Overview
ISO 6141:2015 - Gas analysis: Contents of certificates for calibration gas mixtures defines the minimum metrological information that suppliers must include on certificates for homogeneous gas mixtures supplied in cylinders or other containers for calibration purposes. Pure gases used for calibration are also covered. The standard focuses on metrological aspects (composition, uncertainties, traceability, dating, pressures) and explicitly does not cover safety or legislative labeling requirements.
Key topics and requirements
ISO 6141:2015 specifies mandatory and recommended (optional) certificate data. Key technical topics include:
- Unique certificate identification tied to a specific container (stamped number, batch/lot).
- Producer information and the name/signature of the responsible person who authorizes the certificate.
- Specified components and composition: all stated components must be unambiguous (IUPAC recommended) and preferably expressed in amount-of-substance or mass fractions; if other units are used, the reference temperature/pressure must be given.
- Uncertainty information:
- Expanded uncertainty must be stated for every specified component, with the coverage factor specified (the standard recommends a coverage factor of 2).
- Standard uncertainty must be derivable from the provided information; suppliers should include uncertainty sources and be prepared to supply further details on request.
- Metrological traceability and references: certificate must reference measurement standards or CRMs and indicate traceability chains.
- Methodology: essential features of method of preparation and method of analysis (or validation) should be specified.
- Temporal and pressure data: date of preparation, date of analysis (optional), expiry date (or “not applicable” with justification), filling pressure at a reference temperature, and minimum utilization pressure below which sampling is not recommended.
- Additional product data: container volume, valve outlet connection, storage/utilization temperature, indicative values, nominal composition, customer info (optional).
Practical applications and users
ISO 6141:2015 is used by:
- Calibration gas producers and suppliers to prepare compliant certificates.
- Calibration laboratories and instrument manufacturers who require traceable calibration gases.
- Metrology and QA personnel responsible for procurement, acceptance, and documentation of calibration gases.
Practical value: ensures consistent, traceable, and transparent documentation of calibration gas properties for instrument calibration, quality control, regulatory compliance, and interlaboratory comparisons.
Related standards
- ISO/IEC Guide 98-3 (GUM) - uncertainty of measurement
- ISO 7504 - gas analysis vocabulary
- ISO Guide 31 and ISO/IEC 17025 - cross-references and conformity assessment considerations
Keywords: ISO 6141:2015, calibration gas mixtures, calibration gases, gas analysis, certificate contents, metrological traceability, expanded uncertainty, filling pressure, expiry date.
