TS EN ISO 5459

TS EN ISO 5459 is the Turkish adoption of the standard that addresses how datums and datum systems are identified and understood in the context of Geometrical Product Specifications (GPS). Its subject is the consistent definition of the reference elements used to control orientation, location, and other geometric relationships in technical product documentation.

Datum concept and datum systems

The standard focuses on how one or more datum features are designated, how a datum or datum system is established from them, and how that information is interpreted on a technical drawing or product definition. In GPS terms, a datum is the theoretically exact reference used for measurement, positioning, and geometric tolerancing; a datum system combines multiple datums into an ordered reference framework. That distinction matters because it keeps geometric tolerancing separate from dimension chains and prevents ambiguous interpretation.

Technical framework covered by the document

• It provides terminology, rules, and methodology.
• It addresses the indication and understanding of datums and datum systems in technical product documentation.
• It defines the specification operator used to establish a datum or datum system.
• It states that the verification operator is not the subject of this document; verification may be physical or mathematical and is handled elsewhere.
• It notes that detailed rules for maximum and least material requirements for datums are given in ISO 2692.

In general engineering practice, datums are essential when parts must be manufactured, inspected, and assembled against a common reference. Clear datum definition helps align design intent, inspection strategy, and production setup. In that sense, the standard provides not just notation guidance, but the conceptual structure that supports coherent geometric tolerancing.