HMT Inspection technicians are thoroughly trained and qualified in accordance with the HMT Inspection procedure for qualification and certification of Nondestructive Examination Personnel which is written in light of the guidelines set forth in ASNT Recommended Practice SNT-TC-1A 2006 edition.
Advanced NDE Inspection Equipment Includes:
- Automated Ultrasonic Crawler
- Tank Bottom SLOFECTM Scanner
- Tank Bottom Magnetic Flux Leakage (MFL) Scanner
- Helium Mass Spectrometer Leak Testing
Automated Ultrasonic Crawler
HMT Inspection offers an automated crawler for performing ultrasonic line scans. The system is highly effective for providing continuous ultrasonic thickness data on tank shells and storage spheres.
Tank Bottom SLOFEC™ Scanner
HMT offers reliable tank bottom scanning for fiberglass reinforced polymer coated tank bottoms (FRP). The Saturation Low Frequency Eddy Current (SLOFEC™) tank bottom scanner has the capability to induce sufficient current (flux) to inspect through coatings up to 300 mils thick by using an electro-magnet system. Because eddy current probes are used, the scanner (using the phase angle), can determine whether the defect is product-side, soil-side or both.
Additionally, the eddy current probe is sensitive enough to quantify soil side defects with minimal coating disturbance. The SLOFEC™ technology has the ability to indicate if the coating thickness has changed beyond the calibration range. This precludes problems with sensitivity errors due to coating thickness changes.
The SLOFEC™ tank bottom scanner can handle the “prove-up” of detection areas on the soil side after calibration, and quantify, with sufficient accuracy, in order to make repair decisions. This initial calibration and “prove up” minimizes coating destruction.
Key Benefits of the SLOFEC™ Scanner Include:
- Ability to scan through coatings that are up to 0.300” thick and are reinforced with fiberglass
- Minimizes the need to remove coating to accommodate bottom inspection and / or Ultrasonic “prove-up”
- Does not require Ultrasonic “prove-up” of located defects
- The capability to indicate which side of the plate the defect is located
- Provides accurate depth information and thus remaining wall information on located soil side corrosion pits
- Operates at speeds that are comparable to current MFL equipment
Tank Bottom Magnetic Flux Leakage (MFL) Scanner
HMT offers the latest in NDE equipment for tank bottom inspection including the Magnetic Flux Leakage (MFL) bottom scanners. MFL bottom scanning is also known as MFE (Magnetic Flux Exclusion / Evaluation). MFL is the “best” method to evaluate a tank bottom condition quickly and cost effectively.
HMT’s bottom scanner is a steerable motorized corrosion detection instrument used in aboveground storage tanks to detect metal loss due to corrosion. MFL technology induces a magnetic field into the steel plates and then evaluates any disturbance in the magnetic field. When the magnetic field is disturbed, possible metal loss (either product side or soil side) has occurred and must be evaluated, or “proved-up”. The HMT bottom scanner features “stop on defect” functionality. When metal loss is detected the machine automatically stops, thus reducing human error resulting from missing a screen signal. This facilitates direct marking of the defect positions on the bottom plate surface for further investigation. To address smaller areas in which the larger MFL bottom scanner does not fit, HMT Inspection offers a motorized MFL Mini-Scanner and MFL Manual Scanner.
Post-scan, the inspection reports generate a full fingerprint of the tank bottom. These reports include identification of which side where the defect is located and using an “x”, “y” coordinate system, specific locations on the individual plate and its depth and remaining plate thickness. These reports highlight all areas requiring repair, assisting in establishing corrosion rates and next inspection intervals per API Standard 653.
Key Benefits of the Magnetic Flux Leakage (MFL) Include:
- Evaluates tank bottom condition on bottom plates of ferrous material
- Quick, cost effective process and does not require couplant - “dry application”
- Steerable fast motor driven scanner
- Features “stop on defect” functionality
- Ruggedized touch screen technology for ease of use in the storage tank environment
- Full sized MFL Scanner, motorized MFL Mini-Scanner and MFL Manual Scanner available
Helium Mass Spectrometer Leak Testing
HMT Inspection offers Helium Mass Spectrometer Leak Detection services. HMT Inspection utilizes a Varian 959 Porta-Test Leak Detector with Macro Torr configuration which provides high test pressure capability and is excellent for fast response sniffing applications. This equipment is capable of 1 X 10 -9 atm cc/sec sensitivity, as required by ASME code for detector probe and tracer probe techniques.
HMT is capable of performing leak detection services on single bottom aboveground storage tanks (AST), double bottom ASTs, floating roof pontoons, heat exchanges, process piping, pressure vessels, underground storage tanks, underground pipelines, vacuum units and roof drains.
The use of helium as a tracer gas is advantageous because it is non-flammable, inexpensive, and it quickly diffuses through small leaks. In addition, it is non-reactive with other chemicals and easily permeates through the Earth and asphalt. Due to its minute molecular size and its low concentration in the atmosphere (5ppm), very small leaks may be detected. The use of the helium method enables the location of leaks up to 15 feet below ground. The Varian 959 Port-Test Helium Mass Spectrometer is only sensitive to helium; therefore eliminating false indications due to the presence of any other gases.