Since 2006, the wood preservation laboratory of Cirad is accredited by COFRAC (French accreditation committee – accreditation No. 1-1686) for tests on the durability of wood and wood-based products and on protective efficacy of wood preservatives and termite control products. The metrological approach adopted by the wood preservation laboratory is a key factor on the continuous improvement of practices. Tests to determine the resistance against wood-destroying biological agents are the most difficult of all wood analysis tests. They are aimed at assessing and quantifying the impact of living organism, such as fungi and termites, on a lignocellulosic material. The extent of variability of this impact, which in turn is linked with the diversity of these organisms and of the material, can be readily determined. The validity and reliability of the findings therefore depend directly on the quality of the metrological process, including the choice of measurement devices, their management and compliance with international standards.