The simulation of a resin flow through a porous medium by FE-models has become a very important aspect for the design of a high-performance RTM produced composite part. The key parameter to perform RTM flow simulations is the fibre reinforcement permeability. Unfortunately, permeability measurements are not yet fully standardized and thus many different set-ups have been proposed. A major problem in comparing different set-ups has always been the fact that there exists no reliable reference material on which a comparative permeability measurement can be performed. This paper presents a solid test specimen, produced with a stereolithography technique, which can be used as a reference sample for calibration of test rigs and for comparison of results from different test rigs. Since the permeability properties of the specimen do not vary from test to test, an excellent repeatability of the experiments is obtained and any measured difference must be attributed to the set-up.