What is an asset hierarchy?

What an asset hierarchy is

Think of a filing cabinet. The top drawer holds everything the organization owns. Inside are folders for families of assets, and inside those are the specific kinds of equipment you inspect, maintain and replace. An asset hierarchy is that cabinet written down. It is a tree: every item has one parent and sits at a known level.

Each box in the tree is a class, a kind of asset, such as a plastic main, a pump or a bridge deck. The tree says what belongs to what. That is all it says. It does not say where an asset is, what it is connected to or when it was built. Those are separate questions, and the guide on hierarchy and relationships takes them one at a time.

Why it matters

• One name for one thing. If crews, engineers and finance each call the same kind of pump something different, every report needs translating before anyone can compare it.
• Define once, inherit everywhere. Set install date on a parent class and every class beneath it has it. Nobody retypes it two hundred times, and nobody forgets it on twenty.
• Totals that add up. Counts, costs and risk roll up to any level only if every asset has exactly one place in the tree.
• Somewhere to hang decisions. Data earns its keep when it informs a decision, and a hierarchy tells each decision which assets it covers. That is where data readiness starts.

Levels

A level is one row of the tree. Boxes at the same depth do the same job. The Gas distribution template has four levels:

1. System. The whole network or portfolio. Holds the data points every asset shares.
2. Asset group. A family of assets that are managed, budgeted and reported together.
3. Asset class. Assets alike enough to share a design life, an inspection regime and a cost model.
4. Component. A part that is inspected, maintained or replaced on its own schedule.

Four is typical. Rename the levels to match how your organization talks; the names are only labels. The classes sitting on them matter more.

Classes and instances

A class is a kind of thing. An instance is one particular thing of that kind. Plastic main is a class. The plastic main under one particular street is an instance. A hierarchy holds the classes. The instances, which can number in the thousands or millions, live in your records: the asset register, the maintenance system and the GIS.

Strata works at the class level on purpose. A class carries the data points that apply to every instance of it, such as material, install date and condition score. The value of each one for each particular asset belongs in your systems. That is why a few dozen classes can describe a network with 7,000 assets or 700,000. In the gas distribution template, 27 classes and 33 data points describe the whole system, and Strata holds none of the records themselves.

Common patterns by industry

Put the eight templates side by side and the same shape shows up. The top level is the whole network or portfolio. The second level splits it into families or segments. The third is the class you manage as a unit, and the fourth is the part you inspect or replace. What changes from industry to industry is the vocabulary and the way the second level is cut.

Bridges are cut by type of structure: Girder bridge, Truss bridge, Arch bridge and Culvert. Oil and gas is cut the way the industry cuts itself, into Upstream, Midstream and Downstream. Gas distribution is cut by the kind of equipment, such as Mains and Valves, and water by function, such as Water distribution and Water treatment. None of these is the only right answer. Each suits how that industry plans and spends.

Mistakes to avoid

1. 01

   Mixing location with asset type

   A branch called North district sitting beside a branch called Pumps forces a choice every time: is this pump a pump, or is it in the north district? Pick one way to cut the tree and record the other as a data point. The gas template is cut by kind of equipment (Mains, Services, Valves), and where a meter sits is a data point on its class, Meter location. The aviation template does the same with Operational area.

2. 02

   Too many levels

   Every level is one more thing to keep current and one more thing to explain. If two levels always have one child each, merge them. All eight templates here stop at four, and it is rare to need more.

3. 03

   Data points without a purpose

   A column added just in case costs field time for as long as it exists. Ask what decision each data point serves. In Strata every data point carries its purpose and the decisions it feeds, and the ones that feed none are flagged so someone can ask whether to keep collecting them.

See one working

The quickest way to get a hierarchy is to open one, click a class and see which data points it defines and which it inherits. The gas distribution template opens in Strata as your own editable copy, with nothing to sign up for. The page that describes it in full is the Gas distribution page, and the terms used here are defined in the glossary.