Hierarchical Structure
This topic covers:
A strong argument can be made that the fundamental building block for all of asset management is the asset register. The register is a database that contains a systematic recording of all capital assets that are managed by the organization. The heart of the register is the asset record; indeed, the register is the aggregation of all asset records of the organization.
The register itself is built around two basic concepts:
- The record layout - that is, what attributes about the asset are to be recorded
- The asset hierarchy.
Which attributes are to be collected and how they are to be stored, retrieved, displayed and manipulated are key to an effective asset management system. However, the focus is on how the asset records themselves are to be organized – the asset hierarchy.
Creating an asset register starts with the definition of an asset unit. This is not as simple a step as may first appear. What seems a basic asset “unit” to one person may be viewed as being made up of several separate assets by another - system designers may refer to a lift station as an asset unit, while maintenance may distinguish the piping, valves, motor and building structure as each separate assets.
Getting the structure right is important because data collection is expensive. It is usually even more expensive to have to go back and gather additional data that could have been obtained the first time if the structure of the assets had been carefully developed before going into the field.
As a guiding principle, data should be organized into information systems so that it is aligned with the organization’s asset management responsibilities. Planning’s information needs are typically at a substantially higher level than, say, maintenance or operations. Because maintenance and operations have the most detailed information needs, the lowest level of data collection is termed a “Managed Maintenance Item” or MMI.
MMI designation, in fact, has been largely driven by State requirements for “lock-out/tag-out”, requiring tagging at a level arguably below that really necessary for maintenance and operations outside of safety requirements.
A classic rule of data organization recognizes that data can always be aggregated (rolled-up) to higher levels, but it can never be disaggregated lower than the lowest level collected. That is, if we store data at the lift station level as the lowest level of data, we can never retrieve data at the pump motor or valve level within that pump station.
However, tens of thousands of records at a highly disaggregated level are difficult to make sense of. The data hierarchy is typically deployed to resolve this data dilemma. Data is collected at the lowest level the organization feels it can afford, and then organized into logical roll-up groups that allow users to enter the database and extract information at the level most relevant to them at that time. Using this organized hierarchical approach allows the organization to select a given level of data to start its registry, then to drill down to lower levels as money and time allow or usage indicates a need for.
The graphic below shows a typical hierarchical structure:
Note that the hierarchy model impacts a variety of data, most notably cost data. The more sophisticated information systems simultaneously roll up cost data (maintenance, life-cycle, even operations) to whatever asset unit level is viewed by the user.
Some assets are somewhat mobile, that is, they are capable of being pulled and sent to the shop or back to the manufacturer. While the asset is pulled, asset functionality is maintained by swapping in a back-up unit. This characteristic requires the naming convention to recognize both the physical asset and the primary location of the asset.
Now let's consider the typical types of asset registers that exist today, the parent-child registers that allow us to roll up the performance on costs of the assets, for example in a city:
The type of hierarchies useful for an authority as part of the city is:
Then we can return to the key elements of the systems: collection, treatment and disposal.
In some cases there may not be a treatment plant or a disposal system, but they will all have a collection system.
If we know what we have, where it is, and what condition it is in, we can cost-effectively manage it. The next graphics show the extension of the register to cover the assets down to the MMI.
The more critical the asset data, the further down we need to drill to acquire the relative information.
Once we have determined the data required, then the data standards can be established.
Once we are satisfied with the agreed data standards, we can become more confident with the resultant collection of the data to populate the information systems. We will be able to roll up that information to provide meaningful and accurate data.
In general, the management structure will include an asset management group or committee with permanently responsible officers such as an overall asset management coordinator and in some cases, for larger organizations, coordinator specialists for each of the individual asset groups.
The final structure may follow the example shown below: