Cleanability of Equipment and the Role of the 3-A Sanitary Standards
How clean is clean? Can you have ranges of clean, such as, pretty clean, almost clean, generally clean? Generally, the answer to these questions is, No. There is no such thing as ‘partly’ clean. Either you are or you aren’t. There are, however, degrees of soiling – slightly soiled, minor product residues, soiled, heavily soiled, filthy, “call the HAZMAT crew”, etc.
One of the basic roles of 3-A Sanitary Standards and Accepted Practices is to ensure that equipment designed and fabricated according to the criteria will be cleanable. These criteria include selection of materials of fabrication that are compatible with the product and the aggressiveness of commonly used cleaning and sanitizing chemicals. Also included are fabrication criteria to eliminate or reduce the number of cracks and crevices where product residues may lurk, sufficiently large radii in internal angles to prevent soils from being retained, product contact surface textures that facilitate the removal of soils, and the ability to easily disassemble the equipment for cleaning and inspection as necessary. All of the criteria lead to a design in which every product contact surface that can be touched by product will also be in contact with cleaning solutions at the proper temperature and flow rate so that all product residues are removed.
This would seem to imply that all equipment meeting a 3-A Sanitary Standards or Accepted Practices is suitable for CIP cleaning. This is not accurate and, unfortunately, the source of a misconception concerning 3-A conforming equipment. 3-A Sanitary Standards or Accepted Practices are written to cover the entire range of designs and methods of cleaning from “bucket and brush” methods to full CIP.
The 3-A SSI standards writing guide, the Format and Style Manual, defines the following styles of cleaning.
Clean-in-Place (CIP) Cleaning
(CIP—previously referred to as mechanical cleaning.): The removal of soil from product contact surfaces in their process position by circulating, spraying, or flowing chemical solutions and water rinses onto and over the surfaces to be cleaned. Components of the equipment, which are not designed to be cleaned in place, are removed from the equipment to be COP or manually cleaned.
Product contact surfaces shall be inspectable, except when the cleanability by CIP has been documented and accepted by the regulatory agency. In such accepted equipment all product and solution contact surfaces do not have to be readily accessible for inspection (for example: permanently installed pipelines and silo tanks). Such exceptions shall be noted in those specific Sanitary Standards.
Removal of soil when the equipment is partially or totally disassembled. Soil removal is effected by circulating chemical solutions and water rinses in a wash tank, which may be fitted with circulating pump(s).
Removal of soil when the equipment is partially or totally disassembled. Soil removal is effected with chemical solutions and water rinses with the assistance of one or a combination of brushes, nonmetallic scouring pads and scrapers, and high or low pressure hoses, with cleaning aids manipulated by hand.
Cleaning with a vacuum cleaner and/or dry brushes and other tools.
As you can see, all styles of design and cleaning are provided for.
The goal of production managers is to maximize the amount of time that equipment is engaged in the production of products and minimize the amount of time the equipment is out of production for cleaning and maintenance. The ultimate situation would be for the operator at the end of production to push the “Clean” button, walk away for a break and upon return push the “Run” button. Unfortunately, this scenario is not available – although some have tried it in practice with not so good results.
The definition for Clean-in-Place (CIP)
Cleaning defines two subsets for this method. Very few types of equipment are suitable for complete CIP cleaning in which the entire cleaning process has been documented and validated so that the product contact surfaces do not have to be available for inspection after cleaning. In the dairy industry, this situation can occur for welded pipelines systems. These systems are engineered and installed with an integral programmable cleaning system that controls the cleaning solution additions, temperatures, flow rate, and cleaning times. If the pipeline system incorporated automatic valves, they too must be programmed to cycle during the cleaning regimen in order to assure that all of the seal faces receive adequate cleaning. The sophistication of these systems does place them in the “Run-Clean-Run” button category.
Equipment that falls into the other subset of CIP cleanable equipment does require the removal of some appurtenances for manual or COP cleaning and, since the cleaning regimen has not been documented and validated, are required to be easy to disassemble for inspection and additional cleaning as needed. This subset covers the vast majority of equipment and requires more design and operator intervention to assure cleanability while fully or partially assembled than equipment that will be cleaned by COP or manual methods. Unfortunately, some equipment sold and advertised for compatibility with CIP cleaning is not suitable.
To be compatible with CIP cleaning methods requires more than merely installing a spray device or circulating cleaning solutions through the equipment. To be truly compatible, the method of cleaning has to be part of the initial design planning stage. It cannot be an after thought. Extra care must be taken to design out all crack and crevice areas where product can seep but cleaning solution cannot reach with sufficient flow to remove all traces of the product. If there are areas where this cannot be accomplished, then the areas have to be identified for disassembly for manual cleaning methods. For example, the crevice condition between a plug valve plug and the valve body is not inherently bad or unavoidable. However, it is not compatible with CIP cleaning procedures. The only acceptable method of cleaning this unavoidable crevice is to fully disassemble the plug from the body and manually clean all of the parts. Equipment that is legitimately compatible with CIP cleaning methods have sophisticated designs that have evaluated all of the potential trap areas and dealt with them. When that is accomplished the designers can then locate spray devices so that all of the product contact surfaces identified for cleaning while fully assembled receive adequate flows of cleaning and sanitizing solutions. While a properly designed CIPable piece of equipment may not have to be inspected on a daily basis, it is incumbent on the operator to have a clearly defined inspection schedule to validate cleaning. Correspondingly, it is incumbent on the equipment designer to design the machine so that the product contact surfaces are accessible and easy to disassemble for inspection. An added benefit of the inspection schedule and ease of disassembly allows the operator to perform preventive maintenance and seal or gasket replacement before they become a potential hazard to the product safety. Adherence to the 3-A Sanitary Standards criteria can assure these goals are achieved.
Design features that facilitate the 3-A criteria for readily or easily removable become especially important for equipment that is designed for COP and Manual cleaning methods only. The pertinent Format and Style Manual definitions are:
Readily Removable: Designed, fabricated, and installed to be quickly separated from the equipment with or without the use of simple hand tools.
Simple Hand Tools: A screwdriver, wrench, mallet, or readily available dedicated tool(s) normally used by operating and cleaning personnel.
Modern high volume equipment does not lend itself to parts removable by hand only. Therefore, it is common for plant production and cleaning personnel to use the simple hand tools identified above. Even with the allowance of the use of tools for the disassembly of COP or manually cleaned equipment, there are visual clues that designer should keep in mind when designing the equipment. For example, a cover secured with “wing-nuts” or “T-bolts” readily conveys to cleaning personnel that these fittings are to be removed much more clearly than a series of multiple cap nuts and bolts. The fewer the number of attachment fittings tends to convey ease of disassembly. “R” clips are another method to convey that parts are removable.
Buyers of sanitary equipment can greatly improve their assurances of purchasing equipment which can be effectively cleaned by all of the identified methods if they specify the equipment conforms to the appropriate 3-A Sanitary Standard or Accepted Practice. An even greater assurance can be gained by requesting that the equipment bear a 3-A Symbol. The 3-A Symbol signifies that an independent evaluator has conducted a third party evaluation of the design to confirm conformance with the standards criteria.