As mentioned earlier, the site engineering responsible for construction, then followed by the pre-commissioning team, then project start-up HSE safety team, and finally the commissioning team typically uses the "Issued/Re-Issued for Construction" drawings to construct and modify the plant.ĭuring the construction phase in spite of all the stringent measures, there are surprises now and then, after all, it is designed by humans.
Normally the Standards, Guidelines, Best Practices, and Project specifications are followed to keep the requirements aligned and maintain uniformity. When a new plant is built, there are so many aspects that cannot be visualized sitting in an office. But nowadays it is limited to utmost ten or lesser revisions because of the detailed scrutiny, comment it undergoes at each and every stage. There have been P&IDs of existing plants that have undergone minor modifications with revisions up to a crazy number. And each time they are provided a revision cloud along with a revision triangle. In an existing plant that may be very recent to very old the modifications or revamp may be done over a period of the plant's life and these are generally covered by the title "Revised As Marked", where modifications are done. There may be different revision nomenclature followed plant to plant, a project to project, or country to country, and the typically the terminology used is "Re-issued for_" Issued for Comments or Issued for Review or Issued for IDC The typical sequence of revision cycle could be as follows:ġ. Be it Feasibility, Conceptual, FEED, Basic Engineering, Detailed Engineering, Pre-Bid Engineering, Procurement, Construction, Post Construction, Commissioning, Post Commissioning.Īfter Commissioning, during its course of operation, either due to advancements in technology or due to better or safe or ramping up production, the process design possibilities considering there is a business interest, P&IDs are modified through Plant Change Request (PCRS) or through Management of Change (MOC).
P&IDs like any other documents undergo multiple revisions during the various design stages of the project. To refer in more details, other delvierables of process engineering documents are to be referred. The specification cannot be detailed on P&ID so bare minimum information related the direction of flow, tie-ins, material spec, sizes, type of instruments, symbols, types of equipments, basic process design and capacity data is mentioned in the P&ID so that it doesnt become congested. P&IDs are nothing but the process depicted in a flowchart manner containing information related Piping, Equipments - both static & rotating, Instruments - electronic, transmitters, sensors, transducers, valves mechanical devices such as valves, fittings, welded or fitted located in the plant. Most of you, especially those working in Process Industries (such as Oil & Gas, Petro-chemical, Refining, Chemicals, Fertilizer, Pharmaceuticals, Paints, Food & Beverage) are familiar with what P&IDs are, and their content. P&IDs basically reflect the chemical process plant required by the client and is one of the most important engineering documents for any process plant. Of course, there are many more Process Engineering Deliverables as mentioned below.īut this article is going to focus on P&ID and what As-Built'ing of P&ID is all about and why is it very important. Not many are aware of this aspect of Engineering and Construction Projects and this article intends to put in a very focussed perspective on what "As-Built'ing" is all about.Įveryone into Engineering Procurement Construction (EPC) for Process Industry is aware that during the engineering design phase an important task by the process engineer is to prepare "Piping and Instrument Diagrams", abbreviated as P&IDs.