ISO 16831:2025

Overview

ISO 16831:2025 - "Non-destructive testing - Ultrasonic testing - Characterization and verification of ultrasonic equipment for the determination of thickness" specifies test methods and acceptance criteria for assessing ultrasonic thickness-measurement equipment operating in the 0.5 MHz to 15 MHz frequency range. The standard covers pulse-echo ultrasonic instruments (both numerical display and A-scan types) using single- or dual-transducer probes and focusses exclusively on verifications required for thickness determination (rather than general ultrasonic measurement). Tests are applicable to equipment used in accordance with ISO 16809 and can be used to verify devices covered by ISO 22232-1 and ISO 22232-2 when used for thickness work.

Key Topics and Requirements

• Scope and definitions relevant to ultrasonic thickness determination and pulse-echo techniques.
• Manufacturer’s technical specification requirements (general attributes, display, transmitter, receiver and probe-related information).
• Calibration and test blocks: description of block material, shape, size, resolution and accuracy blocks used for characterization and resolution checks.
• Grouped verification tests:
  • Group 1 - functional and performance tests (e.g., temperature stability, low-battery warning, battery run time, voltage variation stability, pulse repetition frequency, transmitter pulse characteristics, receiver gain and frequency response, display response time, determination performance and resolution).
  • Group 2 - general characteristics and mechanical/external checks.
  • Group 3 - detailed performance checks and mechanical state verifications.
• Probe requirements and tests for operational temperature range and compatibility with the instrument.
• Acceptance criteria for each test are defined within the standard; procedures are adapted to modern digital instruments.

Practical Applications and Who Uses ISO 16831:2025

• Ensures reliable ultrasonic thickness measurement in industries where wall thickness integrity is critical: oil & gas, power generation, aerospace, maritime, petrochemical, and manufacturing.
• Used by:
  • NDT service providers and inspectors for verifying field equipment performance.
  • Calibration laboratories establishing traceable verification of thickness gauges.
  • Equipment manufacturers for product characterization, factory acceptance testing, and technical documentation.
  • Quality managers and procurement specialists to specify acceptance tests and performance criteria for ultrasonic thickness instruments.
• Typical uses include routine verification, pre-survey instrument checks, procurement specifications and compliance with NDT quality systems.

Related Standards

• ISO 16809 - Ultrasonic thickness measurement practices (referenced for application context)
• ISO 22232-1 and ISO 22232-2 - Electronic ultrasonic measuring systems (verification when used for thickness determination)

Keywords: ISO 16831:2025, ultrasonic testing, thickness determination, non-destructive testing, pulse-echo, A-scan, numerical display, transducers, verification, characterization, NDT.