DBB valves save space, reduce the need for costly multivalve systems and provide zero leakage capabilities from upstream to downstream. Such valves also allow for an integrity check of seat seals. In the oil and gas fields, double block-and-bleed valves can be used in a variety of applications and markets, such as liquefied natural gas, petrochemical, transmission and storage, natural gas industrial processes, mainline and manifold valves in liquid pipelines, and refined products transmission lines.