The Sieverts technique is commonly used for determining gas uptake, particularly for hydrogen storage material characterisation. Despite a considerable literature on correct technique, best practice and sources of potential errors, there is still confusion concerning application of this technique. We address three aspects of the Sieverts technique, (thermal transpiration, volume calibration and the effect of valve volume) in the context of a recent publication. Crown Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.