Change control systems definition

Sherwin-Williams has developed such a polymer process control system. The methodology used to accommodate the contrasting requirements has two key elements. First, the software is based on a simple architecture that places the definition of changing reactor hardware elements and characteristics in easily modified configuration files (5). Second, the language uses a small number of basic commands to describe formulations and reactor control. Complex operations are described by reference to commands tables (macros) built using several basic commands or other macros. 

Computerized System Requirements and Electronic Records Increasingly, computerized systems and electronic records are part of a laboratory s operations. However, records may be held in both paper and electronic format and the quality assurance required depends to some extent on the format of the definitive document. Because of space requirements involved with paper records and ease of retrieval of electronic records, the latter are gaining in popularity. The same requirements that we have for paper records, e.g. change control, readability and archiving, will still apply to electronic records. For this to be achieved, new procedures may have to be developed. 

Qualification of equipment and validation of computer systems are not one-time events. They start with the definition of the product or project and setting user requirement specifications and cover the vendor selection process, installation, initial operation, ongoing use, and change control. 

For retrospective validation, emphasis is put on the assembly of appropriate historical records for system definition, controls, and testing. Existing systems that are not well documented and do not demonstrate change control and/or do... 

It is recognized that the URS may be superseded by the FDS as the definitive specification for system design. The URS, however, remains the technical and operations statement of user requirements and must be maintained under change control as an up-to-date document throughout the life of the system. The URS also remains the base document against which PQ is verified, and once the URS is approved a PQ test plan can be generated. 

Because of the sophistication of new automated control systems and the complexity of the growing list of responsibilities, the requirements for a process employee changed. No longer can they be someone who could come in off the street without training or experience and be trained for the job in a few days or even a few weeks. The fact that operators, instrumentation technicians, and analyzer technicians are now more frequently referred to as technicians implies a change in their roles. The definition of technical is having special or practical knowledge of a mechanical or scientific subject. 

Terminology The International Standards Organization has recently defined a corrosion inhibitor as a chemical substance which decreases the corrosion rate when present in the corrosion system at a suitable concentration, without significantly changing the concentration of any other corrosive agent. This last point is significant since it excludes chemicals employed for deaeration or pH control from the definition of a corrosion inhibitor. On the other hand, it should be noted that the inhibitor is .. . present in the corrosion system. . . , and thus arsenic when added to brasses to prevent dezin-cihcation may be classified as an inhibitor. 

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