Overview
EN ISO 19232-3:2025 - Non-destructive testing - Image quality of radiographs - Part 3: Minimum image quality values (ISO 19232-3:2025) specifies minimum image quality values (IQI values) to ensure uniform radiographic image quality in industrial radiographic testing. It defines the required IQI values for the two testing classes A and B (per ISO 5579) and applies to both wire-type and step/hole-type image quality indicators described in ISO 19232‑1 and ISO 19232‑2. This 2025 edition supersedes the 2013 edition and is published as a CEN/EN standard.
Key topics and requirements
- Minimum IQI values: Specifies the minimum image quality values for single‑wall and double‑wall radiography corresponding to testing classes A and B (see separate tables in the standard).
- IQI types: Applies to wire‑type IQIs (ISO 19232‑1) and step/hole‑type IQIs (ISO 19232‑2).
- Single‑wall vs double‑wall: Different image quality tables and evaluation rules for single‑wall radiography and for double‑wall techniques (single‑image and double‑image evaluation).
- IQI placement: IQI should be placed on the source side of the test object; if placed on the detector side, the radiograph must show the letter “F” near the IQI to indicate this arrangement.
- Viewing and evaluation: Film viewing per ISO 5580 and digital image viewing per ISO 17636‑2. For digital radiography, use uncompressed images and a zoom factor between 1:1 and 1:2 for critical analysis.
- Wire IQI evaluation: The IQI value is the thinnest wire clearly visible on the radiograph (accepted visibility includes at least a continuous 10 mm length).
- Gamma radiography: Clause 7 addresses permitted reductions of minimum IQI values when using gamma sources (e.g., Ir‑192) - consult the standard for details.
- Uniform thickness & special arrangements: IQI must be placed where the object thickness is as uniform as possible; application standards may specify special arrangements.
Applications and users
EN ISO 19232‑3:2025 is essential for:
- NDT/radiographic technicians and radiographers
- Welding inspectors and quality assurance managers
- Manufacturing and fabrication facilities using radiographic testing of metallic materials
- Code authorities and inspection bodies specifying acceptance criteria
It helps ensure consistent image quality for weld inspection, pipe testing, castings and forgings, and any radiographic testing governed by ISO 5579 and ISO 17636.
Related standards
Keywords: EN ISO 19232-3:2025, image quality, radiographs, IQI, non-destructive testing, radiographic testing, ISO 5579, wire-type IQI, step/hole IQI, digital radiography.
