This study covers the evaluation of the principal components of the in-plane permeability of fabric reinforcements from experimental data using a resin transfer moulding (RTM) machine. Various techniques are presented for the mathematical analysis of the flow data, including radial flow in an isotropic porous medium or in an orthotropic porous medium, with the material axes at a certain angle with respect to the experimental system of coordinates, and one-dimensional rectilinear flow. Inlet conditions may include either constant modul inlet pressure or transient inlet (changing pressure and flowrate) conditions. a differential and an integral numerical method are proposed for the analysis of flow data under transient inlet conditions. Two techniques are investigated for the monitoring of the flow progress: (a) monitoring of the moving flow front with a camera and (b) measurement of the weight loss in the injection pot on a mass balance.