A System is a logical grouping of Equipment that performs a specific function within a process or operation.
In Reliability Centered Maintenance (RCM), a System is an object defined under a Unit. Systems provide the framework for organizing equipment and conducting analyses. Every piece of equipment included in an RCM analysis must belong to a System.
Systems help define the scope of an RCM study and establish the context for identifying:
Functions.
Functional Failures.
Failure Modes.
Maintenance Strategies.
By organizing Equipment into Systems, teams can evaluate how equipment contributes to process performance and reliability.
Relationship Between Systems and Equipment
A System consists of one or more equipment items that work together to achieve a common objective.
For example, a Hydrodesulfurization (HDS) Unit can be split into three Systems:
Reaction section.
Stripper section.
Recycle gas section.
Various Equipment items belongs to a System, while the System represents the operational function delivered by the group as a whole.
Dividing a process unit into one or more Systems may require process knowledge. You can obtain this information from process descriptions, in operations training material, and plant process technologists or process engineers.
The above example details how to split an HDS Unit into three Systems. For more information, read the full article on the Terms of Reference for IMS-RCM study of HDS unit.
Relationship Between Systems and Functions
Functions are defined at the System level.
The System function describes what the System is expected to do, while Equipment within the System supports that function.