Naples Community Hospital ORs to Become Safer, More Comfortable, and More Energy Efficient
September 11, 2014 | Jim Pretz, Managing Principal & CEO
Fosdick & Hilmer has been retained by Columbus, OH based energy developer Plugsmart to engineer upgrades to the HVAC systems that serve the operating suite at Naples Community Hospital (NCH) in Naples, FL. The existing HVAC systems that serve the NCH Operating Rooms (ORs) are quite old; they largely utilize 100% outdoor air; and energy recovery systems that were originally installed have long since stopped working. In addition, supply and return air distribution to the ORs date back to a time that precedes the advent of low velocity, laminar flow air delivery (with diagonally opposed low returns) that is the current state-of-the-art. Finally, the existing system, like so many older systems in OR suites, does not incorporate individual room control of return air volume; so total air flow through the rooms is not reduced during unoccupied times, because the required positive pressure in the rooms at reduced supply air flow cannot currently be maintained.
F&H engineers, Alex Lukashevich and Jim Pretz travelled to Naples to view the existing conditions, and they devised a plan for installing new air handling equipment on an adjacent roof and then doing phased connections of the ORs to the new air handlers in a way that minimizes outage time in the ORs. Similarly, air distribution modifications are designed such that only one room has to be out-of-service at any given time. Mid-way through design, NCH announced that it is considering major renovations in the OR suite and, therefore, wanted to scale the current phase of HVAC renovation to include only a portion of the suite. F&H engineers rapidly revised the design to a scaled down version that retains the original concepts, reduces the capital cost, and retains the ability to go “full scale” when planning for the OR suite is complete.
The OR HVAC system, when fully implemented, will utilize redundant, roof mounted air handlers that incorporate enclosed and conditioned service corridors to house piping, controls, and electric power equipment. The air handling units will house modular, redundant, variable capacity supply and return fans, cooling coils, humidifiers (yes, they are sometimes necessary in Florida), and primary and final filters. Each OR will be equipped with ceiling mounted laminar flow supply air diffusers over the operating field and low, in-wall return grilles in diagonally opposite corners of the OR. A separate supply and return air terminal box that incorporates variable air volume and terminal reheat will be provided for each OR. Differential pressure controls between each OR and the adjacent corridors will interface with the terminal box controls so that the ORs will remain under positive pressure under all conditions of air flow. An OR control system that is integrated with the hospital’s building automation system will control the air handlers and terminal boxes and will incorporate properly located, precision instrumentation for temperature, humidity, and differential pressure control.
By returning conditioned air to the air handling units and enabling reduced air flow when the rooms are unoccupied, the new system will save significant energy/cost at NCH. And the improved air distribution and temperature control will enhance infection control efforts while improving comfort for the surgeons and nurses in the OR.