The Reality of Testing in Structural Steel: What Actually Happens on the Shop Floor
Engineering in Support of Excavation: Building Down Before Building Up
Table of Contents
- Introduction: Building Down Before Building Up
- Understanding the Need for Support of Excavation (SOE)
- The Story Begins in the Soil: Interpreting Geotechnical Reports
- Turning Soil Into Numbers: Load Calculations and Modelling
- Choosing the Right System: Bracing vs Anchoring
- Engineering in Action: Types of Excavation Support Systems
- Collaboration Across Disciplines in SOE Projects
- Monitoring and Instrumentation: Ensuring Real-Time Safety
- Risk Mitigation: Designing for the Unknown
- From Excavation to Infrastructure: Why SOE Matters
- Closing Reflection: Engineering Below Ground
- FAQ – What is the Engineering Process behind SOE
Table of Contents
Introduction
In theory, testing in structural steel fabrication often sounds straightforward. Apply non-destructive examination (NDE), verify quality, and move forward with confidence.
In practice, it’s more nuanced.
According to Robert Blowatt, Quality Assurance Manager at infraMOD, testing is not the foundation of quality. It is a tool. Used selectively, strategically, and often only when needed.
We recently sat down with Robert to understand the reality & practicalities of testing structural steel. There is theory & then there is what actually happens on the shop floor. Robert helped us understand how testing and by extension quality is taken care of while keeping in mind the customers’ needs. All while maintaining our high standards of safety and quality.
Quality Doesn’t Start with Testing
One of the most important realities Robert highlights is this.
Quality is not inspected into a product. It is built into it.
If all parties involved, that’s engineers, welders, inspectors, all follow established Canadian standards, the final product should already meet required quality levels.
If code is respected and honored, quality is built into the final product. This is done by a system governed by codes such as:
- CSA S16 for design and engineering
- CSA W59 for welding procedures
- CSA W47.1 for welder qualifications
- CSA W178.2 for visual inspection
- CGSB 48.9712 for NDE technicians
The code is not a formality, but a quality system designed to ensure that any final steel product manufactured in Canada is built to the standards set forth by committees that determine the minimum quality requirements required for each respectable industry. In this case, S16 and W59.
These are not just guidelines. They form a complete quality system designed to ensure consistency and reliability across the industry.
NDE Is Not Always Required
A common misconception is that NDE is mandatory for quality assurance.
It isn’t.
Robert makes it clear that:
- NDE is not required by S16 or W59, as long as code compliance is maintained
- It is typically driven by client requirements, not by code mandates
In fact, NDE is often considered a non-value-added (NVA) activity in many cases:
- It adds cost
- It can slow production
- It may not improve quality if processes are already controlled
This is why many fabrication teams aim to optimize quality upstream rather than rely heavily on testing afterward.
What Testing Actually Looks Like in Practice
We conduct NDE as per contractual agreement. What gets tested is up to the client and what they want done. We try to push to conduct internal MPI and visual inspection to minimize NDE downtime and implement in-process inspections that improve throughput in an efficient manner.
While NDE is not always required, that doesn’t mean testing is ignored.
Instead, it is used strategically based on risk.
Robert recommends a balanced approach. He recommends the following NDE surveillance
- 100% visual inspection of all welds
- 100% ultrasonic testing (UT) of all structural CJP welds
- Agreed upon random MPI (5–10%) for fillet welds
- 100% MPI for high-risk elements, including:
- Lifting lugs
- Lifting frames
- 100% MPI of arc strikes and temp welds
This approach focuses effort where failure would have the most serious consequences.
He says – “For visual testing , I always agree with W59 – 100% visual inspection of all welds. Misfits of fabricated components happen but are easy to find during in-process inspections. If a poor weld is pushed through, a catastrophic weld failure has much more of a negative impact than a few bolt holes or a clip in the wrong location. Misalignment has never killed anyone, but there are documented instances where a critical weld failure has caused casualties.”
Not All Testing Methods Are Equal
Another practical insight: not all NDE methods are preferred in real-world operations.
- Ultrasonic Testing (UT) is favored because it is non-invasive
- Magnetic Particle Inspection (MPI) is commonly used for surface defects
- X-ray (radiographic testing) is avoided where possible because it requires shutdowns
- Liquid Penetrant Inspection (LPI) is rarely used for structural steel and is considered messy
The goal is to choose methods that maintain production flow while still ensuring reliability.
The Role of In-Process Inspection
A key difference between theory and practice is timing.
Rather than relying on final-stage testing, Robert emphasizes:
- In-process inspections
- Early detection of misfits and weld issues
- Continuous quality checks during fabrication
This reduces rework, avoids bottlenecks, and improves throughput.
Internal vs Third-Party Inspection
There’s also a common assumption that third-party inspectors are always required.
That’s not the case.
- Codes require certified inspectors, not necessarily third-party ones
- Companies can (and often do) use internal certified personnel
- Internal inspection enables:
- Better scheduling
- Faster feedback loops
- Lower costs
Third-party involvement, according to Robert, can sometimes signal a lack of trust in the fabricator’s quality system.
Testing as a Risk Management Tool
Ultimately, testing decisions come down to one thing: risk.
- High-risk components → more testing
- Temporary or low-risk structures → minimal or no testing
- Reused steel → targeted inspection at stress points
Even though NDE may not always be required, Robert reinforces a practical mindset – It’s better to apply a strategic level of quality checks than to “shoot product through and hope for the best.”
The Bigger Issue: Misunderstanding the Code
One of the more subtle but critical challenges is misinterpretation of standards.
Robert points out that confusion around NDE requirements often comes from:
- Lack of understanding of S16 and W59
- Misinterpretation by industry stakeholders
- Over-specification of testing
The true nature of NDE needs to be considered in a risk analysis and whether the costs justify the means. The above recommended NDE inspections, would give the client a piece of mind by providing proof of weld soundness for critical components like lift lugs, spliced members and major connections that may have a low risk of failure but would cause a catastrophic event if the worst happens. The nice thing about the above inspection methods, especially the visual and MPI, is that they are noninvasive and can be structured in such a way that does not impact production or its throughput.
This highlights the need to have educated, experienced and informed quality personnel who can interpret requirements correctly and guide companies in the right direction. The knowledge must be fact-based and specific to the task at hand.
Closing Thought: Build Quality First, Test Strategically
The takeaway is simple but often overlooked.
Testing is not the backbone of quality. Discipline, process, and code compliance are.
When those are in place:
- Testing becomes a verification tool, not a crutch
- Costs stay controlled
- Production remains efficient
- And most importantly, safety is maintained
In the end, the goal isn’t to test more. It is to build better and test smarter.
Frequently Asked Questions (FAQs)
No, NDE is not always mandatory. As long as fabrication complies with standards like CSA S16 and CSA W59, testing is not required by code. It is typically driven by client specifications rather than regulatory mandates.
No, testing does not create quality—it verifies it. Quality is built into the product through proper design, qualified welders, and adherence to established codes. Testing is only a tool used to confirm that quality.
Key standards include:
- CSA S16 (design and engineering)
- CSA W59 (welding procedures)
- CSA W47.1 (welder qualifications)
- CSA W178.2 (visual inspection)
- CGSB 48.9712 (NDE technicians)
These collectively form a comprehensive quality system ensuring consistency and reliability.
NDE can be considered non-value-added because:
- It increases project costs
- It can slow down production
- It may not improve quality if processes are already controlled
This is why many fabricators prioritize building quality upfront rather than relying on post-production testing.
A risk-based approach is most effective. This typically includes:
- 100% visual inspection of all welds
- 100% ultrasonic testing for critical welds
- Random MPI (5–10%) for lower-risk welds
- Full inspection for high-risk elements like lifting components
This ensures resources are focused where failure would have the greatest consequences.
The most commonly used methods include:
- Ultrasonic Testing (UT): preferred for being non-invasive
- Magnetic Particle Inspection (MPI): effective for surface defects
- Visual Inspection: widely used and often 100% applied
Less preferred methods:
- Radiographic (X-ray): requires production shutdowns
Liquid Penetrant Inspection (LPI): messy and rarely used
In-process inspections help:
- Detect issues early (e.g., misfits, weld defects)
- Reduce costly rework
- Maintain production flow
- Improve overall efficiency
They shift quality control upstream instead of relying only on final inspection.
Not necessarily. Codes require certified inspectors, but they do not mandate third-party involvement. Many companies use internal certified inspectors to:
- Improve scheduling
- Enable faster feedback
- Reduce costs
Testing is applied based on risk level:
- High-risk components → extensive testing
- Low-risk or temporary elements → minimal testing
- Reused steel → targeted inspections
This ensures safety without unnecessary cost or delays.
Confusion often arises due to:
- Misinterpretation of CSA S16 and W59
- Lack of understanding among stakeholders
- Over-specification of testing
Proper knowledge and experienced personnel are critical to applying standards correctly.
The core principle is:
- Build quality first through processes and code compliance
- Use testing strategically for verification
This approach ensures safety, efficiency, and cost control without over-reliance on testing.