Radiographic Inspection

See Inside Your Critical Assets

Radiographic Testing (RT) is one of the most established and trusted volumetric NDT methods in the oil and gas industry. The technique works by directing penetrating radiation — either X-rays produced by an electrical tube or gamma rays emitted by a sealed radioactive isotope — through a test specimen onto a recording medium. As the radiation passes through the material, variations in thickness, density, and internal structure cause differential absorption, producing a permanent image of the component's internal condition on film or a digital detector.

This shadow image reveals a wide range of internal discontinuities that would otherwise remain invisible: gas porosity, slag inclusions, lack of fusion between weld passes, incomplete root penetration, shrinkage cavities, and even tight cracks when oriented favourably to the beam. The resulting radiograph provides a permanent, verifiable record that can be reviewed, archived, and audited years after the inspection — a significant advantage for regulatory compliance and asset integrity management programmes across South Africa's petrochemical sector.

At Oil and Gas Plant Engineer Consultants, our radiography teams deploy both X-ray equipment for workshop and fabrication yard inspections, and gamma ray sources including Iridium-192 (Ir-192), Cobalt-60 (Co-60), and Selenium-75 (Se-75) for field work on pressure vessels, process piping, storage tanks, and pipeline girth welds. The choice of source depends on material thickness, geometry, and site access constraints — and our Level II and Level III technicians select the optimal configuration for every application.

ASME V & BS EN ISO 17636 compliant
Digital and conventional film radiography
Iridium-192 and Selenium-75 sources
Permanent verifiable records

Techniques

RT Methods We Deploy

Conventional Film RT

Traditional film-based radiography remains the gold standard for many code-mandated inspections. High-contrast industrial X-ray film captures exceptional detail, with image quality verified through wire-type or hole-type IQIs. Ideal for ASME Section V and API 1104 weld acceptance criteria where film archives are contractually required.

Digital Radiography (DR)

Real-time digital imaging using flat panel detectors delivers instant results without chemical processing. DR dramatically reduces exposure times and eliminates film consumable costs. The digital workflow enables immediate on-site interpretation, remote review by Level III personnel, and seamless integration with digital asset management systems.

Computed Radiography (CR)

Phosphor imaging plate technology bridges conventional film and full digital workflows. Reusable phosphor plates are exposed like film, then laser-scanned to produce high-resolution digital images. CR offers the flexibility of film cassettes with the archival and processing advantages of digital — well suited to field inspections on pipeline girth welds.

Applications

Where RT is Essential

Weld Integrity Verification

Full volumetric examination of butt welds, socket welds, and branch connections in accordance with ASME B31.3, API 1104, and AWS D1.1. Essential for new construction acceptance and in-service repair verification on critical process piping and structural steelwork.

Casting Porosity Assessment

Detection and grading of internal porosity, shrinkage, and hot tears in cast valve bodies, pump housings, and structural castings. Radiographic assessment per ASTM E446 and E186 reference radiograph standards for acceptance grading.

Corrosion Under Insulation (CUI)

Profile radiography through insulation to detect wall loss, pitting, and localised corrosion without costly insulation removal. A rapid screening technique for carbon steel piping operating between 50 and 175 degrees Celsius in refinery and petrochemical environments.

Pipeline Girth Weld Inspection

Field radiography of pipeline girth welds using crawlers and external exposure techniques. Compliant with API 1104 and ASME B31.4 / B31.8 requirements for cross-country oil and gas transmission pipelines across South Africa's pipeline network.

Pressure Vessel Fabrication QC

100% radiographic examination of longitudinal and circumferential seam welds during pressure vessel fabrication. Full compliance with ASME Section VIII Division 1 and 2 joint efficiency requirements, PED, and SANS 347 regulatory standards.

Safety & Compliance

Radiation Safety Protocols

Radiographic testing involves the use of ionising radiation, and safety is our highest priority. Every exposure is conducted under strict regulatory controls to protect our personnel, your workforce, and the public.

NNR Regulatory Compliance

All radiographic operations are conducted under authorisation from the National Nuclear Regulator (NNR) of South Africa. Our radioactive source licences, transport permits, and operating procedures are maintained in full compliance with the Nuclear Energy Act and the Hazardous Substances Act. Regular NNR audits confirm our continued adherence to regulatory requirements.

Safety Exclusion Zones

Every radiographic exposure requires clearly demarcated controlled and supervised areas, established through radiation survey measurements. Physical barriers, warning signs, flashing lights, and audible alarms are deployed to prevent unauthorised access. Our Radiation Protection Officer (RPO) oversees all exclusion zone setups and verifies boundary dose rates before exposures commence.

Radiation Monitoring

All radiography personnel wear personal dosimeters (TLD badges and electronic direct-reading dosimeters) to monitor cumulative radiation exposure. Dose records are maintained in accordance with NNR requirements, and annual dose limits are strictly enforced. Calibrated survey meters are used before, during, and after every exposure to verify that radiation levels are within prescribed limits.

Need Radiographic Testing?

Our NNR-licensed radiography teams are ready to mobilise to your site anywhere in South Africa — refineries, fabrication yards, pipeline right-of-ways, and offshore platforms.

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