Hi all,
May i request you time to get some explanation regarding the design and the procurement in a major puming statiion. My understanding is like as follows,
1. For the design works, the main contractor will make the Process Flow Diagram(PFD) and the P&ID will follow.
2. The vendor will prepare the design of the major equipments(like pumps, transformers etc) based on the contract specification provided by the main contractor.
3. The P&ID can be finalised based on the input from the vendor(to show the data sheet details of equipments) and the hydraulic design.
4. Hydraulic design can start after the PFD, along with the P&ID.
5. The size and material of the piping in the P&ID will be decided by the main contractor's design team( required hydraulic design completion). Based on this finalized P&ID, the line list, piping layout & isometric drawings will be prepared by the main contractor. Then the vendor will prepare the shop drawings and can start the manufacturing of the pipes.
6. Electrical single line drawings, general layout, Junction box/socket schedules etc will be prepared/decided by the main contractor. or is there any design which will decide the no of junction boxes/panels etc?. I understand that the main contractor will select the supplier for this junction boxes and other minor items with an RFQ. Then the material submittal/approval and the commencement of manufacturing.
Please, anyone having experience in this sector share their views
Thanks
Kannan
Thanks Johannes
Gary,
Thanks for the detailed explanation.
Hi Kannan
Yes, like Gary stated, the engineering and procurement schedule is an iterative process whereby the design, engineering and procurement activities most of the time run in parallel. Where i look for this instance is the milestone when the Requsition for Purchase is to be completed. Just make sure to follow up very closely. Designers and engineers know that the can improve on almost every design activity and they will do so when you not tell them that they should adhere to the agreed schedule.
Regards
Johannes
Kannan,
You've pretty much got it right, but I'm afriad it is rarely as simple as this.
Process design jobs like pump houses are notoriously difficult to build and maintain a schedule for, becuase the design work rarely follows a simple FS style relationship.
For example, contractor may prepare a PFD which will drive the tender package for pumps, motors, transformers, etc. P&ID and hydraulic design work also begins.
Pump contract gets let, vendor design gives you different pump curves and electrical load requirements than expected, which means you have to re-spec your transformers and modify your hydraulic design. Also pump design requires better protection than expected, requiring more instruments and more complicated control measures. This all affects the P&ID.
It can be very iterative. -Often the next cesign work will start when the preceding task is only say 60% complete, and be modified later as and when assumptions are proved to be correct and/or incorrect.
The four key tricks to creating & monitoring a process design programme are:
1) Defining and agreeing very clearly what 100% looks like for a task (is it issue for comment, issue for procurement, issue for construction, etc)
2) Being prepared to ammend logical relationships to suit the developing situation.
3) Understanding the critical activities, and what %age of those activities are actually critical (maybe it's isue for procurement that is critical, but issue for construction has float).
4) Getting the designers to follow the programme and/or discuss with you before changing it.
Good luck!
G