The CIP process (Cleaning in Place) comprises mechanical and chemical processes that are mainly used in the pharmaceutical, cosmetics and food industries. Vessels, pipes and valves are cleaned on all product-contact surfaces between production runs – without prior dismantling.
Practical experience and tests show that the mechanical cleaning effect depends on the flow velocity and turbulence of the cleaning liquid. In addition, the temperature and concentration of the cleaning solution influence the cleaning speed. Therefore, these factors should already be defined when designing a cleaning system.
Product safety, hygiene and efficiency
The CIP process plays a central role in product safety and hygiene. At the same time, the plant should run as efficiently as possible with minimal downtime. Rising costs for water and energy are particularly important here, as is a chemical consumption that is matched to the respective products.
Anyone developing cleaning processes therefore needs to know the properties of the excipients and active ingredients and select a suitable cleaning agent. An unsuitable cleaning agent can significantly extend cleaning times or even prevent complete cleaning.
How thorough a cleaning is depends on many factors. Besides the type of soiling, these include the condition of the product-contact surfaces and their installations. Corners, edges, seal arrangements and low-flow zones – for example in T-pieces, puddles or domes – are just as decisive, as are the operating conditions.
What cleaning effectiveness depends on
- design measures in the plant areas to be cleaned (GMP – Good Manufacturing Practice)
- suitable choice and quality of materials
- suitable cleaning agents
- correct cleaning conditions
Key features of CIP cleaning
- flow velocity in pipes and valves (1–4 m/s depending on pipe cross-section)
- duration of rinsing
- spray pressure at the cleaning heads
- temperature of the cleaning solutions
- alkaline rinsing solutions with additives that keep dirt particles in suspension (preferably non-foaming)
- acid rinses against deposits such as limescale after alkaline cleaning
- disinfection (SIP or chemical)
- contact time and temperature of the cleaning agents
- size of the plant
- reproducible process through fully automatic sequences
- documentation of the cleaning process
Purpose of CIP/SIP cleaning
- complete removal of product residues
- removal of biofilms
- no cleaning agent residues
- sterility of plant parts and pipes
CIP cleaning sequence in the pharmaceutical industry
- 1Pressure hold testFirst, the plant is checked for leaks.
- 2Evacuate and melt offFor greasy products, the plant is evacuated, product residues are melted off with pure steam and drained in concentrated form.
- 3Hot pre-rinseA hot pre-rinse removes coarse soiling.
- 4Alkaline cleaningCleaning with an alkaline agent, if necessary with additives that keep dirt particles in suspension.
- 5Hot rinseDuring draining, cleaning agent and product residues are rinsed out.
- 6Rinse with purified waterNext, the plant is rinsed with purified water during draining.
- 7Acid cleaningAn acid agent removes limescale and caustic scale.
- 8Rinse with purified water againThe plant is then rinsed once more with purified water.
- 9SIP – Sterilization in PlaceEvacuate the plant section, control the steam pressure up to the overpressure range and drain the condensate.
- 10DryingFinally, the plant is dried under vacuum, e.g. with hot, sterile supply air.
The sequence and step times can be adjusted. The concentration of the cleaning medium is also variable. In addition, the detergent concentrates can be combined in a fresh batch to form an optimally effective cleaning solution (stacked cleaning).
Sterilization in Place (SIP)
Sterilization in Place is the in-situ sterilisation of process plants with pure steam. Here, too, no dismantling is necessary. All components that come into contact with the product are sterilised.
The SIP process usually works with saturated pure steam. A sterilisation temperature of 121 °C requires an overpressure of about 1 bar. Depending on the requirements, the temperature is controlled and documented as a function of steam pressure and exposure time.
The plant parts to be sterilised should be evacuated before steam sterilisation. In this way, no air pockets form and the temperature distributes quickly and evenly.
CIP systems integrated into process plants
All internal surfaces of the process plant are primarily cleaned in the cleaning-in-place process. The homogeniser serves as the conveying unit for the CIP solution. Further equipment includes, for example:
- suction hose for liquids
- suction lance for powders
- phase vessels
The mixing plant should be designed so that as much product as possible reaches the target vessels. This also includes the inlet of a filling machine. As a result, little residual product remains and only a minimal amount enters the waste water.
The vessel bottom, wall scrapers and surface as well as the length and slope of the discharge line behind the homogeniser should therefore be designed so that, as far as possible, no residues remain. Furthermore, all pipes within the process plant belong in the CIP process.
Additional equipment for the CIP process must not be a source of physical, chemical or microbiological contamination. Moreover, air gaps in front of all waste water connections prevent recontamination.
Cleaning process in cosmetics plants
The CIP process in cosmetics plants usually consists of the following steps:
- 1Hot flushPlant parts and pipes are flushed with hot water in a single pass. This way, product residues go directly into the waste water without soiling the CIP equipment.
- 2Alkaline cleaningA caustic solution at approx. 70 °C is circulated and removes all visible product residues. The vessel is then rinsed during draining.
- 3Acid cleaning and disinfectionAn acid agent dissolves limescale. Hot water then circulates until the equipment reaches 80–90 °C for a defined period (thermal disinfection).
- 4Cold final rinseFinally, the plant is rinsed with cold DI water in circulation via spray heads and rinsed again during draining.
These steps can follow one another, be repeated or be skipped – with or without additional cleaning agents.
Optionally, a conductivity sensor monitors the cleaning quality (final rinse water < 50 µS/cm at 20 °C).
SEEFRIED Verfahrenstechnik GmbH supports you in the design of CIP and SIP systems, the CIP procedures and the procurement of the associated process equipment.
Frequently Asked Questions about CIP and SIP systems
What is the difference between CIP and SIP?
CIP (Cleaning in Place) cleans vessels, pipelines and valves without dismantling. SIP (Sterilization in Place) then sterilizes the product-contact parts – also without dismantling – using pure steam, typically at 121 °C.
Which factors determine cleaning success?
Key factors are flow velocity (approx. 1–4 m/s in pipelines), temperature, concentration and contact time of the cleaning solution, spray pressure at the cleaning heads, the right detergent and a hygienic design without low-flow zones.
What does a typical CIP sequence look like?
Common steps are hot pre-rinsing, cleaning with an alkaline agent, intermediate rinsing, cleaning with an acidic agent against lime scale and final rinsing with purified water – followed by SIP and drying if required. Sequence and step times can be adapted.
How is cleaning success verified?
For example with a conductivity sensor in the final rinse water (guide value < 50 µS/cm at 20 °C). Fully automated, documented sequences ensure reproducible results.