CIP means different things to different people.  Some consider a CIPable process to be a CIP system which makes a product. Most, however, recognize the CIP Recirculating Unit as the heart of the CIP system controlled by a CIP Program Control system.  Cleaning chemicals are supplied automatically by Chemical Feed Equipment and flush, wash and rinse solutions are delivered to Spray Devices and product piping circuits  through CIP Supply/Return Piping systems.  The most cost effective application of CIP is to apply the appropriate Components and Concepts  to the design of Integrated Processing systems which use a major portion of the required pumps, piping and valves to control both process and CIP solution flow.  Click on the above phrases to obtain a brief overiew of each subject or continue below for an Overview of CIP Technology. 

Historical Background 

A review of the literature reveals that CIP (Clean-In-Place) has been practiced for nearly 50 years, following the introduction of Pyrex heat-resistant glass piping to the dairy industry in 1941 as a means of conserving critical materials (copper, tin and stainless steel) for war use. Approximately 20 experimental installations of glass piping had been made by 1949, and perhaps 40 commercial and college dairies were using glass pipe by 1951.  At that time, all piping, storage tanks and processing and packaging equipment in the nation's dairies was manually cleaned as described in the illustration shown on Manual Cleaning Procedures (Before CIP). 

The introduction of CIP joints and fittings in the early 1950's was followed by the the installation of The FIRST Reported Automated CIP System in 1953.  Rapid development of automated CIP recirculating Units, permanently installed spray devices, CIP cleanable air-operated valves and welded piping systems occurred  prior to 1960. The first dairy plants to apply automated in-place cleaning to an extensive degree were placed into operation in 1960, with considerable equipment in those early operations still being manually cleaned. 

During the decade beginning in 1965, CIP was recognized as the key which would open the doors to many other changes in dairy processing technology. And, during this period, clean-in-place procedures were applied extensively in many non-dairy food  and beverage industries, including brewing, wine processing, meat processing (smokehouses), as well as numerous processes which handled dry or semi-fluid products in stainless steel equipment. All of the products in the photograph to the right were being produced in CIP cleaned processes designed under the writers supervision prior to 1976. The major equipment manufacturers began designing most processing and packaging equipment to be susceptible to CIP procedures during this decade. 

An early application of CIPable design to an IV Solutions process was completed in 1977 and automated CIP cleaned processes were designed for sterile lipid solutions, sterile albumin and blood fractionation in the early 1980's.  CIP Cleanable Processes in the Pharmaceutical and Biotechnology industries now include, but are not limited to, fermentation processes,  purification processes including UF and chromatography systems, bulk solids processes, including crystallization and equipment and piping for sterile filtration of liquids and gases, filtration of the product as a solid, and downstream equipment used for drying, milling, blending and filling into bulk containers. 

Types of Equipment that can be CIP Cleaned 

Processing and storage tanks and process piping systems comprised of pumps, interconnecting piping and valves are well understood to be CIP cleanable. The technology is equally applicable to any equipment in which solution contact can be achieved via spray or pressure recirculation and the applicable equipment may include filter housings, membrane filters, homogenizers, centrifugal machines, heat exchangers, evaporators, dryers and congealing towers, screw and belt conveyors, process ductwork, and a variety of packaging machines. 

The CIP Procedure 

CIP cleaning is usually accomplished via chemical action based on spray or pressure recirculation of the flush, wash, and rinse solutions under controlled conditions of time, temperature and chemical concentration.  The physical action of pressure and flow are of significance, however, and extensive experience suggests that: 

• Piping Systems can be effectively cleaned via recirculation of flush, wash, and rinse solutions at flow rates which will produce a velocity of 5 feet per second or more in the largest diameter piping in the CIP circuit, this velocity being necessary to assure continuous movement of entrained air in long horizontal runs.
• Tanks can be effectively cleaned by distributing flush, wash and rinse solutions on the uppers surfaces at pumping rates equivalent to 2.0 - 2.5 Gpm per foot of circumference for vertical vessels, or at 0.2 - 0.3 Gpm per square foot of internal surface for horizontal and rectangular tanks and other equipment such as mixers, bins, dryers, cyclones and other ductwork. 
•  Integrated Process/CIP Design  may be applied to combine the cleaning of vessels and piping in a single circuit in which instance process piping and pumps are engineered and installed to serve the CIPS/R function, supplying flush, wash and rinse solutions to the sprays, and providing for solution return to the CIP system. This concept accomplishes CIP at the minimal capital cost and is highly effective in reducing the post CIP re-contamination that often follows conventional cleaning of lines and vessels in separate circuits. 

Recirculation is essential to maintain economic operation, for high volumes of solution must be brought into contact with the soiled surfaces for periods of time ranging from as little as 5 minutes to 1 hour or more. 

SIP (Sterilization -In-Place) is the next logical step following CIP and the objective is to sterilize all sterile product contact equipment at its point of use to eliminate or reduce the need for aseptic additions or connections. 

CIP is most applicable to those processes which are designed to handle fluid or semi-fluid products, which will easily confine liquids, and which must be maintained in a very clean or perhaps sterile condition. The process must be constructed of stainless steel or equally corrosion-resistant material sealed and closed with elastomers which are FDA approved for the intended application. 

The most effective and repeatable CIP operations are achieved by the application of considerable automation. Therefore, the highly automated process is generally more easily designed as a CIP-cleanable process as compared to processes which utilize manually operated pumps and valves, or considerable manually assembled product piping. 

To achieve the most effective results it is necessary to design the process and the CIP components and circuits simultaneously, giving equal consideration to the process requirement and the method of cleaning the process. CIP is seldom efficient as an after-thought. 

Copyright Notice - The photographs and line drawings included on the subsequent pages, in the sections listed above, and elsewhere on this site are the property of Dale A. Seiberling. 

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References for Suggested Reading (by others.  See also PUBLICATIONS) 

Adams, D. G. and Agaarwal, D. (1990).  "CIP System Design and Installation", Pharmaceutical Engineering, Vol. 10, No. 6, pp. 9-15. 

Balmer, K. B. and Larter, M. (1993).  "Evaluation of Chelate, Acid and Electropolishing for Cleaning and Passivating 316L Stainless Steel (SS) Using Auger Spectroscopy", Pharmaceutical Engineering, Vol. 13, No. 3, pp. 20-28. 

Baseman, H. J. (1992).  "SIP/CIP Validation", Pharmaceutical Engineering, Vol. 12, No. 2, pp. 37-46. 

Carvell, J. P. (1992).  "Sterility and Containment Consideration in Valve Selection", Pharmaceutical Engineering, Vol. 12, No. 1, pp. 31-35. 

Coleman, D. C. and Smith, P. J. (1992).  "Effective Steam Trapping for Clean Steam Systems in the Biotechnology and Pharmaceutical Industries", Pharmaceutical Engineering, Vol. 12, No. 2, pp. 8-14. 

DeLucia, D. E. (1994).  "Cleaning and Cleaning Validation: The Biotechnology Perspective".  (Personal Correspondence). 

Grimes, T. L., Fonner, D. E., Griffin, J. C., Pauli, W. A. and Schadewald, F. H. (1977). "An Automated System for Cleaning Tanks and Parts used in the Processing of Pharmaceuticals," Bulletin of the Parenteral Drug Association, 31, No. 4, pp. 179-186. 

Hyde, John M. (1994). "Cleaning Validation Strategies", ISPE CIP/SIP Seminar, Kansas City, June 8-10, 1994. 

International Association of Milk, Food and Environmental Sanitarians, "3-A Accepted Practices for Permanently Installed Sanitary Product Pipelines and Cleaning Systems,"  Int. Assoc. Milk Food Env. San., P. O. Box 701, Ames, Iowa 50010, (No. 605-04 Continually revised; February, 1992) 

Kaufmann, O. W., Hedrick, T. I., Pflug, I. J., Pheil, C. G., and Keppeler, R. A. (1960). "Relative Cleanability of Various Stainless Steel Finishes After Soiling with Inoculated Milk Solids," Journal of Dairy Science, Vol. XLIII, No. 1, pp. 28-41. 

Richter, R. L., Bailey, J. and Frye, D. D. (1975).  "A Field Study of Bulk Milk Transport Washing Systems," Journal of Milk and Food Technology, Vol. 38, No. 9, pp. 527-531. 

Sheuring, J.J. and Henderson, H.B., (1951). Southern Dairy Products Journal, pp. 49, 52-53, 64-65. 

Thom, E. (1949). "Glass Sanitary Piping in Dairy Plants," The MILK DEALER, Vol. 39, No. 1, pp42-43, 134-138. 
 
Villafranca, J. and Zambrano, E. M. (1985). "Optimization of Cleanability," Pharmaceutical Engineering, Vol. 5, No. 6, pp. 28-30. 

Zoltai, P. T., Zottola, E. A. and McKay, L. L. (1981). "Scanning Electron Microscopy of Microbial Attachment to Milk Contact Surfaces," Journal of Food Protection, Vol. 44, No. 3, pp. 204-208. 

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