Guide
Cleanroom ventilation – air changes, HEPA filters and pressure cascade
Ventilation is the engine of a cleanroom. It decides which class you can hold, how much energy the facility consumes and how quickly the room recovers after a disturbance.
HEPA filters and filtration
Cleanroom air is filtered through HEPA filters that capture at least 99.95 percent of particles in the most penetrating size. Filters sit in the ceiling as close to the critical process as possible, usually with pre-filters in the air handling unit to extend their life.
Air changes per cleanroom class
The number of air changes per hour is driven by the class. Industry guidance lands around 240–480 changes for ISO class 5, 50–150 for class 7 and 10–25 for class 8. Correct sizing is the difference between a facility that passes validation and one that does not.
Too many air changes means unnecessary energy use and noise.
Too few means the room will not recover within the required time.
Supply and extract placement matters as much as the volume itself.
Pressure cascade and airlocks
Positive pressure against the surroundings keeps dirty air out. We size pressure differentials between zones and airlocks so that air always moves from cleaner to less clean – or the reverse when hazardous substances are handled.
Energy-efficient operation
EC fans, demand-controlled operation and night setback can cut running costs sharply without affecting the cleanliness class. We choose the solution based on how the facility is actually used, not on peak load around the clock.
Want a review of your cleanroom ventilation?
We look at existing flows, filters and pressure conditions and propose measures – no matter who built the cleanroom.