With these caveats, what are some of the key features of 3-A Sanitary Standards and 3-A Accepted Practices?
Scope
Every 3-A Sanitary Standard and 3-A Accepted Practice pertains to the sanitary aspects of a specific type of the equipment or system. For 3-A Sanitary Standards, the scope states the function and limits of the equipment and distinguishes the applicability of the document from those found in other standards. For 3-A Accepted Practices, it identifies the nature of the system, the subject or application, and features that are distinguishable from those found in other Accepted Practices. In both cases, the scope is (or should be) concise, but complete enough to define the boundaries of the equipment or system. Very simply, the scope is the statement of intent.
In some cases, the scope may provide restrictions of the 3-A Sanitary Standards or 3-A Accepted Practices. However, the limits and functions of the equipment or system cannot be overemphasized, since the scope defines the criteria necessary for the rest of the document.
Normative References
A series of Normative References are typically named in the document. Provisions of other 3-A Sanitary Standards are frequently referenced in a typical 3-A Sanitary Standard or 3-A Accepted Practice, such as materials requirements or requirements for specific types of equipment (e.g. valves, fittings) . Other standards and references are also named in a 3-A SSI document. These might include materials specifications, regulatory requirements, guidelines and other publicly available specifications.
Definitions
The Format and Style Manual is a compendium of definitions for terms used in various 3-A Sanitary Standards and 3-A Accepted Practices. These definitions have been painstakingly developed through the consensus process. Why are these definitions and terms so significant? These definitions provide a consistent and uniform reference for various 3-A SSI documents. Even more important, these definitions are the result of a careful consensus development process and the terms reflect a substantial history of use and interpretation among regulatory authorities.
In rare cases, a definition used in a particular document could vary from the Model, but the exception and the reason for the variance will be detailed and limited to the particular document.
A specific 3-A Sanitary Standard or 3-A Accepted Practice will show the terminology and definitions specifically used in the document. The number of definitions depends on the equipment being covered. For example, the standard for membrane modules contains over 80 definitions! All of these definitions were critically needed to cover all the special terminology. Many standards need only 10 to 20 definitions. Just a few of the key definitions include types of cleaning, fittings, inspectable, readily removable, sanitization, surfaces (product contact, nonproduct contact, splash contact, processing air contact and exhaust air contact) and surface modifications, including various treatments and coatings. In addition to greater than 40 more-or-less “standard” definitions found in the Format and Style Manual, other definitions may be specifically needed in certain standards. For example, terminology necessary to describe specific equipment or systems may also be included, especially if they are not standard terminology. Other terms, if needed, rely on standard dictionary references. All additional definitions, when used, are developed through the consensus process.
Materials
Many different types of materials are used in the design of 3-A equipment for different applications. Every 3-A Sanitary Standard includes a materials section, which describes those materials acceptable for product contact and those for nonproduct contact. Sanitary specifications dictate allowed materials, with the ultimate criteria being based on the environment of its intended use.
The accepted materials must be suitable for sanitary application, be durable, and be nontoxic (as defined by the Food, Drug, and Cosmetic [FD&C] Act); they may also be a regulated indirect food additive or be demonstrated not to be a food additive or found on the FDA Premarket Notification List (Refer to www.fda.gov).
The benchmark for materials is the AISI 300, excluding 301, Series Stainless Steel or the Alloy Cast Institute (ACI) for cast equivalents. Metals that can be demonstrated to be at least as corrosion resistant as the AISI 300 Series Stainless Steel and are nontoxic and nonabsorbent are also acceptable. Exceptions to the AISI 300 Series Stainless Steel are usually permitted for specific materials reviewed by the 3-A Working Groups when the required function does not allow for the use of the AISI 300 Series Stainless Steel.
Rubber, rubber-like materials, and plastics are the most common material exceptions to stainless steel. Specific 3-A Sanitary Standards have been developed for rubber, rubber-like, and plastic materials. Thus, whenever these materials are used in product contact areas, they must conform to these materials standards. The specific requirements for rubber-like and plastic materials are described at length in othermonographs in this section.
Other permitted materials include the AISI 400 Series Stainless Steel, ceramic, carbon, and plating materials such as chromium or nickel, and other surface- modifying materials and techniques. The exceptions to the AISI 300 Series Stainless Steels must specify certain parts or functions where required, and their use is then limited to those identified parts or functions.
Fabrication
Criteria for the construction and fabrication of 3-A equipment are critically important. All 3-A Sanitary Standards specify fabrication criteria for equipment to be cleanable and to preclude the contamination of the product. Sanitary criteria always include surface finish requirements (generally equivalent to or smoother than a 32 µin. (0.8 µm) Ra ) that is free from imperfections such as pits, folds, and crevices, limitations of radii, draining requirements, accessibility for cleaning and inspection, and design requirements for the proposed method of cleaning including Clean in Place (CIP), Clean out of Place,(COP), or manual cleaning (wet or dry brushing). The integrity of sealed product contact and nonproduct contact surfaces must not be compromised.
In the development of 3-A standards, the usual procedure is to include verbiage in the Appendix that the 32 µin. (0.8 µm) Ra smoothness is generally achieved by provision of a No. 4 finish, and also that 2B cold rolled stainless steel sheets free of defects are considered satisfactory, where appropriate. This means that such inspected 2B sheets may be used for certain applications (e.g. to construct tanks, spray dryers) with subsequent mechanical No. 4 polishing of only the joining welds. Because of light reflectance differences, the polished areas will be highlighted and will look different. However, the fabrication would conform.
The Format and Style Manual details the minimum radii requirements for product contact surfaces. For some equipment, ¼ in. may be specified as the normative minimum radius, but usually with certain exceptions having lesser specified radii. For other equipment, the appropriate normative radius might be 1/8 in., again with some exceptions. Anyone who has manually cleaned dairy or food processing equipment understands that sharp internal angles are hard to clean; gently curved corners make the job much easier.
Conformance to 3-A criteria does not automatically imply compatibility with CIP cleaning since most Standards provide for both manual cleaning and CIP cleaning. CIP cleaning does not preclude regular breakdown of equipment for inspection. Function is not included unless it is necessary for public health reasons such as ingredient addition, product removal, or in the case of aseptic equipment, automatic shutdown.
Optional Sections
A 3-A Sanitary Standard may include other sections, when needed. These optional sections include:
- Special Considerations—This Section is used where unique fabrication or installation requirements are necessary, such as where HTST pasteurization systems are integral with spray dryer systems or evaporators.
- Installation—This section is optional for standards but required for most practices. Installation criteria, when required, may include but is not limited to the Grade A PMO or other regulatory requirements; proper juxtaposition of equipment, floor, wall or ceiling clearance; and interconnections and hard wiring for required regulatory controls. In 3-A Accepted Practices this section is in the body of the document; in 3-A Sanitary Standards, if used, it may be in either the body or the Appendix.
- Appendix—The Appendix is an advisory or informative section of 3-A Sanitary Standards or 3-A Accepted Practices unless specifically cited in the Fabrication Section as requiring conformance. Although generally optional, this section is usually found in 3-A documents. The Appendix usually includes references to stainless steel materials and provides methods for achieving and measuring the required product contact surface finish. It may also include other advisory information useful for proper construction, material specifications, installation, cleaning and diagrams of the equipment or system covered by the 3-A Sanitary Standard or 3-A Accepted Practice.
Even when not considered as normative by reference, regulatory agencies under their procedures and authority may use the non-normative Appendix information during inspections if no other guidance on Appendix items is available from the fabricator or the processor. The Appendix may also contain representative diagrams of equipment or systems and a suggested format for the Engineering Design and Technical Construction File (EDTCF). The EDTCF is to be maintained by the fabricator for all products, assemblies and sub-assemblies as evidence of conforming to 3-A Sanitary Standards or 3-A Accepted Practices. The maintenance of this file is required for authorization to display the 3-A Symbol.