New Primary Standards for Establishing SI Traceability for Moisture Measurements in Solid Materials

Abstract

A European research project METefnet addresses a fundamental obstacle to improving energy intensive drying process control: due to ambiguous reference analysis methods and insufficient methods for estimating uncertainty in moisture measurements, the achievable accuracy in the past was limited and measurement uncertainties were largely unknown. This paper reports the developments in METefnet that provide a sound basis for the SI traceability: four new primary standards for realising the water mass fraction were set up, analysed and compared to each other. The operation of these standards is based on combining sample weighing with different water vapour detection techniques; cold trap, chilled mirror, electrolytic and coulometric Karl Fischer titration. The results show that an equivalence of 0.2 % has been achieved between the water mass fraction realisations and that the developed methods are applicable to wide range of materials.

A new set-up for the calibration of wood moisture meters

“…The traceability to SI is obtained through traceable measurements of air-flow, air temperature and dew point temperature. The relative expanded uncertainty of 1.6 % has been demonstrated in intercomparisons [4,5].…”

Calibration and Uncertainty Estimation for Water Content Measurement in Solids

“…ADL was sourced from Acros Organics, its reference value was calculated from its molecular formula. The uncertainty of ADLs water content was estimated from METefnet project results [18], the uncertainty estimate was derived from an interlaboratory comparison measurement series with said sample material. The water content and associated expanded uncertainty (U) estimates at 95 % (coverage factor k = 2) confidence level for both standards are given in Table 1.…”