hierarchy levels

Hierarchy levels are structured layers used to describe how functions, systems, and data are organized within a manufacturing or industrial operation. They provide a common way to reference where activities occur, which systems are responsible, and how information flows from the enterprise level down to individual machines and equipment.

Functional hierarchy levels in manufacturing

In regulated and complex plants, hierarchy levels often follow industrial standards that separate business planning from manufacturing execution and physical control. A common model, aligned with IEC 62264 / ISA-95, includes:

• Enterprise / Business level (often called Level 4 or above): Long-term planning, finance, customer orders, and supply chain management, typically managed by ERP and business systems.
• Site / Plant level: Overall plant coordination, capacity planning, and site-wide performance management.
• Area / Line / Cell level (often called Level 3): Manufacturing execution, sequencing, dispatching, detailed scheduling, quality recording, and traceability, typically managed by MES and related execution systems.
• Process control level (often called Level 2): Automatic control of production processes, typically using SCADA, DCS, or PLC-based control systems.
• Equipment / field level (often called Level 1 and 0): Sensors, actuators, tools, machines, and other physical devices that directly interact with materials and products.

These levels are used to clarify which systems own certain data, where control decisions are made, and how responsibilities are divided between IT and OT.

Use in metrics, KPIs, and integration

Hierarchy levels are often referenced when defining and mapping manufacturing KPIs and data flows. For example, ISO 22400 KPIs such as Overall Equipment Effectiveness (OEE) or availability can be associated with specific hierarchy levels to show:

• At which level the raw data is generated (for example, equipment or control level).
• Which system calculates or aggregates the KPI (for example, MES at the area or line level).
• Where the KPI is consumed for decisions (for example, enterprise or plant management level).

In practice, engineering, IT, and operations teams use hierarchy levels to design system architectures, define interfaces between ERP, MES, and control systems, and document data ownership and responsibilities.

Common confusion

• Hierarchy levels vs. organizational hierarchy: Functional hierarchy levels describe systems and control responsibilities, not reporting lines or job titles.
• Hierarchy levels vs. network layers: They are different from network models that describe how devices are connected. A control system and a business system may sit on similar networks but occupy different functional hierarchy levels.
• Hierarchy levels vs. building layout: Physical plant layout (buildings, floors, and rooms) is separate from functional hierarchy, although both may use terms like “area” or “cell.”

Context for aerospace and regulated environments

In aerospace and other regulated industries, hierarchy levels are commonly used to document which level and which system is the system of record for production data, quality records, and traceability. When mapping standardized KPIs or compliance-related metrics, associating each metric with a hierarchy level helps clarify data provenance, validation responsibilities, and how evidence will be retrieved during audits.