OPEN COURT.

Challenging and changing perceptions of the judicial process, Richard Meier's new courthouse in Phoenix uses glass to bring literal transparency to proceedings.

The new courthouse in Phoenix, Arizona, by Richard Meier & Partners, is contained within an enormous glass box in a desert, where summer temperatures can reach 50[degrees]C. Sandra Day O'Connor United States Courthouse is the largest civic building so far to be cooled by a system of evaporation.

The six-storey building in central Phoenix occupies two blocks between the city's government and business districts, and is one of a series of specially commissioned courthouses in an effort by the US General Services Administration to improve design of civic buildings.

The courthouse centre is taken up by an immense, full-height, rectangular glass atrium. At its heart is a two-storey glass cylinder containing the special proceedings courtroom. Distributed round the rest of the building are 18 courtrooms and public galleries looking back into the atrium and through the glass envelope to distant mountains. The transparency of the building is intended to change perception of the judicial process; and as a grand civic space, the atrium is significant in a city of sprawling suburbs.

Design of the courthouse signifies new interest by the American practice in environmental design. Working closely with environmental engineers, Arup New York, it settled on a passive climate controlled system known as adiabatic cooling, which takes advantage of the hot arid climate. Briefly, hot and dry air drawn into the upper level of the atrium is humidified by high-level misters. As moisture is absorbed, the air stream becomes cooler and denser, sinking to the atrium floor. The atrium is a transitional place and does not need to be fully air conditioned, but by this device, together with others such as shading and natural ventilation, temperature can be maintained at a comfortable level throughout the year.