puhtusklasse

Puhtusklasse is a designation used to describe the level of cleanliness required in a controlled environment, most often in cleanrooms and other spaces where airborne particles, surfaces, and sometimes microorganisms must meet predefined limits. The term is used in Estonian documentation and is commonly translated as cleanroom class or cleanliness level in English.

Standards and scope: The most widely adopted framework is ISO 14644, Cleanrooms and Associated Controlled Environments. Under ISO 14644, environments are classified into ISO Class 1 through ISO Class 9, with Class 1 representing the strictest level of cleanliness. In some sectors, particularly pharmaceuticals, related concepts such as Grade A, B, C, and D describe cleanliness in production areas and processing stages.

Definition and requirements: A puhtusklasse is defined by limits on the number of particles per cubic meter of air for specified particle sizes and may also include limits on microbial contamination on surfaces. The class is achieved and maintained through design choices (sealed construction, filtration), operational practices (air changes per hour, filtration efficiency), and protective measures such as clothing and hygiene protocols.

Measurement and management: Monitoring uses particle counters and microbial testing to verify compliance. Controls commonly include HEPA or ULPA filtration, controlled airflow with positive or negative pressure as appropriate, regular cleaning regimes, and standardized gowning. Facilities are validated for their assigned puhtusklasse before use and undergo ongoing audits and revalidation.

Usage and context: Puhtusklasse guides facility design, commissioning, and ongoing operations in industries such as pharmaceuticals, biotechnology, electronics manufacturing, medical devices, food processing, and clinical laboratories. The concept emphasizes that cleanliness requirements are context-specific and driven by regulatory and customer specifications.