En Iso 13920-bf __exclusive__ Site

Building frameworks, trusses, and gantry platforms.

In the ISO 13920 coding system, the second letter regarding geometrical tolerances is either C (Fine) or D (Medium). There is no "F" class for geometry.

The designation is a small piece of text that carries a large weight of meaning. It harmonizes the design, fabrication, and quality control processes. For a design engineer, it provides a time-saving and internationally understood shorthand. For a manufacturer, it offers a clear and practical target. For a quality inspector, it is the definitive guideline for acceptance. en iso 13920-bf

The original 1996 version (EN ISO 13920:1996) was revised by the updated ISO 13920:2023 standard. ISO 13920 An Explained Guide to Welding General Tolerances

The designation specifies standard, workshop-based dimensional and geometrical tolerances for welded constructions. When an engineering drawing cites this specific standard and tolerance class, it dictates the acceptable deviations for linear and angular dimensions (Class B) alongside shape and position tolerances (Class F) . Fabricating large metal structures or machinery components to these exact limits ensures components fit together perfectly without requiring expensive, hyper-precise post-weld machining. Building frameworks, trusses, and gantry platforms

Angular tolerances depend on the length of the shorter leg of the angle being measured. Under Class B, the tolerances are: ±20 minutes (approx. ±6 mm per meter)

If you are looking to define these tolerances in a fabrication drawing, consider if (Coarse) or Class C/G (Fine) might be more appropriate for your project's specific needs. For more information on welding quality levels, you can explore the ScienceDirect Topic on Weld Quality . Din En Iso 13920 Bf - extnag.tacc.utexas.edu The designation is a small piece of text

For Class , the tolerances for common geometric features are defined. The value shown is the permitted deviation based on the length of the measured feature.

If you are a design engineer, using this standard correctly will save your workshop hours of confusion.