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Sigma NDT Services Pvt. Ltd

Sigma NDT has extensive experience across all industries. We help our clients set new standards of excellence.

Product, Service, Training Institute


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The principal company Sigma NDT services which was incorporated in India in September 1997, to provide NDT services for fertilizer plants and pipelines. Today the Sigma NDT Group offers a diverse range of services for clients in the oil & gas, refining, petrochemical, energy, fabrication & construction and marine industries. Sigma NDT also manufactures certain NDT instruments.

These services are executed in India new construction/projects and operations & maintenance (O&M) activities. Today Sigma NDT is a fully integrated inspection company servicing clients working both onshore and offshore in India and abroad. Sigma NDT Services are therefore secure in the knowledge that “We always do quality work”. The client also knows that there is commitment and quality assurance to his project.

To Sigma NDT, the safety of our people, clients and the environment is of paramount importance. We have a proud safety record and are constantly looking for ways to improve all aspects of Health, Safety and Environment without compromising the quality of our services.

All our equipment are constantly tested to meet the most stringent safety standards, and go above and beyond the minimum legal requirements, especially in radiation safety.

Today, Sigma ndt Group has grown to more than 100 staff. We are now able to provide a diverse range of services in any industry that requires NDT and inspection.

Products & Services
Above Ground Storage Tank inspection

SIGMA NDT provides tank floor scanning services using the  Low Frequency Elctromagnetic Technique “Falcon Mark II” system. SIGMA NDT can also inspect the welds using the Hawk eye System.

The Low Frequency Electromagnetic Technique (LFET) does not use permanent magnets as is common in Magnetic Flux Leakage (MFL) equipment. The Falcon Mark II can scan through coatings and tightly bonded scale. The system is lightweight, battery operated, and portable.

The Falcon Mark II is used to scan the floor plates for topside and underside corrosion. Areas identified with the scanner are then marked and verified with ultrasonics. SIGMA NDT also offers a smaller Falcon JR. to inspect inaccessible areas around the floor such as support legs, sumps, buckled annular plates, etc.

The Hawkeye is used to scan the welds. It is used to detect surface and subsurface cracks. SIGMA NDT also offers Magnetic Particle Inspections and Vacuum Box Testing as alternatives.


  • Light weight with no permanent magnets
  • Inspects through coatings and uniform scale
  • Scanner Width up to 13.5”
  • Inspects through ID or OD
  • Smaller scanner to inspect hard to reach areas
  • Optional battery operated
  • Optional encoder
Stack Tower Column Inspections

To date, SIGMA NDT has conducted numerous inspections of Stacks, Columns, and Towers in various types of process facilities. These are primarily conducted on Carbon Steel structures because they are magnetic.

SIGMA NDT uses it’s SIGMA NDT Viper Magnetic Crawler for such applications especially when one cannot gain accessibility via scaffolding or lifts. Data can be collect using either LFET or Ultrasonics.


  • Inspects straight sections and bends
  • Low signal to noise ratio
  • Scanner width of up to13.5”
  • Inspects through topside or underside scale
  • Optional Encoder
  • Optional Battery operated
  • Small Modular PC based design
  • Windows based software
  • 110/220v Operation


Pressure Vessel Inspection

Various types of pressure vessels can be inspected using the Low Frequency Electromagnetic Technique (LFET). Using LFET, the actual wall plates can be inspected from inside or outside the pressure vessel. Welds can be tested for cracking through the usage of the Hawkeye Crack Detection System. Thus, a complete inspection of the pressure vessel can be performed. Our highly trained staff can also provide Dye Penetrant, Magnetic Particle, and Ultrasonic Inspection services.

Waveform from Hawkeye probe showing cracking in a weld
For those clients with boilers, SIGMA NDT, Inc. provides numerous D/A Tank (Deaereator) inspections. SIGMA NDT also provides pressure vessel inspections on Process Columns, Mixing/Agitation Vessels, and Reactors.


  • Fast and accurate inspection of wall plates from the inside or outside of the pressure vessel using LFET.
  • Complete inspections can be conducted using LFET and Hawkeye Crack Detection System.
  • Ability to perform various inspection methods as well as provide appropriate API inspections.
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