THE ROUND-ROBINS Bruno HAY Laboratoire National de Métrologie et d’essais «  Thermal properties » section 1 - Measurements of thermal properties 2 - Development of reference apparatuses LNE takes part in round-robin with others NMI’s: - to compare the measurement methods - to check the estimated uncertainties Journée SFT / AIRBUS - 19 mai 2005

The different types of round-robins Material Attribute a value to a property of a material ISO Guide 35 (1989) Method Laboratory Determine the accuracy of a method Estimate the performances and the capabilities of laboratories NF ISO 5725 (1994 et 1998) ISO Guide 43-1 and 43-2 (1997) What is the objective of the round-robin ? Journée SFT / AIRBUS - 19 mai 2005

The different types of round-robins  Certification of a reference material • One suitable material (homogeneous, stable in time…) • Metrological laboratories • primary methods Material Material Attribute a value to a property of a material ISO Guide 35 (1989) Method Laboratory Determine the accuracy of a method Estimate the performances and the capabilities of laboratories NF ISO 5725 (1994 et 1998) ISO Guide 43-1 and 43-2 (1997) Journée SFT / AIRBUS - 19 mai 2005

The different types of round-robins Material Attribute a value to a property of a material ISO Guide 35 (1989)  Proficiency tests • Same material • Each participant uses its own method Laboratory Method Laboratory Determine the accuracy of a method Estimate the performances and the capabilities of laboratories NF ISO 5725 (1994 et 1998) ISO Guide 43-1 and 43-2 (1997) Journée SFT / AIRBUS - 19 mai 2005

The different types of round-robins Material Attribute a value to a property of a material ISO Guide 35 (1989)  Characterisation of a method • Same material • All participants use the same method Method Method Laboratory Determine the accuracy of a method Estimate the performances and the capabilities of laboratories NF ISO 5725 (1994 et 1998) ISO Guide 43-1 and 43-2 (1997) Journée SFT / AIRBUS - 19 mai 2005

The main steps of a round-robin 1 - Definition of a protocol 2 - Manufacturing of the material and preparation of the specimens 3 - Measurements of the thermal properties according to the protocol 4 - Analysis of results and technical discussions Journée SFT / AIRBUS - 19 mai 2005

The main steps of a round-robin 4 - Analysis of results and technical discussions  to estimate the accuracy of each method, by applying a statistical analysis to the results in order to: - detect aberrant values - compare the measurement methods - understand the origin of possible discrepancy and scattering of the results Journée SFT / AIRBUS - 19 mai 2005

The main steps of a round-robin 1 - Definition of a protocol - selection of the material to be tested - manufacturing of the material - machining and distribution of the specimen - checking of the material homogeneity - experimental conditions - program of measurements good protocol  efficient and reliable round-robin Journée SFT / AIRBUS - 19 mai 2005