Certification of thermoplastic material welders

The qualification of welders for polyethylene and polypropylene pipes and fittings is carried out in accordance with the requirements of the new standard UNI 9737:2016.

The UNI 9737 standard (2016 edition) introduces new groups and subgroups and a different range of weldable diameters. For more information regarding the new groups and subgroups, refer to this link read here.

New requirements are outlined for accessing qualification tests, including apprenticeship with a manufacturer of components for piping systems, showcasing acquired experience, or attending a training course. The final examination involves both a theoretical and practical test.

Services Offered

International Weld is accredited by ACCREDIA, following the ISO/IEC 17024 standard, for the certification of welders for thermoplastic pipes and fittings.

Certification Process

The certification process for welding personnel involves the following steps:

1. Acceptance of the economic offer.

2. Submission of the certification application.

3. Verification of meeting the admission requirements for the exam.

4. Qualification activities, including a practical test and laboratory tests.

5. Deliberation and issuance of the certification.

The qualification activity requires passing a theoretical and practical exam, with the execution of one or more tests specified by UNI 9737, supervised by qualified inspectors from I-WELD.


The choice of the representative sample test is often influenced by various conditions such as the execution location (workshop or construction site), available equipment, joint geometry, acceptability criteria, material thicknesses, and diameters, and accessibility.

Tests required by standards are conducted at laboratories accredited by I-WELD.

Preparation for the test execution can occur through specific training programs or in-house training under the supervision of an expert.

Additional Information

Application opportunities

The standard applies to all specialized technicians involved in the construction and maintenance of low-pressure gas and water networks, and in general, all installers of polyethylene and polypropylene pipes and fittings.

You can send us all documents to the e-mail: info@iweld.it

Guide for the extension of certification of thermoplastic welding personnel

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