In this subtitle the following words have the meanings indicated. “Authorized inspection agency” means an entity that: is accredited in accordance with the National Board of Boiler and Pressure Vessel Inspectors NB–369; or meets the qualification and definition of the National Board of Boiler and Pressure Vessel Inspectors NB–360. “Board” means the Board of Boiler Rules. “Boiler” means: a closed vessel in which water is heated, steam is generated, steam is superheated, or a combination of these functions is accomplished, under pressure or vacuum for use externally to the vessel by the direct application of heat from the combustion of fuels or from electricity or nuclear energy; or a fired unit for heating or vaporizing liquids other than water if the unit is separate from a processing system and is complete within itself. “Certificate” means a certificate issued by the Chief Boiler Inspector to operate a boiler or pressure vessel. “Certificate inspection” means an inspection, the report of which is used by the Chief Boiler Inspector to determine whether to issue a certificate. “Commissioner” means the Commissioner of Labor and Industry. “Heating boiler” means: a steam boiler that operates at pressures not exceeding 15 psig; or a hot water boiler that operates at pressures not exceeding 160 psig or temperatures not exceeding 250 degrees Fahrenheit. “High pressure, high temperature water boiler” means a water boiler that operates at pressures exceeding 160 psig or temperatures exceeding 250 degrees Fahrenheit. “Model steam boiler” means a boiler that is: individually fabricated for noncommercial use; used primarily for demonstration, exhibition, or educational purposes; and not for profit. “Power boiler” means a boiler in which steam or other vapor is generated at a pressure of more than 15 psig. “Pressure vessel” means a vessel in which the pressure is obtained: from an external source; or by the application of heat from: an indirect source; or a direct source other than a boiler. “Pressure vessel” does not include a pipe, piping component, or structure whose primary function is to transport fluids. “Secretary” means the Secretary of Labor.