Metal-carbon eutectic fixed-point construction and characterization are subjects of ongoing investigation within the field of radiation thermometry. National metrology institutes are in constant search of stable eutectic points with minimal uncertainty for the purposes of either increasing the working temperature range of radiation thermometry or obtaining intermediate check points for both contact and non-contact thermometries. The Co-C eutectic point (∼1,324 • C) would be very effective in reducing certain calibration uncertainties at this temperature, once long-term stable and reproducible cells are constructed. For these purposes, one Co-C eutectic cell was fabricated at UME, in collaboration with LNE-INM, while a second Co-C cell was constructed for UME. At UME, the cell was filled (in the Vega-BB3500PG blackbody) using methods developed by LNE-INM. Eutectic plateaux, eutectic temperatures, and their uncertainties have been assessed using the UME Transfer Standard Pyrometer TSP-2, calibrated at UME, and an IKE LP3, calibrated at INM. The two Co-C eutectic cells (one constructed at INM and the other at UME) were compared at UME. The short-term stability and reproducibility of the cells have been assessed for various thermal conditions. A provisional uncertainty budget for the thermodynamic temperature of the Co-C cell as determined by LNE-INM has been established.

Two of the most commonly used solid biomass sources for fuel are wood chips and wood pellets. The calorific value and the moisture content of those biofuels determine the efficiency of the CHP and the biorefinery plants. Therefore, with the increased shift towards a biobased economy, the biomass cost and its physical properties must be precisely determined. Most of the current standards are lacking and provide neither enough details about the issues caused by the biomass heterogeneity nor with the variation in experimental practice. Phenomena such as data scattering, poor repeatability and wide uncertainty, are mostly observed during the measurements of the calorific value and the moisture content. To overcome such issues, an interlaboratory comparison between three national metrology institutes using bomb calorimetry has taken place. The comparison helped to identify the root causes behind the poor reproducibility of the wood samples. Factors such as the equilibrium moisture content of the biomass, the pellet mass, the applied pressure to form the pellet, the handling techniques and the determination errors are highlighted and analyzed. The final results paved the way to provide an enhanced detailed experimental practice where the repeatability and reproducibility have been strongly improved. Moreover, the detailed uncertainty sources and calculations are presented. It has been found that by fulfilling the recommended approach the measurement repeatability improved by up to 50–80%, while the final uncertainty improved by 10–30%. This enhancement leads to a maximum relative expanded uncertainty of around ±1% (coverage factor of k = 2 and a confidence level of 95%).

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