Thursday, April 23, 2009
K-STATE ARCHITECT STUDIES ENERGY-EFFICIENT DESIGN OF A CHICAGO BUILDING STYLE FROM THE EARLY 1900S
MANHATTAN -- A Chicago architect who is a visiting assistant professor at Kansas State University is introducing his design students to a concept whose time may have come again in urban architecture: windows that can be opened for passive or natural ventilation.
Richard Gnat teaches about an architecture style historic to Chicago -- the courtyard apartment building, a low-rise multifamily dwelling built primarily between 1890 and 1930 and originally in response to tenement housing reforms.
At the time of their construction, every occupied room in a tenement building including bathrooms and kitchens was required by code to have at least one exterior window that opened directly upon a street, alley, yard or court. This requirement was well suited to passive ventilation design, Gnat said.
"As energy becomes more expensive, the advantage of passive ventilation inherent in these pre-air conditioning designs becomes apparent," he said.
Air conditioning was not widely available until after World War II, so buildings were planned to allow for cross-ventilation in every apartment, a feature seldom achieved in modern multiunit housing design, he said.
"As air conditioning gained popularity it became possible to ignore passive ventilation and lighting strategies, and, as a result, building footprints became wider and larger," Gnat said. "We either compromised or lost altogether the potential for passive ventilation and lighting. Instead, we imagined new technologies and used them in ways that allow the average homeowner to realize a complete and artificial climate within their home, regardless of the local climate or season.
"I'm not saying we should begin to build without air conditioning," Gnat said. "I do think, however, that as designers we ought to design buildings that allow for the possibility of natural ventilation when the weather permits and give people the option to not use air conditioning."
After two decades of interest in this architecture style, Gnat has identified more than 25 variants of the courtyard building type, neatly integrated into a striking array of urban conditions. He said more than 1,000 courtyard buildings dot the urban and suburban Chicago landscape, and that if you fly into the city you can spot them from the air -- they resemble the letters "C," "S" or "Z."
The buildings are characterized by their wide courts, shallow building width and low height. Typically, the buildings are three stories high and contain about 24 one- to three-bedroom apartments. The largest courtyard building Gnat has indentified so far has 78 units. Residents enter their homes from the street through a semipublic outside landscaped green space, lawn or court. Today, the buildings remain popular as rental units with Chicago's young professionals, and a number of buildings have been converted to condominiums.
Gnat has presented his studies of the Chicago courtyard buildings as a model for sustainable design. He gave the paper "Chicago Courtyard Apartment Buildings: A Type/Varient Analysis" at a conference in late 2008, and the poster "Looking Backward in Order to Move Forward" at the recent K-State Sustainability Conference.
Gnat is a Leadership in Energy and Environmental Design accredited professional, and a city of Chicago registered energy professional. He teaches both studio and seminar courses at K-State.
With regard to sustainability, the 1902 Chicago building code for ventilation -- intended to improve multiunit housing sanitation for the poor -- is, in some ways, more progressive than today's ventilation code, Gnat said.
"The required ventilation was achieved passively and did not require the energy consumption of active mechanical ventilation systems," he said.
The requirement that every occupied room have at least one exterior window that opens directly upon a street, alley, yard or court was spelled out in detail about the design of windows, including size, height and manner of operation, Gnat said. For example, the top half of a window was to be not less than 7 feet above the floor; the upper half was to open to its full width. Such design facilitated passive ventilation and made it possible to use natural convection to vent the room, he said.
Energy efficient building design begins, for an architect, at what Gnat calls the planning stage.
"There's a process to creating a building, and I think the planning stage is critical for making energy use or sustainability considerations, he said. "That's what a designer considers: is this design going to be the most energy efficient one I can create? When a building is not properly planned, it's not enough to think that a fairly new building can be retrofitted for energy efficiency and that makes it sustainable."
Gnat thinks the Chicago courtyard style is an appropriate, sustainable precedent for multiunit housing projects designed in the future. "My conclusion is that, with regard to integrating passive ventilation and lighting strategies for mid-rise, multiunit housing, we reached the height of such planning more than 70 years ago with courtyard buildings," he said.Gnat hopes that aspiring architects will consider giving people who live in multiunit apartment buildings the options and opportunities to refrain from using energy. That's his working definition of sustainability: to have choices, including not consuming any energy when possible.