A pressure relief system for depressurizing a bottled pressure vessel. In one embodiment, the system includes a pressure relief device having a hollow outer member coupled to a fluid port in the vessel and an inner member at least partially disposed in and movably supported by the outer member. The system may further include a rupture disk disposed in the port between the vessel interior and exterior. In operation, the outer member remains stationary while the inner member is advanceable therein towards the pressure vessel. In one embodiment, the inner member includes a piercing element which is projectable to penetrate the rupture disk and into the vessel interior through material deposits that may obstruct the fluid port thereby releasing captive pressure in the vessel.