Puhtausluokista

Puhtausluokista refers to the system of cleanliness classes used to describe air cleanliness in controlled environments such as cleanrooms. The classes define how many airborne particles of specified sizes may be present per cubic meter of air, with lower class numbers corresponding to stricter limits. The aim is to minimize contamination of products and processes in industries such as pharmaceuticals, biotechnology, electronics and healthcare.

The most widely used framework is the international standard ISO 14644-1, which classifies cleanrooms from ISO Class 1 to ISO Class 9. In practice, many facilities operate within ISO Class 5–8 ranges, depending on the application. The ISO system has largely superseded older national standards such as the U.S. FS 209E, though references to older classifications may still appear in some contexts. The classifications are based on maximum allowable particle counts for defined particle sizes, typically including measurements in the sub-micrometer to a few micrometers range.

Measurement and verification are performed with particle counters that sample air at designated points and times. Cleanroom evaluation occurs during commissioning and periodic monitoring to ensure ongoing conformance. In addition to particulate cleanliness, many environments also monitor microbiological cleanliness and maintain defined cleaning routines and validated procedures. Design features such as controlled airflow, high-efficiency filtration (HEPA or ULPA), and controlled access help achieve and sustain the required class.

In Finland, puhtausluokista is aligned with ISO 14644 standards and is applied across industries that require controlled environments. The concept underpins regulatory compliance, quality assurance, and safety, and is supported by training and routine auditing of cleanroom performance.