P&ID Line-by-Line Review (Operational and Maintenance Review)

Conducted by the design/operations team, line-by-line review is the stepwise review of related groupings of design elements. Groupings may comprise an individual piece of equipment or a line with its valving, drains, sample connections, piping classification, insulation, heat tracing, etc. The review follows the general path of process flow.

This review is often used to obtain acceptance or approval by operations. It is logical and sequential (often a yellow marking pencil shows progress, a red pencil additions or changes). However, since the elements in each grouping usually have different functions, the immediate impact of a parallel element review is lost. Further, the process can be tedious, particularly when involving many lines with repeating features. Suggestions for conducting a line-by-line review:

• Break up sessions with parallel element review to dispose of the most repetitive elements
• Use interactive role playing, in which the operator walks through all steps needed to start up, run and shut down the plant. Design engineers, process representatives, etc., point out erroneous or missing piping, equipment and instrument elements