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Advanced NDT Services

Advanced NDT services, are strategic to the portfolio of SiSi Inspection Services.
SiSi has a strategic exclusive alliance with Swiss Approval Advanced NDT laboratory, and promotes in the Italian market the Advanced NDT Solutions, in the following sectors: 

Swiss Approval Advanced NDT based in UK, manage evaluation of the condition of storage tanks, pipelines, pressure vessels and other critical equipment, supporting the integrity management processes to ensure effective and safe operation, through specific Automated UT equipment, for corrosion mapping.  Our Advanced NDT Laboratory operations, are conformed with ISO 17025 requirements.


PAUT & TOFD Ultrasonic, for Corrosion & Critical Weld Inspection

Swiss Approval Advanced NDT based in UK, is delivering advanced Phased Array inspection services, with use of Total Focusing Method (TFM) Technology, the latest option in this specific UT testing. Our Advanced NDT Laboratory operations, are conformed with ISO 17025 requirements. The advantages of TFM technology in Phased Array inspection activities are:

  • Optimal focusing and spatial resolution everywhere
  • Direct imaging of a large area for one probe position
  • All reachable angles with the array simultaneously
  • Defect characterization
  • Comprehensive imaging of defect
  • 3D imaging

TFM imaging and computational process, is a «must» requirement in advanced UT applications. In Europe & US, TFM, is going to become a standard inspection requirement for Phased Array testing and interpretation of results. With Total Focusing Method (TFM) or Total Electronic Focusing (TEF), we do not see just the waves moving on the monitor, we have inspection results clearly stored and displayed for reporting, either on standard or special materials, like austenitic and high alloy materials as well as in Dissimilar Materials.

  • Electronic focusing consists of adapting the receiving delay laws, to focus at many points forming a Grid, after a single pulse which generates a large and/or divergent ultrasonic beam.
  • Effective inspection of anisotropic in-homogeneous materials is often a challenge due to the deleterious effects of the material properties on the bulk wave transmission of ultrasound. Reliable inspection capability for these materials must provide high probability of detection whilst minimizing false calls.
  • Upon detection of an indication, the sizing and plotting of the indication within the search volume must be sufficiently accurate to support disposition in accordance with applicable codes. Common metallic members of this group of materials, includes austenitic stainless steel welds, coarse grain cast stainless steels and dissimilar metal welds.
PAUT Scanning Solutions

Depending of each particular inspection project, Swiss Approval is using the appropriate Crawler / Scanner, in order to get the best results from scanning options. We propose either, Semi-Automatic PAUT (S-AUT) solutions, as well as, full Automatic PAUT (AUT)applications:

  • Multi Probes Crawlers for flat and curved surfaces [S-AUT],
  • Specific crawlers for angle welds and joints [S-AUT]
  • Specific crawlers for High Diameter Pipe Line inspection, on a fixed route [S-AUT]
  • Robotic crawlers for inspection of flat or curved surfaces at height, like tanks shell or similar [AUT]
  • Pipe lines and tubes inspection, with robotic or Semi-Automatic crawlers, depending on diameter and inspection position.

 PAUT Testing Applications

  • PAUT Corrosion mapping to estimate thickness at finite points in pressure vessels, pipes, tanks and structures.
  • PAUT on butt welds in pipes and pressure vessels and large structures, Bifurcation lines, Valve bodies, etc
  • PAUT scans on complex geometries including painted cylindrical, trapezoidal fuel transport tankers
  • Individually tailor development of qualification blocks, configuring rigs for data collection and levels of post-analysis reporting
  • 100% weld volume coverage at scanning intervals of 1mm,  of high pressure and high temperature piping welds at power station sites using encoded scanning  on circumferential and seam welds between 20mm to 75mm wall thickness
  • Inspection of small bore tubes – Internal diameter of down to 38mm; having a minimum wall thickness of 5mm
  • Inspection of complex geometry branch welds with variable weld profile using encoded scanning for accurate sizing of internal defects
  • Turbine and generator components inspections with special  focus on areas of high stress concentration  such as for tree serrations of turbine blade roots and geometry changes along exciter cooling fans
  • Detection of corrosion wastage in wind tower foundation bolts or other similar HOLD DOWN BOLTS with reliable monitoring of corrosion wastage along the length of bolts up to 5 times its diameter
  • In-situ inspection of transverse cracks in shafts, axles, spindles, hold down bolts.
  • Precise detection, measurement and reporting of smaller cracks for condition monitoring or repair.
Time of Flight Diffraction (TOFD)

Time Of Flight Diffraction (TOFD) is an advanced method of Ultrasonic inspection that leverages on existing UT methodologies, thereby bringing a whole new range of testing and detection capabilities to the NDT forefront. Whilst conventional ultrasonic uses shear/transverse waves as the primary mode of detection, TOFD uses longitudinal waves as the primary detection mode. Ultrasonic sensors are placed on each side of the weld. One sensor transmits the ultrasonic beam into the material and the other sensor receives both reflected and diffracted ultrasound from anomalies and geometric reflectors. Using ultrasonic beam spread, TOFD provides a wide area of coverage for anomaly detection in the material being tested. When the beam impinges on a flaw tip, it is diffracted in all directions. Measurement of the time of flight of this diffracted beam, enables accurate and reliable flaw detection and sizing. This is the case even if the crack is not oriented to the initial beam direction. During typical TOFD inspections, A-scans are collected and used to create B-scan (side view) images of the weld.

TOFD Characteristics:
  • Based on diffraction, so relatively indifferent to weld bevel angles and flaw orientation
  • Uses time of arrival of signals received from crack tips for accurate defect positioning and sizing
  • Precise sizing capability makes it an ideal flaw monitoring method
  • Quick to set up and perform an inspection, as a single beam offers a large area of coverage
  • Rapid scanning with imaging and full data recording
  • Can also be used for detecting irregularly shaped areas of metal lossduring corrosion inspections
  • Required equipment is more economical than phased array, due to conventional nature (single pulser and receiver) and use of conventional probes.
  • Highly sensitive to all weld flaw types
Why Advanced NDT is Chosen, over Radiography

Although radiography testing (RT) was the primary NDT method suggested by the manufacturer, SWISS APPROVAL concluded that alternative advanced NDT methods, like ultrasound testing (UTPA), is definitely a more advantageous method.

  • RT inspection would have required twice as many inspectors.
  • Implementation of a safety zone was deemed too difficult. Inspection activities has to be performed during the night, while other employees are not present.
  • It is estimated that the complete project using RT, would take five times longer than UTPA or other advanced UT applications.
  • On top of all the extra costs associated with RT, are consumables such as films, photo chemicals, and waste disposal of the lead foils.
  • The most important aspect of choosing UTPA or similar over RT, is related to the probability of detection. Lack of side wall fusion, which is a critical flaw to measure, is not well detected by radiography.
High Temperature Phased Arrays Applications
  • Phased Array UT presenting ‘A’, ‘B’ and ‘C’ Scans.
  • Corrosion Evaluation, Hydrogen Related Condition Monitoring & Weld Testing.
  • Performed by Certified Level 2 PA technicians and verified by Level 3 PA (not just UT).
  • We apply Phased arrays offline and online up to 200°C actual surface temperature. Continuous water flow ensures that the sensors remain well below their Curie temperature without their operational performance being affected. Thus, accurate evaluation of the structural integrity of the inspected component can be accomplished.
How it is accomplished:
  • Our new approach involves a 64 channel PA sensor using water as coupling.
  • During operation water flows between the hot surface of the component inspected and sensor array allowing heat transfer to take place thus, reducing actual sensor temperature to normal levels.
  • In this way hot measurements are not any longer distorted which means that correction is not needed. This allows straightforward scanning of components t higher temperatures, such as vessels and pipelines, without the need to stop operation and reducing unwanted openings of such equipment during outages reducing significantly maintenance works.
  • Acquired C scans are then stitched together providing a meaningful image of the corrosion profile and its extent.
Calibration Blocks

Swiss Approval Laboratory Staff is working consistently to guaranty the maximum efficiency and reliability of our Testing Results. Specific Calibration Blocks for each method, position, for different materials, related to different International Standards, are designed and developed within our Laboratory, in order to build in house our Know-How, necessary for service delivery of excellence. Development of inspection capacity for this category of materials, usually includes many, if not all, of the following:

  • Modelling,
  • Simulation,
  • Fabrication of mock-ups and samples containing realistic defects,
  • Procedure development,
  • Validation and subsequent training.

Such development of inspection resources and capacity represents for Swiss Approval Top Management, substantial commitments of time, high qualified personnel and significant capital investment.

 

Automated UT Corrosion Mapping

Swiss Approval Advanced NDT based in UK, manage evaluation of the condition of storage tanks, pipelines, pressure vessels and other critical equipment, supporting the integrity management processes to ensure effective and safe operation, through specific Automated UT equipment, for corrosion mapping. Our Advanced NDT Laboratory operations, are conformed with ISO 17025 requirements.Our solution can give almost 100% coverage in a band up to 450 mm wide, significantly increasing Probability of Detection (POD) of defects and corrosion, enabling Clients to determine the optimum repair strategy, and improve remaining life assessment (RLA) & risk based inspection (RBI) maintenance programs.

FLEXIBLE SOLUTION

Magnetic Flux Leakage, Storage Tank, Heat Exchangers

Swiss Approval Advanced NDT based in UK, manage MFL Inspection Services in a wide range of geographical areas, using state-of-the art equipment, for Storage Tank Bottoms, Heat Exchangers, Pipelines & Vessels.  for Storage Tank Bottoms, Heat Exchangers, Pipelines & Vessels. Utilising a variety of MFL gears, it is allowing the quick scanning of tank bottoms. Annular ring inspection, is also possible using miniature MFL hand scanners, allowing approaching the shell to bottom weld. Furthermore, a variety of MFL hand scanners is available for the quick scanning of all diameter pipelines including furnace tubes, a method really fast and particularly effective when combined with Phased Arrays.

 

Thermography Inspection Services

The specific Swiss Approval Advanced NDT Laboratory for Thermography Inspection is based in Italy, and is offering services and coordinates applications in the Infrared or Thermal Inspection sector in different areas within or outside Europe. With our equipment of high characteristics, our experts can discover even small size of defects. Our equipment characteristics of thermal sensitivity, can range from 0,1°C to 0.02°C, depending on sensor dimension, optics and settings. Since infrared inspection is a superficial inspection, in order to perform a complete inspection, we combine both, superficial and volumetric inspection by UT. Volumetric control implies to control the volume of the object. The most common control is by ultrasound or ultrasonic test, which is a contact and non destructive examination. By means of ultrasound it is possible to evaluate thickness’s and internal flaws that cannot be reached by infrared inspection.

Application in Yachts / Marine

Infrared inspection can be applied easily in yacht because is a non-contact and non-destructive operation and do not alter the characteristics of the equipment and materials to be inspected. Depending on type of inspection, there are some requirements that has to fulfil. For hull, keel, rudder, propeller, shaft or ventral fins inspection, the ship should be in dry dock.

Coating Inspection

External coating on hull or structures, can be inspected satisfactorily allowing to identify the most common defects, like blisters, cracks, osmosis, degradation and delamination. It is also possible to identify repaired areas and their condition, since the putty used has different thermal properties from the fiber glass or metal.

Osmosis and blistering Inspection Services

Osmosis is a phenomenon caused by when a fluid with high salt content is separated by a porous media, from a low salt content fluid. In the ship, the high salt content is sea water, and the low content salt is the air. The porous media is aged fiber glass and coating layers. For steel structures, the porous media are the coating layers only, and the low content salt fluid is any bubble of air entrapped during coating. Salinity through the ocean in the world, is not uniform so osmosis can be different depending on the sea. During osmosis the sea water penetrates the coating, and creates some underlayer solid salt accumulation. This salt has different thermal properties of the entire hull, so after thermal exciting, it is possible to identify precisely the area interested.

Fiber Glass condition monitoring services

Fiber glass is a material made of glass flakes, mainly silica, bonded in an epoxy resin matrix. The shape of the object plays an influence on the mechanical properties. When completely cured, the different directions of the flakes, gives an important mechanical resistance which due to shaping flexibility, can be used widely in marine industry. Ageing of the epoxy resin is a process which depends on the environment where the ship operates.

Engines Inspection

The performance of the engines, regardless if they are electric or combustion, can be monitored with infrared camera. More precisely, if there is some misalignment in the shafts or basement, this vibration will produce an abnormal heating that can be easily seen. It is possible to check the thermal insulation of the motors in order to don’t create hot spots inside the ship cabins.

Electrical Installations Inspection Services

Electrical wiring, cabinet, motors can be assessed through a thermal camera. From physics it is known that a current passing through an object produce a heating due to the friction of the electrons. The heat produced a clear image of thermal anomalies.

Moisture Inspection 

If in a room there is a specific value of humidity and temperature, moisture can be formed on the wall and in more aggressive form, can create mould. Conditions can be created by any mean, but normally can be found when there is a transition from a hot area to cold area. Mould and moisture, viewed through a infrared camera, are blue because the water have a lower temperature/emissivity of the surrounding wall.

Reporting and Certification of Thermography Inspection Services

Due to complexity and importance of the controls above mentioned, the performing operator should be duly qualified in order to ensure the highest skill and technical advise of the area inspected. The regulating standard for qualification of the operator is ISO 9712. Being qualified by this international standard, requires a previous experience endorsed by Swiss Approval. For coating inspection, Swiss Approval Inspectors are mainly NACE certified, and can perform inspection services of the highest value. Swiss Approval Certified Perosonnel includes UT and Advanced UT Level II experts, in order to execute specific inspection activities on materials and parts. Depending of the nature of service, a Swiss Approval Report or Certificate of Conformity can be issued, after completion of inspection and the related technical review.   Swiss Approval advanced NDT Laboratory, can provide full inspection service, superficial and volumetric, on coatings, mechanical and electrical parts of any construction or ship. Welding inspectors and qualified Welding Engineers, can monitor and inspect any repair or work on steel parts. Our staff is fully qualified and certified according to ISO 9712 for non-destructive examinations, ultrasonic, infrared, liquid penetrant, magnetic particle and x-ray film interpretation. NACE and / or FROSIO certified coating inspectors can evaluate the condition of the external coating and provide monitoring to tailored repair activities, according customer / project needs.  


On Line Test System for Safety Valves

Swiss Approval Advanced NDT Laboratory, has put in place, and use specific technology for Testing of Safety Valves. Such technology encompasses a comprehensive safety concept to safeguard the User, the Test Object (safety valve) and the Test System itself against damage. The inspection system is supported by specific Software, which generates reporting and maintains traceability of inspection activities. The On Line Inspection System of Valves, enables Plant Managers to test the spring operated safety valves on site without interrupting the process operation. With this so called “hot testing” the safety valve stays on-line, and no dismantling of the valve or plant shut-down is required. The main advantages are:

  • NO PLANT SHUT-DOWN
  • NO DISMANTLING OF THE VALVE
  • NO LOSS OF PRODUCTIVITY & PROFITABILITY

The system is a dedicated test system for on line / on site Safety Valve Testing. To test a safety valve on line or on site, the following tasks have to be dealt with:

  1. Lift the valves disk from the outside using a force generating unit
  2. Measure lifting force, disk lift and system pressure (line pressure) while lifting the disk.
  3. Control the lifting process
  4. Visualise, analyse, print and store measured values

Task 1 – Lifting the valve disk The inspection System is using hydraulic mechanism to generate the lifting force. A hydraulic pump with an attached valve block is used to operate a hydraulic cylinder up and down. The pump and valves are built into the Power Box. The hydraulic cylinder is part of the Test Rig that has to be mounted onto the safety valve and connected with the safety valves spindle via an adapter system. To operate the hydraulic cylinder up and down two hoses lead from the Power Box towards the hydraulic cylinder. Task 2 – Measure Force, lift and line pressure as well as other parameters are measured directly with dedicated sensors. Force and lift sensor are attached to the Test Rig where as others are free to be mounted wherever suitable. All sensors are connected to the Electronic Subsystem, located inside the Power Box. The Electronic subsystem converts physical sensor signals into digital data and sends those via a data communication cable to the specific Software, running on a connected Computer. Task 3 – Control Pump and valves are controlled directly from the Software running on the connected specific computer. Every command as well as every hydraulic pressure adjustment, is generated from the Software itself, and send via a data communication cable to the Electronic inside the Power Box. The Electronic subsystem converts those data into physical signals, send to the pump and valves. Task 4 – Analyse, visualise. Visualisation, analysis as well as printing are handled by the Software running on the connected computer. Storage of recorded data is done in a specific database.

Typical System Graphs and Reporting

The graphs produced are genuine examples from conducted tests. They show typical results of test to be found in every day work. Based on the knowledge gained from the experience, the analysis is absolutely clear and free of doubt. An Inspection report, containing all data used for each specific test, is saved in the system, and available upon request for review and verification.

Calibration Blocks

Swiss Approval Laboratory Staff is working consistently to guaranty the maximum efficiency and reliability of our Testing Results. Specific Calibration Valves for each kind of safety Valves and working pressure values, are designed and developed within our Laboratory, in order to build in house our Know-How, necessary for service delivery of excellence. Such development of inspection resources and capacity represents for Swiss Approval Top Management, substantial commitments of time, high qualified personnel and significant capital investment.  


Eddy Current Array (ECA) System, Using ECT, ECA, TECA, RFT, NFT, NFA, MFL and IRIS Inspection Technology.

Swiss Approval Advanced NDT company, based in UK, is using leading multi-technology instruments, for surface and tubing applications, in order to be achieved the most versatile, reliable, and powerful Eddy Current (EC) platform solutions in the market. Our Eddy Current Array (ECA) Systems, are designed to perform critical surface inspections. Its fast and easy deployment, better PoD, length and depth sizing capabilities, data recording capacity, and consistent results, replacing totally PT and MT. Designed specifically for Air Conditioning (AC) and tubing inspections for Heat Exhangers, our systems are state of the art of the International Market, related to such inspection capabilities. Our ECA inspection System, is definitely superior to radiography/stripping, because it does not require access to both sides or surface preparation, and has no health hazards, making it much more cost efficient. Swiss Approval Eddy Current Array (ECA) Systems, greatly contributes to making quality inspections easier than ever before, with any technology combination, like: ECT, ECA, TECA, RFT, NFT, NFA, MFL, or IRIS. The maximum Eddy Current Technology (ECT) working frequency of our Systems, is of 10 MHz, which offers more flexibility and better performance in a variety of tubing and surface applications. Motor drive for Rotating Pancake Coil (RPC) probes, are also available. Driving motorized rotating pancake coil (RPC) probes is currently possible, thanks to its powerful built-in motor drive. This is useful in applications where RPC probes are used to find contemporary longitudinal and circumferential cracks.

Reporting

The full inspection process is registered in an appropriate Software, and specific reports / tube number, are elaborated and delivered upon request, to the Customer.

Calibration Blocks

Swiss Approval holds specific calibration blocks, which are used in our Laboratory of Advanced NDT for calibration of specific NFA / NFT / RFT and IRIS probes.  


Guided Waves

Guided Wave Testing (GWT) is used by Swiss Approval network, under the supervision of UK Advanced NDT staff of authorised Inspectors. This method is proposed, as, a well-established method for pipeline inspection. The GWT exploits mechanical stress waves that are guided along the wall of the pipe and can travel long distances, so it rapidly provides close to 100% coverage. A transducer injects a wave signal at a chosen location on the line and then receives echoes returning from any features or discontinuities. The arrival time of the echoes indicates the distance of these reflectors from the transducer. The typical test range performance is 50- 100m, but a range up to 500 m can be achieved, provided the pipe condition is excellent. In some cases, there is no alternative inspection method, so the use of Guided Waves avoids expensive invasive investigations such as excavation. Guided wave testing has become a well-established method for inspecting pipelines. It is important to know that it is a screening technique, that should be used to detect, locate, and classify discontinuitiesFollow-up inspection with a quantitative nondestructive testing technique, should be performed to precisely measure discontinuity dimensions. Guided Wave Testing, as a Screening Tool, It is vital to recognize that the conventional role of  guided wave testing today is screening with exceptional advantages. Guided waves can provide full coverage of the pipe within the test range, identifying all locations where a subsequent, thorough, detailed inspection is required. In other words, GWT provides detection, and local follow-up inspection, provides just the correctly assessing the severity.

Choice of Mode

For many years, the equipment with GWT, used longitudinal waves. However, last generation of equipment is using torsional waves. Swiss Approval owned equipment, is using the torsional mode, which is much superior to the longitudinal mode, in the vast majority of applications. This is because of the following reasons:

  • The torsional mode requires only two transducer rows
  • The wave velocity does not change with frequency.
  • It is in-sensitive to liquids inside or outside the pipe.
  • There are two longitudinal modes propagating in the test range, which leads to false indications with this mode; the torsional mode does not have the problem of false indication.

 

Performing a Guided Wave Test

Guided wave equipment can display the results of the test as an A-scan, showing distance along the pipe, and as a C-scan, providing a view of the unrolled pipe.

 

Application Examples

Guided wave testing is applicable to a wide range of different scenarios, offering efficiency and coverage improvements, over alternative NDT methods.

Rapid Long-Range Screening

One of the main strengths of GWT is the rate of inspection coverage of pipelines that can be achieved. This is due to the ability to screen many meters of pipe from a single test point. During the inspection of 508 mm (20 in.) gas pipe, from a single installation of the transducer ring on the pipe, it was possible to inspect 230 m of pipe: 100 m in the negative direction and 130 m in the positive direction. The inspection results indicated that there was no corrosion present in the test range, but they did highlight misalignment in some girth welds.

Corrosion Under Insulation

The widespread problem of corrosion under insulation was one of the driving applications for the initial development of GWT. A short section of insulation (approximately 1 m) is required to be removed from the pipe in order to install the transducer ring. From this test position, many meters of pipe in either direction can be assessed for the presence of corrosion under insulation. This represents a significant improvement in productivity and integrity assurance over conventional techniques of inspecting for this type of corrosion (for example, radiographic techniques), which can miss degraded areas because they do not inspect the full cross section of the pipe.

High Temperature Pipe

Swiss Approval equipment has been specifically designed for the inspection of high temperature pipework, up to temperatures of 350 °C.  In one example, a high temperature inflatable ring was used in the inspection of a 203 mm (8 in.) diesel pipe that was at a temperature of 240 °C. An area of corrosion was identified and followed up with conventional inspection techniques.

 

Calibration Blocks

Swiss Approval Laboratory Staff is working consistently to guaranty the maximum efficiency and reliability of our Testing Results. Specific Calibration Blocks for each Pipe Diameter, for different materials, related to different International Standards, are designed and developed within our Laboratory, in order to build in house our Know-How, necessary for service delivery of excellence. Development of inspection capacity for this category of materials, usually includes many, if not all, of the following:

  • Modelling,
  • Simulation,
  • Fabrication of mock-ups and samples containing realistic defects,
  • Procedure development,
  • Validation and subsequent training.

Such development of inspection resources and capacity represents for Swiss Approval Top Management, substantial commitments of time, high qualified personnel and significant capital investment.