Hygiene and cleanliness standards in the pharmaceutical industry are set by the international GMP standard that covers the whole spectrum of measures from air-conditioning to protection clothes, which all need to be fulfilled in order to achieve a certain class of cleanliness.
There are four classes: A, B, C and D. The A class can usually be achieved exclusively in hermetically sealed laminators. This class is used for filling of sterile products. Class B is the so-called »background class« for the class A. Class C is used in the product preparation procedure and class D is used for rooms for component preparation and partial filling of products.
When we talk about aseptically treated/prepared products, we use class A for preparation and product filling, class B as the »background class«, class C for preparation of filtering-purpose products/components and class D for handling of product after the washing procedures. Separate classes of protection may only be accessed via a special »airlock« system, which is installed between two rooms having a different cleanliness level. This airlock rook is usually also used by the staff to change working protection clothes. Only one class of a higher/lower rank may be accessed at a time. The same is true for transport of material with a special emphasis put on the dividing the material path from the one of the staff.