This document outlines a guideline for creating a comprehensive Cleanroom User Requirements Specification (URS). A well-defined URS is vital for ensuring that cleanrooms are engineered to meet the specific needs of their intended uses. It serves as a foundation for the design, implementation and validation of cleanroom facilities. Primary element

Cleanrooms are meticulously controlled environments that minimize the presence of airborne contaminants. To ensure a consistent level of cleanliness, cleanrooms are classified according to international standards such as ISO 14644 and US Federal Standard 209E. These classifications outline the maximum allowable particle concentration per cubic mete