System of vessels, pipes, and other equipment operating with an internal pressure exceeding atmospheric.
Source: API STD 521, Pressure-relieving and Depressuring Systems, Sixth Edition, January 2014. Global Standards
“Pressure system” means a boiler, pressure vessel, pump, compressor and the piping system connected thereto that contains or is intended to contain a gas, vapour or at a pressure greater than atmospheric pressure.
Source: Nova Scotia Offshore Petroleum Occupational Health & Safety Requirements, Canada-Nova Scotia Offshore Petroleum Board, Canada, December 2000. Regulations