"It's just 0.01 inches of water column. How important can it really be?" As it turns out, that tiny number may be one of the most important measurements in your entire cleanroom. When people think about contamination control, they usually think about HEPA filters, cleanroom gowns, particle counts, or expensive air handling systems. Rarely does anyone get excited about pressure differentials. Yet pressure differentials are quietly working behind the scenes every second of ever

In cleanrooms, one of the most common airflow terms people hear is ACPH. You may see it in a report, hear it during a certification, or have it listed in a design document. But what does it actually mean? ACPH stands for Air Changes Per Hour. In simple terms, it estimates how many times the total volume of air in a room is replaced, supplied, or exchanged in one hour. If a cleanroom is operating at 30 ACPH, that means the airflow system is supplying enough air to theoreticall

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