ISO 3834 – Welding


The fusion welding process is widely used to manufacture simple as well as complex industrial products.
The standards of the UNI EN ISO 3834 series represent a ‘assumption of conformity‘ within European Directives PED, CPD, Simple Vessels whereas their application is mandatory for civil engineering works due to the provisions of MD 14/01/2008.
Application of standards UNI EN ISO 3834 entail advantages for manufacturers in the definition and maintenance of quality requirements for welding and, as guidelines for assessment/qualification of suppliers of welded products, they bring advantages in contractual situations in defining welding requirements.
The standard is laid out so it can be used for fabricating, either in shop or on site, of any type of welded construction by fusion and its application may extend to a wide range of companies:

  • manufacturers of pressure components, assemblies or piping subject to national or international regulations (PED, ASME);
  • manufacturers of welded structures for conventional engineering applications (installations and plants) and for constructions;
  • manufacturers operating in the railway sector and in engineering (chemical and petrochemical plants, energy production, iron and steel etc.).

The company that requires certification can select 3 different levels of quality requirements, applicable both to shop and installation site production:

  • UNI EN ISO 3834-2 Extended quality requirements;
  • UNI EN ISO 3834-3 Standard quality requirements;
  • UNI EN ISO 3834-4 Basic quality requirements.

To select the appropriate level, the company must take into account the requirements specified by the customer’s contract or by standards and regulations applicable for products, as well as criteria such as, for instance, the various types of products and materials, the significance of safety-critical products, any manufacturing defects that might adversely affect the performance of the manufactured product.

ICIM is an ACCREDIA accredited Body according to UNI IEC EN ISO/IEC 17021 and UNI IEC EN ISO/IEC 17065 for UNI EN ISO 3834 certification.

For further information: Edoardo Dossena (phone +39 02 72534259, e-mail

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