Because cleaning is a time-consuming process that requires considerable expertise from the operator, Clean in Place (CIP) cleaning was developed for closed systems. CIP refers to an automatic cleaning of a closed system by recirculating cleaning agents at a defined temperature and concentration. Hygienic design keeps the volume of mixed phases low during product changes and ensures that cleaning agents reach all surfaces within the system with the necessary flow dynamics.

Cleaning Out of Place (COP) is primarily used in systems that are so complex – often due to moving parts – that they can only be cleaned manually after disassembling the components. Hygienic design enables easy disassembly and reassembly or replacement of system components. Such a design makes all surfaces easily accessible. An example of hygienic design in action for a COP system is easily removable conveyor belts. This allows replacement of a dirty conveyor belt with a clean one rather than waiting to clean the dirty belt – reducing the amount of time production must be halted for cleaning.

Successful hygienic design starts simply. The selection of equipment must be appropriate for the process. If – as is often the case – wet cleaning is performed, the IP protection rating of the devices needs to be sufficient for the process. The material of the housings must withstand exposure to both the products and cleaning agents over the long term without deterioration of surface quality or smoothness. The systems must be installed in such a way that they are easily accessible and reachable during cleaning.

Factors like the frame design have a big influence here – an open frame supports ease of accessibility to system components and makes disassembly for cleaning easier. Floors, walls, and floor drains must also be designed accordingly. All surfaces should have a slope of approximately 3° to prevent puddles from forming and to ensure continuous draining or runoff of liquids. Any additions of components to the system should not dilute the original hygienic concept.