Weld Inspection in a Live Yard: Codes, Stages, Methods, Records

Three code families, one yard

A shipyard weld can sit under one code, two, or three at once, and identifying which is in force is the inspector's first decision. Hull structure belongs to the classification society, because the society certifies the hull. ABS Rules for Materials and Welding and the equivalent rules at the other IACS members set consumable approval, welding procedure approval and the inspection requirements the attending surveyor checks before crediting the work.

AWS D1.1, Structural Welding Code, Steel, covers welding requirements for welded structures made from commonly used carbon and low-alloy constructional steels. Its clause structure maps directly onto the shop: Clause 5 prequalification of WPSs, Clause 6 qualification, Clause 7 fabrication, Clause 8 inspection. It governs a great deal of yard steelwork outside the certified hull envelope, and it is the code most US inspectors already hold a certification against.

AWS D3.5, Guide for Steel Hull Welding, sits alongside both as marine practice guidance. It covers steel plates, shapes, castings and forgings and their weldability, welding processes and design for welding, hull construction in terms of material preparation, erection and fitting, control of distortion, qualification of procedures and personnel, and inspection methods. It informs how a yard works. It does not replace the class rules the surveyor applies, and confusing guidance with a governing requirement is expensive.

Fit-up is where the inspection actually starts

Weld inspection starts before the arc does. Joint preparation, bevel angle, root gap, alignment, cleanliness of the faying surfaces and preheat are all visual inspection points, and every one of them becomes unrecoverable once the joint is filled. A poorly fitted butt in shell plating produces exactly the lack-of-penetration indication a UT operator will find three days later, far more expensively, with the block already erected and staged.

Material control belongs to the same stage. Steel grade, heat number and mill certificate have to trace to the piece mark being welded, because hull steel grades and the consumables approved for them are matched by the class rules. A plate substitution nobody caught at receipt turns into a production weld made under a procedure that was never qualified for the material actually in the ship, and the correction runs backwards through the whole block.

In-process inspection covers the parameters the Welding Procedure Specification fixes: preheat and interpass temperature, travel speed, current and voltage ranges, electrode handling and interpass cleaning. The inspector's leverage is highest here and falls steadily afterwards. Fit-up and in-process checks prevent defects, while post-weld NDT only finds them, and finding them in an erected block is the expensive outcome. That is the whole economic argument for staffing the front of the process.

Procedure qualification versus welder qualification

Procedure qualification and welder qualification answer different questions, and yards lose audits by conflating them. Procedure qualification proves the recipe works. A Welding Procedure Specification names the process, material, joint design, position, consumables, preheat and electrical parameters, and a Procedure Qualification Record documents the coupon tests supporting it. AWS D1.1 places both inside Clause 6, splitting it into WPS qualification and performance qualification.

AWS D1.1 offers a shortcut for common work through Clause 5, which sets the requirements for exempting a Welding Procedure Specification from qualification testing. A WPS built entirely inside the prequalified envelope, using prequalified joint geometry, an approved base metal and filler combination and parameters inside the prequalified ranges, needs no supporting Procedure Qualification Record. Step outside that envelope and the procedure has to be qualified by test.

Welder qualification proves the person. A performance qualification record shows an individual can deposit sound welds using an approved procedure in a specific process, position, thickness range and joint type, and D1.1 lists the essential variable changes that require requalification. Class rules add the society's own approval of the yard's procedures and welders. On hull structure that approval is what counts, and a welder qualified only under D1.1 is not automatically approved for classed hull work.

Why UT beats RT in a live yard

Radiography and ultrasonics both examine the weld volume, and the yard's schedule chooses between them. Radiography clears the compartment: every other trade stops, the boundary is roped and monitored, and the exposure happens between shifts or overnight. On a block under erection with fitters, welders, painters and staging crews working at once, that is a shift lost across a whole area rather than across a single weld.

Ultrasonics is contact work with no exclusion zone. A technician scans a butt weld while the compartment keeps working around them, and the result arrives immediately rather than after processing. Phased array and time-of-flight diffraction extend that further by producing encoded, reviewable data with a permanent record, which was radiography's traditional advantage. Current ABS guidance addresses advanced methods including phased array, time-of-flight diffraction and digital radiography.

Radiography still holds ground where it belongs. Geometry that defeats an angle beam, thin sections below practical UT range, root conditions in single-sided welds, and client or contract specifications that name RT all keep it in the yard. The decision framework, which method for which joint and on what evidence, is the subject of our post on RT versus UT for weld inspection, and it is the discussion an inspector has to be able to hold with a surveyor.

Surface methods and where they belong

Surface examination runs ahead of volumetric examination and catches a different failure mode. Visual inspection covers profile, undercut, overlap, arc strikes, crater cracks and reinforcement. Magnetic particle inspection follows on ferromagnetic hull and structural steel and finds surface and near-surface cracking, including toe cracks that visual inspection misses. Penetrant inspection covers austenitic stainless, aluminium and other non-magnetic materials a yard handles on tanks, piping and outfitting.

Method selection follows the rule set rather than preference. The ABS approach is explicit: radiographic or ultrasonic inspection, or both, is used where the overall soundness of the weld cross-section is to be evaluated and for internal inspection, while magnetic particle or liquid penetrant inspection, or another equivalent approved method, is used for surface inspection of welds. Substituting a surface method for a volumetric requirement is a finding, not a shortcut.

The hold period before you can inspect higher-strength steel

Higher-strength steel introduces a delay the schedule has to carry. Hydrogen-assisted cold cracking develops after the weld cools, over hours rather than minutes, so an examination performed immediately after welding can pass a joint that cracks that night. The ABS Guide for Nondestructive Inspection of Hull Welds requires NDT of weldments in steels of 400 N/mm2 yield strength or greater to be conducted at a suitable interval after welds have been completed and cooled to ambient temperature.

The intervals are specific: a minimum of 24 hours for steels at 400 N/mm2 yield strength and a minimum of 72 hours for steels above it, unless specially approved otherwise, with the Surveyor free to require a longer interval or additional random inspection later. At the Surveyor's discretion the 72-hour interval drops to 24 hours for RT or UT, provided complete visual and random MT or PT inspection is carried out at 72 hours.

That hold period is a planning fact rather than an inspection detail. Where delayed cracking is encountered in production, previously completed welds are re-inspected to the Surveyor's satisfaction, and the Surveyor can require requalification of procedures. A yard that schedules NDT for the shift after welding on higher-strength steel discovers all of this at handover, when the surveyor asks for the timestamp on the report.

Navy work is a different regime

Navy work runs on a separate stack, and a commercial-yard inspector cannot simply walk onto it. NAVSEA S9074-AQ-GIB-010/248 contains the requirements for qualification of welding and brazing procedures and for welders, welding operators, brazers and brazing operators, and those qualifications have to be met before any production fabrication starts. Nothing carries over automatically from commercial practice, and the tests are devised to demonstrate the adequacy of the procedure and the ability of the individual.

NAVSEA T9074-AS-GIB-010/271 covers the testing itself: the requirements for conducting nondestructive testing to determine the presence of discontinuities in metals, together with the minimum requirements to qualify NDT personnel, procedures and equipment. It defines the Level III NDT Examiner as equivalent to Level III in ASNT SNT-TC-1A, the Level II NDT Inspector as equivalent to Level II, and the Level I NDT Operator as equivalent to Level I.

The certification regime hardens noticeably. Personnel are certified in accordance with the activity's written practice, and SNT-TC-1A is invoked as mandatory minimum requirements rather than recommendations or guidelines. Recertification runs at intervals not greater than three years for Operators and Inspectors and five years for Examiners, and recertification by evidence of continuing satisfactory technical performance, or on the basis of ASNT certifications granted without examination, is not permitted.

Acceptance is separate again. MIL-STD-2035 provides acceptance criteria for visual, radiographic, magnetic particle, liquid penetrant, ultrasonic and eddy current examination, segregated by class, with the applicable class named in the NAVSEA drawing, specification, contract, order or directive. NAVSEA Standard Item 009-12, Weld, Fabricate, and Inspect; accomplish, pulls the stack into an availability's work package, and our NAVSEA requirements consulting covers how a commercial yard builds toward it.

The dossier the surveyor receives

The record is the deliverable. A surveyor or a government inspector does not re-examine the welds; they examine the evidence that the welds were examined correctly. That means approved Welding Procedure Specifications with supporting Procedure Qualification Records, current welder performance qualification records mapped to the individuals who made the production welds, and material certificates traceable to piece marks. Missing traceability at any of those three points reopens the whole weld population.

The NDT side carries its own file: written procedures approved by a Level III, personnel certification records under the employer's written practice, equipment calibration records, reference blocks, and the examination reports keyed to weld identity. A weld map showing every joint, its examination status and its repair history is what makes the file navigable, and it is what an experienced surveyor asks for before looking at a single report.

Repairs are where dossiers fall apart. Every excavation, re-weld and re-examination has to appear against the original weld identity, with the repair procedure referenced and the re-test result recorded. Yards tracking this on spreadsheets lose the chain at the second repair on the same joint. Structured NDT reporting and ERP that keys every report, radiograph and scan file to a weld identity removes the reconstruction work at handover.

Training a yard weld inspector

A yard weld inspector needs three layers, and most training covers one. The method layer is NDT certification under a written practice built on ASNT SNT-TC-1A, where Level II performs and directs testing and interprets and evaluates results, and Level III establishes and validates techniques and procedures and designates the methods to be used. That is the layer the market recognises, and on its own it does not qualify anyone to work a shipyard.

The code layer comes next: reading a WPS against the joint in front of you, knowing which acceptance criteria are in force, recognising when a prequalified procedure has drifted outside its envelope, and understanding the class approval sitting over the yard's welding. The third layer is the process layer, knowing where in the build sequence each examination belongs and what the hold points cost when they move.

O*NET reports a median annual wage of $78,350 for Non-Destructive Testing Specialists in 2025, within the broader engineering technologist category, with projected employment growth of 1 to 2 percent through 2034. The premium in a shipyard sits with inspectors holding all three layers. We build that as a company programme: see corporate NDT training, the ASNT certification pathway, and the sibling courses at special survey drydocking NDT and tank and ballast space inspection.

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