Cleanliness-suitable consumables

© Photo Fraunhofer IPA, Rainer Bez

Selecting consumables suitable for clean production processes is no easy task. This is because the cleanliness quality of products available on the market is often only characterized by air cleanliness classes according to ISO 14644-1. However, such information about quality is not only insufficient but also incorrect, since consumables are not cleanrooms and therefore cannot be assigned an air cleanliness class. Particulate contamination generated when using consumables is clearly one of the most important criteria to determine cleanliness suitability. This can be reproducibly proven in tests by subjecting them to defined loads typically experienced in practice. By comparing results with limit values for air cleanliness classes and through statistical assessments, suitability for use in specific air cleanliness classes can be determined if there is an adequate degree of certainty that limit values will not be exceeded.

 

Besides particulate emissions, other criteria may also be important depending on the use of the consumable concerned:

  • Outgassing behavior (e.g. the release of molecular substances from gloves, overalls, sticky mats, etc.)
  • Electrostatic properties (e.g. the capacity of overalls to discharge static electricity)
  • Resistance to chemicals
  • Resistance to microorganisms (e.g. ability of plastics and lubricants to resist metabolism)
  • Surface cleanliness (e.g. packaging films, gloves)
  • Cleaning properties (e.g. cleaning efficacy of cloths and mops)
  • Etc.

 

Altogether, the relevant criteria characterize the suitability of a consumable for use in conjunction with specific clean production processes. Apart from legal requirements, since the spectrum of process-specific requirements is very broad, only the user can decide on the weighting of the various relevant criteria. It may not be forgotten that consumables are mostly used in the direct vicinity of human operators.