Completeness of Coverage

We may follow all the procedural recommendations given above, and still not identify all issues within the scope of the study. This can occur if all the Process and Instrumentation Diagrams (P&IDs) in the scope have not been studied, or if not every section of the P&IDs are subjected to study. It is also possible if the P&IDs are out of date, and omit recent changes. Our procedure therefore calls for a statement of scope listing all P&IDs to be studied, and a requirement that only if the team specifically agrees should particular P&IDs not be studied, and that this will require a suitable explanation.

It is normally the Leader's responsibility to ensure that all equipment on each P&ID has been studied, and if this is done by marking each study section on a master file drawing, the completeness of cover is documented, and can be checked later by a QA reviewer.

The Leader in the study of an existing plant who is informed that a P&ID is not up to date (by a team member) must put that drawing aside until it can be accurately marked up or updated. He should not accept that a team member mark up the drawing in the study: physical checking is essential. This is a mandatory part of our procedure.

For batch systems, it is also necessary to ensure that all sections are studied for each process step. This can normally only be checked against the log sheets.