If you’re involved in fabrication, construction, structural steel, pipework, or district heating, chances are you’ve come across weld inspection standards and felt overwhelmed by the codes attached to them. We regularly speak to clients who produce excellent welds but feel uncertain about which standards apply, what the codes mean, and how inspections are judged as acceptable or not.
At S.T. & W Inspections Ltd, we work with these standards every day. In this guide, we break down BS EN ISO weld inspection standards so you can understand what’s required, why it matters, and how it affects your projects.
If you’d like to speak to our team at any point, call 01795 432 634 or email info@standwinspections.co.uk.
Weld inspection standards don’t exist to catch people out; they exist to protect safety, quality, and reputation. At S.T. & W Inspections Ltd, we help businesses understand and apply these standards correctly, not fear them.
What Are Weld Inspection Standards?
Weld inspection standards are formal documents that define how welds should be made, inspected, tested, and accepted. They provide consistency across industries and ensure welded components are safe, reliable, and compliant.
In the UK and Europe, most weld inspection standards fall under the BS EN ISO framework. These standards cover:
Some of the key reasons timber cabins work year-round include:
- Welding procedures
- Welder qualifications
- Inspection methods
- Acceptance criteria for defects
Without clearly defined standards, weld quality would be subjective, leading to disputes, failures, and serious safety risks.
Why BS EN ISO Standards Matter In Welding
BS EN ISO standards are not optional in most regulated industries. They are often required for:
- UKCA and CE marking
- Factory Production Control (FPC)
- ISO 9001 quality management systems
- Insurance and contractual compliance
From our experience carrying out non-destructive weld testing, applying the correct standard early in a project prevents costly rework later.
Understanding BS, EN, And ISO – Explained Simply
Let’s demystify the terminology:
- BS – British Standard
- EN – European Norm
- ISO – International Organisation for Standardisation
A standard labelled BS EN ISO means it has been adopted in the UK, Europe, and internationally. This alignment enables welds and inspections to be recognised across borders, which is particularly useful for extensive infrastructure and energy projects.
Key Weld Inspection Standards You Should Know
Not all timber cabins are built the same. Selecting the right construction system is crucial to ensure a cabin that performs well in every season.
1. BS EN ISO 9606 – Welder Qualification
This standard governs how welders are tested and approved. It ensures a welder can produce acceptable welds using:
- A specific process
- A defined material group
- A set welding position
At S.T. & W Inspections Ltd, our Responsible Welding Co-Ordinators regularly oversee welder qualification and six-monthly renewals to maintain compliance.
2. BS EN ISO 15614 – Welding Procedure Qualification
Before welding begins, the procedure itself must be proven. This standard confirms that a Welding Procedure Specification (WPS) can produce sound welds when followed correctly.
Procedure qualification often includes:
- Visual inspection
- Ultrasonic testing or phased array
- Destructive testing, such as macros or hardness
This ties closely with our weld procedure qualification services and laboratory testing support.
3. BS EN ISO 17637 – Visual Inspection Of Welds
Visual inspection is the foundation of all weld inspection standards. This standard defines:
- What inspectors must check
- Lighting, access, and tools required
- When inspections must take place
We often recommend visual inspection training for welders alongside independent inspection, which aligns with our Visual Inspection & RVI services.
4. BS EN ISO 5817 – Acceptance Levels For Weld Imperfections
This is one of the most misunderstood weld inspection standards. It defines three acceptance levels:
- Level B – Stringent
- Level C – Intermediate
- Level D – Moderate
The acceptance level must be specified before inspection. Without this, disputes are almost guaranteed. Our inspectors regularly help clients select appropriate acceptance criteria based on service conditions.
How Weld Inspection Standards Link To NDT
Different weld inspection standards specify which inspection method is appropriate. This is where non-destructive testing becomes essential.
Depending on the standard and application, this may include:
- Ultrasonic inspection
- Phased array ultrasonic testing
- Magnetic particle inspection
- Liquid penetrant testing
Our non-destructive weld testing services ensure inspections are conducted to the correct standard, with results clearly reported against the acceptance criteria.
Common Mistakes We See With Weld Inspection Standards
From over a decade of industry experience, we regularly see:
- Standards applied after welding instead of before
- Incorrect acceptance levels used
- Welder qualifications outside the scope
- Inspection methods are not suitable for material thickness
These issues are easily avoided through early consultation, which our team actively supports through RWC services and inspection consultancy.
Who Is Responsible For Compliance?
Ultimately, responsibility sits with the manufacturer or contractor. However, many businesses rely on external expertise to manage compliance effectively.
A Responsible Welding Co-Ordinator (RWC) can:
- Oversee welding activities
- Ensure standards are applied correctly
- Manage documentation and audits
- Coordinate inspection programmes
This integrated approach is often more cost-effective than reacting to non-conformances later.
Conclusion: Making Weld Inspection Standards Work For You
Weld inspection standards don’t need to be confusing. When applied correctly, they protect quality, safety, and reputation while giving clients confidence in the finished product.
At S.T. & W Inspections Ltd, we don’t just inspect welds; we help businesses understand the standards behind them. Whether you need inspection, qualification, consultancy, or ongoing compliance support, our team is here to help.
Call us on 01795 432 634 or email us at info@standwinspections.co.uk.
FAQs
1. Are weld inspection standards mandatory in the UK?
In most regulated industries, yes. Standards are often contractually required and essential for UKCA marking and insurance compliance.
2. Which standard determines if a weld passes or fails?
Acceptance standards such as BS EN ISO 5817 define whether a weld meets the required quality level.
3. Can one standard cover every weld?
No. Standards vary depending on material, thickness, service conditions, and industry requirements.
4. Do all welds require NDT?
Not always. The required inspection method depends on the applicable standard and project specification.
5. Who can interpret weld inspection results?
Only qualified and certified inspectors should interpret results against weld inspection standards.
