Radiographic Testing (RT) — X-Ray, Gamma + Digital Radiography 2026

Atlantis NDT delivers the complete radiographic testing curriculum + consulting stack — film radiography, digital radiography (DR), computed radiography (CR), and gamma radiography with Ir-192, Co-60, Se-75, Yb-169 isotopes. Real-time radioscopy (RTR) + digital detector array (DDA) per ASME V Articles 22 + 27. ASME Section V Article 2, API 1104 pipeline radiography, ISO 17636-1/2, AWS D1.1, AWS D17.1 aerospace welding compliant. ASNT NDT Level I/II/III RT training (96% first-pass) + radiation safety officer consulting + outsourced Level III RT consulting.

RT Method Physics + Source Selection

RT uses ionising radiation (X-ray or gamma) penetrating the test object to produce a 2D radiograph showing density variations from internal discontinuities. Source selection per material thickness: X-ray (constant potential 100-450 kV) — high resolution, thin sections, controllable; Ir-192 gamma (0.6 MeV avg) — most common field use, 12-75 mm steel; Co-60 gamma (1.25 MeV avg) — thick sections 50-200 mm steel; Se-75 gamma (low-energy) — thin sections 5-25 mm steel with better contrast; Yb-169 — ultra-thin + small-diameter pipe. Digital detectors (DDA) replace film with 14-bit grey-scale + SNR per ASME V Article 27.

IQI + Sensitivity + Exposure Geometry

Image quality indicators (IQI) verify technique sensitivity: ASTM E1025 hole-type (1T/2T/4T penetrameter) or ASTM E747 wire-type (ISO + EN preferred). Sensitivity typically 2% (2T/wire essential per Code). Exposure geometry per ASME V Article 2 Mandatory Appendix: single-wall single-image (SWSI), double-wall single-image (DWSI), double-wall double-image (DWDI elliptical for small-diameter pipe per ASME V T-275). Source-to-film distance + geometric unsharpness Ug = source × thickness / SFD calculation.

Code + Acceptance Criteria

RT acceptance per: ASME Section V Article 2 (general RT) + Mandatory Appendices; ASME Section VIII Div 1 + 2 Mandatory Appendix 4 pressure vessel acceptance; ASME B31.3 piping acceptance; API 1104 pipeline welding; AWS D1.1 + D17.1 aerospace; ISO 17636-1/2 EU weld RT; ASTM E94 standard guide + E747 + E1025 IQI; IACS Rec-20 marine. Indication classification: porosity, slag inclusion, incomplete fusion, incomplete penetration, crack, undercut, concavity. Acceptance level dependent on material thickness, weld type, service.

Radiation Safety + Regulatory

RT involves ionising-radiation hazard requiring strict safety: NRC + state licensing in US, IAEA + national-regulator licensing internationally, controlled-area survey, source-pit shielding, radiation-area dose-rate calculation, personnel TLD + electronic dosimeter, transport per IAEA TS-R-1, source-change-out per manufacturer + regulatory. Atlantis NDT delivers radiation safety officer (RSO) consulting per applicable jurisdiction. See consulting for RSO scoping.

Atlantis NDT RT Procedure Pack

Turn-key RT pack: written procedure (ASME V Article 2 + ISO 17636 aligned), technique sheet (per source + thickness + geometry), film density + IQI sensitivity log, ASNT NDT Level III sign-off, inspector training (96% first-pass via Atlantis Academy), free retake-grade backstop. Plus RSO + radiation safety procedure pack. Integrated with Atlantis NDT ERP for source-cert + cert tracking, Reporting Software for digital radiograph archival, Digital Twin for 3D defect overlay, Atlantis AI for NDT (DR/CR defect classification with mandatory Level III approval).

RT Frequently Asked Questions

Q1: When should we use DR/CR vs film RT?

A: DR/CR replaces film for most applications: instant image review, no chemicals, archivable digital records, real-time radioscopy possible. Film RT still preferred for: extreme thickness (Co-60 + thick concrete), legacy customer specifications, regulatory carry-over. ASME V Articles 22 + 27 govern DR/CR acceptance.

Q2: What's the minimum sensitivity required?

A: 2% (2T/2T essential, or appropriate wire size) per ASME V Article 2 Mandatory Appendix. Achieved via IQI per ASTM E1025 (hole-type) or E747 (wire-type).

Q3: How is gamma source replaced?

A: Per manufacturer + NRC/regulator change-out procedure with shielded transport, hot-cell receipt, dose-rate survey. Atlantis NDT delivers full source-change-out compliance consulting via RSO.

Q4: What ASNT cert is required for RT inspection?

A: Level II independent acquisition + interpretation; Level III procedure authoring + final disposition + multi-method oversight. Plus radiation-safety officer (RSO) certification per applicable regulator. Atlantis Academy covers all.

Q5: Pricing for RT consulting + training?

A: No published pricing — varies by region + scope + radiation-safety jurisdiction. Free 30-min consultation + tailored quote. Affordable, accessible, fully customizable.

Get a free RT consultation. See also RT training, ASNT, UT pillar, Level III consulting, AI for NDT.

What you receive from a radiographic examination

A radiographic inspection is only as useful as the record it leaves behind. Every examination is delivered with the image itself, the technique record stating source, energy, geometry and exposure, evidence that the required sensitivity was achieved through the image quality indicator, and an interpretation against the acceptance criteria in your governing construction code. Those four together are what an auditor, an insurer or a client's own engineer needs in order to rely on the result years later.

Where radiography is the right choice

Radiography images volume, which makes it strong on the discontinuity types that occupy space — porosity, slag inclusions, incomplete penetration seen along the beam, and root condition. It also produces a permanent image that a third party can re-read independently, which is why owners and insurers still specify it for critical fabrication even where ultrasonic alternatives are permitted.

It is correspondingly weak on tight planar flaws lying across the beam. A crack presenting a fraction of a millimetre of missing material along the radiation path may produce no discernible density change, and lack of fusion on a bevel face frequently escapes. Where those are the credible failure modes, ultrasonic examination belongs alongside radiography rather than instead of it — and a specification that names only one is worth questioning before work starts.

Technique selection, and why it is not a formality

Source and energy are matched to wall thickness. Iridium-192 suits mid-range steel sections; cobalt-60 penetrates heavy wall but at a cost in contrast, so using it on thin material produces a flat image that will not meet image quality requirements. Selenium-75 occupies a useful middle ground on thinner sections where contrast matters. Geometry — source-to-film distance, source size, and the resulting geometric unsharpness — is what decides whether fine detail survives to the image at all.

Digital capture changes the workflow rather than the physics. Detectors have far wider exposure latitude than film and allow immediate review, but they introduce their own requirements around spatial resolution, signal-to-noise and constrained processing, because an image that can be adjusted can also be adjusted until an indication disappears.

Codes the work is performed and judged against

ASME Section V Article 2 governs the examination method in the ASME world and defines image quality indicator selection and placement; ISO 17636 covers radiographic testing of welds with its own class system; API 1104 addresses pipeline girth welds and carries its own acceptance criteria, which differ genuinely from ASME's. The examination standard never sets acceptance — the referencing construction code does, and the same image can pass under one and fail under another.

Radiation safety and site control

Industrial radiography is a licensed activity with real exclusion requirements. Controlled area boundaries are established by calculation from source activity, distance and shielding, then confirmed by survey with a calibrated instrument — scatter from surrounding structures routinely produces dose rates above what a line-of-sight calculation predicts. Where a shutdown cannot accommodate exclusion, that constraint should shape technique selection early rather than being discovered on the night.

Frequently asked questions

Can ultrasonic testing replace radiography on our welds?

Many codes now permit ultrasonic examination as an alternative for thick-section welds, and it detects planar flaws radiography can miss. It does not produce an equivalent image, so where a specification or an owner requires a radiograph, substitution has to be agreed in writing rather than assumed.

Do you provide digital radiography or film?

Both, chosen against what the specification requires and what the site allows. Digital gives immediate review and archives that do not degrade; film remains specified on some contracts. Where a specification predates the digital provisions in the applicable code, that needs resolving before work begins.

How do we know the image was good enough to rely on?

The image quality indicator. If the required hole or wire is not visible in the image, the required sensitivity was not achieved and no interpretation drawn from that image is supportable. It is the first thing to check on any radiograph you are handed, from any provider.