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The rate of deposition of airborne particles determines the risk of product contamination and demonstrates the operational quality of a cleanroom. The particle deposition rate at a particular location and time depends on the deposition velocity and the concentration of particles. The concentration of particles larger than 10 µm cannot be measured easily; therefore the deposition rate of falling particles should be measured.
Specific particle deposition meters, that measure the particle size distribution and rate of particle deposition, have been available since the end of 2013. In the past, particle deposition measurements were complicated and expensive and were therefore only carried out in specific cleanroom applications or to investigate contamination problems. Nowadays it is easy to carry out particle deposition measurement in various cleanrooms where operator activities are important. The new instruments also make real time particle deposition measurements possible. Practical experiences with these instruments in various applications are described in this article.
← Close.This article is a guide on how to treat rouging or discolouration on stainless steel surfaces. The article starts with a description of the different types of stainless steel and how stainless steel develops a chromium-enriched corrosion-resistant layer by passivation either from the oxygen in the air or by chemical means. X-ray photoelectron spectroscopy (XPS) is used to measure the depth of the layer. When stainless steel corrodes, this shows as a discolouration that is known as rouge. Rouge can be anything from reddish brown to blue or black. The article describes three types of rouge that result from deposited oxidized metal particles, in-situ oxidization and high temperatures or steam. Finally the article explains how rouge can be removed and surfaces repassivated. Routine procedures for inspection and treatment are recommended.
← Close.The discussion in this part of the history of isolator and containment technology reviews the development and use of various devices that permit the aseptic transfer of components such as sterile vials, syringes, bottles and other types of container as well as the actual product itself into and out of the aseptic filling area of an isolator or RABS (restricted access barrier system).
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