Is Your Particle Capture System Actually Working — or Just Running? Is it capturing particles? Do you need to replace your filter? 

There’s a critical difference between a particle capture system that’s operating and one that’s performing. One protects your process. The good news: verifying which one you have is straightforward.

In the latest Ask Dr. Static video, Stephen walks through one of the most overlooked variables in particle capture system performance: face velocity. Specifically, why a minimum of 170 ft/min (fpm) is the threshold that separates a system that’s genuinely capturing particles from one that’s giving you false confidence.

Face velocity — the speed of air moving across the intake surface of your capture system — determines whether contaminants are actually being pulled in and removed, or simply passing by. If you don’t have at least 170 fpm at the face of your particle capture unit, you’re at risk of what’s known as “bounce back.”

Bounce back occurs when the item being blown off doesn’t get captured — instead, the insufficient draw allows particles to rebound back onto your clean products or clean area. It’s one of those failure modes that’s easy to miss because the system appears to be running normally. The face velocity simply has to be sufficient to capture the particles before they can escape. At 170 fpm or above, you hit the minimum performance threshold for reliable capture.

Stephen demonstrates two practical ways to verify your system is hitting that mark: a visual capture test using a physical indicator to confirm draw, and an anemometer measurement to get an exact fpm reading at the face. Both can be performed in-house — no specialized lab equipment required.

If you’re relying on your particle capture system to protect a cleanroom, semiconductor process, medical device assembly line, or any other contamination-sensitive application, knowing your face velocity isn’t optional. It’s the baseline measurement that tells you whether your system is actually doing its job.

Watch the full video here:    If you can’t measure it, you can’t manage it.