Iso 13920-bf: En

is considered "medium" or customary workshop accuracy for welded parts. F (Shape and Position): This refers specifically to straightness, flatness, and parallelism

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.

Adhering to EN ISO 13920-BF is essential for several reasons:

If you are currently setting up a project using this standard, tell me: What is the of your welded assembly? en iso 13920-bf

The standard covers four main categories of dimensional variations: Lengths of welded parts. Angular Dimensions: Angles between welded components.

This is the "intermediate" class for lengths and angles. It defines the allowable deviation for dimensions such as the length of a beam or the angle of a joint. For a 1-meter span, class B might allow a variation of a few millimeters, providing a balance between functional fit and manufacturing speed.

If a junction has a 90° angle, the F (Medium) class might allow a deviation of ± 1° or ± 2°, depending on the leg length. is considered "medium" or customary workshop accuracy for

EN ISO 13920-BF is frequently cited in technical drawings and specifications for: Structural steel frames. Bridge construction components. Machinery baseplates. Pressure vessel supports.

(ISO 13920 has no BF). It most likely means: "Weld edge preparation type BF according to ISO 9692-1, with general tolerances according to EN ISO 13920."

EN ISO 13920 (Welding – General tolerances for welded constructions) Class: BF Status: Active (Harmonized across EU) Angular Dimensions: Angles between welded components

: This refers to the tolerance class for linear and angular dimensions (length, width, height, and angles) . It is based on "customary workshop accuracy" and is the most common class used in general engineering .

If you are operating under Class B, you must consult the tables within the ISO 13920 standard.