A Pressure Vessel is a container designed to hold gases or liquids (generally) at a pressure substantially different from the ambient atmospheric pressure.
Pressure vessels (PV) are only one type of pressure containing item more broadly known as Pressure Equipment (PE). They are used in a variety of applications in both industry and the private sector. They appear in these sectors as industrial compressed air receivers to large high pressure steam boilers. Other PE within this group of items, known as PE but not limited to, pressurised hot water storage tanks, recompression chambers (hypo/hyperbaric), distillation towers, pressure reactors, autoclaves andsterilisers, and many other vessels in mining operations, oil refineries, petrochemical plants, nuclear reactor vessels, submarines and associated PE, pneumatic reservoirs, hydraulic reservoirs under pressure (accumulators), rail vehicle airbrake reservoirs, road vehicle airbrake reservoirs, and storage vessels for liquefied gases such as ammonia, chlorine, and LPG (propane, butane) and refrigeration and air-conditioning vessels.
Pressure piping and Pressure relief devices (PRD) also defined as Pressure Relief Valves (PRVs), Bursting discs (PBDs)and Vacuum Pressure Reliefs (VPRs) among other reliefs all fall under this group.