Refers to a new, 1000-bed teaching hospital in the Netherlands sue to be completed around the year 2000. Nine atria will cover the pedestrian areas. The atria are neither heated nor mechanically ventilated. Smoke extract openings in the roof are used to provide natural ventilation. Notes measurements carried out in the first atrium, completed in 1988 and computer simulations to help determine air movement (if any) between the atria, which will be linked by pedestrian walkways. Describes the environment created using the original design data, measured results, experiences of the users and computer simulations.

KEYWORDS: Hospitals, case studies, Netherlands, atria, air flow, measuring, calculating, ventilation, natural ventilation, smoke ventilation.