Airborne Particle Sampling Techniques

Airborne Particle Sampling Techniques

LWS offers testing service for particle losses according to ISO/TR 14644-21 at the customers site.

Understanding ISO/TR 14644-21:2023

The Importance of Accurate Sampling Techniques

Delve into the intricacies of ISO/TR 14644-21:2023, the pivotal technical report that sets forth the standards for airborne particle sampling in cleanrooms and controlled environments. This document is the cornerstone for ensuring compliance with ISO 14644-1:2015 for cleanroom classification and ISO 14644-2:2015 for particle monitoring, providing a framework for capturing precise data to support air cleanliness verification. It’s not just about meeting regulatory requirements; it’s about embracing a methodology that safeguards the integrity of your processes and products.

Sampling Quality vs. Data Quality

Balancing Sample Integrity with Data Precision

ISO/TR 14644-21 addresses potential misinterpretation of the use of ISO14644-1: 2015, C.4.1.2 in informative Annex C, which suggests the use of limited tubing length for sampling macroparticles. The phrase in question has been applied beyond the context intended in ISO14644-1, to other applications. This TR also provides extra clarity on the use of the M Descriptor in ISO14644-1: 2015, Annex C, specifically in relation to consideration of >5,0 µm alongside ISO Class 5 (EU-PIC/S GMP Grade A and B at rest).

It provides information on the potential uncertainty associated with sampling particles ≥5,0 µm and macro-particles, and measures that can be taken to reduce that uncertainty.

It addresses the importance of understanding that:

— for classification, the quality of the sample is the most important factor;
— for monitoring, the quality of the data is the most important factor;
— direct sampling without tubing is preferred. However, sample tubing is sometimes necessary to get a representative sample at a significant or critical location;
— to reduce sampling loss in tubing, this tubing is as short and straight as possible;
— a sampling system is evaluated to assess the impact of any compromises in its set up.

An evaluation of legacy systems can deem them suitable for continued use even if the installation is assessed as less than optimal

Direct Sampling Techniques

Optimizing Sampling with Direct Techniques

ISO/TR 14644-21:2023 advocates for direct sampling methods as the gold standard for minimizing sample loss and contamination. This approach eliminates the need for lengthy tubing, which can compromise sample quality, especially when dealing with larger particles. Our comprehensive overview provides insights into the advantages of direct sampling and offers practical advice on implementing these techniques to capture the most representative samples from critical locations within your cleanroom.

Isokinetic Sampling

Achieving Representative Sampling in Unidirectional Airflow

Isokinetic Sampling is essential for obtaining an accurate representation of airborne particles within a cleanroom’s unidirectional airflow. This technique ensures that the sampled air velocity matches the surrounding airflow, thereby preventing particle distortion and loss. Our detailed section on Isokinetic Sampling will guide you through the process of setting up an optimal sampling environment, helping you to achieve the precision required for thorough and reliable cleanroom validation.

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