ISO 10723:2012

Overview

ISO 10723:2012 - Natural gas - Performance evaluation for analytical systems specifies a standardized method to determine whether an analytical system for natural gas analysis is fit for purpose. The standard addresses how to use a specified calibration gas to either:

• define the range of gas compositions for which an analytical method meets predefined maximum errors and uncertainties, or
• quantify the errors and uncertainties when analysing gases within a defined composition range.

The method applies to systems that measure individual component amount fractions (for example gas chromatography-based systems used to calculate calorific value, density, Wobbe index and other properties).

Key topics and technical requirements

• Response functions and calibration: Establishes how to identify the instrument’s assumed and true response functions (calibration and analysis functions) and to validate them by regression against reference gas data.
• Calibration gas mixtures (CGM) and working measurement standards (WMS/CRM): Requires known composition and uncertainty of the calibration gas used routinely and explains the role of certified reference gas mixtures (CRMs) and WMSs.
• Experimental design: Specifies multi-point calibration experiments using a designed set of reference gas mixtures covering the intended measurement range, and that the experiment be performed within an interval comparable to routine calibrations.
• Uncertainty and error evaluation: Uses uncertainty principles (referencing the GUM) to calculate standard and expanded uncertainties for component amount fractions and for properties derived from composition.
• Interpretation and benchmarking: Provides procedures to determine analytical ranges, selection of hypothetical compositions for simulation, and guidance for periodic re-evaluation. Informative annexes illustrate application with on-line gas chromatography and provide benchmarking rationale.

Practical applications and users

Who benefits:

• Analytical laboratories and metrology institutes validating gas analysis systems
• Gas transmission and distribution operators verifying on-line or custody-transfer analysers
• Instrument manufacturers benchmarking and selecting calibration gas compositions
• Calibration service providers and QA teams ensuring measurement traceability and uncertainty compliance

Typical uses:

• Determining the composition ranges where a gas analyser meets performance requirements
• Quantifying measurement uncertainty for custody, billing, safety, and process control
• Optimizing calibration gas composition to minimize errors across the operating range
• Establishing periodic performance-evaluation schedules and corrective actions

Related standards

Normative references in ISO 10723:2012 include:

• ISO/IEC Guide 98-3 (GUM) - Uncertainty of measurement
• ISO 6143 - Comparison methods for calibration gas mixtures
• ISO 6974-2 - Uncertainty calculations for GC composition
• ISO 6976 - Calculation of calorific values, density and Wobbe index

Keywords: ISO 10723:2012, natural gas analysis, performance evaluation, calibration gas, measurement uncertainty, gas chromatography, certified reference gas mixture, working measurement standard.