Cleanroom classification is one of the most confusing – yet important – parts of designing and building your cleanroom. If you’re installing a cleanroom for the first time, you’re bound to have a lot of questions. Here are some answers to the most common cleanroom classification questions we receive.


1. What classification do I need?

It depends on your industry. The requirements will vary depending upon what size particles need to be filtered, the sources of contamination present, and recommended air change rate. If your industry is government regulated, you can check applicable regulation to see what classification is required. If there is no government-mandated or industry default classification, you’ll need to determine the appropriate classification, based on your application.


2. How are cleanrooms classified?

There are two different classification scales that are generally used, the U.S. General Service Administration standards (FS209E) and International Standards Organization (ISO) classifications. The classes are determined by the maximum acceptable numbers of particles (by size) in the air per cubic meter. See Cleanroom Classifications & Standards here.


3. How often do I need to test my cleanroom to see if it’s meeting classification requirements?

ISO requires that air pressure difference and air flow be tested every 12 months for all classifications. Particle count tests must be performed every 12 months ISO Class 6 and above, every six months for ISO Class 5 and below. There are also tests recommended for all classes, every 24 months: installed filter leakage, containment filter leakage, recovery, and airflow visualization. These tests are regulated by ISO document 14644-2 Cleanroom Testing and Compliance.


4. How often do I need to have my cleanroom inspected?

This depends on your classification. The more stringent classifications will require more regular inspection. Inspection may coincide with compliance testing, which, depending upon the cleanroom classification may occur every six or 12 months.


5. How does cleanroom classification affect my budget?

Essentially, the more stringent the classification, the greater the cost. Strict classifications will require more air, energy, advanced technology, and equipment. See How Does Cleanroom Classification Affect Your Cleanroom Budget? for a more detailed breakdown of the costs.


If you have more questions about your cleanroom classifications, check out our post What You Need to Know About Cleanroom Classifications, and make sure to give Angstrom a call! We’d love to help.