THE BASIC PROTOTYPE FOR OFFICE BUILDINGS IN THE UNITED STATES has changed remarkably little in the past half-century. This model has taken an almost adversarial relationship to the environment, sealing the building’s occupants in an airtight box and using massive HVAC systems to blast cold air in the summer and hot air in the winter. * The more we learn about how buildings and their occupants interact, the more we see that this model is a recipe for poor IAQ and less healthy, less productive employees. The required HVAC systems also use massive amounts of energy and create a high percentage of an office building’s carbon-dioxide emissions. San Francisco’s new U.S. Federal Building challenges many such concepts. Designed by Santa Monica, Calif.-based Morphosis, the structure is a model of efficient design principles and uses natural airflow for cooling and ventilation. Its orientation takes advantage of natural daylight for much of the interior. These and other features significantly reduce the structure’s overall energy consumption when compared to conventional commercial buildings in the U.S.
SHARE ALIKE The project began in 2000 and was intended to be a re-examination of generic office patterns. “It’s looking at the function of office space,” says Brandon Welling, Morphosis’ project architect for the U.S. Federal Building. “If you look at the history of architecture in the U.S., there has been little advancement in the design of generic office space since the 1950s. The diagram is for developers to build 15-year buildings as cheaply as possible to house people in the short term and then tear them down to make as much money as quickly as possible.”
Morphosis was approached by the Washington, D.C.-based General Services Administration for the project and sought a different approach. “When you look at the original program for the federal building, it is basically a spec office building,” Welling says. “The only unique thing is that all the tenants are federal agencies.”
Indeed, the building is home to the San Francisco offices of the U.S. Department of Agriculture, U.S. Department of Defense, U.S. Department of Health and Human Services, U.S. Department of Labor, U.S. Office of Personnel Management and U.S. Social Security Administration. The building had to serve many masters.
In a way, it was like working with several owners, each with their own requests and needs. When all the wish lists were lined up, redundancies surfaced. “We started asking questions like, ‘How often do you really use this auditorium? Another agency has the same requirements. Couldn’t you share an auditorium?’ That has a direct translation in the amount of space you build and the resources you use in construction,” Welling recalls.
A HOLISTIC APPROACH Efficiencies like these were important to the design team for a number of reasons. The amount of resources and energy could be decreased in construction and in the operation of the building. There also is a human side to this approach.
“We looked programmatically at the interaction of people who use the building, trying to get federal office workers to communicate with each other better and streamline their efficiencies,” Welling explains. “A pool of resources and shared conference and meeting space helps accomplish that. We took holistic ideas about how people work with each other and created opportunities for social interactions in the lobbies and stairwells.” This is exemplified by the large elevator lobbies throughout the building. A unique aspect of the vertical transportation system is that it uses a dual elevator system, with the majority of elevators only stopping every three floors. Floors between are accessed via large open stairs with oversized landings and views of the city and bay.
Another reason to seek efficiency simply has to do with dollars and cents. The budget for the project, which was the same as for a standard federal office building, was appropriated by Congress and not subject to change. There were no additional funds to make the building environmentally friendly. The design team needed to find ways to meet their goals within the existing budget.
“The way costs shake out for this building are somewhat unique when you apply them to a standard building, but the bottom line is still the same,” Welling says. “The mechanical costs are very low because a large amount of air conditioning has been taken out across the board. However, the façade numbers are somewhat high because we took that money and put it into the shading on the exterior of the building.”
BREATH OF FRESH AIR
One of the most unique aspects of the 605,000square-foot (56205-m2), 18-story federal building is its approach to heating, cooling and lighting. San Francisco’s mean temperature ranges between 44 and 78 F (7 and 26 C) throughout the year, a climate ideal for a naturally ventilated building. “You don’t have to be in an enclosed, hermetically sealed box,” Welling says. “You can use windows and won’t need air conditioning.”
The first five floors use a standard, energy- efficient HVAC system. Above the fifth floor, however, the majority of the building is naturally ventilated. A building automation system, or BAS, controls and monitors the environment in the building, opening and closing windows, vents and sunscreens in response to internal and external temperature conditions. At night, the BAS opens windows to flush out heat buildup, allowing night air to cool the building’s concrete interior.
Lighting also is regulated with a daylight harvesting system, maintaining the same level of light regardless of where the sun is. Electric lights dim and brighten only as needed, saving a great deal of energy. The total energy savings throughout the building are significant. “You have to look at the building holistically,” Welling says. “The extreme efficiency in the upper levels kind of carries the somewhat more typical, albeit efficient, lower levels.” Because the building has not been in operation for a full year, complete energy data is not yet available, but models estimate the building to be 12 to 20 percent above the requirements of California’s Title 24, established by the Sacramento-based California Energy Commission, a standard that is already more stringent than other energy codes in the U.S.
The design team took daylight and wind ventilation into account when orienting the building. “One of the things we realized about the site initially was that there is a very predictable wind pattern,” Welling says. “There are constant high winds coming from the ocean, across the city to the site. We have a large glass façade oriented to take advantage of those winds.”
Orientation also was very important in utilizing the sun for light and temperature control. “The first step in taking air conditioning out of a building is to prevent the heat from entering in the first place,” Welling explains. “The southern façade, which gets most of the sun throughout the day, has an operable perforated metal sunscreen over it. It prevents a lot of the heat gain on the south side of the building, and many of the panels open for views. The north façade has a series of fixed translucent glass fins, also for shading purposes in the late afternoons some months of the year. Much of the building is constructed of reinforced concrete. While there may have been cost advantages relative to schedule to build out of steel, concrete offers benefits to natural temperature control because of its thermal mass. “The concrete in the building uses a high-volume slag replacement,” Welling points out. “That takes half the cement out of the project, which is equivalent [in CO2 reduction] to taking 1,000 cars off the road.”
Using natural ventilation and light also meant an adjustment to the way the building is laid out. “Our ideas of a naturally ventilated building dictated a lot of our space-planning philosophy, which is reversed from a typical developer-driven office building in terms of the way the floor plate is laid out,” Welling says. “It’s a very long, thin floor plate. That is driven by the fact that we want natural-light penetration and cross ventilation. We want air to move in one side of the building and go out the other side.”
This required a shift in traditional thinking. “If you imagine your typical, developer-driven tower, you have a big, square floor plate with a service core in the middle. All the important people are around the outside, with their corner and window offices while all the worker bees are in the middle with no access to light or air,” Welling continues. “Because we have this requirement for cross-ventilation, we essentially reversed that diagram.”
In this building, the enclosed offices and meeting spaces run down the central spine. The walls in these spaces stop short of the ceiling, which allows air to come in one side and go over the top. The outer edge consists of open workspace where staff has access to natural light and air. The concept was a tough sell to managerial types accustomed to a corner office, Welling admits, but the benefits of the idea were clear. “A lot of management staff understood it’s progressive and it makes sense. People will perform better if they are healthier, have views, air and light,” he says. The U.S. Federal Building had its grand opening in July of last year. It was not originally slated for the Washington-based U.S. Green Building Council's LEED certification, but the GSA now is pursuing a LEED Silver rating. For Welling, the main accomplishment is the building itself. He takes pride in its energy savings and the way it creates a healthy, productive workplace for its federal workforce.
“One of the most rewarding things about this project is that it was constructed by the federal government, which is pretty radical when you think about it,” Welling relates. “It was a complex building with a lot of challenges. Our tax dollars constructed this. It’s a building for the American people and the dollars it saves in energy and in worker productivity goes back to the government.”
DEVELOPER / U.S. GENERAL SERVICES ADMINISTRATION, Washington, D.C., www.gsa.gov ¦ LEAD DESIGN ARCHITECT / MORPHOSIS, Santa Monica, Calif., www.morphosis.net ¦ EXECUTIVE ARCHITECT / SMITH GROUP INC., San Francisco, www.smithgroup.com ¦ CONSTRUCTION MANAGEMENT / HUNT CONSTRUCTION GROUP, Scottsdale, Ariz., www.huntconstructiongroup.com ¦ GENERAL CONTRACTOR / DICK-MORGANTI JOINT VENTURE DICK CORP., Pittsburgh, www.dickcorp.com, and THE MORGANTI GROUP, Houston, www.morganti.com ¦ STRUCTURAL, MECHANICAL, ELECTRICAL AND PLUMBING ENGINEER / OVE ARUP AND PARTNERS, Los Angeles, www.arup.com ¦ NATURAL VENTILATION MODELING / LAWRENCE BERKELEY NATIONAL LABORATORY, Berkeley, Calif., www.lbl.gov ¦ LANDSCAPE ARCHITECT / RICHARD HAAG ASSOCIATES INC., Seattle, (206) 325-8119, with JJR, Chicago, www.jjr-us.com ¦ CIVIL ENGINEER / BRIAN KANGAS FOULK, Redwood City, Calif., www.bkf.com ¦ GEOTECHNICAL / GEOMATRIX, Oakland, Calif., www.geomatrix.com ¦ LIGHTING CONSULTANT / HORTON LEES BROGDEN LIGHTING DESIGN INC., Los Angeles, www.hlblighting.com ¦ CURTAINWALL / CURTAIN WALL DESIGN & CONSULTING INC., Dallas, www.cdc-usa.com ¦ COMMISSIONING AGENT / ENOVITY, San Francisco, www.enovity.com ¦ BLAST ENGINEERING / HINMAN CONSULTING ENGINEERS, San Francisco, www.hce.com
MATERIALS AND SOURCES
CUSTOM CLEAR ANODIZED WINDOW WALL / PERMASTEELISA CLADDING TECHNOLOGIES, Windsor, Conn., www.permasteelisausa.com ROOFING / TREMCO ROOFING, Beachwood, Ohio, www.tremcoroofing.com EXTERIOR GLASS GLAZING / VIRACON, Owatonna, Minn., www.viracon.com INTERIOR GLASS GLAZING / OLDCASTLE GLASS, Fremont, Calif., www.oldcastleglass.com LINOLEUM AND ACOUSTICAL CEILINGS / ARMSTRONG, Lancaster, Pa., www.armstrong.com CARPET / INTERFACE INC., Atlanta, www.interfaceinc.com FURNITURE / HERMAN MILLER, Zeeland, Mich., www.hermanmiller.com DOWNLIGHTS / ZUMTOBEL, Highland, N.Y., www.zumtobel.com, and CON-TECH LIGHTING, Northbrook, Ill., www.contechlighting.com PUBLIC CORRIDOR EXPOSED DOWNLIGHTS / DELRAY LIGHTING, Burbank, Calif., www.delraylighting.com LANTERN FIXTURES / LIGHTING SERVICES INC., Stony Point, N.Y., www.lightingservicesinc.com OFFICE TROFFERS / DAY-BRITE LIGHTING, Tupelo, Miss., www.daybritelighting.com EXTERIOR LANTERNS AND STEPLIGHTS / BEGA, Carpinteria, Calif., www.bega-us.com LIGHTING CONTROLS / LUTRON, Coopersburg, Pa., www.lutron.com