ISO 25902-1:2009

Overview

ISO 25902-1:2009 defines an eddy‑current non‑destructive testing (NDT) method for detecting flaws in titanium seamless and welded tubes (including titanium alloys). It targets quality assurance for titanium tubes used in critical heat‑exchange applications - the standard text specifically cites use in steam surface condensers for steam‑power plants, “anatomic‑power plants” (as printed in the document) and desalination plants. The standard sets requirements for equipment, reference pieces, test procedures, acceptance criteria and reporting.

Key topics and requirements

• Applicable dimensions: tubes with outside diameter 10–150 mm and wall thickness 0.3–10 mm are covered; the standard highlights that detection sensitivity varies with outside diameter and uses a 38.1 mm division when specifying reference standards.
• Test method: encircling (concentric) test coil of self‑comparison type; eddy‑current frequencies from 1 kHz to 512 kHz - select a frequency that detects the chosen reference standard.
• Reference standards: two classes - rectangular groove (N) and drilled hole (D). Materials and surface condition of the reference piece must match the tubes under test. Dimensions and tolerances for grooves/holes are specified and used for instrument sensitivity setting.
• Apparatus & verification: eddy‑current instrument (oscillator, signal processor, display/recorder), tube feed device, automatic alarm/recorder. Performance verification and periodic checks are required (see ISO 15548‑1 for instrument verification).
• Sensitivity & adjustment: instrument sensitivity adjusted so the reference standard gives about 50% of the recorder scale; sensitivity confirmation at least every 4 hours, after interruptions or at end of operations.
• Acceptance criteria: tube is accepted if no signals equal to or greater than the reference‑standard signal are detected, except for benign signals from straightening marks, ring marks, rough surface, dents, or similar harmless features.
• Reporting: date, inspector, tube grade, dimensions, equipment, reference standards used, test coil and frequency, detection conditions (feed speed, sensitivity, phase) and results.

Applications and users

Who uses ISO 25902-1:2009:

• NDT technicians and inspection engineers in tube manufacturing
• Quality managers and purchasers specifying acceptance for titanium heat‑exchanger tubing
• Third‑party inspection bodies and plant operators (power plants, desalination plants)
• Designers and maintenance teams responsible for condenser and piping integrity

Related standards

• ISO 25902‑2 - Titanium pipes and tubes, Part 2: Ultrasonic examination (complements eddy‑current testing for longitudinal flaw detection)
• ISO 15548‑1 - Equipment verification for eddy‑current instruments (normative reference)

Keywords: ISO 25902-1:2009, eddy-current examination, titanium pipes and tubes, non-destructive testing, titanium tube inspection, reference standards, NDT, condenser tubing.