ISO 6412-2:2017

Overview

ISO 6412-2:2017 - Technical product documentation - Simplified representation of pipelines - Part 2: Isometric projection - specifies supplementary rules for producing clear three-dimensional isometric pipeline drawings. It is intended to be used with ISO 6412-1 (general rules and orthogonal representation) and gives rules for showing essential pipeline features in isometric view so that fabrication, installation and tender documents are clearer and drawing work is reduced.

Key Topics

• Scope and purpose: Supplementary rules for isometric representation where three‑dimensional clarity is required.
• Coordinates: Use of Cartesian coordinates consistent with the overall installation; coordinates of pipes/assemblies must be indicated on drawings or associated documents.
• Line conventions: Follow ISO 6412-1 conventions for flow lines and hidden/visible lines.
• Deviations from coordinate axes: Indication of non‑axis‑parallel pipes using auxiliary hatched projection planes; rules for pipes in vertical, horizontal or arbitrarily angled planes.
• Auxiliary projection planes: Hatching, rectangular prism or rectangle conventions to show projection planes when pipes are not parallel to axes.
• Dimensioning and special rules:
  • Diameters and wall thickness (outer diameter d, wall thickness t) indicated per ISO 5261; nominal sizes may use “DN”.
  • Longitudinal and angular dimensions per ISO 129-1; lengths referenced from outer faces, flanges or joint centres.
  • Pipes with bends: dimension from centre line to centre line or to pipe end; radii and functional angles of bends indicated; simplified arc projections allowed for clarity.
  • Levels and direction of slope: standard methods for indicating levels, slope triangles and references to datum levels.
  • Positions of pipe ends: coordinates may be given for end-face centres; references for adjacent drawings.
  • Redundant dimensioning and special notes for pipe‑bending machine dimensioning.
• Graphical symbols: Use ISO 3545-1, ISO 5261 and ISO 6412‑1 symbols drawn in isometric projection; examples include valves, transition pieces, supports, crossings and flanges.

Applications

ISO 6412-2 is practical for:

• Piping designers and CAD technicians producing isometric pipeline drawings
• Piping engineers and plant designers preparing fabrication and erection drawings
• Fabricators and pipe-bending machine programmers who need unambiguous dimensioning
• Contractors and installation teams who rely on clear three‑dimensional documentation for site work Use cases include process plant piping, machine construction, building services and pipeline tender documentation.

Related Standards

• ISO 6412-1 (General rules; orthogonal representation)
• ISO 128-20 (Technical drawings - presentation)
• ISO 129-1 (Dimensioning and tolerances)
• ISO 3545-1 (Tube symbols)
• ISO 5261 (Simplified representation of profiles)

Keywords: ISO 6412-2, isometric projection, simplified representation of pipelines, pipeline isometric drawings, technical product documentation, pipe dimensioning, graphical symbols.