August 27, 2026
What 20 Years Inside a Hospital Actually Teaches You
Insights from Casey Wilson PE, LEED AP, Associate VP, Assistant Building Services Unit Leader
The operating rooms at Memorial Hospital Belleville are vital to the day-to-day operations of the facility. So when the 40-year-old air handler serving 11 operating rooms reached the end of its life, we had a challenge: replace it and don’t take a single room offline. We did it in four phases. Zero rooms dark.
But the reason we were the team trusted to pull that off starts long before the air handler.
Most engineers inherit a project. We inherited a relationship. That changes everything about how you show up.
I’ve been walking the halls of Memorial Hospital Belleville since I joined Horner & Shifrin in 2014. But the firm’s relationship with that campus goes back well before me. I inherited it from my predecessor Brian Heideman, a mechanical engineer who had spent years building trust with the facilities team there. Brian’s personal connection to Memorial dated back to 1981, and his father’s went back even further, to 1962. When Brian retired, I stepped into something that had already been earned. My job was to keep earning it. That’s the only way relationships like this survive.
A Hospital Built in the 1950s Doesn’t Stop Needing Engineers
Memorial Hospital Belleville opened in 1958. The infrastructure that keeps it running: the chillers, the air handlers, the piping, the controls — has been replaced, upgraded, and replaced again over the decades.
Our projects align with the hospital’s master plan and infrastructure assessments, focusing on minimizing operational disruption and delivering maintainable, energy-efficient solutions. When challenges arise, how we respond matters just as much as the design.
How we handle the tough situations is how we’ve built trust… It’s not an easy situation to be in, but I think it’s how you handle those situations and work as a team to resolve it.
Innovation and agility are important, but lasting relationships are built on trust and reliability. That trust develops over time, 20 years in the case of Memorial, built by understanding the hospital’s needs, navigating challenges together, and consistently being there when it matters.
Knowing the Building Before the Project Starts
One of the things I hear from facilities managers at other hospitals is how much time and money gets spent just getting a new engineer up to speed. Where are the drawings? What was changed in the last renovation? What’s actually in the ceiling above that corridor?
About 10 years ago, we recommended that Memorial scan and digitize its entire physical drawing archive. Every plan in the plan room, converted to a digital format. Today, it saves real money on every project we do there.
They’ll call me and ask me for plans… just because I’ve been looking through them for the past 12 plus years, I know where to go.
More recently, our Survey & Geospatial team scanned the roof, power plant, tunnels, and equipment rooms, giving the facilities team an accurate digital record of existing conditions across the campus.
That institutional knowledge compounds over time. When we start a new project at Memorial, we’re not recreating as-built conditions from scratch. We already know what’s there. That means faster design, fewer surprises in the field, and lower fees for the client.
Keeping 11 Operating Rooms Running While Replacing Their Air Handler
When the 40-year-old air handler serving the operating room suite reached the end of its life, we had to replace it without taking a single room offline for more than a planned, minimal window. The existing unit couldn’t meet the temperature and humidity requirements the operating rooms needed. We designed a new air handler using fan wall technology, a dedicated glycol chiller for precise air temperature and humidity control, supply air temperature reset, and economizer operation for improved energy efficiency. Then we designed the project for four separate phases of construction, so the operating rooms stayed safe for patients and operational throughout.
It’s the kind of project that looks straightforward on paper and is genuinely complex in execution. The contractor has to sequence work around active surgical schedules. Every phase has to be coordinated with the facilities team and clinical staff.
Replacing a hospital’s mechanical systems while it stays fully operational is, in its own way, surgery on the building that performs surgery.
Designing for the Next Pandemic During the Last One
The Intensive Care Unit (ICU) renovation at Memorial began in September 2021 — during the COVID-19 pandemic. What the pandemic was exposing about hospital infrastructure in real time shaped every decision we made.
The renovation converted a former labor, delivery, and nursery unit into a modern 20-bed intensive care unit. The space had extremely tight floor-to-floor heights — fitting new ductwork, piping, and electrical infrastructure above the ceiling required careful coordination across every discipline.
But the detail we’re most proud of is something we built into the design in direct response to what COVID was teaching the industry and the world about infection control. We designed each patient room to switch between neutral and negative pressure through the building automation system. Negative pressure rooms pull air inward rather than outward, preventing airborne contaminants from escaping into adjacent spaces — a critical control for infectious disease isolation. Facilities staff can reconfigure the rooms for negative pressure without a construction project. The hospital is ready for whatever comes next.
Our work impacts the facility. We’re part of that patient care in a different way. And that’s something really cool to be a part of.
What I Tell Junior Engineers on Their First Hospital Site Visit
When I bring newer engineers into a health care project, the first thing I tell them is to step back before they start designing anything.
A project doesn’t exist in a vacuum. The air handler we’re replacing is connected to a controls system that’s connected to a maintenance schedule that’s connected to a budget cycle. If you don’t understand the full picture, you’ll solve the wrong problem.
That’s what 20 years of relationship-based work teaches you. The engineering is the easy part. Understanding the facility, and the people who run it, is what makes the difference.
I’ve worked in those operating rooms — and my family member had surgery in one of them. When you’re fixing the systems that serve that room and you realize someone you love has been in there … that’s pretty neat.
The work we do inside hospitals isn’t abstract. It affects real people. That’s worth remembering every time we walk through those doors. Every campus has its own history, its own systems, its own people. The work is never generic. Neither is the relationship.
Casey Wilson, PE, LEED AP, is Associate Vice President and Assistant Business Unit Leader for Building Systems Engineering at Horner & Shifrin. With more than 18 years of mechanical engineering experience, she leads the firm’s health care and science and technology market sectors, overseeing a practice that spans HVAC system design, infrastructure planning, and comprehensive facility assessments. Her work in active, occupied health care environments spans a wide range of infrastructure, clinical, and facility improvement projects for major health systems throughout the St. Louis region. Casey has been the lead engineer on the Memorial Hospital Belleville campus since 2014, managing a relationship that predates her tenure and now extends across the East Region of BJC Health.