Abstract: An orientation-independent compartment pressure relief valve comprises a housing with a throughflow channel having an intake and an exhaust. A flange disposed around the inner wall of said housing defines an aperture within the throughflow channel and sealing flap is secured to the flange sealingly covering said aperture. Sealing flap is comprised of a relatively pliable layer and a relatively rigid layer and is oriented such that relatively pliable layer is in contact with flange. Pliable layer allows sealing flap to flexibly open in response to compartment pressure and rigid layer acts to close sealing flap irrespective of pressure relief valve's orientation in relation to a gravity vector.