1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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