The quality of a welded joint can be partly ascertained through product controls, but it must be "designed" in parallel with the product itself: from this requirement derives the introduction of the ISO 3834 standard which defines the "Quality requirements for fusion welding of metallic materials".

The standard is applicable at the manufacturing stage, both in the workshop and on site, to any type of construction welded by fusion.

Already widely used in the construction of machinery, pressure equipment and plants, with the new European regulatory scenario that requires CE marking for metal structural components according to EN 1090-1, compliance with the requirements of ISO 3834 becomes mandatory and propaedeutic for all companies that produce structural components using welded joints.