ISO 16828-2025 PDF

Full title and description

St ISO 16828-2025 — Non-destructive testing — Ultrasonic testing — Time-of-flight diffraction technique for detection and sizing of discontinuities. This international standard specifies general principles and minimum requirements for applying the time‑of‑flight diffraction (TOFD) ultrasonic technique to detect and size discontinuities (including in welds) in metallic components, with guidance for application to other materials when appropriate considerations are made for geometry and acoustic properties.

Abstract

ISO 16828:2025 (Edition 2) updates and replaces the 2012 edition. It defines the TOFD technique’s principles, recommended probe positions and scanning directions (with examples for welds), acceptance of test sensitivity, and application limits by test‑object categories. The document provides requirements for detection and sizing of discontinuities in low‑alloy carbon steels and gives guidance for use on other materials, together with references to related ultrasonic inspection documents and acceptance criteria.

General information

• Status: Published
• Publication date: July 10, 2025
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 19.100 — Non-destructive testing
• Edition / version: Edition 2 (2025)
• Number of pages: 21

Scope

This standard applies to the use of the TOFD ultrasonic technique for detection and sizing of discontinuities in components — primarily low‑alloy carbon steels — and may be applied to other materials provided appropriate consideration is given to material acoustical properties, geometry, and required sensitivity. It addresses application to test‑object categories (as defined in ISO 16811) with unrestricted use for category 1, specified restrictions for categories 2 and 3, and special procedures for categories 4 and 5. Examples and probe/scan guidance reference weld inspection practice for clarity, while maintaining general applicability to other test objects.

Key topics and requirements

• Fundamental principles of the TOFD technique for both detection and sizing of discontinuities.
• Recommended probe types, frequencies, and orientations for typical TOFD inspections.
• Probe positioning and scanning directions with illustrative examples for weld inspection.
• Signal interpretation, time‑of‑flight measurement, and sizing methodology.
• Minimum sensitivity and calibration requirements, including reference blocks and procedures.
• Application limits by test‑object category (ISO 16811 categories 1–5) and required special procedures for higher‑risk categories.
• Guidance on adapting TOFD to non‑steel materials considering geometry and acoustical differences.
• Cross‑references to relevant standards for complementary techniques and acceptance criteria (e.g., ISO 10863, ISO 15626, ISO 16810, ISO 16811).

Typical use and users

Primary users are nondestructive testing (NDT) practitioners, ultrasonic inspection technicians, inspection supervisors, welding inspectors, quality and asset integrity engineers, certification bodies, and regulatory compliance teams in industries such as oil & gas, petrochemical, power generation, pressure vessels, pipeline, and structural fabrication. The standard is used to define TOFD inspection procedures, train personnel, specify equipment/configuration, and support conformity and acceptance decisions.

Related standards

Key related standards include the withdrawn ISO 16828:2012 (superseded by this edition), ISO 16810 (general NDT principles), ISO 16811 (test‑object categories and classes), ISO 10863 (TOFD techniques for weld testing), ISO 15626 (acceptance criteria for TOFD), and various EN/ national adoptions (e.g., BS EN ISO, DIN EN ISO, NS‑EN ISO) that publish harmonized regional versions.

Keywords

time‑of‑flight diffraction; TOFD; ultrasonic testing; non‑destructive testing; NDT; weld inspection; discontinuity detection; flaw sizing; calibration; inspection procedure; ISO 16828:2025.

FAQ

Q: What is this standard?

A: ISO 16828:2025 is an international standard that specifies principles and minimum requirements for applying the TOFD ultrasonic technique to detect and size discontinuities in components, with emphasis on low‑alloy carbon steels and guidance for other materials.

Q: What does it cover?

A: It covers TOFD fundamentals, probe selection and positioning, scanning directions (examples for welds), calibration and sensitivity requirements, measurement and sizing methods, and application constraints by test‑object category. It also references related standards for complementary procedures and acceptance criteria.

Q: Who typically uses it?

A: NDT technicians and supervisors, welding inspectors, quality managers, asset integrity engineers, test procedure authors, and certification bodies in industries requiring ultrasonic flaw detection and sizing.

Q: Is it current or superseded?

A: Current. ISO 16828:2025 (Edition 2) was published on July 10, 2025 and supersedes ISO 16828:2012 (withdrawn).

Q: Is it part of a series?

A: Yes. It is part of the ISO family of nondestructive testing documents (ISO 16810, ISO 16811, etc.) and aligns with other ultrasonic and TOFD‑related standards such as ISO 10863 and ISO 15626. Regional and national standards bodies often publish harmonized EN or national versions based on this ISO edition.

Q: What are the key keywords?

A: TOFD, time‑of‑flight diffraction, ultrasonic testing, nondestructive testing, flaw detection, flaw sizing, weld inspection, calibration, inspection procedure.