Pressurisering

Pressurisering, or pressurisation, is the process of maintaining or establishing a defined pressure inside a closed volume. It counteracts external atmospheric conditions, supports human occupation, protects equipment, and enables processes that require non-atmospheric pressure. In most systems, pressurisering is achieved by supplying a gas or liquid from a supply through regulators and control valves, and by venting excess pressure via relief devices to keep the pressure within set limits. The pressure can be described as absolute pressure or as a differential pressure relative to the outside environment, and designs consider material strength, temperature, and cyclic loading.

Applications of pressurisering span aviation, spaceflight and spacecraft, submarines, medical therapy, chemical processing, and laboratory research. In aviation, cabin pressurization maintains a safe cabin altitude despite high ambient cruising altitudes, using an environmental control system that regulates pressure through bleed air and outflow valves. Submarines keep interior pressure near surface levels to protect the crew, while spacecraft maintain a controlled atmosphere at roughly one atmosphere with a regulated oxygen mix. Hyperbaric chambers apply higher-than-atmospheric pressures for medical treatment. In industry, pressurization drives chemical reactions, prevents contamination, or supports storage and transport of gases.

Key components and methods include pressure vessels, compressors or pumps, regulators, valves, and pressure relief devices, along with sensors and control systems to monitor and adjust pressure. Safety considerations emphasize overpressure protection, controlled depressurization, structural integrity, and adherence to relevant standards and codes, such as those governing pressure vessels and safety devices.