Women’s & Children’s Hospital AHU-12 Replacement

The University of Missouri operated Women’s and Children’s Hospital is Missouri’s leading hospital offering the most comprehensive healthcare to women and children. To ensure that their facility was running at peak capability, the University sought to replace the 40-year-old Air Handling Unit (AHU) 12 which serves Operating Rooms 5 through 10. Additionally, the university sought to install return air terminal units in the zones served by AHU-12 to ensure pressure relationship control and adequate airflow. While the project began as a simple AHU replacement, the scope of the project was modified to accommodate a revised temperature and humidity mandate established by the University after the start of the project. McClure Engineering reviewed Master Plan details with the University to confirm the scope of the project was in line with the long-term plans for the portions of the building that would be included in the renovation.

Performing a system replacement in a healthcare environment proved challenging since systems are within active facilities that have a limited ability for a shutdown. To ensure the minimal amount of shut-downs and outages for utilities and systems during construction activities, the project was sequenced into 6 phases.

Phase 1: The first phase included the installation of a temporary AHU above the existing penthouse to keep the surgery suite active during the project.

Phase 2: After the temporary AHU unit was running, the old unit was disabled and removed.

Phase 3: The new AHU-12 was then installed in the penthouse. At the end of this phase, there was a brief shutdown after hours to tie the new unit back into the existing ductwork to the surgery suite and take the temporary unit offline. At this point, the new unit was able to serve the existing spaces with the operating room temperatures temporarily limited to 72°f-75°f. The new unit was then tested by Testing and Balancing Contractor Dynamic Air Solutions for total airflow and all operating rooms were then certified. Power was fed to the new AHU -12 VFD via a 100amp breaker to replace the existing 40amp breaker previously feeding the old unit.

Phase 4: Once the new unit was working, the temporary unit was removed along with the duct connections required in the penthouse to tie the new AHU-12 into the surgery suite.

Phase 5: After the temporary unit was removed, the new ventilation unit was installed in its place. At the end of this phase, there was another brief shutdown after hours to tie the new ventilation unit ductwork into the new AHU-12 in the penthouse. After this point, the operating room temperatures were set at the design specifications of 65°f-75°f. The new ventilation unit was then tested by Testing and Balancing Contractor Dynamic Air Solutions. The 100amp breaker serving the temporary unit was then replaced with a new 30amp breaker to feed the new ventilation unit.

Phase 6: Once the new units were installed, several return VAV boxes were installed on the 2nd floor. Each operating room was then certified after the associated return box installation. This certification included verification of both pressures and air changes in the operating room. Two exhaust fans were also replaced. Only one operating room was completed at a time, requiring additional after-hours coordination. Once the replacement was complete, McClure’s Commissioning team started the process of conducting installation verification of the new systems. Additionally, the Commissioning team conducted training with the owner, introducing the facility operators to the general design intent and operation of the new systems and fielding questions about the operation and performance of the system during a turnover to ensure that the operators felt comfortable with the new equipment. A warranty walk-through was then conducted after the completion of the commissioning activities.