Overview
ISO 19232-2:2013 - Non-destructive testing - Image quality of radiographs - Part 2 defines a device and method for determining the image quality value of radiographs using step/hole-type image quality indicators (IQIs). The standard specifies IQI geometry, manufacture, marking, material selection and placement, and the procedure to read the image quality value (the thinnest hole clearly visible on a radiograph). It applies to both film and digital detectors and updates earlier editions to align with related ISO/CEN documents.
Key topics and requirements
- IQI design and dimensions: The standard uses an IQI system of 18 steps/holes (hole numbers H1–H18) grouped into four overlapping ranges (H1–H6, H5–H10, H9–H14, H13–H18). Steps and hole diameters are specified with tolerances and manufacturing rules (e.g., some thin steps contain two holes).
- Materials and marking: All parts of an IQI must be the same material and embedded in a protective cover that does not affect image quality. Marking must identify the smallest hole number, IQI material (e.g., FE, CU, TI, AL) and standard designation. Example designation: IQI ISO 19232-2-H 5 FE.
- Selection of IQI: IQI selection depends on specimen material and thickness. Table guidance maps hole-number ranges to IQI material for common groups (steel, aluminum, titanium, copper/alloys).
- Placement and orientation: IQIs are normally placed on the side of the test section facing the radiation source and away from the detector; alternative placement adjacent to the detector-side must be marked on the radiograph (letter “F”).
- Determination of image quality value: Under the viewing conditions specified in ISO 5580, the smallest hole number clearly visible on the radiograph is recorded as the image quality value. When a step contains two holes, both must be visible.
- Conformity and documentation: Each IQI must be supplied with a declaration of conformity per ISO/IEC 17050-1 and uniquely identified by the producer.
Practical applications
- Quality assurance and acceptance testing in industrial radiography (weld inspection, castings, forgings)
- Routine image quality verification in non-destructive testing (NDT) programs
- Supplier and equipment qualification where objective image-quality metrics are required
- Development and calibration of radiographic procedures for both film and digital detectors
Who should use this standard
- NDT technicians and radiographers
- Quality/inspection engineers in manufacturing, oil & gas, aerospace, power generation
- NDT procedure writers, auditors and certification bodies
- IQI and radiography equipment manufacturers
Related standards
- ISO 19232-1, -3, -4, -5 (other parts of the Image quality of radiographs series)
- ISO 5580 (radiographic illuminators / viewing conditions)
- ISO/IEC 17050-1 (supplier’s declaration of conformity)
- EN 462-2 (equivalent IQI designation for step/hole-type indicators)
Keywords: ISO 19232-2, image quality of radiographs, non-destructive testing, step/hole image quality indicator, IQI, image quality value, radiographic quality control.