Posted by Vidisco, March 31, 2022
Non-destructive testing (NDT) is paramount for quality assurance. Used to determine the quality of pipe welding and detect defects, NDT is infinitely important to ensure suitability and safety in oil and gas pipes, aircrafts, shipyards, manufacturing equipment, and many other uses.
Quality in NDT testing is of upmost importance, as anything missed in testing can lead to catastrophic consequences. For this reason, there are several international NDT standards in place that govern the quality of NDT testing methods. These standards layout appropriate methods and techniques for testing, inspection, and evaluation to ensure optimal results of NDT activities.
There are several organizations with standards for NDT testing, including the International Organization for Standardization (ISO), the American Society for Testing and Materials (ASTM), the American Society for Mechanical Engineers (ASME), the American Society for Nondestructive Testing (ASNT), and more.
Below we will discuss some of the top standards relating to the digital radiography method of NDT testing. DR technology is a superior form of NDT testing because it allows for instant and accurate results.
Here are the top international NDT standards for DR technology and why they are important.
While ISO has several standards relating to NDT testing, ISO 17636-2:2013 specifically relates to DR technology for examining welded joints in metallic materials, including the joints of plates, pipes, and other cylindrical bodies such as tubes, penstocks, boiler drums, and pressure vessels. The standard specifies requirements for digital radiography x- and gamma-ray testing, either by computed radiography or radiography with digital detector arrays. It also identifies fundamental techniques for carrying out DR NDT testing to ensure satisfactory, economical, and repeatable results. All techniques are based on generally recognized practices and fundamental theory on DR testing.
When conducting NDT with DR technology, digital detectors provide a grey value image that is evaluated on a computer or tablet screen. This standard recommends the procedure for detector selection and radiographic practices including permitted exposure and acquisition of digital radiographs with sensitivity for imperfection detection that is equivalent to film radiography.
It should be noted that this standard does not focus on selecting equipment such as computers, software, monitors, or printers. Nor does it focus on viewing conditions or the acceptance levels for anything found on images during inspection. It specifically covers the procedures for conducting NDT via digital radiography.
ASME Section V Article 2
Governing quality over the wide-ranging engineering community, ASME is known for developing extensive codes and standards for many industries. Its standard relating to DR technology for NDT inspection thoroughly describes requirements for radiographic examination of materials including castings and welds.
The standard details requirements for NDT testing from preparation to documentation. Firstly, it outlines how to prepare for NDT testing, including specifying equipment and methods to be used, preparing the testing objects, and the scope of the examination. Secondly, it outlines necessary components for equipment, materials, and calibration. Thirdly, it details techniques and technical requirements for examination. This is followed by specifications on how to evaluate testing, including image quality and density. Lastly, the standard lays out how to document radiographic testing results to include specific methods and technical details used and how to prepare documentation for review.
This may sound very thorough, yet there are also additional requirements for specific products, techniques, and applications such as in-motion radiography, real-time radioscopic examination, nuclear applications, and metallic castings. There are also additional requirements for acquiring digital images, and displaying, storing, interpreting, evaluating, and the disposition of results.
Boeing 7044 Ver C
As one of the world’s largest aerospace companies, Boeing’s 7044 Ver C standard relates specifically to qualifications to be an aerospace industry manufacturer. Suppliers undergo functional tests, data reviews, process control checks, and system equipment inspections for quality assurance requirements for approved suppliers. The standard also certifies that companies have an approved quality management system.
Much of this certification is based on the ISO standards, however, Boeing does conduct its own audit and performance review. Companies must exhibit quality levels and performance that adhere to Boeing’s quality management system in order to receive approval.
Specifically for NDT solutions, Boeing values portability for stationary and in-field use, image quality, automation, and immediacy of results. With NDT inspection, the Probability of Detection (POD) is extremely important, combined with high sensitivity and a dynamic range of image color levels, or shades of gray. It is also important that objects of all sizes and materials do not need to be moved for inspection and that results are fast and nearly real-time.
ASTM’s Standard Practice for Digital Imaging and Communication in Nondestructive Evaluation (NDE), also known as DICONDE, facilitates the interoperability of equipment used for non-destructive evaluation imaging and data acquisition by specifying accepted terms for image data. The purpose of this standard is to harmonize different NDT imaging systems or modalities with the international standard for image data acquisition, review, storage, and archival set by the National Electrical Manufacturers Association (NEMA) for medical digital imaging and communication. The goal of ASTM’s practice is to create a standard so that data can be displayed on any system that conforms to the format, no matter which equipment was used to acquire the data. The practice addresses how digital information is exchanged between equipment.
NDT data acquisition techniques evolve, and it is imperative that past data remains accessible and decipherable. Using a standard image data file format ensures that images are preserved despite technological changes. This standard eliminates issues from archiving and analyzing data gathered from different equipment or techniques, and ensures that a variety of image types (CT, CR, Ultrasonic, Infrared, and Eddy Current) can all be viewed on a single workstation without any compromise on quality or technique.
Vidisco’s Digital Radiography NDT System
Vidisco’s portable digital radiography NDT solution complies with all of the aforementioned standards. Vidisco’s testing systems are easy-to-operate, optimized for efficient NDT inspection in harsh conditions, and ensure high-quality images and long-lasting performance.
Founded by military and professional experts, Vidisco is a pioneer in digital x-ray technology and is trusted by leading organizations in a variety of industries. Vidisco’s NDT systems can be customized for specific requirements and updated as needs change.