This IEST (Institute of Environmental Sciences and Technology) standard provides methods for specifying and determining product cleanliness levels for contamination-critical products.
The emphasis is on contaminants that can impact product performance.
The requirements set forth in this standard are not required for all products but are intended for use in procurement and design contracts for those items where contamination control limits for parts, components, or fluids are necessary to ensure reliability and performance.
This standard provides mutually agreed-upon limits for defining significant surface cleanliness and liquid cleanliness with respect to particles and molecular residue. The standard has been modified to include alternative cleanliness level designations that are better suited to accommodate user-specific applications.