The following frequently asked questions arose at a presentation given by PMS Senior GMP Scientist, Mark Hallworth, on the 6th of December on the topic of EU GMP Annex 1 Air Speed Strategies for Unidirectional Flows.
Why do manufacturers like ESCO, ThermoFisher Scientific, and Nuaire adopt different air speed values for 2A2 and 2B2 biological safety cabinets compared to the suggested range of 0.36 m/s to 0.54 m/s?
These manufacturers guarantee unidirectional airflow based on the speed ratings determined according to the specific equipment model. While the suggested range is 0.36 m/s to 0.54 m/s, the manufacturers may choose different values that they believe are optimal for their equipment.
Should the speed criteria for unidirectional flows, different from Annex 1: 2023, be justified in any way?
Yes, any deviation from the suggested range in Annex 1: 2023 should be justified. Manufacturers need to demonstrate through airflow visualization studies that their chosen air speed values meet the criteria of the system. This involves ensuring that any particles generated are effectively swept away from the critical processing area.
Why do airflow velocities vary among Clean Air devices, with some manufacturers using 0.3 m/s as the standard at the filter face?
Airflow velocities are dependent on the design of Clean Air devices. Many manufacturers adhere to a standard of 0.3 m/s at the filter face. The language in Annex 1 provides a range of values, recognizing the variability in design preferences. Historically, the standard used to be 0.45 m/s +/- 20%, but this has been relaxed to accommodate different design considerations.
Why does Annex 1 provide a range of values instead of a specific standard for airflow velocity?
The range of values in Annex 1 acknowledges the diversity in design and manufacturing approaches. The standard used to be more specific (0.45 m/s +/- 20%), but this was relaxed to allow flexibility. The current range of 0.36 m/s to 0.54 m/s is provided as guidance, and manufacturers may choose values within this range based on their equipment models.
How should manufacturers justify and demonstrate different air speed values for unidirectional flows?
Manufacturers should perform airflow visualization studies to justify and demonstrate that their chosen air speed values effectively meet the criteria of the system. This involves ensuring that any particles generated are swept away from the critical processing area, providing evidence of the system’s efficacy despite deviating from the suggested range in Annex 1: 2023.
*These FAQs are intended to provide insights into EU GMP Annex 1. Always refer to the specific standards and guidelines for your industry and location.
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