This critical initiative involved the replacement of two existing air handling units servicing the third floor operating rooms and one servicing the third floor patient areas. The crucial element of this project was to safely execute this work without interruption to the operating suites. The design plan included the installation of a third temporary air handling unit that was connected to the existing supply air duct and chilled water system. The unit served as the temporary back-up for both of the existing units scheduled to be replaced. In addition to these installations, the team also added all new chilled water, steam, and condensate piping.