ISO 3834: Quality Requirements for Fusion Welding

Author: Maren Fichtner | August 27, 2026

Definition: What is ISO 3834?

ISO 3834 specifies the quality requirements for fusion welding of metallic materials. The standard defines the requirements that an organization must meet regarding personnel, equipment, processes, and documentation to ensure standards-compliant, traceable welding production, and is divided into three graded quality levels depending on the complexity and safety relevance of the manufactured components.

Publisher: International Organization for Standardization (ISO)

Current edition: DIN EN ISO 3834:2021

Who is ISO 3834 intended for?

The standard is intended for all companies that perform fusion welding on metal components—from metal fabrication shops to mechanical and plant engineering firms to steel construction companies. It is particularly relevant for companies that manufacture load-bearing or safety-critical structures and are seeking certification under EN 1090, for which ISO 3834 is a key prerequisite.

Overview of Core Requirements

Qualified Welding Coordinator: the person technically responsible for planning and supervising welding processes
Qualified welders: Proof of welder certification in accordance with ISO 9606 for each process used
Welding ProcedureSpecifications (WPS): documented procedure description for each welded joint
Welding Process Qualification Record (WPQR): Practical evidence that the WPS achieves the required quality
Traceability: Assignment of material batch, filler material, and the welder who performed the work to each weld
Inspection and Acceptance: defined procedures for non-destructive and destructive testing of welds

Difference from EN 1090

ISO 3834 specifically governs the quality requirements for the welding process itself. EN 1090, on the other hand, is the more comprehensive standard that covers the entire execution of a steel or aluminum structural system—from design documentation and material verification to assembly. For companies that manufacture load-bearing structures, ISO 3834 is therefore not a substitute for EN 1090, but rather an integral part of it: EN 1090-2 refers directly to ISO 3834 for the verification of weld quality.

Consequences of Noncompliance

Missing or inadequate welding quality records not only jeopardize EN 1090 certification but, in the event of an emergency, also the structural safety of the manufactured component itself. During audits, gaps in WPS/WPQR documentation or missing welder qualifications lead to nonconformities that can result in the loss of contracts during EN 1090 or customer audits; in the event of actual component failure, there is also the risk of significant liability consequences.

Frequently Asked Questions About ISO 3834

Is ISO 3834 required by law?

Not directly, but in fact essential, since EN 1090-2 for load-bearing structures refers directly to it.

What are the different quality levels?

ISO 3834-2 (comprehensive), ISO 3834-3 (standard), and ISO 3834-4 (basic), categorized by complexity and safety relevance.

What are WPS and WPQR?

WPS refers to the welding procedure specification, while WPQR refers to the certification that this specification has been validated through a practical test.

What is the difference between this standard and ISO 9606?

ISO 3834 governs the entire welding operation, while ISO 9606 governs the testing and certification of individual welders.

Successfully Implementing ISO 3834

The greatest effort is required to ensure that welder qualifications, WPSs, and material lots are consistently assigned to each individual weld—especially in complex assemblies with many welded joints. Connected worker platforms such as weasl automatically block welding steps for unqualified welders, link the appropriate WPS directly to the work step, and document each weld in a manner that is auditable for EN 1090 and ISO 3834 certifications.

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ISO 3834