The journal to enhance your knowledge of cleanroom, clean air and containment technology


ISSUE 26: April 2016

Main features

Airborne particle deposition in cleanrooms:
Relation between deposition rate and airborne concentration

W Whyte, K Agricola and M Derks

This is the third and final article in a series that discusses the deposition of airborne particles onto critical surfaces in cleanrooms. This article explains a method for calculating the amount of particle or microbe-carrying particle deposition onto critical cleanroom surfaces, such as product, and a method for calculating the airborne particle cleanliness class, or airborne microbial concentration that is required to obtain a specified and acceptable amount of product contamination.

Air change rate for cleanrooms with non-unidirectional airflow
Alexander Fedotov

Air change rate (ACR) is widely used in the specification of cleanrooms, partly by tradition and partly to compare different cleanrooms or designs. Recommended ACRs have also been a feature of guidelines and standards over the years, notwithstanding the fact that it is volume flow rate and not ACR that is directly related to the removal of airborne contamination. This article describes how ACR can be determined for cleanrooms based largely on equations developed by Camfil starting in the 1990s. It also shows practical ways of using analytical calculations and describes a flexible approach for determining ACR through the design, testing and operation stages to avoid overdesign and to save energy. Practical examples are included for illustration.

Ensuring the air supply rate to a cleanroom complies with the EU GGMP and ISO 14644-3 recovery rate requirements
W Whyte, N Lenegan and T Eaton

The European Union Guidelines to Good Manufacturing Practice (EU GGMP) includes a recommendation for a ‘clean-up’ of airborne particles in the cleanroom after completion of operations, where the concentration should decay by up to 100, or 10 fold, in 15 to 20 minutes. When designing a ventilation system for non-unidirectional airflow EU GGMP Grade B and C cleanrooms, it is necessary to determine if the proposed air supply rate will be sufficient to provide the air change rate for the clean-up specified in the EU GGMP, and such a method is provided in this article. The air change rates for other decay times and reductions in particle concentrations in cleanrooms can also be calculated by this method.


Update on the ISO 14644/14698 series of standards – April 2016
John Neiger


Pharminox Isolation wins its largest order yet for isolator sleeves
Air Techniques International acquires DOP Solutions and the Academy for Cleanroom Testing
BioClean™ Pharma Covers – protecting your product processing from environmental impurities
Review your fumigation protocols with Crowthorne Hi-Tec Services
Clean Room Construction Ltd follows up at University of Leeds
Cleanzone 2016: Registration is off to a good start
Cleanroom Guangzhou 2016 set up ready to go

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