Report on the CCM WG TG1 pilot comparison to measure water vapour sorption on stainless steel mass standards.

This report summarises the results of a comparison to measure the water vapour sorption correction on stainless steel masses when they are transferred between moist air and vacuum. The three sorption artefacts consisted of an integral 1 kg cylindrical stainless steel mass and two 1 kg cylindrical stainless steel stack weights with different surface areas. This report also summarises the results of the measurement of the mass of the integral artefact both in air and in vacuum.