Clean Air and Containment Review

Issue 12: October 2012

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Main features
The application of the ventilation equations to cleanrooms
Part 1: The equations
W Whyte1, WM Whyte1 and T Eaton2
1 School of Engineering, University of Glasgow, Glasgow G12 8QQ
2 AstraZeneca, Macclesfield, Cheshire SK10 2NA
This is the first article in a three-part series that considers the application of the 'ventilation equations' to the design and testing of the air supply systems of non-unidirectional airflow cleanrooms. By means of these equations, the 'build-up' and 'decay' of the concentration of airborne contamination in cleanroom areas can be established. The equations can also be used to determine the likely 'steady-state' airborne concentration of contaminants in the operational state, or the air volume supply rate required to ensure that the concentrations of airborne particles, or microbe-carrying particles, are not exceeded. The most suitable equations have been identified, and adapted for use with microbe-carrying particles, where surface deposition will affect the airborne concentration. These equations can also be used to recognise the key variables involved in establishing the airborne concentration of contamination in non-unidirectional airflow cleanrooms.
From dust to dust:
Vacuum cleaners for toxic powders and for cleanrooms
Rick Hollebon
This article describes the different grades of safety vacuum cleaner in accordance with EN60335-2-69 and explains how to choose the right one in relation to the Occupational Exposure Limits (OELs) of any hazardous dusts that might be present. In addition, some dusts, when mixed with air, represent a known explosive risk. An employer has legal duties under the ATEX 137 Directive to conduct a risk analysis on his processes, including cleaning, and to then select ATEX approved equipment intended for use in high risk areas. ATEX approved safety vacuum cleaners for combustible dusts are constructed in such a way that static electricity is safely routed to earth and the motors used do not create sparks. The article also describes vacuum cleaners for cleanrooms. These have slightly different requirements. As the amount of dust to be removed is very small, the container size is usually small. The ULPA filtration should be downstream of the motor if the motor is of the carbon brush type. If the vacuum cleaner has to be sterilized, its component materials must be suitable.
Speedier automated microbial methods for environmental monitoring of cleanrooms
Tim Sandle
Conventional microbial methods for environmental monitoring of cleanrooms are very slow. This paper describes a new method whereby the process is both automated and accelerated by using the natural auto-fluorescence of the living cells to achieve early analysis and enumeration of any growing colonies. The paper is in the form of an interview with Steve Delity, President and CEO of Rapid Micro Biosystems.
Regulatory reflections
Quality by Design (QbD) in cleanroom technology: 
Some pragmatic comments
Dr Hans H Schicht
The Quality by Design (QbD) procedure was introduced for the development of pharmaceutical products and processes. The focus upon a) risk analysis and process improvements resulting from it, b) consideration of the entire life cycle from development until discontinuation and c) continual improvement based on operating experience are some of the outstanding features of the QbD procedure. Reported major benefits from the application of QbD include reductions in batch failures and a positive impact on direct production costs. As a consequence of the urgency of fighting the warming-up of the earth's atmosphere, life cycle considerations also require a powerful energy saving policy to be incorporated into the essential elements of QbD.
WHO GMP update 2012
Standards update
John Neiger
Professor Raymond Clark rewarded for services to standards development
Conference reports
ICCCS Symposium, Zurich, 3 - 7 September 2012
John Neiger
Vital vocabulary
S is for...
Tecomak, Pharminox, Helapet, Energy and Carbon, Envirco, Facility Monitoring Systems, Facility Monitoring Systems, Contec, CRC, Fishers Services and Nitritex, schulke
Training Courses
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