3 replies to this topic

[Aditya Karve]

P&ID is the most key document for any process plant so mistakes and inconsistencies must be avoided to improve the quality of P&IDs and to save rework. After working so many years in process industry I realized that making mistakes in P&IDs can put you in deep trouble. So please beware and recheck the P&IDs before issuing it to the client. I am listing here some of the key points you must check while preparing and developing P&IDs in any stage of engineering.

 

• Have you incorporated P&ID review meeting comments or some points are still open?
• Have you incorporated HAZOP comments?
• Equipment numbers and short spec checked with process datasheets?
• If there is a change in PFD, is it incorporated in PFD?
• All lines must have line no. and line sizes. if not put HOLD (project specific).
• Fluid description, line spec and insulation class should be checked.
• Spec breaks. (This is the most common mistakes beginners bound to make.)
• Show package boundaries.
• Line continuity must be checked before final issue.
• Valve type, slope, valve symbol.
• Minimum distance.
• Reducer/ Expander. 
• Destination of vents and relief points
• Set pressure of PSVs/ No isolation device/ No pocket comments.
• Instrument numbering according to project philosophy.
• If there are comments from other disciplines like piping, instruments, project, electrical. It must be reviewed first before representing it on P&IDs.

Regards,
AK

Edited by Aditya Karve, 27 August 2016 - 05:56 AM.

[Aditya Karve]

I will explain more about P&IDs in my upcoming posts.

[amad]

- Compare P&IDs to the legend & symbol because it is reference for making P&ID.
- Same with line continuity, instrument and package limit continuity must be checked if any.

- Do not forget to check the revised sheet (revision number, date & initial, description, etc). This item is also common mistake.

[Art Montemayor]

All:

 

There is something missing in this topic, and that is the specific identification of The STAGE of P&ID product we are discussing.  There are various stages of P&ID product:

• Preliminary P&ID - issued as tool for cost or investment estimate;
• Design P&ID - issued during the various facets of the total process design;
• Final P&ID - issued prior to being submitted to Hazop review;
• Issue for Construction - P&ID for specifying and purchasing key equipment and issued for construction;
• Revised Final P&ID - version used for commissioning and startup with all updated field revisions;
• Issued P&ID - P&ID issued to operations for process operation and control; subject to being revised as time goes on in operations.

The various points brought out have importance and value at different stages of development.  It is important to know whether we are discussing the P&ID development as it proceeds within an engineering contractor's scope or as the final operations P&ID developed for operations to employ and maintain during the life of the process.  As can be seen, this thread will take on the semblance of confusion if the various recommendations and suggestions are not specifically identified with respect to what stage of P&ID applies.  And if that is done, I can foresee a considerable amount of posts that will make this thread very, very lengthy.

 

Perhaps the topic can best be handled in an article or paper that is presented and posted in the web site, as are other topics.  I am presuming that the original poster has the experience and tools to discuss all the important points of this topic and so, could formulate such a paper or article.  I am totally open to all opinions and comments on this subject.