This briefing note provides details of ISO 10723:1995- Natural gas – Performance evaluation for on-line analytical systems

EffecTech uses this standard to quantify the performance characteristics of your instrument in conjunction with their UKAS site accreditation according to ISO 17025.

Why do I need a quantitative performance test?

• To improve energy efficiency costs
• To conform with EU emissions trading legislation
• To validate your analytical system
• To highlight instrument limitations
• To reduce potential financial exposure

EffecTech uses instrument performance characteristics to

• Set analytical specifications
• Design the most appropriate calibration gas composition
• Determine the bias and uncertainty of the analytical system

What is ISO 10723?

The standard (ISO 10723:1995 - Natural gas - Performance evaluation for on-line analytical systems) was issued in December 1995 by ISO Technical Committee 193. It has been issued subsequently by BSI as a dual number equivalent BS 3156 part 11.5 and by CEN as a European standard.

EffecTech personnel were responsible for writing and testing major parts of the standard. Subsequently, through practical experience, they have refined the procedures for carrying out the tests and processing the raw data produced.

Applying the standard gives you measures of performance which can be compared with a specification or benchmark which has been set previously.

It does not tell you whether the instrument is fit for purpose.

Objective

The objective of the performance evaluation is to give a measure of the instrument’s performance in terms of

• Component separation
• Repeatability of measurement
• Maximum bias errors

Principle

The analytical system is set up according to the manufacturer’s / supplier’s instructions for installation and operation. The system is examined by analysing test gases, each made up of a mixture of components typically found in natural gas, with compositions covering a range wider than that for which the system has been specified.

The test gases, prepared according to an appropriate standard, are injected into the analyser to test

• The ability of the system to measure the components specified in the analytical method (system efficiency)
• The repeatability of the measurement of individual components over their specified range
• The relationship between response and concentration of individual components over their specified range
• The absence of interference between components at different concentration ratios.

Accuracy of measurement is not included in this list, as it is principally controlled by the accuracy with which the calibration gas composition is known.