The most important contamination control issue within cleanrooms is air, given that air can distribute contamination around the Cleanroom, as well as the way that Particles behave in air in relation to a tendency to settle. With this regard particles should not be thought of as 'passive' contaminants. Hence the essential part of cleanroom design is through established principles designed to control airborne particles.
On this basis Tim Sandle has written a paper:
“While the mechanisms of particle control are, with reference to cleanroom design, well described and limits are in place for the permitted maximum concentration of particles in a defined volume of air (a cubic meter), the Distribution of particles within a cleanroom and the likelihood of particles settling is not so well described. Moreover, measuring the concentration of particles in the air and calculating these as the cumulative number does not inform the cleanroom user as to what proportion of these particles are likely to settle out from the air onto a surface. In discussing particles, this paper is not so much concerned with sources of particle generation; instead the focus is on a less discussed subject: particle distribution within the cleanroom environment and the risks of particles settling onto surfaces.”
The reference is:
Sandle, T. (2017) Distribution of Particles Within the Cleanroom: A Review of Contamination Control Considerations, Journal of GXP Compliance, 21 (6), 1-10: http://www.ivtnetwork.com/article/distribution-particles-within-cleanroom-review-contamination-control-considerations
Posted by Dr. Tim Sandle
