The current approach of communicating P&ID uncertainty by highlighting the uncertain area with a “cloud” and marking it with the word “hold” is inefficient. Research indicates that while the current approach is widely used, it is unsatisfactory for the following reasons (RS47-1, p. 14):
- No specific information about what is uncertain in the “hold”
- No contact point for P&ID users to clarify the information pertaining to the “hold”
- No time of reference for when the information will become firm
- No recommendation for follow-on action
Tool 1 – specifies those information items that will remain uncertain, which discipline/engineer to contact for clarifying “on-hold” information, and when “on-hold” information will be released.
Tool 2 – adds an estimated level of certainty of an “on-hold” P&ID item, and suggests a course for follow-on action.