- To put it simply, a cleanroom is a closed room into which almost dust-free and germ-free air is let in via a filter system. The number of particles per cubic meter of air determines the quality of the cleanroom.
- A distinction is made between cleanrooms according to their type of classification. In ISO cleanrooms, the main focus is on removing airborne particles that are not allowed to deposit on sensitive products. In GMP cleanrooms, microbiological contamination via germs and spores must also be prevented.
- The cleanroom classifications according to ISO standard 14644-1 or according to GMP guidelines Annex 1 determine the overall design of the cleanroom. The more sensitive the processes, the stricter the requirements for cleanliness in the cleanrooms. Cleanroom classes range from ISO 1-ISO 9 and GMP A-D, with the lower numbers indicating higher standards for particle removal.
- Depending on the cleanroom class, the air in the cleanroom has to be completely replaced differently. This takes place via laminar air currents that lead clean air into the cleanroom and force airborne particles out of the cleanroom.
In cleanrooms, the particle concentration in the ambient air is reduced to a low, uncritical level. Correction of the damaging influence of particles and microorganisms ensures significantly higher quality and safety. The use of cleanroom technology is therefore increasingly essential for reliability and cost-effectiveness for products with high quality requirements. Without controlled production processes under cleanroom conditions, a variety of sensitive products today, such as in the semiconductor industry, microtechnology or medical technology, where even the smallest particle deposits can make the end product unusable, could not be produced. Another important aspect of cleanroom technology lies in the reduction of germs and microorganisms, which is mandatory in the manufacturer of medications and pharmaceutical products, but also leads to significant quality improvements in the food and cosmetic industries.
The term "cleanroom technology" covers all technical and organizational measures that control the number of particles brought into or originating in the cleanroom. By using and coordinating the different elements of cleanroom technology, a defined quality and safety standard can be guaranteed:
To operate a cleanroom better, particle measurements must be carried out during acceptance and during operation. Based on these measurements, the cleanliness of the room can be classified. Categorisation into cleanroom classes describes the particulate burden in the room's atmosphere from particles of different sizes per room volume.
The DIN EN ISO 141644-1 standard, which categorises air purity into cleanroom classes from 1 to 9 based on particulate count per m³, has become the globally uniform standard.
The pharmaceutical industry defines its own GMP classes A, B, C and D, which are based on the ISO standards in terms of particle concentration, but specify additional limits for harmful microorganisms. (see table)
To remove contaminants from the air, filtered, low-particulate air flows into the cleanroom through high-performance particulate filters, displacing the particle-burdened air and forcing it out of the cleanroom through exhaust openings. The air speed of the incoming air and the rate of air exchange per hour vary depending on the cleanroom class. Air filtration is regulated using the settings on the filter-fan unit and the air conditioning technology used.
A cleanroom is not a standard product. Depending on the industry and its purpose, different technical and design requirements apply that are also widely distributed along a cost spectrum. The success and efficiency of a cleanroom system depend primarily on the quality of planning in advance. Cleanroom size and cleanroom quality should be adapted specifically to the process required. Modular concepts offer greater planning reliability here, since additions and changes can be carried out after construction.
The operation of a cleanroom facility is very energy-intensive. Keeping energy costs low without giving up on safety can only be achieved with the latest air circulation technology and the best materials that ensure a good seal. Operating costs are significantly reduced with the latest air handling processes, heat recovery and drive technology with low power consumption. A system that is more expensive to purchase can amortise quickly.