Overview - ISO 16664:2017 (Gas analysis, handling of calibration gases)
ISO 16664:2017 provides guidelines for the safe and reliable handling of calibration gases and gas mixtures used in gas analysis. It addresses factors that can change the composition of pure gases and homogeneous gas mixtures during their utilization period, and gives practical advice on storage, withdrawal from cylinders, transfer to instruments, and methods for assessing mixture stability. The standard was prepared by ISO/TC 158 (Analysis of gases).
Key topics and technical requirements
- Scope and applicability: Applies only to calibration gases within the manufacturer‑declared utilization period; emphasizes following national/international safety regulations.
- Storage and transport:
- Protect cylinders from extreme low/high temperatures and excessive humidity.
- Store cylinders horizontally for long‑term storage (to avoid rolling and improve homogeneity); separate flammable from oxidizing gases.
- Cylinder valves must be clean (free of grease) and protected with caps/guards.
- Withdrawal mode:
- Follow manufacturer guidance on minimum utilization pressure to avoid composition changes and contamination.
- Control temperature, pressure reduction and flow to maintain mixture integrity.
- Consider cylinder position changes and replacement procedures.
- Transfer system and sampling:
- Transfer system defined from cylinder valve to instrument inlet; includes purging procedures, pressure/flow‑reducing equipment, and material selection to minimize adsorption, permeation and leaks.
- Design considerations for sampling lines to preserve homogeneity and minimize response time.
- Stability assessment:
- Outlines a method for end‑users to check mixture stability, taking into account the certificate‑stated composition uncertainty and the user’s own measurement uncertainty.
- Rehomogenization guidance (e.g., bring cylinder to ambient and rotate) and when to contact the manufacturer if exposure outside recommended conditions occurs.
Practical applications and who uses it
ISO 16664:2017 is essential for:
- Calibration gas producers and suppliers (quality assurance, packaging guidance)
- Analytical laboratories and metrology labs performing gas calibrations
- Environmental monitoring and emissions testing facilities
- Instrument manufacturers and field technicians using gas standards for calibration and validation
- QA/QC managers responsible for measurement traceability and uncertainty control
Practically, the standard helps ensure accurate calibrations, prolong shelf life of gas standards, reduce calibration errors caused by handling, and support traceable measurement results.
Related standards
- ISO 6142-1 (reference to expiry/maximum storage life practices)
- ISO 7504:2015 (terminology for gas mixtures)
- ISO/IEC Guide 99:2007 (measurement standards and uncertainty)
Keywords: ISO 16664:2017, calibration gases, gas mixtures, gas analysis, handling of calibration gases, cylinder storage, transfer system, stability assessment, measurement uncertainty.
