If you work around cleanrooms, pharmacies, hospitals, laboratories, or biological safety cabinets, you’ve probably heard the phrase: “The HEPA filters passed integrity testing.” But what does that actually mean? For many people, HEPA leak testing feels a little mysterious. A technician wheels in equipment, introduces some kind of fog or aerosol into the system, scans the filters with a probe, and eventually places a certification sticker on the equipment or room. To the avera

If you’ve ever watched a technician roll into your cleanroom with what looks like a high-tech suitcase on wheels and start “vacuuming the air,” you might’ve wondered: Are they cleaning? Measuring? Hunting invisible dust gremlins? The answer is: yes… kind of. They’re performing a non-viable particle count , one of the most important (and most misunderstood) tests in cleanroom certification and monitoring. And despite the intimidating name, the concept is actually pretty simple

When containment is compromised: what puff-back testing reveals inside a B2 cabinet. If you’ve ever been told your Type B2 Biological Safety Cabinet needs “puff-back testing,” your first reaction might be: “That sounds serious… but also… what is that?” You’re not alone. Puff-back testing is one of the most misunderstood (and honestly, poorly named) tests in the controlled environment world. But once you understand it, it becomes one of the most important safety concepts to g