In this work a global permeability model is developed and applied to a biaxial Non-crimp stitched fabric (NCF). This model focuses on a detailed meso-scale description of the fabric geometry, which takes into account the local permeability distribution in a fabric due to perturbations of the geometry as well as the geometrical features which arise from the stitching process. It is shown in this work that these features significantly affects the global permeability. The influence of the amount and type of perturbation of a fabric is also studied in this work. It is shown that perturbation of the fabric geometry affect the global permeability but not as much as the stitching process. The model developed is finally validated with experimental permeability data and it is suggested how to use the model for an arbitrary lay-up.