HSE has identified inconsistencies in the application and supervision of welding of safety-critical metallic components, leading to failures with high consequences. Examples include loss of containment of dangerous substances, major structural collapses, and fatalities. HSE specialists carried out a study to identify common causes of these and to highlight priority areas for improvement of weld quality in the industry. Cases from HSE’s historical investigations and provided by external organizations were assessed. Forty-seven individual incidents in which the weld quality was a contributory factor were identified. These were reviewed against a range of causal types, and computer analysis was carried out to identify the primary contributory factors. Case studies were developed to illustrate the key findings and a visual set of examples of welding defects compiled.
Findings:
- The most common failure modes identified were fatigue and ductile or brittle failure due to overload of the welds
- In 49% of cases, the result was a complete collapse of the structure
- 21% of the incidents led to injuries, and 11% led to one or more fatalities
- Crack-like or volumetric flaws in weldments and poor or undersized weld geometry were the commonest weld quality deficiencies leading to failure
- The most prevalent causes of weld quality deficiency were inadequate welder supervision, insufficient percentage coverage of inspection and joints not designed for ease of fabrication
Source: https://www.hse.gov.uk/Research/assets/docs/annual-science-review.pdf