Overview
EN ISO 19232-2:2013 (ISO 19232-2:2013) defines a device and a method for assessing the image quality of radiographs using step/hole-type image quality indicators (IQIs). It is part of the ISO 19232 series on radiographic image quality for non-destructive testing (NDT) and is published by CEN/ISO to standardize how radiographic image quality values (IQVs) are determined for film and digital detectors.
Key topics and technical requirements
- Scope and purpose: Specifies the design of step/hole-type IQIs and the method to determine the image quality value - the thinnest detectable element (hole number) on a radiograph.
- IQI construction: The device is a series of 18 steps with corresponding holes (hole numbers H1–H18) organized into four overlapping ranges (H1–H6, H5–H10, H9–H14, H13–H18). Steps below 0.8 mm contain two holes; steps ≥0.8 mm contain one hole.
- Dimensions and tolerances: Nominal hole diameters and step thicknesses are specified (see Table 1 in the standard). Holes must be perpendicular, not bevelled, and positioned with minimum clearances.
- Materials and marking: IQIs must be of a single material (e.g., FE, CU, TI, AL) embedded in protective covering. Markings must show the smallest hole number, material letters and ISO designation; image marking absorption should not cause glare and is recommended to be no more than twice the absorption of the thickest step.
- Selection and placement: IQI selection is based on specimen material and thickness; using the same material for IQI and specimen is preferred. IQIs are normally placed on the side facing the radiation source and remote from the detector. If placed adjacent to the detector-side surface, the radiograph must show the letter “F” to indicate this arrangement.
- Determination of IQV: Viewing conditions per ISO 5580 apply. The image quality value is the smallest hole number that is clearly visible on the radiograph (both holes must be seen when a step has two holes). Verification frequency can be agreed between parties when exposures are reproducible.
- Conformity: Each IQI must be supplied with a declaration of conformity in line with ISO/IEC 17050-1.
Applications and users
- Primary users: NDT radiographers, inspection engineers, quality assurance professionals, NDT laboratories, and manufacturers of radiographic IQIs and detectors.
- Practical uses: Verifying radiographic image quality in industrial radiography (weld inspection, casting inspection, pressure equipment), establishing acceptance criteria, and ensuring consistent sensitivity across film and digital radiography systems.
Related standards
- ISO 19232-1, -3, -4, -5 (other parts of the image quality series)
- ISO 5580 (radiographic illuminators / viewing conditions)
- ISO/IEC 17050-1 (supplier’s declaration of conformity)
Keywords: EN ISO 19232-2:2013, ISO 19232-2, image quality of radiographs, step/hole-type IQI, image quality value (IQV), non-destructive testing, NDT radiography.
