TS 88-22 ISO 128-22

TS 88-22 ISO 128-22 is part of the ISO 128 series for technical drawings and addresses how leader lines and reference lines are used. In this standard, the focus is on the general principles for arranging information placed on or beside these lines in different kinds of technical documents, so that annotations are presented in a consistent and unambiguous way.

What leader and reference lines do in technical communication

In general technical practice, leader lines connect a note, dimension, symbol, or callout to the feature it describes, while reference lines point to a specific part, surface, location, or characteristic. These line types help link text to geometry, which is especially important in dense drawings, assembly views, and detailed layouts where clarity and traceability matter.

Organisation principles covered by this part

According to the scope, the standard covers general rules for the components of leader and reference lines, as well as the arrangement of instructions on or near those lines. This provides a common framework for presentation in drawings and related technical documents. As part of the ISO 128 family, it supports a shared visual language for technical documentation, while the broader practical meaning of the line types comes from established drafting conventions.

• Shows how information is linked to the related graphic feature in a drawing.
• Supports readability and consistent interpretation.
• Standardises the placement of notes associated with lines.
• Applies to technical drawings and other technical document types.