Overview
EN ISO 19232-4:2013 (ISO 19232-4:2013) is part of the ISO 19232 series on image quality of radiographs used in non‑destructive testing (NDT). This Part 4 gives instructions for the experimental determination of image quality values (IQV) and the establishment of image quality tables when the prescriptive IQI requirements (ISO 19232‑3) cannot be applied. It ensures that image quality values used for acceptance are validated under the same radiographic conditions as subsequent inspections.
Key topics and requirements
- Purpose: Provide a repeatable method to determine the image quality value for a given radiographic setup and material.
- When to use: Required where IQI material and inspected material absorption coefficients differ significantly (for example, by more than 30%), or when ISO 19232‑3 IQI rules are not applicable.
- Test exposures:
- Use the same radiographic conditions and IQI that will be used for inspection.
- Perform two test exposures under the specified conditions.
- If both exposures produce the same image quality value, accept that value; if they differ, repeat the procedure.
- Image quality tables:
- For varying penetrated thicknesses of the same material, derive an image quality table mapping penetrated thickness ranges to minimum required image quality values.
- Experimental values are interpolated and converted into a step‑curve to define thickness bands and their corresponding IQVs.
- Terminology: Defines IQI (image quality indicator), image quality, and image quality value (the thinnest detectable IQI element).
Applications and users
EN ISO 19232-4:2013 is useful for:
- NDT and radiographic testing (RT) professionals validating radiograph image quality.
- Radiographers and inspection technicians establishing acceptance criteria for specific radiographic setups.
- Quality managers and weld inspectors in industries where material absorption varies (e.g., aerospace, oil & gas, power generation, heavy fabrication and manufacturing).
- Certification bodies and laboratories that must document and justify acceptance IQVs for procurement, contract specifications, or regulatory compliance.
Practical benefits include consistent, auditable image quality acceptance, tailored IQVs for specific materials and thickness ranges, and reduced ambiguity when standard IQI rules are inapplicable.
Related standards
- ISO 19232 series (Part 1, Part 2, Part 3, Part 5) - other methods and classes for radiographic image quality.
- ISO 5579 - Radiographic testing of metallic materials using film and X‑ or gamma rays (basic rules).