Compliance with is verified using standard workshop tools such as steel straightedges , tape measures, and vernier callipers. It is important to note that this standard covers dimensional accuracy, not weld quality (like cracks or porosity), which is instead governed by ISO 5817. IS0 13920 - iTeh Standards
is a specific technical designation used in engineering drawings to define general tolerances for welded constructions. It combines two distinct precision levels from the ISO 13920 standard to ensure that welded parts fit together correctly without needing individual, complex dimensioning for every single weld. Breaking Down the Code: "BF" en iso 13920-bf
It acts as a universal language for international contracts, ensuring a manufacturer in Europe and a client in the Middle East have the same expectations for accuracy. Compliance with is verified using standard workshop tools
The actual permissible deviation (in millimeters or degrees) depends on the of the part. For example, a 1,000 mm beam in Class B will have a specific allowed variation, whereas a 10,000 mm beam will have a larger allowable margin. Type of Measurement Class for "BF" Key Focus Areas Linear Dimensions B (Medium) Length, width, and height of parts. Angular Dimensions B (Medium) Deviations in angles and slopes. Shape & Position F (Medium) Straightness, flatness, and parallelism . Testing and Verification It combines two distinct precision levels from the
This standard is widely used in machine construction , steel structures , rail vehicles, and shipbuilding. Tolerance Tables Overview
Specifying "Class B" avoids the high costs associated with the ultra-precise "Class A," while preventing the safety or assembly risks of the looser "Class C".