Professional division of labor for processes and instrumentation during the process package design phase

Looking forward to experts' replies:victory:

In our unit, the instrument numbers are proposed by the process engineering team, and then reviewed and modified by the instrumentation team; at least the leading digits remain unchanged, while the letters indicating the functional combinations may require adjustments on the part of the instrumentation team. The process specifies the control conditions, medium conditions, and environmental conditions, which are then forwarded to the instrumentation team. The instrumentation specialists first assess the Rationality of these conditions, suggest any necessary modifications if there are doubts, select appropriate instruments based on those conditions, and at the same time convey the relevant requirements to the other involved teams. As for the PID diagrams, I obtain them directly from the process flow, making only certain modifications to highlight the aspects related to instrumentation. PS: This is just my opinion; if there are any shortcomings, please point them out so that we can all learn together and help one another.

Thank you, I think this explanation is reasonable.

Step 1: The process engineering team specifies the control requirements and works together with the instrumentation team to develop the PCD, which represents a general control strategy. Step 2: The process engineering team further refines this approach to create the PFD. Step 3: The process system is established, and the system is used to balance the pressure levels, allowing for further refinement. Step 4: The initial version of the P&ID is sent to the instrumentation team, who assign tag numbers; it is then sent back to the system for further improvements. This process is repeated until the client gives his approval.

During the process package design phase, instrumentation should not be selected yet; at most, it can be determined from the numbering whether it is a temperature, pressure, flow, or level measurement and analysis instrument, as well as whether it is for local use or remote transmission. Selection of instruments is part of the detailed design work, and providing information on the installation conditions of these instruments to the piping and electrical teams is also part of the detailed design tasks. The numbering of instruments on the PID should be determined by the instruments themselves. However, since cross-referencing is common in current designs, even when there are many process packages, it’s not necessary to redraw the PID diagrams; therefore, in many cases, the instrument numbers don’t need to be assigned from scratch – slight adjustments are sufficient. Of course, the numbering of instruments can’t be done arbitrarily either; it’s necessary to take the owner’s opinions into account. If the owner doesn’t provide any suggestions, then another approach may be needed. Still, unless a new control room is built for the facility where the process packages are located, it’s best to consider the owner’s views. Of course, these matters are mainly handled by those responsible for the detailed design. In the end, the PID diagram that is produced is the same as one related to the process and instrumentation. Therefore, any changes are made within the same PID diagram. In fact, on the old design drawings, the PID diagram required signatures from all three parties involved in the process and instrumentation aspects. But these days, after various drawings are referenced against each other, the role of the instrumentation team in making changes to the PID diagram has become increasingly limited. So, in small design institutes like ours, signatures from the instrumentation team are now only required for approval; it’s not clear what the practice is in larger design firms!