The FORTRESS premium isolation valve is a bidirectional barrier valve that isolates reservoir fluids in the lower completion and allows operators to transition from the lower to the upper completion without intervention. The valve is designed to withstand deepwater and other severe debris environments and optimize the available actuation energy— predictably, consistently, and reliably. Schlumberger isolation barrier valves safeguard reservoirs by providing a reliable barrier between the wellbore and formation and by containing fluids during completions and workover operations—preventing damage to the formation and minimizing workover costs.