A standard unpressurised laboratory liquid nitrogen dewar operates at or near atmospheric pressure, with a pressure relief valve that vents nitrogen gas as it evaporates to prevent pressure build-up. Pressurised liquid nitrogen dewars designed for liquid dispensing typically operate at working pressures between 0.5 and 2.5 bar gauge, depending on design and application. Large bulk storage tanks designed for industrial or high-volume laboratory supply operate at higher pressures, often between 5 and 17 bar, to facilitate liquid withdrawal and distribution through pipework systems. In all cases, the vessel must never be completely sealed without appropriate pressure relief, as evaporating liquid nitrogen expanding to gas at approximately 700 times its liquid volume generates pressure that can rupture a sealed container. Understanding the pressure rating and pressure relief system of any vessel in use is a fundamental safety requirement. Cryolab’s liquid nitrogen storage vessels are supplied with full technical specifications including pressure ratings and relief valve data.