Using P&ID Diagrams to Establish Location and Asset Hierarchies

Feb 16, 2023 | Materials Management Articles, Technical / Equipment, TRM Blog | 0 comments

John Q. Todd

Sr. Business Consultant/Product Researcher

Total Resource Management (TRM), Inc. 

By John Q. Todd, Sr. Business Consultant / Product Researcher at TRM.

Piping and Instrumentation Diagrams (P&ID) are foundational documents that give engineering, operations, and maintenance staff insight into the elements, interconnections, and relationships a system may have. As with any architectural type of diagram, they have a language of their own that a person needs to have at least a basic understanding of to get the most out of them.

There are many excellent sources of this knowledge, for example:  and

If your organization is involved in supporting process environments it is highly likely you have stacks of P&IDs available to you in some form or another.


Where to begin

It is often said that once something is committed to paper (or in a database) it becomes obsolete within a few minutes (or seconds!). P&IDs are no different. Often the contractor who built the system will provide them as part of their “as-built,” package. How consistent they are with reality is always a question worth asking.

Before getting all excited about the P&IDs you have, it is always a good idea to verify them against what is out on the production floor or in the walls. They will be close, but you will always find opportunities for a redline to adjust the drawing. Most likely your company has an official process to get these changes made.


Location, Location, Location

If you take a drone view of the P&ID on the desk in front of you, you may find lines of distinction that define the rooms, floors, and areas where the various components of the system reside. As you review the diagram you may find that V-123 (a valve of some sort) is in Room 101 and V-124 is in Room 102. This is important information for your Location hierarchy. The section of pipe in between these two valves, going through the wall, could be characterized as a linear asset (more on that later).

Immediately you have a decision to make: How low do you go when it comes to establishing your Locations from the P&ID? Many the arguments have occurred around this concept, so allow us to add some fuel to the fire.

Is it reasonable to suggest that the Location for V-123 should just be Room 101? Or, in the context of how your organization captures costs, should V-123 be its own Location within (under) Room 101? In that case the hierarchy would look like:



Room 101

V-123 (location)

Valve asset – S/N 344556

Or will the simpler approach suffice?



Room 101 (location)

Valve asset – S/N 344556

Other assets in Room 101…

The subtly here is that V-123, as listed on the P&ID, is acting more as a Location than an Asset. V-123 is a description of where the device is in the system, not the actual piece of equipment (a valve) that is at that Location.

While the initial design specifies the type of valve that needs to be at Location V-123, over time as the valves are replaced, completely different looking, yet the same form/fit/function valves, may be present at V-123.

If your cost accounting approach within your EAM/CMMS needs to be able to resolve costs down to the V-123 level (and follow the Asset during its lifecycle), then a Location for V-123 will need to be constructed. If just Room 101 is low enough for costing, then perhaps a Location for V-123 is not needed (other than Room 101).


What is the difference between a Location and an Asset?

Using V-123 in the P&ID as our example. Is that a Location or an Asset (a piece of equipment)? When you are translating a P&ID to a Location/Asset hierarchy for an EAM/CMMS system, V-123 is a Location.

What is at that Location is an Asset. The actual piece of equipment that is taking up space. Last week there was a valve with S/N 344556 at Location V-123, and today (due to a replacement), there is a valve with S/N 233445 there. Assets move in and out of Locations.

Linear assets are things like pipes, roads, cables, etc. that are typically broken up into segments for ease of identification. Remember that pipe between V-123 and V-124? The section of it in Room 101 would be an Asset at that Location and the section in Room 102 would be an Asset at that Location. Modern EAM/CMMS systems have accommodation for linear assets.


What if I don’t put Assets at Locations – everything is a consumable?

We assumed earlier that you are putting Assets with serial numbers at Locations. This is the typical case where not only are you tracking where the equipment is, but also the costs involved with moving Assets in and out of Locations. Perhaps when the equipment is replaced it goes out to a repair facility and returns to you in a refurbished condition. Perhaps too it gets placed back into inventory to be used in the future at a different (or even the same) Location.

If rather the equipment you are switching in and out is consumable… a replaced valve gets thrown away or recycled… then having the Location level of V-123 might still be important.

By having Location V-123 in your hierarchy, any work done at that Location… such as replacing those throw-away valves… can be captured. If you only had the Room 101-level Location, you would have no way of knowing “which” valve in Room 101 got replaced. “Somewhere in Room 101 we replaced a valve.” Not good, but maybe in your context that is ok.


What about systems definitions?

Modern EAM/CMMS software programs have accommodation for defining systems as well… but it is typically done via Locations. A Location is defined to play a role in a System. Assets, at the Location, are in the System by inference… they are at a Location in the System.

In our case, let’s pretend V-123 is part of the fire suppression system, as is V-124. Any Assets at those Locations are considered part of the fire suppression system. This makes finding what pieces of equipment makeup a System much easier.


Can P&IDs help me define Asset hierarchies?

Let’s define first what an Asset hierarchy is before we use it. In general, they relate parent and children Assets and by extension the spare parts needed for either or both. This gets a little tricky, so let’s use an example to illustrate.

Let’s pretend that the Asset that is present at V-123 is two: One is the valve itself (S/N 233445) and the other is the valve controller (S/N XCT1234). These two Assets might just be one unit that move around together. Or, you might have the situation where they could be separated and treated as individuals. In this case, the valve is the Parent, and the controller is the Child. Over time, the Parent valve may have many different controllers move in and out of the Child position.

The decision for you to make is the value of establishing this Parent/Child relationship at the Asset level if they are never separated. Maybe just defining a single asset (the valve S/N 233445) is enough.

Yet another element of an Asset hierarchy are spare parts. No matter the “level,” that an Asset is, it may need spares. Consumables such as belts, filters, fluids, gaskets, o-rings, etc. may all be parts you need to have a ready supply of. Knowing what those parts are, where you can get them, and any cross-references with equipment you already have, are important elements to track. The initial specifications for the equipment represented in the P&IDs are an excellent source.


How can TRM/IDCON help?

We have spent years helping clients form their Location and Asset hierarchies for their EAM/CMMS software programs. Same is true for establishing required spare parts (and their reorder frequencies) to support efficient preventive maintenance activities. No matter the industry nor the output of you production systems, we have the experience to make a difference.


Want more on location and asset hierarchies? Check out our Location and Asset Hierarchies 2.0 article. 


Reach out to us at if you have any questions or would like to discuss deploying MAS 8, Maximo AAM, or Asset Care Essentials (ACE) for condition-based maintenance/monitoring.




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