A valve operable to control flow between two adjacent pipe sections and having a system for relieving pressure from an enclosed cavity within the valve. The valve includes a first pressure port, a second pressure port, and a seal. When the valve is closed, the first pressure port is in fluid communication with one pipe section and the second pressure port in fluid communication with the enclosed cavity. The seal isolates the second pressure port from the first pressure port when fluid pressure within the enclosed cavity is less than a pre-selected valve and is displaceable to enable fluid communication between the second pressure port and the first pressure port when fluid pressure in the enclosed cavity is equal to or greater than the pre-selected value.