ISO 1219-3:2016

Overview

ISO 1219-3:2016 - "Fluid power systems and components - Graphical symbols and circuit diagrams - Part 3: Symbol modules and connected symbols in circuit diagrams" supplements ISO 1219‑1 and ISO 1219‑2 by specifying rules for generating and combining symbols of connectable components in hydraulic and pneumatic circuit diagrams. The standard formalizes how symbols are grouped into symbol modules, how interface and external connection points are drawn, and how modules are arranged to improve clarity, reduce piping and shorten the design envelope for manifold and stacked assemblies.

Key topics and requirements

• Scope and purpose: Rules to represent modular functional units (e.g., manifold assemblies, stacked valve assemblies, FRL - filter/regulator/lubricator units) by combining standardized symbols.
• Symbol modules: Definition of a module as one or more ISO 1219‑1 symbols or lines enclosed in a frame and capable of connection via identical interfaces.
• Connection points:
  • Interface connection points - located on the module frame for direct connection between modules.
  • External connection points - drawn per ISO 1219‑1 and used to connect modules to lines or other symbols.
• Graphical rules:
  • Frame thickness: modules enclosed by a solid line of 0.1M or 0.175M.
  • Frame size: width and height should be 2M or multiples of 2M; limit the variety of sizes for clarity.
  • Spacing and distance rules for lines and frames (see standard for full specifications).
• Examples and informative annexes: Several annexes (A–D) provide sample hydraulic and pneumatic circuit diagrams illustrating best practices for module stacking and connections.
• Normative references: ISO 1219‑1, ISO 1219‑2 and ISO 5598 (vocabulary) are normative for correct application.

Applications and users

Who benefits from ISO 1219‑3:2016:

• Hydraulic and pneumatic system designers who create manifold and valve-stack layouts.
• CAD drafters and technical illustrators producing circuit diagrams and documentation.
• Component manufacturers standardizing product symbolization for catalogs and data sheets.
• System integrators and maintenance teams who rely on clear diagrams for installation, troubleshooting and servicing.

Practical uses:

• Reducing piping complexity and physical envelope by using connected symbol modules to represent manifolded units.
• Creating consistent, machine-readable circuit diagrams for manufacturing and maintenance documentation.
• Improving cross-disciplinary communication by applying standardized graphical symbols for fluid power systems.

Related standards

• ISO 1219‑1 - Graphical symbols for conventional use and data‑processing applications
• ISO 1219‑2 - Circuit diagrams
• ISO 5598 - Vocabulary for fluid power systems

Keywords: ISO 1219-3:2016, fluid power systems, graphical symbols, circuit diagrams, symbol modules, connection points, hydraulic, pneumatic, manifold assemblies, FRL units.