Overview
ISO 12963:2017 - "Gas analysis - Comparison methods for the determination of the composition of gas mixtures based on one- and two-point calibration" provides standardized methods for calibrating gas analysis instruments using a minimum number of calibration gas mixtures. The standard covers procedures to:
- calibrate an instrument with one- or two-point calibration gas mixtures,
- determine the composition of gas samples, and
- evaluate and report the measurement uncertainty linked to calibration gas uncertainties and measurement process contributions.
Although described for amount-of-substance fractions, ISO 12963:2017 is also applicable to mass fractions, volume fractions, and concentrations, and is intended to balance cost and analytical accuracy in routine gas analysis.
Key technical topics and requirements
ISO 12963:2017 defines the principle, procedure and acceptance criteria for limited-point calibration designs and includes requirements for performance evaluation and quality assurance:
- Calibration designs covered
- SPEM - Single-Point Exact-Match calibration (direct transfer of certificate value)
- SPO - Single-Point Through Origin calibration (assumes straight-line through zero)
- TPB - Two-Point with Blank (single point + blank)
- TPC - Two-Point Bracketing (two calibration gases bracketing sample)
- Reference to MPC - Multipoint calibration (≥3 points) for broader contexts
- Performance evaluation (Clause 8): establish system linearity, nonlinearity contribution u(Δ), and overall uncertainty before routine use
- System stability: demonstrate stability over normal calibration intervals; see Annex A for stability checks when using SPEM and TPC
- Uncertainty assessment: propagate uncertainty from calibration gas certificates and measurement process following GUM principles (ISO/IEC Guide 98-3)
- Reporting and documentation: calibration gas certificates and analysis reports, with traceability and evaluation results
Practical applications and users
ISO 12963:2017 is intended for organizations that require reliable, cost-effective gas composition measurement with minimal calibration complexity:
- National metrology institutes and calibration laboratories validating simpler calibration approaches
- Industrial gas producers, process-control and safety monitoring teams
- Environmental and emissions monitoring laboratories
- Instrument manufacturers and service providers that supply or maintain gas analyzers
- Applications where traceability, documented uncertainty and acceptance criteria are required but multipoint calibration is impractical
Related standards
ISO 12963:2017 is designed to work with and reference:
- ISO 6141 (calibration gas certificate contents)
- ISO 6143 (comparison methods and multipoint calibration)
- ISO 7504 (vocabulary)
- ISO/IEC Guide 98-3 (GUM) and Guide 99 (VIM) for uncertainty and metrology terms
Keywords: ISO 12963:2017, gas analysis, one-point calibration, two-point calibration, calibration gas mixtures, measurement uncertainty, gas composition, SPEM, SPO, TPB, TPC, metrology.
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