Computer system validation ? increasing supplier value 3



Figure 2
Also noted in Figure 2 is the situation regarding requirements that are satisfied within product specifications. If the required functionality is provided in a commercial-off-the-shelf (COTS) product then this functionality has been tested by repeated use across many installations and so does not need to be tested as part of the system tests. Only where the supplier project team has configured standard functions do you need to test that the configuration is correct. As a purchaser, however, you cannot absolve yourself of responsibility during the requirements trace process. First, the URS should be structured so it helps produce a trace matrix by
  • limiting each clause to a single requirement
  • giving a unique number to each clause
  • indicating whether the clause is for information or is a requirement to be satisfied under the contract.

Second, you need to be satisfied that the references in the matrix do actually relate to each of the stated requirements. Including the trace matrix within the supplier's scope also encourages discussion on each of the clauses in the URS and anything that promotes communication between purchaser and supplier is a good thing.
Regarding supplier training, you must ensure that the test records are going to meet the needs of documented evidence. This guidance should include:
  • The generation of test cases for each major section of the FDS, with sign-off points for each individual function, rather than signing off whole sections or pages.
  • Using initials and date to sign-off tests rather than simply using tick marks. This also requires a separate list of names, responsibilities, signatures and initials.
  • The use of black or blue ball-point pen rather than red (which may not photocopy) or pencil.
  • The deletion of text by a single line strike-through, so that the original text is still legible, with the addition of initials and date.
  • The command to never use liquid paper to alter a document.
Because the FATs will be witnessed by your own staff, they can help ensure the propriety of all test records. They will also be signatories to the tests, therefore, you will have evidence of who performed the tests and who witnessed not only their correct execution, but also that the desired result was obtained.
Case study
The supply of an automation system for an API manufacturing plant can help illustrate the concepts discussed above. In this case, an existing pharmaceutical manufacturing plant was modified to produce a new product, while still retaining the capability to make the product for which it was originally designed.
Because the existing control system could not be further expanded, input/output modules for new parts of the plant, and new controllers and operator interface were added to the existing field interface equipment. Product was made for stock so as to maintain supplies during the plant shutdown.

Table 2
The URS, produced by the purchaser, was structured to aid traceability. A small extract from the URS is shown in Table 2, where numbered clauses can be seen along with a distinction between information and requirement clauses.

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