Operating Room Airflow and Pressurization at McLaren Macomb
- Resolute Team
- Jun 4, 2021
- 3 min read
A Look Back at a 2020 Phoenix Controls Case Study
Operating rooms depend on careful coordination between airflow, room pressure, ventilation, temperature, humidity, and room use. When those conditions drift from their intended operation, the visible issue may be only one part of a larger system-performance problem.
Published in September 2020, a Phoenix Controls case study documented how McLaren Macomb Surgery Center used building-system data and new airflow-control equipment to improve operating-room airflow and pressurization.
The Challenge: Airflow and Pressurization
McLaren Macomb Surgery Center was experiencing concerns with operating-room pressurization and air-change rates.
Resolute Building Intelligence reviewed the available building data and identified fluctuation and drift in the existing Variable Air Volume boxes. Based on that analysis, airflow was estimated at approximately 40–50 air changes per hour under some conditions.
The project documentation referenced a target of 20 air changes per hour while the rooms were in surgery mode. The estimated airflow levels indicated an opportunity to improve control while reducing unnecessary HVAC demand.
Understanding Actual Operating Conditions
The issue was not simply whether the HVAC equipment was operating. The larger question was whether airflow and pressurization were being maintained consistently as room conditions and operating modes changed.
Resolute provided visibility into several areas of system performance:
Air-change rates
Airflow fluctuation
Room pressurization
VAV performance
Occupied and unoccupied operation
This information helped the project team compare actual operating conditions with the intended performance of the operating rooms.
Supporting Tighter Airflow Control
Resolute and the project team selected Phoenix Controls venturi valves for the supply and exhaust airflow.
The project also included room monitors and external touchscreens displaying temperature, humidity, occupancy, air-change rates, and room pressure. Staff could place each room into surgery or unoccupied mode based on its use.
When a room was placed into unoccupied mode, the airflow setting could decrease from 20 to 10 air changes per hour. This reduced airflow demand while maintaining controlled operating conditions within the space.
Project Results
The installation was originally expected to take five weeks. Resolute and the contractor teams completed the project in approximately two weeks during the 2020 pandemic shutdown.
Once the system was operational, staff reported more consistent air-change rates and improved visibility into temperature, airflow, pressure, and other room-performance indicators.
Reducing airflow from 20 to 10 air changes during unoccupied periods decreased airflow by half. Based on a rough estimate developed at the time, Resolute identified approximately $250,000 in potential annual operating-cost savings for the Surgery Center. The original case study presented this amount as an estimate rather than verified realized savings.
Why This Example Still Matters
Although the project was completed in 2020, the operational lesson remains relevant.
Critical-space HVAC performance cannot always be evaluated from equipment status alone. Trend data can help facility teams determine whether airflow, pressure, equipment operation, and room schedules are working together as intended.
The McLaren Macomb project demonstrates how building data can support:
A clearer understanding of operating-room performance
More consistent airflow and pressure control
Informed controls and equipment decisions
Reduced unnecessary HVAC operation
Verification of occupied and unoccupied strategies
Resolute connects to existing building systems and organizes operational data to help healthcare facility teams evaluate actual performance across critical spaces, equipment, buildings, and portfolios.
Frequently Asked Questions
What problem was McLaren Macomb experiencing?
The Surgery Center was experiencing concerns with operating-room pressurization and air-change rates. The existing VAV boxes were fluctuating and drifting, making consistent airflow control difficult.
What did Resolute identify?
Resolute’s analysis indicated that airflow may have reached approximately 40–50 air changes per hour under some conditions, compared with the 20-air-change surgery-mode target referenced in the 2020 project documentation.
What equipment was installed?
Phoenix Controls venturi valves were installed for supply and exhaust airflow. The project also included room monitors and touchscreens displaying pressure, temperature, humidity, occupancy, and air-change information.
How did the unoccupied strategy reduce HVAC demand?
The system allowed airflow to decrease from 20 air changes per hour in surgery mode to 10 air changes per hour while the rooms were unoccupied, reducing the amount of air that needed to be moved and conditioned.
Read the Original Case Study
Read the complete project story from Phoenix Controls and Honeywell Building Automation.
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