Advance NDT is mostly digital, fast and accurate & repeatable. Advance NDT is evolving technology and understanding of equipment is very essential. Advance NDT equipment are job specific and purpose based. Many of the advance methods are still under review by specifications but well accepted by industry as a useful tool to precisely indicate type and sizes of flaws.
Nondestructive testing (NDT) - use test methods few listed below to examine an object, material or system without impairing its future usefulness. Non-destructive testing is often required to verify the quality of a product or a system. Commonly used techniques are:
Visual testing or inspection offers a wide range of options to secure proper system or product quality. This is one of the basic technique and very effective in detecting almost all surface irregularities. Inspecting is by sharp eyes and good experienced person is the key to visual inspection.
Techniques used to detect and locate leaks in pressure containment parts, pressure vessels, and structures. Leaks can be detected by using liquid and gas penetration techniques, electronic listening devices, pressure gauge measurements or soap-bubble tests for gross leaks. Fine leaks are detected using mass spectrometer detector using Helium gas as a tracer gas. Typically Leakage Classification of Control Valves is conducted by checking seat leakage classification through control valves and also pressure drop calculations and charts in plants. Flanged fittings are also tested by required hydrostatic test pressure.
Acoustic Emission Testing takes advantage of the sharp sound that PCCP emits when it breaks or slips to identify areas of active distress within a construction. AET can be used to verify the structural integrity of pressure vessels, spheres, high temperature reactors and piping, coke drums, above ground storage tanks, cryogenic storage tanks and more. The inspection is executed externally and shut-down of the process may often not be necessary.
After an impact a specimen will vibrate in certain characteristic modes and frequencies that can be measured by a microphone or laser vibrometer. Acoustic sonic and ultrasonic resonance analysis is a non-destructive testing technique that allows testing of a wide range of test objects. Typical detecting faults are cracks, cavities, detached layers, material inconsistencies, hardness deviation in materials.
Electromagnetic testing is the process of inducing electric currents and/or magnetic fields inside a test object and observing the response. A defect in the test object may be detected where electromagnetic interference creates a measurable response.
Infrared testing is a technique that uses thermography, an infrared imaging and measurement camera, to see and measure infrared energy emitted from an object. Can be used to heat development, lack of insulation, thin walls in constructions and more. Dimensions of insulation and heat loss diagrams in pipes and tubes, materials and capacities.
Positive Material Identification, Ferrite Measurement, Hardness Testing are one of the many methods to detect integrity of final welds.
In general NDT in Industrial environment are applied as per the job specification based on Risk, Reliability and Safety factors in Process Control Systems . The Performance requirements of NDT tests are defined in various codes. Standards such as ASME, ANSI, ASTM, AGA, ANSI, API, AWS, AWWA, BS, ISO, DIN provide standard directions and rules for conducting and reporting test results.