Overview
EN ISO 6412-1:2018 / ISO 6412-1:2017 - "Technical product documentation - Simplified representation of pipelines - Part 1: General rules and orthogonal representation" - defines conventions and rules for creating simplified, orthogonal drawings of pipes and pipelines made of any material (rigid or flexible). The standard is intended for use whenever pipes or pipelines must be shown in a simplified manner (including analogous ductwork for ventilation and air‑conditioning when “duct” substitutes “pipe”).
This standard is essential for consistent, clear piping drawings, supporting interoperability across engineering teams, CAD documentation, procurement and maintenance records.
Key topics and technical requirements
- Representation of pipes: Flow lines represent the central path of pipes as a single continuous thick line (type A). Bends may be simplified or shown with circular arcs to improve clarity.
- Projection method: Focus is on orthogonal representation (projectors at right angles to the projection plane). Isometric rules are provided in ISO 6412-2.
- Scale and drawing conventions: If drawings are to scale they must be indicated per ISO 5455 (scales).
- Line types and thickness: Line thickness and types follow ISO 128 series; where multiple thicknesses are required, specified proportions and selection rules apply.
- Lettering and dimensioning: Lettering styles and dimensions follow ISO practices (e.g., ISO 3098‑2, ISO 129‑1). The standard addresses presentation of lettering, dimension placement and tolerancing.
- Crossings, connections and fittings: Rules for showing crossings, connections, flanges, fittings, supports, hangers and adjoining apparatus ensure unambiguous interpretation.
- Direction of flow and equipment: Conventions for showing flow direction and simplified representation of equipment and components are included.
- Examples and illustrations: Figures illustrate conventions (not as design examples) to aid correct application.
Applications and who uses it
- Piping designers and mechanical engineers creating simplified layout drawings for process plants, utilities and MEP systems.
- CAD technicians and draftsmen standardizing pipeline drawings and documentation.
- Plant engineers, maintenance teams and procurement staff who rely on clear, standardized pipeline documentation.
- HVAC and ventilation designers using the document for ductwork representation by substituting "duct" for "pipe".
- Technical illustrators and publishers preparing manuals, parts lists and process diagrams.
Related standards
Relevant cross-references include:
EN ISO 6412-1:2018 provides a practical, standardized basis for producing clear, interoperable piping drawings that improve communication across engineering, fabrication and maintenance processes.
