VDI 2083 Sheet 19 describes how the tightness of cleanrooms is tested and classified. The directive provides valuable guidance, but should always be considered in the context of the specific application.
In this article, we show where the requirements make sense, which applications are particularly affected and how operators can make informed decisions based on a risk analysis.
Why tightness values are defined
VDI 2083 Sheet 19 responds to increasing risks in sensitive areas. Among other things, it mentions
- Frequent use of hydrogen peroxide (H₂O₂) and other decontamination media
- Increased use of toxic substances in pharmaceutical processes
- Increasing handling of dangerous pathogens and genetically modified organisms
In order to make such hazards manageable, the directive introduces an airtightness classification from 0 to 7 classification.
Proof is provided using standardized measurement methods such as the blower door test – including clear requirements for test conditions, evaluation and documentation.
Whether a leak test is necessary depends crucially on the protection goal depends:
– Product, personal, environmental or environmental protection
– Type and extent of possible hazards in the event of leaks
Proof of tightness serves to ensure process reliability and ensures that the required protection is maintained during operation. The protection objective also determines whether the room should be operated with positive or negative pressure in relation to the environment and which tightness class should be used, depending on the potential risk.
Where tightness values make sense - and where they don't
Strict tightness requirements: sensible and necessary
1 Containment and handling of hazardous substances
In the case of toxic chemicals, biological hazards or genetically modified organisms, a high level of tightness is essential to prevent contamination or leaks.
Typical applications:
- Cytostatic laboratories
- Production and analysis of mRNA
- Vaccine production
- Blister packaging of medicines
- Filling of bioreactive substances
- Sensitive manufacturing processes that react to cross-contamination
- Mushroom laboratories
2. H₂O₂ fumigation and chemical decontamination
For reliable decontamination processes, the room must have a defined tightness. Leaking areas would lead to incomplete gassing or uncontrolled leakage.
Proof of tightness optional
If neither escaping nor penetrating substances pose a risk due to possible leaks, the tightness does not provide any added value beyond the pure information content.
Examples:
1. cleanrooms with low hazard: ISO 7-9 / GMP C-D
The focus here is on particle control – not the barrier effect of the room.
Lower tightness requirements are completely sufficient and are sometimes not even necessary in practice.
2. rooms without a critical protective function: ISO 5-6
If neither hazardous substances are used nor H₂O₂ fumigation is carried out, a high tightness class is technically unnecessary and economically disadvantageous.
Excessive tightness improves neither product quality nor process safety.
Typical applications:
- ISO 6 areas in semiconductor production
- Optics assembly
- Electronics production
Theory vs. practice: keeping an eye on the protection goal
The VDI guideline defines technical standards that serve as recommendations and practical guidelines. Its core is a clear protection goal:
– Potentially hazardous substances → Leak test required
– No critical protective function → Strict tightness specifications often superfluous
In addition to the risk assessment, the directive also takes the cleanliness class into account. If a leak test is required, different requirements apply depending on the classification:
- Tightness class 1 for cleanrooms ISO 7-9 or GMP C/D
- Tightness class 2 for rooms that must be kept under controlled negative pressure during fumigation
- Tightness class 3 for cleanrooms ≤ ISO 6
Our CleanCell cleanroom system
We have tested our modular cleanroom system specifically for the described application and carried out a comprehensive practical test on our demo cleanroom. The result confirms the high performance of the system: with our modular design, we achieved a tightness class of 1.5 in the test – a value that is well above the usual requirements of many applications.
This means that our cleanrooms already meet an energy-efficient operating level with very low leakage rates as standard. For special, clearly defined protection targets, we can easily ensure the required higher classes by means of additional sealing measures.
Conclusion: The risk analysis is decisive
VDI 2083 Sheet 19 is a valuable aid – especially in the case of real hazards from toxic or biological substances. It makes products comparable, as a guideline has been defined as the basis for testing for leaks as the state of the art.
Important:
– High tightness where it is relevant to safety
– Pragmatic solutions where process requirements allow it
With a well-founded risk analysis, operators can decide exactly when leak tests are necessary – and when they only provide informational value.
With modular cleanrooms in particular, the complete prevention of micro-leaks means considerable technical effort and high costs – without offering any additional safety benefits in non-hazardous applications.
If you would like to check which tightness class makes sense for your application, please contact us for advice.
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