The designation EN ISO 13920-BF a specific set of general tolerances for welded constructions, combining two different accuracy classes defined in the for linear/angular dimensions and for form and position Breakdwon of "BF" When this standard is cited on a drawing (e.g., ISO 13920-BF ), it indicates the following requirements: B (Linear/Angular Dimensions):
Q: Can EN ISO 13920-BF be used for non-welded constructions? A: No, the standard is specifically designed for welded constructions and parts. Other standards may apply to non-welded constructions.
Tolerances for lengths, such as external sizes, internal sizes, and step sizes. Range of nominal sizes (mm) Tolerance (mm) ±1plus or minus 1 ±2plus or minus 2 120 to 400 ±2plus or minus 2 400 to 1000 ±3plus or minus 3 1000 to 2000 ±4plus or minus 4 2000 to 4000 ±6plus or minus 6 2. Shape and Position (Class F) Tolerances for straightness, flatness, and parallelism. Range of nominal sizes (mm) Tolerance (mm) Up to 1000 1000 to 2000 2000 to 4000 4000 to 8000 Application in Industry This standard is commonly cited in technical drawings for: en iso 13920-bf
Correct usage (per ISO guidelines):
F (Shape and Position): This refers to tolerances for straightness, flatness, and parallelism. Class F is the "intermediate" tier for these geometric features. It ensures that a welded frame is sufficiently "square" and flat for its intended use without requiring expensive post-weld machining. Why use "BF" instead of other classes? The ISO 13920 standard offers four classes for dimensions ( ) and four for shape ( are the finest (tightest) and are the coarsest. Intermediate Very Coarse Dimensions (Length/Angle) B Shape & Position F The designation EN ISO 13920-BF a specific set
Industry Use: It is commonly used in heavy-duty fabrication, such as for filtration distributors, corona rings, and offshore mattressing structures.
EN ISO 13920-BF emphasizes the importance of inspection and verification to ensure that welded constructions and parts meet the specified tolerances. The standard provides guidelines for the measurement and inspection of welded joints and parts, including the use of non-destructive testing (NDT) methods. Tolerances for lengths, such as external sizes, internal
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.
This covers the "straightness" of the beam or the "flatness" of a plate. It ensures that while the part might be the right length, it isn't "banana-shaped" or twisted.