Unfired pressure vessels are containers for the containment of pressure either internal or external. Section VI11 of the ASME Boiler and Pressure Vessel I Code (BPVCI) covers unfired pressure vessels. These include towers, reactors and other oil and chemical refining vessels, heat exchangers for refineries, paper mills, and other process industries, as well as storage tanks for large and small air and gas compressors. See BOILER CONSTRUCTION CODE.
