate and the water from the circulation loop is routed through the hydronic heating coil instead of through the condenser. The circulation loop temperature is controlled based on outside air temperature. As outside air temperature drops, the setpoint temperature of the loop rises and gas-fired boilers are used to raise the water temperature. As outdoor temperature rises, the loop setpoint temperature drops and a fluid cooler is used to remove heat from the loop, maintaining the required lower temperature.
The energy benefits, or innovations, of the hybrid system are:
• Only a single circulation loop is needed to serve units operating in both heating and cooling modes. This reduces energy costs due to the need for only one pumping system compared to two for the fan coil.
• During cooling mode, only the units requiring cooling operate and can function very efficiently, even at higher circulation loop temperatures. In a fan coil system, a larger chiller must be used, operating at very low part-load efficiency during times when only a few units need cooling.
Due to the design response to site conditions, the majority of the vision glazing is located on the north half of the building which in turn resulted in significantly less cooling loads. Operable windows are evenly distributed across the façade to provide natural ventilation.
Local and Sustainable Materials:
The primary materials for the tower are concrete, reinforcing steel, metal studs, gypsum board, aluminum, and glass. All of these materials incorporate recycled materials in their manufacturing, and are also recyclable as construction waste. The contractor achieved 95% recycling of construction waste. In addition, these materials were selected because they are durable and relatively low-maintenance over the life of the building. Nearly two-thirds of the exterior envelope consists of an aluminum unitized curtainwall system that is engineered to respond to differential, thermal, and seismic loads. The remaining one-third consists of aluminum metal panels and multi-colored stainless steel shingles on structural metal stud framing.
Over 17% of the overall costs of materials was expended on materials with post consumer and/or post-industrial recycled content. Over 41% of the materials were manufactured regionally with over 27% also extracted regionally.
All interior doors, the insulation, door casing and floor base, rough carpentry backing, and the cores of the cabinets are all urea-formaldehyde free. The carpets are 100% wool. The specified paints and adhesives and sealants all comply with the low-VOC requirements of Green Standard GS-11.
Sustainable Water:
The design of the new landscaped plaza created a gently sloping public space that extends from 5th Avenue over the roof of the low-rise structure. The supporting structure created an interstitial space large enough to contain a 27,000 gallon cistern. The roof drains from the existing office tower were re-routed to the cistern, along with the roof drains from the new residential tower. The landscaping plant palette, combined with a high efficiency irrigation system at the landscaped plaza, has been balanced with the cistern’s storage capacity to ensure that all of the irrigation requirements will be met from captured rainwater.
All residential units have dual-flush toilets and water efficient shower heads, and bathroom and sink lavatories that achieve water savings of 30% over EPACT code standards. An additional benefit realized by these lower flow fixtures is reduced energy requirements for the lower domestic hot water demand.
IEQ and Comfort:
The residential tower is tall and thin with floor to ceiling windows utilizing high light-transmittance glass. The amount of glazing coupled with narrow floor plates means that interior spaces having expansive views to the exterior and abundant access to natural light meeting 100% of LEED Credits 8.1 and 8.2 requirements.
Perimeter living spaces within each unit have 10’-5” ceilings that are uplit to accent the spacious volumetric nature of the design. With a 7 inch floor slab and a double stud, double layer of gypsum board, acoustically insulated demising wall between units, the acoustic separation provided meets the luxury standards established by the industry. The fire and acoustic seal of the demising and the corridor walls also prevents the passage of cigarette smoke between units and into the corridor.
Operable awning windows, “tilt ‘n turn” windows at Juliet balconies, and sliding glass doors at exterior balconies allow access to fresh air, and help to further minimize the barrier between interior and exterior.
The building incorporates floor to ceiling glass on the north half of the floor plan. The southeast and southwest corners of the building have glass that extends from a raised sill to the ceiling. The center portion of the south façade is opaque as the stairs and elevators are located directly behind it. The majority of the exterior skin consists of a unitized aluminum curtainwall system that is thermally broken. The vision glass is a high-performance low-e insulated unit with a 70% visible light transmittance. The NFRC tested average U-factor for the vision glazing is 0.40.
Materials have been selected to have low volatile organic content and to be formaldehyde-free. During construction, SMACNA best practices were followed by the contracting team to minimize the contamination and mold growth on ductwork, and mechanical equipment was sealed to keep it free of construction dust and debris.
Collective Wisdom and Feedback:
All members of the design team contributed to the sustainable execution of the project in a truly integrated manner. Of particular significance is the balancing of the desire for a high percentage of vision glazing for enhanced daylighting and views while achieving a significant level of energy efficiency when compared to industry standards. Our energy consultant, the design-build mechanical subcontractor, and the curtainwall subcontractor all contributed their expertise in achieving the end solution.
Likewise, creating a site that requires no potable water for irrigation while significantly reducing the impervious surface and heat island effect of the existing plaza relied heavily on the expertise of our landscape architect, our civil engineer, and our sustainability consultant.
The building includes an energy management system that will track the actual energy use by the building systems. Performance of the cistern will be monitored by building maintenance staff as the landscaping is maintained.
Regional/Community Design:
Fifth and Madison added an over 1/3 acre plaza that is open to the public. The project re-energized an existing “tired” building stock and transformed a desolate street frontage in the Seattle Financial District to a vibrant 24/7 community by adding a residential use as well as a public open space. Its refined curtainwall and exterior palette provides an elegant counterpoint to the downtown Seattle Central Library.
Fifth and Madison represents design concepts that have been prevalent in Europe for decades. These concepts include high-density development, work and living spaces in close proximity to each other, shallow floor plates for light penetration both internally and between structures, publicly accessible landscaped areas between structures, and maximizing the use of existing infrastructure. Fifth and Madison illustrates how these principles can be applied in an economically viable manner in today’s marketplace.
