ISO 17636-2:2013 pdf download.Non-destructive testing of welds -Radiographic testing -Part 2:X- and gamma-ray techniques with digital detectors.
This part of ISO 17636 specifies fundamental techniques of digital radiography with the object of enabling satisfactory and repeatable results to be obtained economically. The techniques are based on generally recognized practice and fundamental theory of the subject.
This part of ISO 17636 applies to the digital radiographic examination of fusion welded joints in metallic materials. It applies to the joints of plates and pipes. Besides its conventional meaning, “pipe”, as used in this International Standard, covers other cylindrical bodies such as tubes, penstocks, boiler drums, and pressure vessels.
NOTE This part of ISO 17636 complies with EN 147842.[6)
This part of ISO 17636 specifies the requirements for digital radiographic X- and gamma-ray testing by either computed radiography (CR) or radiography with digital detector arrays (DDA) of the welded joints of metallic plates and tubes for the detection of imperfections.
Digital detectors provide a digital grey value (GV) image which can be viewed and evaluated using a computer. This part of ISO 17636 specifies the recommended procedure for detector selection and radiographic practice. Selection of computer, software, monitor, printer and viewing conditions are important, but are not the main focus of this part of ISO 17636. The procedure specified in this part of ISO 17636 provides the minimum requirements for radiographic practice which permit exposure and acquisition of digital radiographs with equivalent sensitivity for detection of imperfections as film radiography, as specified in ISO 17636-1.
This part of ISO 17636 does not specify acceptance levels for any of the indications found on the digital radiographs.
If contracting parties apply lower test criteria, it is possible that the quality achieved is significantly lower than when this part of ISO 17636 is strictly applied.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 5576, Non-destructive testing — Industrial X-ray and gamma-ray radiology — Vocabulary ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 16371-1:2011, Non-destructive testing — Industrial computed radiography with storage phosphor imaging plates —Part 1: Classification of systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in Iso 5576 and the following apply.
3.1
computed radiography
CR
storage phosphor imaging plate system
complete system comprising a storage phosphor imaging plate (IP) and a corresponding read-out unit (scanner or reader), which converts the information from the IP into a digital image
3.2
storage phosphor imaging plate
IP
photostimulable luminescent material capable of stonng a latent radiographic image of a material being examined and, upon stimulation by a source of red light of appropriate wavelength, generates luminescence proportional to radiation absorbed
NOTE When performing computed radiography, an IP is used in lieu of a film. When establishing techniques related to source size or focal geometries, the IP is referred to as a detector, i.e. source-to-detector distance (SDD).
3.3
digital detector array system DDA system
electronic device converting ionizing or penetrating radiation into a discrete array of analogue signals which are subsequently digitized and transferred to a computer for display as a digital image corresponding to the radiologic energy pattern imparted upon the input region of the device
3.4
structure noise of imaging plate structure noise of IP
structure due to inhomogeneities in the sensitive layer (graininess) and surface of an imaging plate
NOTE 1 After scanning of the exposed imaging plate, the inhomogeneities appear as overlaid fixed pattern noise in the digital image.
NOTE 2 This noise limits the maximum achievable image quality of digital CR images and can be compared with the graininess in film images.ISO 17636-2 pdf download.