ISO 14644-9:2022

Overview

ISO 14644-9:2022 defines a standardized procedure for assessing surface cleanliness by particle concentration (SCP) in cleanrooms and associated controlled environments. It applies to all solid surfaces - walls, ceilings, floors, work surfaces, tools, equipment and products - and covers particles in the range 0.05 µm to 500 µm. The standard provides a grading system (SCP grades 1–8), guidance on test and measurement methods, and annexed information on surface characteristics and factors that influence surface particle deposits.

Key topics and technical requirements

• Scope and limits: Applies to solid surfaces only; particle sizes from 0.05 µm to 500 µm. The standard explicitly excludes cleaning procedures, material suitability requirements, selection of statistical methods, and particle attributes such as electrostatic or microbiological properties.
• SCP grading system: Surface cleanliness is expressed as an SCP grade number (1 to 8) tied to a considered particle size (D µm). The designation format is “SCP grade level N (D µm)” and must include measured surface type, surface area, and measurement method.
• Measurement and conformity: Procedures for demonstrating conformity include sampling and reporting requirements. Annex D lists measurement methods (direct and indirect), while Annexes A–C cover surface characteristics, descriptors for specific size ranges, and parameters that influence SCP assessments.
• Reporting and designation: Test reports should contain details of sampling technique, devices used (e.g., surface particle counters), and the representative surface area tested. The considered particle size should be agreed upon between customer and supplier.

Practical applications and users

• Who uses ISO 14644-9: cleanroom designers, quality managers, process engineers, validation specialists, QA/QC teams, regulatory auditors and suppliers of cleanroom equipment and substrates.
• Common uses:
  • Specifying surface cleanliness limits for acceptance testing of equipment, tools and production zones.
  • Monitoring critical control points where particle deposition on surfaces impacts product quality (e.g., semiconductor wafers, optical components, pharmaceutical production lines).
  • Supplier verification for components and substrates intended for contamination-sensitive processes.
  • Complementing airborne particle classification (ISO 14644-1) when surface particle levels are an additional process attribute.

Related standards

• ISO 14644‑1 (airborne particle classification and cleanroom grades)
• Other parts of the ISO 14644 series and ISO 14698 (biocontamination control) for broader cleanroom design, operation and microbiological considerations.

Keywords: ISO 14644-9, surface cleanliness, cleanrooms, surface particle concentration, SCP, cleanroom standards, particle contamination, surface cleanliness assessment.