ISO 14617-3:2002

Overview

ISO 14617-3:2002 - Graphical symbols for diagrams - Part 3: Connections and related devices - defines standardized graphical symbols used in technical diagrams to represent functional connections, mechanical links, pipelines and related devices such as connection joints, ports, terminals, quick‑release couplings and connectors. Part 3 is one element of the ISO 14617 series that builds a harmonized library of symbols for engineering and process documentation.

Key topics and requirements

• Scope and purpose: Specifies symbol sets and application rules for connections and related devices in diagrams (see ISO 14617-1 for indexes and ISO 81714-1 for symbol design rules).
• Basic connection symbols: Includes symbols for functional connections (e.g., symbol 401), mechanical links/shafts (402/403/404), pipelines and ducts (405), and group or planned pipelines (406/412).
• Supplementary symbols: Provides modifiers to indicate media or properties - hydraulic (434), pneumatic (433), electric (435), flexible (444), internal connection (451), bus types (442/443), shapes (445–447), and more.
• Joints and pipeline ends: Defines representation for T‑joints, closed ends and joint markers (e.g., 501) and prescribes size rules (R501).
• Specified-design devices: Symbols for flange couplings, screwed joints, welded joints and reducers (511–518) used when design must be indicated (R521).
• Ports and connectors: Covers ports, quick‑release couplings and connector symbols (e.g., 561) used to show terminations and disconnections.
• Application rules and examples: Rules R401–R413 and numerous example diagrams explain crossing lines, single‑line representations, internal connections and leader‑line placement.
• Compatibility: Cross‑references ISO 2553 (weld symbols), ISO 4063 (welding processes) and IEC terminology where applicable.

Practical applications

ISO 14617-3 is used to:

• Create consistent engineering drawings and process diagrams for chemical, power, HVAC and manufacturing plants.
• Standardize P&IDs, instrumentation diagrams, electrical/mechanical schematics and installation diagrams.
• Improve clarity in technical documentation, CAD libraries and digital diagram templates for multinational projects.
• Reduce ambiguity in design handovers, maintenance manuals and compliance documentation.

Typical users:

• Process and mechanical engineers, instrumentation and controls specialists
• Technical authors, CAD/draughting teams and documentation managers
• Plant designers, system integrators and standards compliance officers

Related standards

• ISO 14617-1: General information and indexes (symbol registration and use)
• ISO 81714-1: Design of graphical symbols - basic rules
• ISO 2553: Symbolic representation for welded, brazed and soldered joints
• ISO 4063: Welding process nomenclature

Using ISO 14617-3 helps organizations produce clear, interoperable technical diagrams that reduce interpretation errors and support international collaboration in engineering documentation.