Case study: Hospital pivots to adjust for COVID-19
For the Parkview Regional Medical Center Core Tower expansion, engineers were able to modify design to accommodate COVID-19 patients as the project was in progress
As COVID-19 began to loom in early spring 2020, the executive team at Parkview Health in Fort Wayne, Ind., quickly started to evaluate how to handle both the upcoming surge while also preparing for more permanent solutions systemwide. An active construction project on the Parkview Regional Medical Center campus was midconstruction, and included a horizontal patient tower expansion that was a prime candidate for consideration.
This new 165,000-square-foot expansion project will house 72 new patient beds with the ability to further expand to 143 total beds. Included within the project is a patient tower finish-out of the top floors, with the bottom three floors being shelled. The new tower is connected to a 900,000-square-foot existing tower that was completed in 2012. Design started on the Core Tower expansion project in 2018 and included a phased turnover per floor with the first phase, the top floor — Level 06 — which opened in September 2020.
Included within the mechanical design are two large air handling unit systems, enclosed within a penthouse. General and isolation exhaust systems stack throughout the tower to carry exhaust to discharge at the exterior. These air systems distribute to multiple floors, which lends itself to an efficient design, with equipment housed in one location and built in redundancies in all the equipment. It also allows for the floor plates to be maximized for patient care and all preventive maintenance to occur on the top floor.
When evaluating the needs of the facility to identify the most optimal location to isolate COVID-19 patients, it was determined that the top floor would be the most appropriate choice. Although all of the overhead systems were nearly complete, the design and construction team worked swiftly to evaluate how to accommodate the future floor to be adjusted to function either as a normal med/surg patient floor or as a COVID-19 unit. Although it was a complicated endeavor, the existing design was flexible, which limited the need for major changes to the building system infrastructure.
Based on the flexibility of the design and air distribution systems, a few motorized dampers were added to the return system and the airstreams were intercepted with new ductwork, dampers and exhaust fans to allow the air to be fully exhausted to the exterior. Permanent pressure monitors were specified at each patient room to indicate that the pressure relationship is maintained and additional door sweeps were added so the rooms could maintain a negative pressure range of 0.01 to 0.03 inches water column. This negative pressure relationship is achieved through an airflow offset between supply air and exhaust air, similar to an airborne isolation room.
Although air valves at each space were considered to allow for a more automated means to switch between the pressure relationship, they were not feasible given the state of construction and already installed mechanical systems. Therefore, a manual pre/post balance is required when switching between modes to ensure the correct code required airflows and pressure relationships are maintained.
Utility vent set fans were specified with bag-in/bag-out high-efficiency particulate air filtration to protect personnel when maintaining the fan systems or equipment nearby. Special line-of-sight studies were performed by the architect to ensure that the additional equipment views were minimized. In addition to the Level 06 modifications, provisions were made including dedicated exhaust shafts with new ductwork and exhaust fans, which will allow Level 03 to be designed as a pandemic floor when the build out occurs. Air valves will be considered in this buildout to allow for easier switch ability between the modes (see Figure 3).
When evaluating the air balance of Level 06, careful consideration was given to how to correctly pressurize each space and what rebalances of the overall AHU system would be required to ensure that the correct amount of outside air is introduced to the air system to maintain an overall positive building. The floor was designed to be slightly negative in relation to the adjacent existing tower with extra monitoring provided to indicate the relationship at the suite entrance.
Evaluation of the equipment components was completed to ensure that the base equipment could handle the additional outside air load and achieve the airflow rates required and no major modifications were required to the AHUs or building infrastructure.