By David Burks, CxA, CxA+BE, CAPM, BECxP, FMPC
When people walk into a laboratory, they usually notice the finishes first, marveling at the clean lines, glass walls and bright lighting. Such a room might look sleek and controlled, but, in a lab, appearance doesn’t equal performance. Behind the scenes, laboratory spaces are some of the most demanding environments we commission, with concerns that go beyond heating and cooling. We concern ourselves with pressurization, airflow, safety, and protecting both the people inside and the work they’re doing. When something is off—even slightly—it can create risks that aren’t immediately visible…and that’s a problem.
That’s where commissioning (Cx) becomes critical. Our job isn’t just to confirm that systems are running. It’s to verify they’re performing exactly the way they’re intended to perform. And in a lab, “close enough” isn’t good enough.
The Driving Force: Pressurization and Airflow
Two of the most critical contributors to laboratory performance are airflow and pressure relationships. Most lab environments require negative pressure relative to adjacent spaces so that contaminants will stay contained within the lab. However, it doesn’t stop there—the adjacent corridors often need to remain pressure-positive relative to non-lab areas. That layering of pressures is where hidden problems tend to live. While pressure balance affects a wide variety of critical factors in a lab’s performance, I want to focus on a few that can make or break a project.
Fume Hoods and Face Velocity
Take fume hoods, for example. The typical face velocity target is an average of 100 feet per minute, +/- 10%. Set it too low, and fumes can backdraft toward the user. Too high, and you can create turbulence that disrupts containment. Both conditions create an unsafe environment for the user and/or specimen. I’ve seen situations where the exhaust system looked operational on paper, but it wasn’t drawing at the correct face velocity, meaning it wouldn’t protect the person standing in front of it. That’s the difference between a system that’s “on” and a system that’s performing. And it doesn’t stop at the hood. You have to maintain proper exhaust while also controlling temperature and humidity. Those systems are interconnected. Push too hard in one direction, and you can compromise another.
In a typical commercial building, a balancer can do a decent job and the system will function within acceptable tolerances. However, the balancer in a lab needs to operate at a 98–100% level of precision because comfort cooling isn’t the issue. We’re talking about maintaining strict directional airflow to protect people and experiments. Even though temperature and humidity are in range, pressure relationships could still be off—and that’s when problems begin.
Air Distribution: The Hidden Nuance
As we focus our attention on how air moves within the space, we start to see just how important precision can be. There are items in labs—sensitive instruments, tissue samples, research setups—that cannot tolerate direct airflow across them. Even minor air disturbance can distort measurements or contaminate samples, so things like diffuser placement and throw patterns matter even more. So, we often integrate ceiling level distribution systems and specialized perforated diffusers into our designs to control the air movement then we use velgrids and gas tracers to study airflow patterns in detail. Those tools aren’t common in everyday commercial commissioning—but they’re vital in labs.
Even rooms that hold temperature perfectly and maintain humidity in range can have airflow patterns disrupting the work within them, so deeper investigation must be done.
The Exterior Wall Problem
Labs with an exterior wall introduce another level of complexity because they may need positive pressure relative to the outdoors while still maintaining negative pressure to surrounding interior spaces. I’ve encountered labs positioned along an exterior wall with beautiful architectural selling points like natural light and sweeping views, but real engineering problems in the form of pressure control. In short, exterior walls can create ongoing challenges for labs—especially as curtain walls and storefront systems age. If you’re maintaining negative pressure inside a lab, and the exterior wall isn’t truly airtight, you can end up pulling in unconditioned or contaminated air through that wall assembly, making temperature and humidity control unsustainable. Additionally, the pressure relationships can fail between the lab and adjacent spaces because the path of least resistance is through the exterior wall. It’s just a matter of time before system performance degradation exacerbates the issue.
I remember one renovation project in which a non-lab space was converted into a lab along an exterior wall. Maintaining proper pressure relationships became almost insurmountable because that exterior wall was the failing part of the containment barrier. If I were designing a lab from scratch, I’d place it toward the center of the building with isolation corridors. I’d layer the pressure zones, control the air paths deliberately and organize the building around function, not just appearance. After all, function has to win out in laboratory environments.
Three Rules for Success
Over the years, I’ve seen a couple of essential requirements hold true. If you want a lab to perform, three principles matter:
- Establish three-tiered pressure control zones. Layer your pressures intentionally.
- Design and build for airtightness. Standard drywall on metal studs doesn’t automatically create a tight envelope for laboratories.
- Verify everything. Follow the air paths. Measure actual flow. Confirm the distribution matches the design intent.
And, as a bonus, make sure you have the right team. Architects need to understand how layout decisions affect pressure control. Engineers must design clear air pathways. The TAB contractor needs proper tools and calibration. Because in a lab, you can’t afford guesswork, and everyone’s contributions matter.
Fortunately, the commissioning discipline helps uncover the hidden issues before they become emergencies because we test beyond the surface. We simulate failure modes. We study airflow patterns. We verify performance under real operating conditions. We collaborate with our partners across the disciplines to find workable solutions because success in a laboratory space isn’t defined by how it looks, but how it performs—every minute of every day.