HMT Inspection offers a complete line of NDT services and engineering evaluation capability for Aboveground Storage Tanks, pressure vessels and piping systems to report and advise on applicable guidelines and compliance with API Standard 653, API Standard 570, API Standard 510, STI Standard SP001, AWWA, Underwriters Laboratories and other industry inspection standards such as those issued by The Fertilizer Institute, The Fiberglass Tank Institute, and The Plastics Institute. HMT Inspection also provides evaluations of containment areas for SPCC and DOT compliance purposes.

Certified inspectors trained and qualified per ASNT Recommended Practice SNT-TC-1A and experienced professional engineers work closely together to provide inspection reports with targeted repair recommendations and appropriate engineering assessments for coordinated repair planning in a timely manner. Post-repair follow-up inspection and NDT testing capabilities give our clients the needed documentation for regulatory compliance purposes.

HMT Inspection provides these services for clients in the oil refining, oil storage and pipeline movement industries, petrochemical and chemical processing industries, agricultural products industries, food service and storage industries, and water storage industry. Since 1994, HMT Inspection has worked all over the United States (all 50 states) and several foreign countries, including most Caribbean islands and Pacific island nations, performing over 25,000 inspections in that time.

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:
  • Long Range Ultrasonic Testing (LRUT ), on piping using a Guided Ultrasonics Limited (GUL) G4mini system
  • Medium Range Ultrasonic Testing (MRUT), performed by Electromagnetic Acoustic Transducer (EMAT)
  • Phased Array Ultrasonic Testing (PAUT)
  • 3D MFL Mapping
  • Automated Ultrasonic Crawler
  • Tank Bottom SLOFECTM Scanner
  • Tank Bottom Magnetic Flux Leakage (MFL) Scanner
  • Helium Mass Spectrometer Leak Testing

Long Range Ultrasonic Testing (LRUT)
Long Range Ultrasonic Testing is performed on piping, using a Guided Ultrasonic Limited (GUL) G4mini wave system. Guided wave tests can be performed on piping from 2” diameter up to 96” diameter and very long length to inspect corrosion type defects. For piping of nominal wall thickness, gaseous product, without welded supports the distance of one single examination, can exceed 300’ in each direction from the transducer ring.

Medium Range Ultrasonic Testing (MRUT)
Medium Range Ultrasonic Testing, performed by Electromagnetic Acoustic Transducer (EMAT) is typically performed by EMAT (Electromagnetic Acoustic Transducer). Guided waves, shear waves, shear-horizontal waves, surface waves, and longitudinal waves, travel outward from the transducer location, while inspecting corrosion defects in in hard to reach places. Such applications include, but not limited to, areas beneath saddle supports on piping and vessels, into the annular ring of a storage tank from the outer protrusion, and many similar circumstances of limited access.

Phased Array Ultrasonic Testing (PAUT)
Phased Array Ultrasonic Testing is an ultrasonic method using an array of piezocomposite elements which are timed (or phased) to send ultrasonic energy which will react together forming the beam of choice. PAUT is used in weld quality testing in lieu of radiography, crack or defect sizing, corrosion mapping, composite materials bond testing, as well as many other applications. For ASME B31.3 and B31.1 PAUT can be used alone for weld quality examinations. For ASME Section VIII (Division 1 / Division 2) PAUT can be used in parallel with TOFD (Time of Flight Diffraction) for weld quality examinations. A similar PAUT/TOFD method can also be utilized for API 653 Annex U new tank construction projects for testing welds in lieu of radiography. PAUT examinations provide 3-dimensional flaw sizing giving a position across the part’s surface, a length of defect, as well as a depth and height size of a defect. The data from a PAUT examination is stored and can be easily transferred with internet access for level 3- or third-party review.

3D MFL Mapping
HMT Inspection offers the latest in floor mapping technologies, the 3D MFL (Magnetic Flux Leakage). This technology improves accuracy compared to traditional MFL techniques and provides flexibility in reporting and analysis.

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.


The HMT’s Inspection group understands the importance of accurate, quality and timely reporting. All field inspection data, engineering analysis and evaluation of work performed is translated into the proper report format and delivered in a timely manner. HMT inspection reports are user friendly and include a Management Summary with concise data presented in an organized, understandable manner. In addition to standard inspection reports, HMT prepares reports for specific needs and projects.

    These reports address topics such as:
  • Integrity testing
  • Suitability-for-service evaluation
  • Verticality studies
  • Seal inspections
  • Foundation settlement
  • Seismic evaluations
  • Repair recommendations
  • Post-repair inspections

    HMT provides engineering services for aboveground storage tank evaluations and calculations including:
  • Settlement evaluations
  • Corrosion rate calculations
  • Safe fill height calculations
  • Seismic evaluation
  • Brittle fracture evaluations
  • Maximum working pressure
  • Fitness for service evaluations
  • State specific environmental inspections
  • Inspections
  • Out of roundness surveys
  • Verticality evaluations
  • Additional evaluations referenced in the API and STI standards

    HMT uses the latest in NDE equipment for tank inspections and all HMT Inspectors are certified per ASNT SNT TC-1-A (Level I, II, and III), for a large array of NDE techniques including but not limited to:
  • Ultrasonic Thickness (UT)
  • Magnetic Particle Testing (MT)
  • Liquid Penetrant (LP) Inspection
  • Visual Inspection (VT)
  • Vacuum Box Testing
  • 3D MFL Mapping
  • Slofec™ Inspections
  • Alternating Current Field Measurement (ACFM) Inspection
  • Helium Testing / Mass Spectrometer Leak Testing (MSLT)
  • Piping Inspection
  • B-scan
  • C-scan
  • Low Pressure Storage Spheres / Pressure Vessels

Inspection Methods / Technique Details

Alternating Current Field Measurement (ACFM) Inspection: ACFM is a non-contact technique to detect and size surface breaking crack-like defects through coatings up to a thickness of 0.200 inch. HMT uses this method to detect crack-like defects in tank shell-to-bottom welds, tank bottom lap welds, sumps, nozzle and appurtenance welds, and Stress Corrosion Cracking (SCC) in ethanol service. A benefit to the ACFM method is that surface preparation is reduced compared to other NDE techniques.

Helium Testing / Mass Spectrometer Leak Testing (MSLT): HMT’s Helium leak testing program is a proven, effective method used to detect leaks in petrochemical applications, including tank bottoms, roof pontoons, roof drain systems and heat exchangers.

Piping Inspection: HMT’s piping inspection program includes MFL Pipe Scan services, which provides near 100% inspection coverage for aboveground un-insulated straight runs of piping and vessels up to 0.750 inch wall thickness. HMT’s API 570 inspections and engineering evaluations provide NDE data, visual inspection, and engineering assessments that include Maximum Allowable Working Pressure (MAWP) and remaining service / life calculations.

B-scan: B-scan is a data presentation method applied to pulse echo techniques. It produces a two-dimensional view of a cross-sectional plane through the test object. The horizontal sweep is proportional to the distance along the test object and the vertical sweep is proportional to depth, showing the front and back surfaces and discontinuities between.

C-scan: is a data presentation method applied to pulse echo and transmission techniques. It yields a two-dimensional plan view of the object. No indication of depth is given unless special gating procedures are used.

Low Pressure Storage Spheres / Pressure Vessels: HMT’s vessel inspection program includes a full line of NDE inspection services for low pressure storage spheres, pressure vessels and bullet tanks, including a staff of experienced API 510 inspectors. HMT’s offers inspections with automated ultrasonic crawlers and MFL wallscans.

    On November 10, 2011 EPA SPCC Part II compliance requirements for aboveground storage tank inspection became effective and now cover many tanks not previously required to have certified inspections performed.

    HMT has been a leading innovator and service provider in the aboveground storage tank industry since 1978 and inspects more than 3,000 tanks a year. HMT has offices from coast to coast to efficiently provide inspection services. With the newly implemented SPCC regulations, we can assist you in planning and performing the inspections required by SPCC. We have extensive experience in executing SPCC-specific inspection programs in a manner that will save you time and money.

    There are many different types of tanks which fall under the new regulations. Determining a scope of work for inspection that meets “Industry Standards” is an area where we excel. We have already inspected thousands of SPCC tanks and have scopes of work in place for many different tank styles and configurations. Our inspection sales team is equipped to assist you in a plan to implement your SPCC inspection program.

      Certified Inspector Qualifications
      Inspections performed for SPCC compliance shall be performed by:
    • American Petroleum Institute (API) Standard 653 Certified Inspector with Steel Tank Institute (STI) SP001 Adjunct Certification
    • OR
    • Steel Tank Institute (STI) SP001 AST Tank System Inspector

    • Table 5.4 Examples of Tank Configuration and AST Category Classifications
    • Category 1 – Low Risk
    • Category 2 – Medium Risk
    • Category 3 - Elevated Risk

    • Tank Classification Criteria
    • Continuous Release Detection Method (CRDM)
    • Release Prevention Barrier (RPB)
    • Spill Control
    • Single Wall Tank in contact with ground
    • Elevated Tanks not in contact with ground
    • Double Bottom or Double Wall
    • Overfill protection

    Inspection Requirements can be found in Table 5.5
    “Table of Inspection Schedules” in STI Steel Tank Institute’s “Standard for the Inspection of Aboveground Storage Tanks”, SP001 (latest edition)

HMT provides turnkey maintenance management services to include any or all of the various maintenance services provided by HMT, including maintenance planning, cleaning, inspection, repair, product installation, civil and mechanical work, testing, painting and coating, and commissioning.

HMT assists owners with maintenance management programs, providing a customized service designed to meet specific facility needs and requirements. HMT’s experienced turnkey personnel oversee each phase of turnkey projects from design approval to project completion and everything in between. The result is a turnkey project with exceptional safety performance and unequaled quality workmanship.

US Inspection Office Locations
Houston, TX; Beaumont, TX; Baton Rouge, LA; Warren, OH; Anaheim, CA; Benicia, CA (Bay Area); Greensboro, NC ; Tulsa, OK