En Iso 13920-bf Access

EN ISO 13920-1:2014, also known as "Hot finished structural hollow sections - Part 1: General requirements", is a European Standard that defines the requirements for hot-finished structural hollow sections (HSS) made of steel. I'll break down the article into sections to make it easier to understand.

is the "sweet spot" for many industrial steel constructions: covers linear and angular dimensions (Fine/Medium balance). handles straightness, flatness, and parallelism. Using a standardized tolerance like Clear Communication:

This article will serve as a definitive guide to everything you need to know about the EN ISO 13920-BF standard, from its fundamental structure to its practical application.

These values apply to nominal sizes such as lengths, widths, heights, and distances between components. Nominal Size Range (mm) Tolerance Class b (mm) Over 30 to 120 Over 120 to 400 Over 400 to 1000 Over 1000 to 2000 Over 2000 to 4000 Over 4000 to 8000 Over 8000 to 12000 Over 12000 to 16000 Over 16000 to 20000 Over 20000 Tolerances for Angular Dimensions (Class b) en iso 13920-bf

Linear tolerances scale with the overall size of the component. The longer the segment, the wider the allowable variance window to account for cumulative heat distortion. 1. Linear Dimensions (Lengths, Widths, Offsets)

Angularity governs the deviation from a straight, 90-degree, or specified angle. Class B ensures that joints, corners, and junctions maintain precise geometry, preventing misalignment during assembly. 3. Straightness and Flatness (Class F)

Source: DIN EN ISO 13920 Standard.

All relevant personnel—designers, welders, and inspectors—must understand what the tolerance classes mean in practical terms. Training should connect the abstract tolerance class to real-world outcomes, explaining how tighter tolerances influence welding sequences and distortion control and how cost escalates when unnecessary precision is specified.

Class B does not account for accumulated shrinkage. If you weld a 10-meter truss, expect 5–10 mm of overall shrinkage. The tolerance of ±8 mm may still be violated if you do not pre-set angles or use back-step welding techniques.

The standard covers the following aspects: EN ISO 13920-1:2014, also known as "Hot finished

: ±20 minutes of a degree (approx. ±6 mm per meter).

The suffix tells the manufacturer exactly which tolerance "bracket" to use for different types of measurements:

This review is designed for engineering, quality assurance, and drafting departments to determine if this standard is suitable for a given project. handles straightness, flatness, and parallelism

This is the critical section for quality control.