Phased Array UT (PAUT) Inspection (PAUT) Services in Qatar 2026 — Atlantis NDT

How Phased Array Ultrasonic Testing (PAUT) works

A phased array probe contains many small elements pulsed with controlled time delays, which steers and focuses the beam electronically. One probe position can therefore sweep a range of angles (sectorial scan) or step a focal law along the array (linear scan), producing an imaged cross-section of the weld or component instead of a single A-scan trace.

What it detects

• Weld defects across a range of angles from one probe position — lack of fusion, lack of penetration, slag and cracking
• Corrosion mapping with encoded C-scans that reproduce between campaigns
• Crack sizing and depth measurement with imaged confirmation of the interpretation
• Complex geometry — nozzles, branch connections, dissimilar-metal welds — where fixed-angle probes cannot achieve coverage

What it will not do

Coverage must be demonstrated by a documented scan plan; a phased array scan that looks thorough on screen can still leave a volume unexamined if the focal laws and probe positions were never modelled. Encoded scanning also needs surface condition and access good enough to run the scanner reliably.

When Phased Array Ultrasonic Testing (PAUT) is the right choice

Choose PAUT where you need imaged, encoded, reproducible data — for repeat corrosion surveys, for weld examination replacing radiography, or where geometry defeats conventional angle-beam probes.

Codes and acceptance criteria

Examinations are performed to written procedures qualified against ASME Section V Article 4 Mandatory Appendices IV and V, ASME Section VIII Division 1 Appendix 12, ISO 13588, ISO 19285 for acceptance, API 1104 Annex A, and AWS D1.1 Annex H for ultrasonic weld examination. Acceptance criteria come from the construction or in-service code governing the item — ASME Section VIII for pressure vessels, ASME B31.3 for process piping, API 510, API 570 and API 653 in service, AWS D1.1 for structural steel — and the applicable edition is recorded against the examination so the disposition can be reconstructed later.

Qatar context

Qatar is the world's largest LNG exporter, with QatarEnergy operating the Ras Laffan Industrial City — home to 14 LNG trains under Qatargas and RasGas (now unified), the Pearl GTL plant (Shell, world's largest gas-to-liquids facility), the Oryx GTL plant, and the new North Field East and North Field South expansions adding 48 mtpa of LNG capacity by 2027. The QatarEnergy NFPS (North Field Production Specifications) inspection-engineering standard governs the world's largest LNG construction wave. Cryogenic 9% Ni weld inspection, brittle-fracture screening, and sour-service gas integrity (NACE MR0175) make digital twin damage-mechanism modelling a strategic capability for every contractor working Qatar's downstream.

How the examination is controlled

Every examination carries its own evidence chain: the technician's certification for the method and level under ASNT SNT-TC-1A or ISO 9712, current on the day of inspection; the calibration status of the instrument, probes, wedges and reference blocks used, traceable under ISO 17025; and the revision of the procedure and technique sheet in force at the time. An ASNT NDT Level III reviews and signs the final disposition. That bundle is exactly what a client or accreditation audit asks for, and it is recorded as the work happens rather than assembled afterwards.

What you receive

• A report in your required format, with indications located against the component and, where relevant, against a persistent corrosion monitoring location so trends stay continuous between campaigns
• Raw data files in the instrument-native format plus an open export, so the dataset outlives any single supplier relationship
• The procedure revision, technician certification state and instrument calibration status applicable at the time of examination
• Where a finding affects continued service, a clear statement of the code clause that governs the acceptance decision

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