October 25, 2007
Harborview expansion has complicated mechanics
By DAVID MALONE
University Mechanical Contractors
University Mechanical Contractors was given the difficult challenge of designing and building mechanical systems for the Ninth & Jefferson Building (NJB), which is under construction near the main entrance to Harborview Medical Center on Seattle’s First Hill.
The NJB will house expanded Harborview outpatient services in orthopedics, spine, neurosciences and sleep disorders, as well as such notable tenants as the King County Medical Examiner, the University of Washington School of Medicine and the Department of Global Health.
We completed the core and shell design of the NJB last spring.
The NJB was originally designed as a five-story building, and was part of a publicly funded expansion of Harborview that included the new Inpatient Expansion Building. Due to an array of complications and budget constraints, the construction of the original NJB stalled after completion of excavation and shoring. It remained in limbo until an alternate plan was developed.
The new plan, headed by developer Wright Runstad & Co., breathed life back into the project and allowed it to move forward again, this time as a 14-story tower. The building is now a public/private partnership financed by 63-20 tax-free bonds.
Wright Runstad’s approach to construction is a collaborative effort between design and construction. The design/build approach to this project, lead by Turner Construction Co. and NBBJ, allowed for a larger and more efficient building than originally planned.
Our role as a design/build partner was to design efficient mechanical systems for the building both in terms of construction cost and operational cost. These systems include heating, ventilation, air conditioning and plumbing. The primary goal of the mechanical design was to provide systems that were flexible and robust enough to accommodate tenants with specialized needs, but also simple enough to serve generic office space.
Our approach to this challenge was to provide a centralized heating and cooling plant serving the entire building with two distinct ventilation systems, each designed to be incorporated into the building architecture.
Cooling and heating systems
The NJB is air conditioned by a chilled water system, which cools the air supplied to the building. High-efficiency, variable-speed chillers are at the heart of the cooling plant, conditioning more than 300,000 square feet of space. The chilled water system will exceed the demanding requirements of the Seattle Energy Code and provide a cooling source that is efficient and easy to operate.
The building will use Seattle Steam to generate hot water, which is in turn pumped throughout the building. During the heating season, hot water will heat the air being supplied to the building. Using hot water as a heat source is more energy-efficient and provides a comfortable environment.
Ventilation and AC systems
The two ventilation systems are separated by their function. The first is designed to serve laboratory and hospital space. It will have high airflow rates, high air-filtration requirements, and all of the air provided will come directly from the outside. That means the air will not get recirculated and will always be fresh. The main reason for this type of system is to provide a clean, safe work environment for the end user.
The second system serves the medical office tower and is delivered by innovative “fan wall” technology. This type of system literally has a wall of small fans supplying the air to the space. These numerous small fans are more efficient than the traditional approach of one or two large fans. The fan wall system also has acoustical benefits.
The medical tower will have higher ventilation rates than a normal office building for improved indoor air quality.
The plumbing system was designed with efficiency in mind as well, with water conservation as a priority. The less water the building uses, the less water is heated and/or put down the drain. The building will use efficient plumbing fixtures throughout, including low-flow faucets and showers, dual-flush toilets and ultra low-flow urinals. Combined, the fixtures will save more than 40 percent of the water used by a typical office building.
The building had one additional challenge complicating its design it will house a number of critical systems for its sister building, the Inpatient Expansion Building. These systems include emergency power, medical air, medical vacuum, oxygen and other medical gases. These systems will have to be functioning a year prior to the completion of the NJB and remain in operation during the remainder of the construction process.
The NJB with its flexible systems, efficient equipment, increased ventilation rates and water-saving plumbing fixtures will take a very sustainable outlook on life. The end result is a building that benefits the users and the environment for years to come. Wright Runstad has further shown its commitment to sustainable design by seeking a LEED silver rating on the project.
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