Application Note

Calculating Clean Room Cleanliness: How Many FFUs And Lights?

Source: Terra Universal

Terra Universal will certify its cleanrooms to guarantee “as built” compliance with cleanliness standards. What matters, though, is how the cleanroom performs in real world applications—in your application, with your personnel and processing equipment.

The cleanest modular cleanroom incorporates filter/fan units (FFUs) in every 2' x 4' ceiling bay. This near-100% ceiling coverage provides a laminar flow of filtered air to quickly remove contaminants from the cleanroom, meeting Federal Standard 209(E) for Class 10 or Class 1 environment (depending on the filter types selected, HEPA or ULPA).

Most cleanroom facility engineers agree that Class 1 and Class 10 applications require near-100% ceiling coverage, producing a laminar flow of clean air traveling downward at a velocity of about 90 feet/minute (measured 12" below the filter face). This design ensures a positive pressure inside the cleanroom, which blocks the influx of contaminants through leaks in the cleanroom wall or curtain, and guarantees swift removal of particles generated by people or process equipment inside the enclosure.