ISO 16811:2012

Overview

ISO 16811:2012 - "Non‑destructive testing - Ultrasonic testing - Sensitivity and range setting" defines general rules for setting the timebase range and sensitivity (gain) of a manually operated ultrasonic flaw detector with A‑scan display. The goal is reproducible measurement of reflector location and echo height using single contact probes (single or twin transducers). The standard excludes immersion techniques and multi‑probe methods.

Key topics and technical requirements

• Scope and applicability
  • Applies to contact single‑probe ultrasonic testing (straight and angle beam) with A‑scan displays.
  • Excludes immersion technique and techniques using more than one probe.
• Probe index and beam angle
  • Procedures for determination of probe index and beam angle for flat and contoured probes, including mechanical and reference‑block techniques.
• Timebase (range) setting
  • Rules for setting timebase for straight‑beam and angle‑beam probes, multiple reflector and reference‑block techniques, and alternative settings for curved surfaces.
• Sensitivity setting and echo height evaluation
  • Methods for evaluating echo amplitude and setting gain: Distance Amplitude Curve (DAC) and Distance Gain Size (DGS) techniques.
  • Consideration of impingement angle and preparation/use of reference blocks and DAC/DGS diagrams.
• Probe contouring and geometry categories
  • Defines five categories of test objects (plane, uniaxially curved, multi‑curved, circular solid, complex shapes).
  • Rules for probe shoe contouring to ensure uniform contact and constant beam angle; includes quantitative condition for convex surfaces: D_obj < 10 · l_ps (longitudinal) or D_obj < 10 · w_ps (transverse).
• Transfer correction
  • Methods to correct for coupling/transfer effects (fixed path length, comparative techniques) and compensations for local variations.
• Annexes
  • Normative annexes provide quantities/symbols, reference block requirements, sound‑path/impingement calculations for curved objects; informative annexes include DGS diagrams and transfer correction determination.

Practical applications

• Standardizes setup for reliable ultrasonic inspection of:
  • Plates, sheets, tubes, rods/bars, dished ends, nozzles and other complex components.
• Used where consistent measurement of reflector position and echo amplitude is required: weld inspection, fabrication QA, in‑service inspection and NDT calibration.
• Helps reduce variability between operators and instruments by defining reference blocks, procedures and correction methods.

Who should use this standard

• NDT technicians and inspectors, ultrasonic equipment manufacturers, calibration laboratories, quality assurance engineers, and organizations developing inspection procedures.

Related standards

• ISO 16810 (Ultrasonic general principles), ISO 16823, ISO 16826, ISO 16827, ISO 16828, and normative references ISO 2400, ISO 7963, EN 12668‑3.