ISO 20484:2017

Overview

ISO 20484:2017, "Non‑destructive testing - Leak testing - Vocabulary", is an international vocabulary standard that defines terms used in leak testing. Prepared jointly by CEN/TC 138 and ISO/TC 135/SC 6, it replaces EN 1330‑8:1998 and provides harmonized, authoritative definitions to ensure consistent communication across leak testing, quality assurance, procurement and technical documentation.

Keywords: ISO 20484:2017, leak testing vocabulary, non‑destructive testing, tracer gas, leakage rate, helium leak detector

Key Topics

This standard organizes and defines terminology across the full technical scope of leak testing. Major topic areas include:

• Atomic/molecular structure
  • e.g., concentration, ionization potential
• Pressure and vacuum
  • e.g., atmospheric pressure, partial pressure
• Gas–solid interaction
  • e.g., gettering, permeation, permeability coefficient
• Properties and flow of gases
  • e.g., ideal gas, conductance, flow rate, pV‑throughput
• Gas leakage and leak types
  • e.g., leak, conductance leak, orifice, capillary, molecular, viscous, permeation leak, virtual leak, leakage rate, total leakage rate
• Test techniques and procedures
  • Defined leakage tests: accumulation, carrier gas, vacuum tracer gas, bombing (back‑pressurizing), bubble, hood, pressure change, flow measurement, pressure dye, chemical reaction, radionuclide
  • Procedure elements: preparation, calibration, performance limits
• Test equipment and components
  • e.g., tracer gas leak detector, helium leak detector, mass spectrometer leak detector (MSLD), halogen detector, differential Pirani gauge, ultrasonic leak tester

The document contains no normative references and points users to ISO and IEC terminological resources (ISO OBP, Electropedia).

Applications

ISO 20484:2017 is primarily used to:

• Standardize terminology in technical reports, specifications, and certificates for leak testing and non‑destructive testing (NDT)
• Support test method selection, equipment procurement and calibration by providing unambiguous definitions (e.g., pV‑throughput, leakage rate)
• Aid training, inspection procedures and cross‑discipline communication between engineers, NDT technicians, and quality managers
• Facilitate regulatory compliance and international collaboration by harmonizing language used in contracts and standards

Typical users include NDT laboratories, leak testing specialists, QA/QC engineers, manufacturers of vacuum and pressurized systems, and standardization professionals.

Related Standards

• Replaces: EN 1330‑8:1998 (Terminology - Terms used in leak tightness testing)
• Related parts of EN 1330 series and referenced ISO standards such as ISO 12718 and ISO 12706 (as noted in the introduction)

By adopting ISO 20484:2017, organizations ensure consistent, internationally recognized terminology for leak testing and related NDT activities.