ISO 18173:2026

Overview

ISO 18173:2026 - Non-destructive testing - General terms and definitions is an international standard developed by the International Organization for Standardization (ISO). This document provides harmonized definitions of essential technical terms used across multiple non-destructive testing (NDT) disciplines. By establishing a unified vocabulary, ISO 18173:2026 enables clearer communication and more consistent application of NDT methods within global industries such as manufacturing, construction, aerospace, and energy.

Clear and precise terminology is vital for effective collaboration between manufacturers, inspectors, regulatory bodies, and all stakeholders using NDT. The standard supports consistency in interpreting results, compliance with standards, and best practices in quality control.

Key Topics

ISO 18173:2026 covers a range of fundamental terms and concepts for non-destructive testing. Key topics include:

• Acceptance criteria & acceptance level: Definitions for thresholds and parameters used to assess the acceptability of test objects.
• Discontinuity, flaw, and imperfection: Terminology for describing deviations, interruptions, or imperfections in a test object.
• Detection, detection sensitivity, and detection threshold: Concepts central to evaluating the ability of NDT methods to identify and characterize flaws.
• Indication types (relevant, non-relevant, false): Standardized language for categorizing NDT results and their significance.
• NDT methods, techniques, and procedures: Clarification of the hierarchy and relationship between various NDT processes.
• Calibration, standardization, and reference blocks: Terms relating to ensuring the repeatability and reliability of NDT measurements.
• Signal-to-noise ratio and resolution: Concepts critical to the accurate identification and sizing of defects.
• Recording, sizing, and evaluation: Definitions to support documentation and assessment of non-destructive test results.

These terms form the general technical foundation needed for practitioners of non-destructive testing and are not always defined within method-specific standards.

Applications

The standardized terminology in ISO 18173:2026 is beneficial in diverse practical applications:

• Quality assurance: Facilitates consistent interpretation of NDT results, supporting better quality management and defect assessment.
• Compliance and procurement: Provides universally accepted definitions for contract documentation, inspection protocols, and regulatory compliance.
• Training and certification: Supports NDT personnel in gaining a clear understanding of commonly used terms, aiding programs aligned with ISO requirements.
• Cross-industry communication: Enables efficient collaboration and reduces misunderstandings across international supply chains and multi-disciplinary teams.
• Development of method-specific standards: Serves as a reference for drafting, revising, and harmonizing further standards in NDT disciplines-such as ultrasonic, radiographic, and magnetic particle testing.

Organizations adopting ISO 18173:2026 benefit from improved clarity, reduced risk of errors, and enhanced reliability in non-destructive testing activities.

Related Standards

To support comprehensive understanding and implementation, the following related standards and resources are recommended:

• EN 1330-2 - Non-destructive testing - Terminology
  European standard offering complementary definitions in NDT.
• ASTM E1316 - Standard Terminology for Nondestructive Examinations
  Widely used terminology standard from ASTM International.
• ISO/IEC Directives, Part 1 and Part 2
  Procedures and editorial rules for the development and maintenance of ISO standards.
• ISO Online Browsing Platform
  Central repository for ISO terms and definitions in standardization (https://www.iso.org/obp).
• IEC Electropedia
  Online resource for electrical and electronic terminology (https://www.electropedia.org/).

By referencing ISO 18173:2026 together with these related standards, organizations and professionals ensure a robust, standardized approach to non-destructive testing terminology and practice.