But what exactly does this mean? What is it that makes a clean room, well…clean? It can be boiled down to three main components that are all equally critical:
Internal Surfaces
According to GMP compliance, all surfaces in a cleanroom should be “smooth and impervious”. They shouldn’t peel, flake, corrode, create dust, or offer a place for microorganisms to multiply. The surfaces should be easy to access, easy to clean, and should not shatter, dent, crease, or crack easily.
While there are plenty of material choices available, the best option would probably be glass—although there are other options that work as well.
Control/Quality of Airflow
In most facilities, clean room AHUs (or “air handling units”) use over 60% of the site power. The cleaner the room needs to be, the more air it will use. This is because clean rooms need quite a lot of special air that is humidity- and temperature-controlled.
A good air handling system ensures that the air keeps moving throughout the clean room. At the heart of a good clean room design is knowing the appropriate location of where the air is brought in (supply) and taken out (exhaust).
In order to reduce the cost of modifying the air’s temperature or humidity, AHUs are designed to recirculate around 80% of the air through the room, removing particle contamination as it’s created, while keeping the air where it needs to be.
Any air that’s introduced into a cleanroom is totally controlled, as well as the air that’s removed. The air that is taken out of the room is typically re-circulated through the air handling system, where particles are filtered out. High levels of moisture, noxious vapors, gases, or raw materials can’t be re-circulated back into the clean room, so the air in these clean rooms is often exhausted to atmosphere, and then 100% fresh air is introduced into the facility.
Operation
A clean room is only as good as its operation (the staff). The most effective way of ensuring that air quality is maintained in a clean room is to have the right operation. This means regularly cleaning and maintaining the facility and equipment to standard requirements, monitoring the air filters and air flows regularly, minimizing potential contamination that comes from manufacturing, and keeping strict control of access to the clean room. Only trained members of staff should have access, and even then a very limited amount.