Devices and methods for addressing permeation of a gas through a liner of a pressure vessel involve a porous layer between the liner and a composite shell of the pressure vessel around the liner. The porous layer provides fluid communication with atmosphere for gases that permeate through the liner. Such porous layers may be provided in a continuous wound set of fibers about the liner. Further, an inner composite structure may be provided between the liner and the porous layer to reduce the rate of permeation to the porous layer.