Non-destructive testing, or NDT, is the inspection for faults, material inconsistencies and hazardous substances in something without damaging the object of the test. Destructive testing methods measure a product’s resistance to environmental stress; non-destructive techniques, however, discover structural faults through testing methods both non-invasive and potentially more revealing, harnessing the power of ultrasonic, infrared and laser technology. Conducting NDT saves money and time, reducing production costs by preserving the article under test and allowing engineers to experiment with several testing parameters before returning to research and troubleshooting.
Engineers look to the American Society for Nondestructive Testing (ASNT) for NDT personnel qualification and certification practices. When selecting an engineer to perform NDT on your product, machine or facility, refer to the following standards to verify their ASNT compliance.
- Guidelines for developing your own in-house NDT certification program; includes recommended skill levels for all tiers of NDT qualification, including training/experience hours and examination eligibility.
- ANSI/ASNT CP-189
- Establishes the minimum standards for qualifying/certifying NDT personnel. An American National Standard which differs from the “recommended practices” of SNT-TC-1A by detailing hard requirements rather than educated suggestions.
- ANSI/ASNT CP-105
- Outlines training for Level I and Level II personnel as well as topical outlines of Level III qualifications. Details minimum training courses for each.
- ANSI/ASNT CP-106
- An adoption of ISO 9712:2005 which describes certification requirements for engineers to conduct the following: Electromagnetic Testing (ET), Magnetic Particle Testing (MT), Liquid Penetrant Testing (PT), Radiographic Testing (RT), Ultrasonic Testing (UT) and Visual Testing (VT).
- ANSI/ASNT ILI-PQ-2010
- Focuses on the requirements for certifying in-line inspection (ILI) personnel who will be evaluating pipes and pipelines.
reasons for conducting ndt
Ensures products, equipment and facilities are safe for the public. Employers with the foresight to rent infrared cameras and conduct building envelope testing, for example, could avoid the corrosion of structural members in an old building, which could be ripe with potential lawsuits in case of a collapse or dangerous mold contamination.
Non-destructive testing assesses the reliability of a device or system, empowering project managers to make informed decisions on repairs, remodels and replacements. A flow meter will indicate to facility managers whether a new piping system is a financially sound investment or whether the current system is dependable, perhaps saving thousands of dollars.
NDT fulfills requirements for numerous organizations, including the following and more:
- International Organization for Standardization (ISO)
- American Society of Mechanical Engineers (ASME)
- American Society of Testing and Materials (ASTM)
- Aerospace Industries Association (AIA)
- American Petroleum Institute (API)
- American Welding Society (AWS)