These data, presented in an excel spreadsheet, where each tab is a different sample (corresponding to the names in the publication), shows the fluid flow volume through time during a permeability measurement, plus the calculation of permeability. These permeability data were used in the publication by Weaver et al. 2023 (https://doi.org/10.1016/j.epsl.2023.118410) The data was collected and analysed at the University of Liverpool and each sample is made of volcanic glass fragments from Hrafntinnuhryggur, Iceland. The geographical location of the samples is here inconsequential for the dataset, the specific obsidian was chosen for its physical properties alone. The experiments were conducted and the data collected and analysed in 2021 and 2022 for publication in 2023. Experiments consisted of placing loose volcanic glass fragments in a crucible and placing the assembly in a high temperature oven (1006 oC) for variable amount of time to sinter them into a coherent material, before cooling and measuring permeability. The permeability measurement was made using the constant head permeability method with synthetic oil as a permeating fluid. This involves the filling of a given height of oil above the sample, creating an overburden that drives fluid flow. Details of the method are provided in detail in Weaver et al., 2023. The data were collected to assess the permeability evolution of fragmental systems undergoing diffusive outgassing, vesiculation and sintering to try to understand the longevity and impact of fragment-filled cracks present in volcanic environments.