Overview
EN ISO 5261:1999 specifies complementary rules to ISO 128 and ISO 129 for the simplified representation of bars and profile sections in assembly and detail drawings. The standard focuses on clear, compact designation and schematic depiction of common bar and profile elements used in mechanical and construction drawings. Figures in the standard are shown in first angle orthographic projection and linear dimensions are given in millimetres.
The simplified representation typically consists of the relevant ISO designation followed, if necessary, by the cutting length separated by a hyphen. Where no ISO designation exists, a graphical symbol may be followed by necessary dimensions according to the tables provided.
Key Topics
- Designation format: Use the ISO designation then the cutting length (e.g., Angle profile ISO 657-1 - 50 x 50 x 4 - 1000).
- Graphical symbols: Table 1 and Table 2 in the standard list graphical symbols for common bar and profile sections and indicate alternative uppercase letter symbols for simplification (for example, L, T, I, H, U, Z).
- Dimensioning rules: When an ISO designation is not available, compose the designation from the graphical symbol followed by the necessary dimensions (millimetres).
- Schematic representation: Compound frames can be shown by continuous thick lines indicating centroidal lines; distances between centroidal reference points should be indicated on the schematic.
- Dimensional chains: Closed dimensional chains are permitted; for cumulative tolerances, indicate which dimension is to be equalized.
Examples from the standard:
- Angle profile: L 89 x 60 x 7 - 500
- Rectangular solid bar: p 50 x 10 - 100
- Equal-leg angle (ISO 657-1): ISO 657-1 - 50 x 50 x 4 - 1000
Applications
EN ISO 5261:1999 is directly applicable to drawings and documentation for:
- Structural metalwork (plates, profile sections, compound elements such as bridges and frameworks)
- Lifting and transport appliances
- Storage tanks and pressure vessels
- Lifts, moving stairways and conveyor belts
- Assembly and detail drawings, item lists and schematic representations where space or clarity demands simplified depiction
Practical benefits include improved drawing clarity, reduced clutter in assembly drawings, consistent designation across projects, and faster interpretation by manufacturing and construction teams.
Related Standards
- ISO 128: General principles of presentation for technical drawings
- ISO 129: Dimensioning
- ISO 10209-1: Vocabulary and terms relating to technical drawings (definitions referenced)
- ISO 7573: Item lists (filling in item lists with simplified designations)
- ISO 657-1: Example for equal-leg angle designations
Use EN ISO 5261:1999 in conjunction with these standards to ensure uniform, concise, and unambiguous representation of bars and profile sections in technical documentation.
