About T Squared
An independent company, with our contracting activities as our core business, we are focussed on deriving and delivering innovative ways of working.
Our keenly honed short lines of decision-making enable fast introduction of any change in the ways we operate which we believe will produce benefits to customers and staff alike.
Our personnel are carefully selected to ensure their characteristics can follow through our belief that each and every person needs to be the best they can be.
From Laboratory and Cleanroom Design to Build, and Management to Maintenance, we can take care of as much or as little of the project as you require.
Cleanroom Classifications
There is much confusion between the different methods of classifying Cleanrooms that are currently in use. To simplify this we can ignore the standards used in Japan, France, Germany, Australia et al as the United States and UK standards are those which we all deal with on a day to day basis.
The Federal Standard FS 209 E (1992) classification is the Cleanroom equivalent of "old money" or the "imperial" measure and in many ways is very simple to understand. There are six classifications ranging from Class 1 to Class 100,000 with the numbers relating to the maximum numbers of 0.5 micron particles in a cubic foot of Cleanroom air. A metric equivalent of FS 209 E was produced to complicate matters and this resulted in classifications that sat between the imperial measures so this produced seven levels of cleanliness M1 to M7 - e.g. Class 1 in metric terms is Class M1.5.
In the UK there was BS 5295 which had classifications "C" through "K" which was similar to FS 209 B but not the same. Engineers in the main were happier working with the "old money" FS 209 generation of classifications.
In 1997 the ISO 14644-1 was released by the International Standards Organisation and this expanded the range of cleanliness levels with nine degrees of magnitude ISO Class 1 to ISO Class 9 in descending order of cleanliness.
Finally there is the classification of Cleanrooms for the production of sterile pharmaceutical products to "Good Manufacturing Practices (GMP)". Again here the GMP's from either side of the Atlantic are not harmonised with different conditions and labelling being applied but in general there are four grades ranging down from Grade A to Grade D. The following table does its best to bring all of the above into a common frame to assist engineers and users alike.
| ISO Classification Number | US FD 209 E | BS 5295 | cGMP (operational) |
|---|---|---|---|
| ISO 1 | |||
| ISO 2 | |||
| ISO 3 | M1.5 (1) | "C" | |
| ISO 4 | M2.5 (10) | "D" | |
| ISO 5 | M3.5 (100) | "E" or "F" | A (B*) |
| ISO 6 | M4.5 (1,000) | "G" or "H" | |
| ISO 7 | M5.5 (10,000) | "J" | B (C*) |
| ISO 8 | M6.5 (100,000) | "K" | C D |
| ISO 9 | |||
| * - at rest condition |