There is a crucial difference between looking at your P&IDs and reading your P&IDs. When was the last time you sat down and actually read your P&IDs? Have you taken the time to go line-by-line and understand what the P&IDs are depicting? We can imagine your answers to these questions, so next ask yourself, — “If not you, then who?”.
A facility’s P&IDs act as the foundation for so many other efforts at a facility. They serve as the starting point for PHAs, relief system and effluent handling design, operating procedures, capital projects and modifications, and control screen design. P&IDs are a vital part of the day-in and day-out safe functioning of a facility.
The scope of what we are discussing here does not include getting your P&IDs to match what is in the field — that is a much larger effort that entails walkdowns, red-lines, and CAD efforts. The low hanging fruit that we have found most of our clients have yet to pick is achieving consistency and readability with their P&IDs. From our experience, this effort can be completed in just a few days with little time or monetary investment by the facility.
So, what do we mean when we say consistent and readable P&IDs:
- Do the valves, lines, equipment, and instrumentation match the legend?
- Do lines leaving one P&ID connect properly to the next P&ID (line size, line name, line description, and P&ID numbers)?
- Does each manual valve, control valve, instrument, and PSV have a unique tag?
- Are flow arrows oriented in the proper direction?
- Are equipment blocks fully filled out?
- Are regulators oriented in the proper direction?
- Are bypass valves shown as normally closed?
- Is the P&ID spaced reasonably and is the P&ID readable?
The selection of questions posed above are just a handful of items someone can identify simply by critically reading your P&IDs.
When Cognascents gets contracted by a company to perform a PHA, we come across these types of errors on the P&IDs during our preparation. When we create our node boundaries and highlight each line on the P&IDs, we often find the first batch of P&ID errors. Then, as we are prepping all the causes of a PHA by opening/closing every valve, we find the rest. The key thing to note here is that often we have never even been to the facility, and yet we can find errors by going into the granularity that is required to prepare for a PHA.
There are PHAs where a handful of errors are found on each P&ID, which sums up to hundreds across the PHA. Circling back to all the other efforts that P&IDs serve as the foundation (PHAs, relief system and effluent handling design, operating procedures, capital projects and modifications, and control screen design), it becomes easy to see how errors propagate through a facility’s documentation.
Please take our experiences from across the oil, gas, and chemical industries (including upstream, midstream, and downstream) and apply it to your site. It will not take you long, and it will not cost your company much money because we are saying you can do it internally within a few days’ time. Take the opportunity to pick a low hanging fruit and make your facility safer.