ISO 16811:2025

Overview - ISO 16811:2025 (Non‑destructive testing - Ultrasonic testing - Sensitivity and range setting)

ISO 16811:2025 defines the general rules for setting the time‑base (range) and sensitivity (gain) of manually operated ultrasonic instruments with an A‑scan display so that reproducible determinations of reflector location and echo height can be made. The standard applies to contact ultrasonic techniques using a single probe (single or dual transducers) and explicitly excludes immersion testing and techniques employing more than one probe. This second edition updates normative references, integrates previous annex material into the main text, and refines editorial content.

Key technical topics and requirements

• Time‑base (range) setting: Procedures for defining the instrument range for straight‑beam and angle‑beam probes, including reference block techniques and alternatives for flat and curved surfaces.
• Sensitivity (gain) setting and echo evaluation: Methods for consistent echo‑height assessment, including Distance‑Amplitude Curve (DAC) and Distance‑Gain‑Size (DGS) techniques, and use of reference heights.
• Probe definition and calibration: Determination of probe index point and effective beam angle for flat and curved probes (longitudinally/transversely curved), and handling probes curved in two directions.
• Test equipment and probes: Requirements and selection guidance for instruments, transducer frequency/dimensions, dead‑zone, damping, focusing probes and coupling media.
• Reference and specific test blocks: Use and preparation of calibration blocks, reference reflectors and specific test blocks for reliable range and sensitivity settings.
• Transfer correction: Procedures (fixed‑path, comparative, local compensation) to correct for differences between reference block and test‑object coupling or geometry.
• Personnel and qualification: Expectations for suitably trained and qualified operators to perform reproducible settings and evaluations.
• Informative annexes: Guidance on sound path and incidence angle determination, general DGS diagrams and contact transfer correction factors.

Practical applications and target users

ISO 16811:2025 is essential for practitioners who perform or supervise manual ultrasonic NDT where A‑scan instruments and contact probes are used. Typical users include:

• NDT technicians and inspectors setting up ultrasonic surveys
• Quality and inspection engineers in manufacturing, oil & gas, automotive and aerospace
• Calibration labs and personnel responsible for probe/instrument configuration
• Training providers and certification bodies for ultrasonic testing

Adoption of ISO 16811 helps ensure consistent echo‑height assessment, accurate location of reflectors and repeatable inspection outcomes across equipment and personnel.

Related standards and implementation notes

• ISO 16811 is part of the wider body of ultrasonic NDT guidance; users should implement it alongside other ultrasonic procedure, calibration and personnel qualification standards and any applicable national or industry documents.
• The document was prepared by ISO/TC 135 in collaboration with CEN/TC 138; consult your national standards body for adoption and implementation details.