Pressure and vacuum vessel fabrication is the fabrication of vessels which contains liquids or gases with a pressure that is considerably different from the surrounding pressure.
Pressure and vacuum vessels are sheet metal containers that can handle pressure differences safely. A pressure difference is always potentionally dangerous as it can cause the vessel to explode. That is why the fabrication of pressure vessels are regulated by stringent laws. Within the European Union this is controlled by EN 13445 (previously PD5500 or BS 5500 in the UK). For example; if the vessel is punctured, it is supposed to rupture along its wall to allow the pressure to adapt smoother to the surrounding pressure.
Usually a pressure or vacuum vessel have a cylindrical shape with spherical ends. This design is common because it has proven to be the safest and it also makes it relatively easy to estimate the vessel's properties.
Because of the complications associated with pressure and vacuum vessels, there are workshops which specialize in this kind of work.
