Contamination
Why most cleanroom contamination starts outside the cleanroom
Cleanrooms are designed to control contamination at the highest possible level. Air quality is monitored, pressure differentials are controlled and procedures for gowning and cleaning are clearly defined. Standards such as ISO 14644 and the IEST Recommended Practices provide detailed guidance on how to design, operate and maintain controlled environments. And yet, contamination incidents still occur. Not because cleanrooms fail, but because contamination often originates before products, tools or carriers ever enter the cleanroom.
Contamination does not start in the room
ISO 14644 addresses that contamination control is not limited to the cleanroom itself, but applies to the entire controlled environment and all interfaces connected to it. IEST guidance reinforces this view by emphasising the importance of proper handling, preparation and cleaning of items that enter the cleanroom. In practice, this is where a gap often appears. Trays, carriers, containers and tooling are frequently cleaned outside the cleanroom, in areas that are far less controlled. These pre-cleaning steps are often manual, dependent on operator behaviour and influenced by local conditions. While the cleanroom itself may be validated and continuously monitored, the steps before entry are not always subject to the same level of control, documentation or repeatability. This creates variability, and variability is one of the main sources of contamination risk in cleanroom operations.
Manual pre-cleaning introduces variability
Both ISO 14644 and IEST documentation stress the importance of repeatability and consistency in contamination control. Manual cleaning makes this difficult to achieve. Different operators, different shifts and different interpretations of what is considered clean enough all influence the outcome. Even when procedures are in place, manual execution introduces natural variation. This variation is rarely visible at the moment it occurs, but it can have consequences further downstream. When contamination is detected later in the process, the root cause is often hard to trace. Cleaning steps performed outside the cleanroom are frequently overlooked during investigations, simply because they are perceived as supportive rather than critical.
The delayed impact of insufficient cleaning
One of the reasons pre-cleaning risks are underestimated is timing. Particles or residues introduced before cleanroom entry do not always cause immediate failure. Their impact may only become apparent during later production stages, yield analysis or audits. This delayed effect makes contamination control more complex and reinforces the need to treat cleaning before the cleanroom as an integral part of the controlled process rather than a preparatory activity. ISO 14644 explicitly recognises that contamination control extends beyond cleanroom boundaries and requires a chain approach in which all steps influencing cleanliness are aligned and managed accordingly.
From activity to controlled process
Critical cleaning is not about cleaning more often or more aggressively. It is about turning cleaning into a controlled and reproducible process that aligns with cleanroom requirements. This means defined cleaning parameters, consistent execution and reduced dependence on manual handling. It also means clear responsibility for performance and continuity. When viewed through this lens, cleaning before the cleanroom becomes a strategic element in contamination control rather than a secondary task.
Supura SiteCare: maintaining control on site
With Supura SiteCare, organisations gain structured support in maintaining control over critical cleaning processes on site. Cleaning installations are kept performing consistently, availability is safeguarded and responsibilities are clearly defined. By supporting the reliability and repeatability of cleaning systems, SiteCare helps reduce variability in the steps leading up to cleanroom entry and supports alignment with the intent of ISO 14644 and IEST guidance.
Supura FullCare: predictability across the process
Supura FullCare extends this approach by taking full responsibility for the cleaning process. Performance, continuity and costs become predictable, while organisations retain control over outcomes. For cleanroom environments where risk reduction and consistency are essential, FullCare supports a long-term, structured approach to critical cleaning that aligns regulatory expectations with operational reality.
Cleanrooms are only as clean as what enters them
Cleanroom performance does not start at the cleanroom door. It starts upstream, with how items are cleaned, handled and prepared for entry. When cleaning is treated as a controlled process that reflects ISO 14644 principles and IEST Recommended Practices, risks decrease, consistency increases and cleanroom performance becomes more robust.
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