The Invivo2 / Concept / Concept-M Series Workstations have been recently remodelled, and now include a standard HEPA filter. This report details the HEPA filter testing and results for the common body of these workstations to determine air cleanliness using EN ISO 14644-1 as a reference for performance limits and test methods, as well as measurement against US FED STD 209E, and EU GMP Annex A. Using these standards, the new Workstations are determined to achieve ISO Class 4, Class 10, and EU Grade A air determined by particle count.
Baker Ruskinn design and manufacture workstations for the anaerobic microbiology, cell biology, stem cell and regenerative medicine markets. These workstations have historically controlled temperature, humidity, Oxygen, and Carbon Dioxide concentration. As technology and science develops, our workstations will too, grow. This new upgraded model has been redesigned to meet and exceed these new expectations, one of which is to provide and maintain a clean working to avoid contamination of the end users’ cultures.
A standard measure of the cleanliness of the workstation is to measure the particulate levels that are inside the working environment to ensure that there are no potential sources of contamination during normal operation, or unwanted external sources. HEPA filters are common tools used to reduce particulate load in an airflow system like this one. Particle counters are the primary tool used for determining their effectiveness as outlined in several international standards, such as EN ISO 14644-1, US FED STD 209E, and EU GMP Annex A.
A PMS Particle Counter, Model # 9310-02 particle counter was placed inside the workstation and programmed to sample the work area atmosphere and take a cumulative count of the particles giving a result as particles/m2. The Particle counter was configured to measure 196 L of atmosphere over a time of 6 minutes and 23 seconds (approximately 30 L/min) and calculate the result as number of particles per cubic meter, in accordance with EU ISO 14644-1, using Class 3 and 0.3µm as a maximum for sample size calculation (Formula A.2 of ISO 14644-1). This was then scaled to the equivalent of measuring 1000 L of air, to be compared to the international standards.
Figure 1: Particle counter within work area of the InvivO2 workstation for example placement.
As seen in Table 1, the amount of particles present in the work area air of varying sizes were counted, and scaled to a full volume of 1000 L.
Since the counts of particles 1µm or larger had the greatest for its classification, when compared with the table of regulations supplied by ISO 14644-1 (Appendix 1), we can see that without a HEPA filter installed, the air is classified as Class 8, which is equivalent to Class 100,000. Using the measurements at 0.5 µm and 5 µm and the EU GMP Annex A classification (Appendix 2), the air would be classified as Grade C.
Using the data for the particle counts taken with the HEPA filter installed and the tables shown in Appendices 1 and 2, the air would be classified as Class 4, Class 10, and Grade A.
| Ch1 0.3µm | Ch2 0.5µm | Ch3 1µm | Ch4 3µm | Ch5 5µm | Ch6 10µm | |
|---|---|---|---|---|---|---|
| No HEPA | 2210035 | 290919 | 290919 | 4982 | 2509 | 1237 |
| With HEPA | 380 | 201 | 58 | 0 | 0 | 0 |
Table 1: Results from particle counting within the work area of the remodelled workstation, with and without a HEPA filter installed.
Based on the results of the testing using the method described in ISO 14644-1, the air cleanliness within the remodelled workstation work area can be claim compliance as ISO Class 4, US FED STD Class 10, and EU GMP Grade A air.
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