A hierarchy is an arrangement of items (assets, in our case) in which the items are represented as being above, below or at the same level as one another.

This forms a 'tree' structure - like that found below.

At their most basic level, they help to give what would otherwise be a large, daunting pool of assets a sensible, understandable and more easy-to-digest structure.

Examples of hierarchies include…

• An Organisational Chart
• The ISA-95 standard for process documentation

In most cases, ARDI hierarchies aren't there to illustrate that one item is 'superior' to another or controls it - instead, they are used to arrange your site from the most general location (the site as a whole) to a very precise one (a single machine or component).

The example above is a sample of a Location hierarchy. The Sensor is inside Cabinet 1A, which itself is in Building B, which is in turn in our main site.