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ISA-95 Equipment Hierarchy

The ISA-95 Equipment Hierarchy outlines how physical assets and control systems are structured within an organization.

It is broken into the following levels:

  • Enterprise: The top level, representing the entire organization. This includes overall business processes and decision-making entities, typically supported by ERP systems.
  • Site: Represents a specific geographic location or facility. Each site can have its own management systems and local production control.
  • Area: An operational division within a site, often a functional area such as packaging, assembly, or warehousing.
  • Process Cell: The basic unit of manufacturing within an area. It encompasses all the equipment required to produce a specific product or perform a specific function.
  • Unit: A distinct part of the process cell, responsible for a specific function such as mixing, heating, or assembling.
  • Equipment Module: A modular piece of equipment that performs a specific task within a unit. For example, in a mixing unit, the module could be a heating element.
  • Control Module: The lowest level, representing individual devices or controllers such as sensors, pumps, actuators, or PID control loops that handle direct control of physical processes.