OPEN RABS are classified as “passive or active open RABS sterile systems” and systems for the containment of HPAPI products – also called “active open RABS”.
Both systems are usually installed in cleanrooms and use the room filtered air.
Here we will focus on the active open RABS. They protect the operators against a potent product by maintaining the containment area at a negative pressure compared to the cleanroom pressure. This negative pressure acts as a barrier between the operator and the product being processed.
The system is called “active” because it sucks already-filtered air from the surrounding environment and releases it into the containment area via a negative forced ventilation system.
Active open RABS can be used in blister and counting machines: here, belts continually convey empty thermoformed blister packaging, film, plastic or glass bottles to the containment area, where the packaging is filled with tablets or capsules. On this type of machines, the mouse holes through which the belts run are used to suck filtered air from the clean room.
Of course, the larger or more numerous the holes, the bigger the ventilation and the filtration system and the larger the fans and filters. Besides a ventilation system in the working chamber, these machines usually have a deduster, which removes dust from the most critical areas of the machine. This reduces downtime to replace filters.
Air filtration is key. The air that is sucked into the containment area is filtered by H14 absolute filters. The air ejected by the ventilation system of the open RABS is also generally expelled from the room. The air consumption of the open RABS is therefore a key factor in the design and operation of the cleanroom HVAC system.