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The consultant was more interested in updating our process and instrumentation diagrams (P&IDs) than meticulously matching them to equipment in the field. His first attempt was a mark-up that was as “colorful” as it was difficult to read. He made some remarks about the inaccuracy of the P&ID to my boss, knowing full well that I had walked down part of the drawing as part of a project.
I told him to try again — this time using a grading system I had created. In addition, I pushed to start the asset list from scratch. Needless to say, he resisted. Corporate wasn’t on my side either because it was their list. However, after the next project review, the value of my approach became obvious. The consultant had spent over one hundred hours comparing asset spreadsheets against field walkdowns and P&IDs for two areas of the plant; 80% of the hand valves weren’t on the asset spreadsheets and many weren’t even on the P&IDs. Moreover, the drawing was speckled all over with leak points, designated “FLs” for flange leaks, including ones on either side of a flanged connection. Practically speaking, you probably can’t detect the source of a leak in a ¾-in. threaded valve — it could emanate from either of the two threaded connections or even the stem of the valve; so, just use one FL.
The next project review pointed up additional problems. The consultant flashed on the screen a marked-up P&ID that showed weigh-cell tanks as well as bucket conveyors and silos. I called out, “Whoa,” and then asked, “Does anyone see what’s missing?” Nobody, including the people on Skype got it. “Okay,” I said, “Either the weigh cells are reading zero or something ridiculous like 4,000 lb. Then, there’re the silos — where’s the air lock?” None of the young engineers in the room understood that tanks on scales and silos both use boots, which certainly are items you want to note in an asset program. This highlighted the need for my system.
This system uses letter designations from A to G, keyed to a “yes, no” (Y, N) checklist, to identify any discrepancies in assets as detailed on the P&ID, the asset list and in the field (via a walkdown):
A — not shown on the P&ID or asset list but found in the field (N, N, Y);
B — on the P&ID and the asset list but not found in the field (Y, Y, N);
C — not on the P&ID but on the asset list and found in the field (N, Y, Y);
D — on the P&ID but not on the asset list or found in the field (Y, N, N);
E — not on the P&ID but found on the asset list but not in the field (N, Y, N);
F — on the P&ID and the asset list and found in the field (Y, Y, Y); and
G — on the P&ID but not on the asset list but found in the field (Y, N, Y).
The lettering system allows someone to identify the efficiency of each criteria. Of course, you only should include items found in the field, i.e., those with a “Y” in the third column, on an asset spreadsheet.
Any “B” designated item, i.e., one that appears on the P&ID and the asset list but not in the field, demands investigation. Was it removed? Was it never installed? Is there a drawing error? Why is it listed on the asset list?
Never attempt to compile an asset list from drawings known to be inaccurate or incomplete.
This particular asset-list development coincided with preparations for a hazard and operability study. I was updating 20 key drawings on the site while the consultant was working with plant staff to create the asset list. Their efforts proved illuminating. For instance, as already noted, they found that 80% of the hand valves in the field weren’t on the asset list. I wasn’t surprised. I had a similar experience elsewhere. I also noticed that the consultant’s markups were far less accurate than mine. Remember, a consultant can clean up drawings if they’re at least 90% accurate; no consultant budgets the time to undo the disaster when drawings are just plain wrong.
Our next meeting set things on the right course. The site is using my method and planning more frequent meetings to keep efforts aligned and achieve accurate results.
