Cleanroom Air Changes Calculator
ACH and HEPA coverage by ISO class.
Enter your values
Enter the room area in sq ft.
Enter the ceiling height in ft.
Choose one of: ISO 8 (Class 100k), ISO 7 (Class 10k), ISO 6 (Class 1k), ISO 5 (Class 100).
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Air changes
- 60 ACH
- Supply airflow
- 3,600 CFM
- HEPA ceiling coverage
- 15-25%
- Room volume
- 3,600 cu ft
- 2x2 ft HEPA modules at 500 CFM
- 8
Quick answer
Cleanroom air changes rise sharply with class, from about 20 ACH at ISO 8 to several hundred at ISO 5.
CFM = volume x ACH / 60
At a glance
| What it does | ACH and HEPA coverage by ISO class. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Room area, Ceiling height, ISO class |
| Main output | Air changes |
| Formula | CFM = volume x ACH / 60 |
| Cost | Free — no sign-up, no download |
How to use the Cleanroom Air Changes Calculator
- 1Enter room dimensions and target ISO class.
- 2Distribute HEPA modules evenly to hit the coverage percentage.
- 3Hold the room positive to adjacent lower-class spaces.
Inputs explained
- Room area(sq ft)
- Enter the room area in sq ft.
- Ceiling height(ft)
- Enter the ceiling height in ft.
- ISO class
- Choose one of: ISO 8 (Class 100k), ISO 7 (Class 10k), ISO 6 (Class 1k), ISO 5 (Class 100).
Worked example
Using the values the calculator loads with:
Inputs
- Room area400 sq ft
- Ceiling height9 ft
- ISO classISO 7 (Class 10k)
Results
- Air changes60 ACH
- Supply airflow3,600 CFM
- HEPA ceiling coverage15-25%
- Room volume3,600 cu ft
- 2x2 ft HEPA modules at 500 CFM8
Frequently asked questions
Why does class drive airflow so hard?
Cleanliness depends on dilution and sweep — more air changes means particles are removed before they settle.
Unidirectional flow?
ISO 5 and cleaner usually need unidirectional 90 FPM airflow, not just high ACH.
What do I need to enter into the Cleanroom Air Changes Calculator?
Just 3 values: room area, ceiling height, iso class. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Cleanroom Air Changes Calculator work out the answer?
Cleanroom air changes rise sharply with class, from about 20 ACH at ISO 8 to several hundred at ISO 5. It applies the formula CFM = volume x ACH / 60 and shows the working so you can check each step by hand.
Is the Cleanroom Air Changes Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.