Pressure vessel being inspected

Asset owners and operators demand the highest quality design and construction of new industrial plant and equipment in order to achieve their project cost and strategic goals. Throughout the process, projects must comply with local and international regulations during the construction, fabrication, and repair/replacement of assets, while ensuring that human and environmental safety are maintained while ensuring project cost controls. Extensive expertise, experience, and the knowledge of relevant industry regulations, construction codes, legislation, QA/QC and NDT techniques are required.

UT in Lieu of RT Code Compliant Weld Examinations

For new construction and repair/replacement weld examination services, SNS are experts in the design and implementation of code compliant ultrasonic testing programs to replace radiography under ASME Pressure Vessel & Piping division per the requirements of B31.1 and B31.3, and ASME Code Case 189. SNS can design and implement comprehensive Performance Demonstration Qualifications and Trials, including procedure development, PAUT scan plans, documentation of ASME code compliance, and evaluation of ultrasonic examination results to ECA criteria.

Since these exams can be conducted concurrent with construction activities (i.e., no radiation source requiring barricades or vacating personnel from the area), this allows for higher welding production rates, more timely delivery of results, and better inspection data for any repair needs. Once flaws are accurately identified and characterized, our Level III subject matter experts can assist with appropriate code evaluation and mitigation measures.

Weld Defect Probability of Detection (POD) and Flaw Sizing

SNS offers statistical analysis consulting to improve accuracy in probability of detection (PoD) and sizing of weld flaws. Our SMEs deliver advice for engineering critical assessment (ECA) and fracture mechanics calculations to develop flaw rejection criteria. We ensure that the NDT method meets all of the client’s requirements, delivering the best inspection solution, and provide oversight of associated vendor and subcontract services. Our subject matter experts can guide our customers through the technical and regulatory complexities of developing advanced PAUT procedures and advanced NDT techniques that are code compliant and meet rigorous industry technical and production requirements.

Engineering Critical Assessment (ECA)

Welding fabrication codes specify maximum tolerable flaw-sizes and minimum tolerable charpy-energy level based on good workmanship. Achieving these standards, however, does not ensure that a certain minimum risk tolerance has been obtained. ECA is an analysis based on the principles of fracture mechanics to determine if a given material (with known properties) with certain flaw characteristics can resist fracture, fatigue, creep or plastic collapse under specified loading conditions. Working with client and constructor welding engineers and crafts, SNS can provide the following:

  • Assisting in the choice of welding procedure and inspection technique during the design phase of an installation to ensure component inspectability and ultimate code compliance
  • Assessing the significance of known defects that are unacceptable for the given fabrication code and determining the applicable NDT method’s probability of detection for the specific flaw
  • Identifying potential failures to meet the requirements of applicable fabrication and inspection codes
  • Evaluating ultrasonic testing results to ECA criteria