A pressure relief apparatus for venting a tank comprising an inlet port, an outlet port, a closure member retained, relative to the inlet and outlet ports, for preventing, or substantially preventing, fluid communication between the inlet port and the outlet port, a trigger mechanism including a temperature response portion, and a compartment for receiving pressurized fluid from the outlet port and communicating the received pressurized fluid to the trigger mechanism. The trigger mechanism and the closure member are cooperatively configured to release the closure member and establish fluid communication between the inlet port and the outlet port, thereby venting the tank, upon detection of a temperature at or above a predetermined temperature threshold or upon pressurization of the compartment at or above a predetermined pressure threshold.