Industrial inspection support · India · UAE · Global enquiries
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APPLICATIONS & INSPECTION PLANNING

Start with the asset. Build the inspection around the decision.

A weld, pipe or pressure component does not need a technique by name; it needs a defined examination volume and a result that supports a decision. Use this guide to identify the likely method options and the information IAIS needs to assess your application.

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HOW TO USE THIS GUIDE

Match the inspection question to the component and conditions.

The same asset can require different ultrasonic strategies. A fabrication weld may need volumetric examination against a construction code. An operating line may need a targeted assessment of an indication or a map of remaining wall thickness. A complex material may need a specially demonstrated procedure before the method can be applied with confidence.

The examples below are starting points for a technical discussion . The final technique, probe arrangement, calibration, coverage, personnel and acceptance basis must follow the governing specification and project procedure.

APPLICATION GUIDE

Common inspection questions and possible approaches

01 / FABRICATION

New welds and construction joints

Pipe girth welds, vessel seams, structural welds and similar fabricated joints.

What the client needs to know

Has the required weld volume been examined, where are any reportable indications, and how are they evaluated against the specified acceptance criteria? The answer depends on joint configuration, weld preparation, thickness, material and the applicable construction specification.

Methods to discuss

PAUT can provide planned angle-beam coverage and encoded views. TOFD can add diffraction-based information and through-wall sizing in suitable welds. A combined examination may help address different response mechanisms, particularly around areas where one method has a coverage limitation.

What to send IAIS

Weld map, joint details, nominal thickness, material grade, weld cap condition, examination stage, applicable code and access on each side of the weld.

Check before selecting: root and cap coverage, probe travel, surface preparation, calibration reflectors and any restrictions from the governing procedure.

02 / OPERATIONS

In-service piping and weld assessment

Accessible process lines, circumferential welds, elbows and connections during service or shutdown.

What the client needs to know

Is a known or suspected indication present, how does it relate to the weld or adjacent base material, and what information can support engineering review? Operating history, likely damage mechanism and prior inspection findings are often as important as the nominal pipe size.

Methods to discuss

PAUT may be used for targeted weld examination with probes and scanners chosen for diameter and access. TOFD may be considered where probe spacing and surface geometry permit a suitable scan. TFM can be assessed for a specific region of interest when an imaging procedure is validated.

What to send IAIS

Pipe OD and wall thickness, material, weld profile, insulation or coating status, temperature, access restrictions, previous reports and the question the inspection must answer.

Check before selecting: small diameters, elbows, nozzles, adjacent fittings and limited scan clearance can change the usable probe setup and coverage.

03 / EQUIPMENT

Pressure vessels, reactors and tanks

Shell welds, longitudinal and circumferential seams, selected nozzles and accessible pressure boundaries.

What the client needs to know

Does the examination concern weld quality, an in-service indication, remaining wall thickness or a specific degradation mechanism? These are different scopes. The inspection zone, material and physical access determine whether one ultrasonic method or several complementary examinations are needed.

Methods to discuss

PAUT and TOFD can be considered for suitable weld seams. For a localized indication that needs further imaging, TFM with FMC data may be assessed. Broad-area wall-loss mapping calls for a dedicated thickness-mapping setup rather than assuming a weld scan will provide it.

What to send IAIS

Equipment drawings, weld identification, material and cladding details, nominal thickness, inspection history, operating conditions, access plan and the governing inspection requirement.

Check before selecting: curvature, cladding, coarse-grained weld metal, internals and site conditions can affect sound propagation and scan coverage.

04 / WALL LOSS

Corrosion and thickness mapping

Defined areas of pipe, vessel or tank wall where remaining thickness or localized metal loss is the question.

What the client needs to know

Where has material been lost, how extensive is it, and what remaining-wall data are needed for an engineering assessment? A useful mapping scope defines the area, grid or encoded coverage, minimum reportable thickness and how data will be tied to the asset location.

Methods to discuss

A suitably configured phased-array thickness-mapping approach may produce a mapped record of the examined area. Localized conventional ultrasonic thickness measurements or another technique may also be required under the project plan. TOFD is primarily discussed here for specific weld-root questions, not as a general substitute for broad-area corrosion mapping.

What to send IAIS

Asset drawing and location map, expected corrosion area, nominal thickness, material, coating or insulation condition, surface temperature and required grid or resolution.

Check before selecting: coating, surface profile, pitting geometry, inaccessible areas and the coupling arrangement can affect the reliability of thickness data.

05 / INVESTIGATION

Complex indications and difficult geometry

Questions involving indication orientation, location, sizing or material response that need more than a routine scan.

What the client needs to know

What uncertainty remains after the initial inspection? The aim may be to locate an indication within the weld volume, estimate its extent or test a suspected damage mechanism. The technique should be chosen to answer that exact question, with reference reflectors and a validation plan where needed.

Methods to discuss

PAUT can provide complementary beam angles and scan views. TOFD can contribute diffraction information. FMC acquisition and TFM reconstruction may provide a more focused image for a defined region of interest. More image detail does not automatically improve detection for every geometry.

What to send IAIS

Raw or reported prior inspection findings where available, suspected indication position, material and weld details, access constraints and the decision the new examination must support.

Check before selecting: material velocity, attenuation, mode selection, aperture, focal region and reference block response require technical review.

06 / SPECIALIST

High-temperature hydrogen attack assessment

A specialist inspection question for relevant equipment exposed to hydrogen at elevated temperature.

What the client needs to know

Is the asset susceptible under its material and operating history, and what locations require examination? HTHA assessment is not resolved by a generic ultrasonic scan. Inspection planning should account for temperature and pressure history, material, welds and heat-affected zones, the expected damage stage and the engineering decision.

Methods to discuss

Focused PAUT , TOFD and TFM may be considered as complementary ultrasonic approaches under a validated HTHA-specific procedure. FMC may support the TFM acquisition. Technique performance needs demonstration on relevant reference or validation samples for the proposed scope.

What to send IAIS

Material and fabrication records, service conditions, operating history, previous inspection data, component dimensions, weld locations and the applicable integrity assessment requirements.

Check before selecting: early damage can be difficult to detect. A negative ultrasonic result should not be presented as proof that HTHA is absent; engineering assessment and the approved inspection program remain essential.

EXTENDED APPLICATION LIBRARY

More components and inspection questions

Ultrasonic techniques can be adapted to many components, but their use is never universal. The examples below explain what a client may ask for, which methods are worth evaluating and what would be needed to develop a defensible scope.

Weld and fabrication configurations

The weld configuration determines probe placement, sound path and scan coverage. These examples describe technology possibilities; the governing code and a demonstrated procedure determine the actual examination.

Pipe girth welds

Inspection question. Determine whether the full circumferential weld volume and heat-affected zones can be covered, including the root and cap. Diameter, wall thickness and nearby fittings drive scanner and wedge selection.

Methods to assess. PAUT is often the starting point; TOFD may add diffraction-based sizing when both sides of the weld are accessible. For small diameter pipe, a dedicated scanner and coverage demonstration may be necessary.

Scope inputs. Pipe OD, schedule or measured thickness, weld profile, access around the full circumference and required acceptance basis.

Longitudinal pipe and vessel seams

Inspection question. Examine a long axial weld with a repeatable scan position and traceable location along its length. Curvature and plate thickness influence the sound path.

Methods to assess. Encoded PAUT and, where geometry suits, TOFD may be considered. The scan plan must define both sides of the weld and any changes near seam intersections.

Scope inputs. Seam length, shell diameter, weld drawing, thickness, seam crossings and access to the examination surface.

Nozzle, branch and attachment welds

Inspection question. Check welds whose local curvature, reinforcement and intersecting geometries make standard straight-weld scans difficult.

Methods to assess. PAUT may be adapted using multiple probe positions or specially designed wedges. TFM can be considered for a defined region after validation. TOFD requires a feasible probe-pair path and should not be assumed suitable around a nozzle.

Scope inputs. Nozzle orientation and diameter, attachment profile, thickness transitions, access and the exact weld volume of interest.

Thick-section and heavy fabrication welds

Inspection question. Plan adequate depth coverage and sensitivity through thick material, where one probe arrangement may not cover the whole volume.

Methods to assess. Multiple PAUT scan plans and TOFD zones may be required. TFM/FMC can be evaluated for a targeted indication, with sound paths and imaging zone demonstrated on representative material.

Scope inputs. Section thickness, material and heat treatment, weld preparation, reference block and any prior indications.

Dissimilar metal, stainless and clad welds

Inspection question. Address beam distortion, attenuation and backscatter that may arise in coarse-grained or anisotropic weld metal or at an interface.

Methods to assess. Specialized PAUT probe modes and qualified setups may be explored. TOFD and TFM are not automatic substitutes; each requires evidence of performance in the actual material and geometry.

Scope inputs. Base and filler metals, cladding or overlay thickness, weld procedure, grain structure where known, and representative calibration material.

Operating assets and degradation

For an operating asset, the suspected damage mechanism should be stated before selecting a scan. Weld examination, metal-loss mapping and crack investigation need different setups.

Pipe elbows and curved surfaces

Inspection question. Locate and measure thinning or erosion at the intrados, extrados and downstream regions of an elbow. The curved surface changes contact and scan tracking.

Methods to assess. A flexible-array or otherwise qualified PAUT thickness-mapping setup may be suitable. A conventional weld PAUT scan or TOFD scan does not provide the same area map.

Scope inputs. Elbow radius, diameter, wall thickness, material, expected thinning region, insulation status and requested map resolution.

Weld-root corrosion and erosion

Inspection question. Investigate localized metal loss near a weld root or adjacent heat-affected zone, where geometry can complicate a simple thickness reading.

Methods to assess. Targeted TOFD or PAUT may be assessed against a specific inspection objective and suitable reference sample. Complementary wall-thickness measurements may be needed to quantify remaining material.

Scope inputs. Weld profile, access, nominal and prior thickness, process direction, prior inspection data and suspected affected length.

Tank and vessel shell wall loss

Inspection question. Produce a location-referenced picture of remaining thickness over a defined area, possibly around a known corrosion mechanism.

Methods to assess. Dedicated encoded PAUT corrosion mapping may support broad-area records on suitable surfaces. Weld-seam PAUT or TOFD can be scoped separately for weld integrity.

Scope inputs. Asset drawing, grid and coverage area, nominal thickness, coating condition, surface access and minimum reporting requirements.

Corrosion under insulation after access

Inspection question. Examine a selected surface once enough insulation or coating is removed for reliable ultrasonic coupling. Ultrasound generally cannot be assumed to inspect through arbitrary insulation.

Methods to assess. PAUT thickness mapping or spot UT may be chosen for exposed areas. The inspection plan should define removal windows and areas that remain unexamined.

Scope inputs. Insulation type, proposed removal pattern, surface temperature, corrosion history and the area needing thickness data.

Suspected cracking and service-related indications

Inspection question. Find and characterize a specific indication in a weld or accessible component, then provide data for engineering review. Orientation and surface access matter.

Methods to assess. PAUT beam sets can be planned for expected crack orientation; TOFD may add tip-diffraction information. TFM/FMC may help a validated targeted assessment when conventional views leave uncertainty.

Scope inputs. Damage mechanism, indication location, prior reports, material, geometry, operating history and sizing objective.

Specialist components and sectors

Some assets need custom procedures, reference blocks, scanners or manufacturer-approved inspection methods. These are general industry applications, not a claim that IAIS is approved for every sector.

Wind turbine tower and structural welds

Inspection question. Inspect long circumferential and longitudinal welds in large fabricated structures, with attention to access, height and position tracking.

Methods to assess. Encoded PAUT and TOFD can be considered for suitable tower welds. The project plan must address scanner guidance, surface preparation and any work-at-height requirements.

Scope inputs. Tower section drawings, weld map, thickness, site access, inspection stage and governing specification.

Offshore and marine welded structures

Inspection question. Assess accessible welds or pressure components where coatings, marine exposure and restricted access shape the execution plan.

Methods to assess. PAUT/TOFD may be candidates for suitable welds. Any class, client or project approval must be verified for the exact work scope before it is claimed or relied upon.

Scope inputs. Component and weld drawings, coating, access method, environmental constraints and required authority or client acceptance.

Forgings, shafts and large machined components

Inspection question. Screen or investigate internal reflectors in thick solid components, where grain structure and beam penetration are important.

Methods to assess. Straight-beam or angle-beam PAUT may be configured for a defined examination volume. FMC/TFM can be explored for targeted imaging only after suitable performance demonstration.

Scope inputs. Forging geometry, material, heat treatment, grain characteristics, surface finish and required reflector sensitivity.

Castings and complex-shaped parts

Inspection question. Examine suitable cast components where rough surfaces, variable thickness and coarse microstructure can make ultrasound difficult.

Methods to assess. Specialized PAUT may be investigated with representative samples and sensitivity trials. No method should be promised before attenuation and geometry are assessed.

Scope inputs. Casting process and alloy, drawing, finish, expected defect type and representative reference material.

Composite and bonded components

Inspection question. Identify delamination, disbond or internal features in a material system that differs substantially from metallic welds.

Methods to assess. Purpose-designed phased-array ultrasonic setups are used in industry for some composites. TOFD weld procedures are not transferable; TFM/FMC suitability depends on layup, attenuation and validation.

Scope inputs. Material stack and layup, component geometry, bond design, thickness, access and acceptance specification.

Rail and transport components

Inspection question. Investigate defined welds or critical components under the sector’s own maintenance and qualification rules.

Methods to assess. PAUT can be a candidate technology where an approved procedure and suitable equipment exist. Sector-specific approvals and demonstration must be established before offering the application.

Scope inputs. Component type, material, inspection standard, service history, defect target and access constraints.

Important distinction: these are documented technology application areas, not a statement that IAIS holds a particular sector approval or has a ready-made procedure for every component. IAIS must review each enquiry, demonstrate suitability where needed, and confirm the exact personnel, equipment, code and acceptance basis in the proposal.

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INDUSTRY CONTEXT

Where these questions arise

Applications occur across several industries. The sector helps explain the operating environment, but it does not select the ultrasonic technique on its own.

Oil, gas & petrochemicals

Process piping, pressure equipment and shutdown or in-service integrity questions.

Power generation

Fabricated welds and operating components requiring defined examination coverage.

Manufacturing & fabrication

Weld quality verification and inspection records during production and construction.

Marine & offshore

Accessible welded components and pressure boundaries, subject to site and governing requirements.

METHOD SELECTION

Compare the role of each method

This table is an orientation aid. It is not a code-compliant procedure or a guarantee of coverage.

Method Typical contribution Planning question
TOFD Diffraction-based weld examination and sizing information in suitable geometry. Can both probes travel as required, and how are near-surface zones addressed?
PAUT Controlled sound paths and scan views for welds or a dedicated mapping setup. Which probe, wedge, focal laws and scan positions demonstrate the required volume?
TFM Focused image reconstruction within a defined region of interest. Has image quality and performance been demonstrated for this material and geometry?
FMC Array data acquisition for processing such as TFM. What acquisition and processing plan produces the required evaluable result?

FROM QUESTION TO SCOPE

What happens after you send an enquiry?

01

Define the decision

Identify the component, suspected condition, required examination volume and the client’s acceptance or engineering question.

02

Review feasibility

Check material, thickness, geometry, access, applicable specification and whether a suitable calibration or validation approach is available.

03

Agree the deliverable

Set the method, procedure, scan coverage, reporting format, personnel, equipment and schedule in the project proposal.

APPLICATION ENQUIRY

Describe your asset and the decision you need to make.

Send drawings, material, wall thickness, suspected condition, inspection history, site location, governing specification and target dates. IAIS can review which approach is feasible for your application.

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