TOFD and its principles are well documented. Utilizing diffracted energy in the detection of flaws, the technique is less reliant on flaw orientation and morphology than standard pulse echo techniques, leading to improved sizing and probability of defect detection (POD). Additionally, computerized electronic data capture and storage, in conjunction with scanning manipulators enable rapid scanning speeds to be achieved TOFD has now been accepted as an alternative to Radiography in Pre-Service Inspections with standards such as ASME, and its use in pipe weld and thick walled pressure vessel fabrication is now common place.

Due to its’ sensitivity and sizing accuracy, TOFD is also an excellent tool for in-service material and flaw monitoring. Engineers who are monitoring root erosion, stress corrosion cracking, vessel cladding, Hydrogen Attack, Weld and Steam Chest cracks for example, are all now utilizing TOFD as part of an on-going inspection regime.

Ultrasonic phased arrays are a novel technique for generating, receiving and imaging ultrasound. Instead of a single transducer and beam, phased arrays use multiple ultrasonic elements and electronic time delays to create beams by constructive and destructive interference. As such, phased arrays offer significant technical advantages for weld testing and plant monitoring over conventional ultrasonics as the phased array beams can be steered, scanned, swept and focused electronically from a fixed probe position. Beam steering permits the selected beam angles to be optimized ultrasonically by orienting or focussing them perpendicular to the predicted discontinuities.

Integrity NDT personnel have over 20 years of experience in planning, managing and carrying out TOFD&PAUT on pre-service and in-service projects, around the globe. We can advise and develop TOFD&PAUT procedures and have developed specialist scanning equipment for carrying out inspections.

Eddy Current Inspection is well-established and widely used in Petrochemical Refinery, Chemical Processing and Power Generation facilities, in the examination of Tubing in System Heat Exchangers, Air Coolers, Power Plant Steam Turbine Generator Condensers and Feedwater Heaters.

Systems are reliant on these critical components and hence avoidance of failure is of high importance. Heat exchangers are typically made-up of ‘bundles’ of tubes, small in diameter and thin walled, which can extend to 1000’s in number.

The Eddy Current Tube Test Method has numerous application variables, and method selection is dependent upon tube material, tube dimension and equipment/tubing type. The inspection is used to detect typical tubing associated defects such as; pitting, corrosion, longitudinal and circumferential cracking, fretting, wall thinning and erosion at tube-support plates. Early detection of these defects can prevent failure and the determination of potential failure mechanisms, providing plant engineers not only with a tool to assess condition from a digitally recorded data set, but also facilitating the estimation of remaining life. The assessment results provide valuable data, from which to plan strategic plant operational and maintenance programs and ongoing unit monitoring.

At Integrity NDT we have experienced personnel, using the latest technology for Eddy Current Tube inspection, with the following method/material type capability:

  • ECT – Conventional Eddy Current Inspection (Nonferrous metals)
  • PSEC – Partial Saturation Eddy Current Inspection (Ferrous Metals)
  • RFT – Remote Field Testing (Ferrous Metals and Heavy Wall Thickness)
  • NFT – Near Field Testing (Finned Tubes)
  • IRIS – Internal Rotary Ultrasonic Inspection*

*IRIS is an ultrasonic application; however, as it is used in tube inspection, it is shared here under Eddy Current section

Having secured long-term contracts to support continual refinery shutdown programs, our equipment and probe portfolio is wide ranging.

Integrity NDT also manufacture Eddy Current Tube Inspection Probes ‘in-house’, widening the inventory to suit each project workscope.

Guided wave is the rapid screening system for assessment of piping corrosion.

Integrity NDT provides guided wave ultrasonic inspection service with collobration NDT Global Services Ltd. UK.

Guided Wave Ultrasonic inspection abilities are;

Detection and positioning of corrosion in straight pipe and bends

  • Inspects under insulation
  • Road crossings and hidden penetrations
  • Surface Pipelines
  • Jump Overs
  • Lamp Posts
    1″ to 36″ diameter Range

Incorporating enhanced flaw detection with variable wave modes and frequencies.
On line interactive reporting
No need to remove paint
Only needs to the removal of a narrow ring of insulation for transducer application
Up to 50metres tested to either side of a transducer ring
Typically 100 metres of pipe inspected from a test position

EMAT is working based on non-contact ultrasonic sound generation mechanism. Sound is generated directly into the material by using magnitising ability. Result of working princible, testing technique does not require couplant. Due to couplant free inspection ability; EMAT is particularly useful for inspection of cold, hot, scaled materials.

Integrity NDT provides newest EMAT technology for industry. Due to minimum surface preparation and high sensitive inspection ability of the system, plant Engineering chooses EMAT inspection system for their power and process equipment, piping and tubing.

Due to formation of oxide scales on the inner tube walls, the heat transfer rate and the boiler efficiency gets affected, and in a worst case scenario, it may lead to overheating of the boiler tube and eventually, its rupture.

The boiler tubes are generally of low alloy steel grade material, thickness ranging from 5 – 10 mm and diameter from 50 – 60 mm. The solution described is capable of measuring oxide scale thickness down to 200 microns (depending upon the sound velocity characteristics in the oxidized layer).

To estimate the life of tubes used on boilers heated with fossil fuels, it is necessary to determine the thickness of the oxide layer on the tube`s inside surface.

Integrity NDT is using very high frequency special ultrasonic transducers for measuring internal oxide thickness.


Corrosion mapping by ultrasonics is a nondestructive technique which maps material thickness using ultrasonic waves. Variations in material thickness due to corrosion can be identified and graphically portrayed as an image. The technique is widely used in the oil and gas industries for the in-service detection and characterization of corrosion in pipes and vessels. The data is stored on a computer and color coded to show differences in thickness readings.