Pressure vessel meaning

A pressure vessel is a robust enclosed container designed to hold gases or liquids at a pressure above ambient. In legal practice it is the principal item of “pressure equipment” and part of a “pressure system”, engaging product safety and workplace safety obligations. In Great Britain, the Pressure Equipment (Safety) Regulations 2016 (retained EU law, derived from the Pressure Equipment Directive) govern design, manufacture, conformity assessment and UKCA/CE/UKNI marking. The Pressure Systems Safety Regulations 2000 regulate installation and operation, including written schemes of examination, safe operating limits, inspection by a competent person and record‑keeping. In Northern Ireland and Ireland, product safety follows the EU Pressure Equipment Directive 2014/68/EU with CE marking; operational duties are substantively similar. Usage is consistent across England and Wales, Scotland, Northern Ireland and Ireland. Typical examples include boilers, heat exchangers, air receivers and autoclaves. In the nuclear sector, a reactor pressure vessel encloses the reactor core and commonly contains or supports the moderator, neutron reflector, thermal shielding and control‑rod mechanisms. Legal significance: classification by pressure, volume and fluid type determines conformity modules, overpressure protection, material and welding requirements, technical documentation and declarations of conformity. Breach may lead to enforcement action and criminal liability.