En Iso 13920-bf -

When working with EN ISO 13920-BF, keep the following rules in mind:

You aren't paying for "precision machining" tolerances on a heavy structural frame where they aren't needed. Interchangeability:

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. en iso 13920-bf

Linear values dictate lengths, widths, heights, and distances between parts: : ±1plus or minus 1 Over 30 to 120 mm : ±2plus or minus 2 Over 400 to 1,000 mm : ±3plus or minus 3 Over 1,000 to 2,000 mm : ±4plus or minus 4 Over 2,000 to 4,000 mm : ±6plus or minus 6 Angular Dimensions (Class B) ISO 13920 An Explained Guide to Welding General Tolerances

Large electrical cabinets, hoppers, and storage bins. When working with EN ISO 13920-BF, keep the

While Class B is versatile, it is not always the right choice.

ISO 13920 Welding General tolerances for welded constructions 000 to 2

Understanding the standard requires isolating the two distinct tolerance classes combined within the "BF" identifier: