Overview
EN ISO 20486:2018 - "Non‑destructive testing - Leak testing - Calibration of reference leaks for gases (ISO 20486:2017)" - defines internationally accepted procedures for calibration of reference leaks used to adjust leak detectors and to determine leakage rates. The standard explains how routine reference leaks become traceable to a primary standard, either by comparison with a known reference leak or by direct/volumetric calibration methods. It is part of non‑destructive testing (NDT) and leak testing best practice for gas leakage measurement.
Key Topics
- Calibration approaches: comparison methods (Methods A, As, B, Bs) and volumetric methods (Methods C–G).
- Comparison methods are preferred for helium leaks because helium is selectively measured by a mass spectrometer leak detector (MSLD) (see ISO 20484 for MSLD definition).
- Volumetric/pressure techniques include direct flow (C), under‑water bubble measurement (D), gas meter (E), pressure change in known volume (F), and volume change at constant pressure (G).
- Applicability: comparison calibrations are practical for reference leaks with reservoirs and leakage rates below 10−7 Pa·m3/s.
- Classification of leaks: permeation, conductance (capillary, aperture/orifice, compressed powder), with guidance on preparing and handling each type.
- Measurement procedure and uncertainty: set‑up, temperature accommodation, connection to leak detectors, measurement sequence, evaluation, and factors that influence measurement uncertainty and traceability.
- Reporting, labelling, handling: requirements for documentation, labelling of calibrated reference leaks, and storage/handling to preserve calibration.
Applications
EN ISO 20486:2018 is relevant for organizations that perform or rely on accurate leak testing and calibration:
- NDT and leak testing laboratories establishing traceable reference leaks
- Manufacturers and calibrators of leak detectors and MSLDs
- Quality and metrology teams in aerospace, automotive, vacuum technology, semiconductor, and gas instrumentation industries
- Calibration service providers who must report uncertainty and ensure traceability for leak rate measurements
Practical benefits include improved accuracy of leak detection, standardized calibration methods, and consistent reporting that supports compliance, quality assurance, and equipment acceptance testing.
Related Standards
- ISO 20484 - definition and requirements for mass spectrometer leak detectors (MSLD)
- Supersedes EN 13192:2001 (now replaced by EN ISO 20486:2018)
- ISO/IEC Directives and traceability guidance relevant to calibration and uncertainty reporting
Keywords: EN ISO 20486:2018, leak testing, calibration of reference leaks, non‑destructive testing, helium leaks, mass spectrometer leak detector, reference leak calibration, volumetric calibration, measurement uncertainty, traceability.
