<p>A hot permeability test was designed to provide time series data to examine venting characteristics in foundry sands at an elevated temperature. This was achieved by modifying the standard AFS mold quality indicator (MQI) permeability tester and applying induction technology to create a hot-surface tip which is in contact with the sand specimen. This technique can be used for both green and chemically bonded sand specimens. The focus of this study was to investigate any potential deviations in permeability number of foundry sand specimens at ambient and elevated temperatures to form a correlation within the mold-metal interface and venting characteristics in foundry sand. For each sand system in this study, the time evolution of the permeability number was measured from ambient to 500°C. From this time series data, the rate of change of the permeability number and an overall change in permeability number were captured by calculating a permeability index. Furthermore, Darcy’s number was calculated using the permeability number and characteristic length of the sand system. The results from these tests show that as the green sand moisture (compactability) condensation layer is driven back in the specimen due to heat transfer, the permeability number changes and its rate of change can be determined. Correspondingly, hot permeability rates of change are shown among various chemically bonded sand binder specimens at various binder levels. The finding of this study offers an enhanced understanding of the gas flow venting in foundry sand systems. The measured time series data at elevated temperature can provide improved information to casting simulations regarding venting characteristics of foundry sand.</p>