Alternating Current Field Measurement (ACFM) is an electromagnetic technique that identifies and sizes surface breaking cracks in welds and metallic components without the need to make contact with the material’s surface.
Infrared inspections (IR) provide thermal images of equipment using high-resolution imaging devices with video and still photography capabilities.
With infrared imaging, components can be monitored in real-time, meaning thermal changes can be identified simultaneously as changes occur in:
Positive material identification (PMI) provides alloy chemistry and grade ID information in seconds using a hand-held scanner.
PMI is also commonly used to ensure:
- the composition of the parent material is correct
- the correct filler material was used during equipment repair.
Pulsed eddy current (PEC) technology uses electromagnetic induction to inspect corrosion of ferromagnetic material without the need to make contact with the material’s surface.
National Techincal Services provides both film-based and digital radiographic services for field inspections and shop fabrication inspections.
- inspect material of varying density and composition
- inspect assembled and in-service components
- be performed with minimum surface preparation
- detect both surface and subsurface defects
- deliver a permanent record of the inspection.
Shear wave testing, also known as angle beam inspection, is an ultrasonic testing technique used primarily for weld inspections.
Awkward weld geometry and the presence of a weld crown or bead typically require shear wave testing, which entails placing a probe to the side of a weld and generating beams at an angle toward the weld.
Short range wave ultrasonic testing (SRUT) is designed to produce accurate wall thickness measurements of difficult-to-access locations of tanks, vessels, and piping, such as:
- areas underneath supports, clamps, and composite repairs
- the annular plate of above ground storage tanks.
National Techincal Services offers a comprehensive selection of remote video inspection equipment, including:
- video crawlers.
National Techincal Services's 3D structured light inspections use a projected light pattern to assess dents, gouges, corrosion pits, and other defects on the exterior of pipes, vessels, and structures.
After the inspection we provide all the data to:
- determine whether or not repair or replacement is necessary
- prioritize in-line-inspection (ILI) data
- assess the remaining-life of the equipment.
Acoustic emission testing (AET) is a powerful screening technique that provides real time, 100% volumetric monitoring of in-service equipment.
AET uses advanced equipment to detect the acoustic signals produced within material that is under stress. Software analyzes the collected signals and identifies the location and severity of any structural defects found, such as:
Automated corrosion mapping employs multiple ultrasonic techniques to:
- perform a 100% surface scan of equipment
- produce a detailed map of the corrosion experienced by equipment
- size the length, width, depth, and orientation of defects.
The software used by National Techincal Services for automated corrosion mapping, RSTRENG®, provides fitness-for-service (FFS) assessments. The U.S. Department of Transportation accepts this as an evaluation technology.
Guided wave ultrasonic testing (GWUT), also known as long range ultrasonic testing (LRUT), is a screening tool for rapidly testing long lengths of pipe from a single inspection point.
GWUT provides 100% coverage of the pipe wall without having to remove insulation or coating. It quickly identifies areas of corrosion or erosion that may then undergo more detailed inspections using other NDT techniques, such as radiography or 3D structured light.
Phased array ultrasonic testing produces real-time sectorial scans (S-Scans) that provide a full volumetric examination from a single inspection point. Phased array equipment can detect defects regardless of their orientation to the transducer.
Phased array ultrasonic testing can be used for:
- inspection of welds
- thickness measurements
- corrosion inspection
- crack detection.
Time of flight diffraction (TOFD) is an ultrasonic screening tool that can rapidly scan welds and produce very accurate measurements of any defects found.
TOFD operates using a pitch and catch technique with two probes on either side of a weld. One probe transmits a series of ultrasonic pulses and another receives them. If a crack or other defect is present in the weld, the ultrasonic waves will diffract and the time of flight between transmitter and receiver will be affected. Based on the change in time of flight, weld defects can be located and sized.