Unfortunately, just because a cleanroom looks clean does not always mean it is clean enough or compliant. Since particles and airflow are often far too difficult to see with the eyes alone, several cleanroom testing methods can be employed to help reveal problems with your space. In this article, we’ll define what cleanroom testing is, as well as cover a few common procedures that are used across industries.
What Is Cleanroom Testing?
Cleanroom testing is just what it sounds like. It consists of various methods that measure or verify the performance aspects of a controlled environment. The specific testing you will need for your cleanroom will depend on what your cleanroom is being used for, as well as related industry requirements/regulations, such as GMP, FDA, and ISO.
Cleanroom testing may focus on particles (both viable and non-viable), airflow, filter integrity, pressure, and more. Just about every type of cleanroom will need to be tested regularly. Testing is done frequently in pharmaceutical cleanrooms, biotech cleanrooms, medical device cleanrooms, semiconductor and electronics cleanrooms, and aerospace cleanrooms.
Common Cleanroom Testing Procedures
As we’ve hinted at already, most cleanrooms will require many different tests to make sure that all aspects are working properly. Some of the most common tests include:
Airborne Particle Counting
This type of testing consists of using particle counters to measure the concentration of particles in the air (at various locations within the space). It can confirm whether or not the room meets the ISO 14644-1 classification. For example, when counting particles for an ISO 5 cleanroom, one of the particle requirements is that it ought to have no more than 3,520 particles per cubic meter (at 0.5 micrometers or larger).
HEPA/ULPA Filter Testing
Also known as Dispersed Oil Particulate (DOP) or Poly Alpha Olefin (PAO) testing, these check the filters for leaks. A special aerosol is released in front of the filter, and a photometer checks the air on the other side to see if any particles leaked through.
Airflow and Pressure Testing
For this type of testing, technicians use anemometers to measure air velocity at diffusers or laminar flow units. Pressure gauges are also used to check for the correct differential pressures between zones or areas so that air flows in the right direction.
Airflow Visualization (Smoke Testing)
To observe how and where air is flowing, smoke sticks are used to make sure airflow is as it should be. This type of testing is often used to ensure airflow is laminar/unidirectional flow, or to find dead zones.
Room Recovery Testing
Finally, there’s room recovery testing, which measures how quickly a cleanroom can return to its required particle levels after a contamination. It’s usually performed during qualification or requalification and helps verify the performance of the HVAC and filtration systems, especially their ability to restore conditions within an acceptable time frame.
Bottom Line
In most cases, cleanroom testing isn’t optional. It’s a basic requirement for certification, compliance, safety, and basic quality control. Whether that’s in the form of measuring particle levels, checking airflow, or testing filters, each procedure is important to keep your cleanroom running as it should.
