​

Why Independent RT Level III Oversight Matters

Radiography is one of the most shortcut-prone and misunderstood NDT methods performed in the field. The science itself is based on achieving a certain probability of detection. 

​

Probability of Detection in Industrial Radiography

Radiography is not simply about producing an image of a weld.
It is about producing an image with sufficient quality to reliably detect discontinuities that the code requires to be found. This is known as Probability of Detection (POD). POD is the likelihood that a discontinuity of a certain size and type will be visible on the radiograph. That probability is not random — it is controlled by specific, measurable radiographic variables.

The two most important of those variables in film radiography are:

• Film Density

• Radiographic Sensitivity (IQI performance)

​

When performing CR or DR, the term "Film Density" is described as "Intensity" and refers to the bit depth of the pixel.

​

Where Problems Quietly Begin

​

​Production pressure is constant

Radiography is usually on the critical path of the project schedule. Welders are waiting, crews are staged, and delays are costly. In that environment, speed often takes priority over precision. Small technique compromises made to “keep things moving” can accumulate into non-compliant results across an entire job.

​

Radiographic interpretation is subjective without strong supervision

Radiographic Interpretation is a learned skill that requires tons of practice and training, feedback and oversight. Without routine Level III involvement, technicians rely on habit rather than strict code interpretation. Two qualified technicians can review the same film and reach different conclusions, creating inconsistency in acceptance standards. This issue is compounded with the addition of new technology like Computed Radiography (CR) or Digital Radiography (DR) techniques.

 

Exposure techniques are often copied, not engineered

Exposure charts and setups are frequently reused from previous jobs without recalculating for the actual wall thickness, material, source size, SFD, and geometric requirements of the weld being examined. The radiograph may appear acceptable while still failing to meet required sensitivity. It is imperative that the density (Intensity for DR/CR) and sensitivity requirements are met when performing radiography.  

​

Documentation is rarely reviewed at a Level III standard

Technique sheets, reports, and film identification are often treated as routine paperwork instead of compliance documents. Missing data, incorrect references, and poor traceability often go unnoticed until an audit or client review exposes the issue.

​

Most contractors only provide Level II oversight on site

Level II technicians are qualified to perform radiography, but they are not responsible for program compliance, procedure integrity, or code interpretation at the Level III level. Without that higher authority present, deviations from procedure often go uncorrected.

​

The Hidden Risk This Creates for Owners and Project Managers

These issues rarely show up during daily production. They surface later:

• During audits

• During client or owner reviews

• When weld packages are rejected

• When a failure forces records to be re-examined

• During regulatory review or litigation

By the time the problem is discovered, the cost to correct it is far greater than the cost to prevent it.

​

Why the Contractor’s Level III Is Not Enough

The contractor’s Level III works for the contractor. Their priority is to keep production moving, support their technicians, and avoid delays.

An independent Level III has a different responsibility:

Protecting the client from non-compliance, risk, and future liability.

That independence is what makes the oversight valuable.

​

What Independent RT Level III Oversight Actually Provides

• Verification of exposure techniques — not just radiograph appearance

• Unbiased film interpretation review

• Confirmation of compliance with ASME, API, AWS, and client specifications

• Review of technician qualification, certification and performance

• Defensible documentation that withstands audits and scrutiny

• Radiation safety program review that protects the client from regulatory exposure

• Integrity of testing

The Bottom Line

Independent RT Level III oversight is not about questioning the contractor.

It is about verifying that the radiography program is being performed correctly, compliantly, and defensibly from the start — before small issues become expensive problems. So next time the radiographs don't look right, when weld packages are rejected that don't appear to be bad, when audits uncover radiography issues or when you need an independent verification, call WB NDT to set your mind at ease or get you back on the right track!

Hard work, Honest answers