As used in this chapter, the following terms shall have the following meanings:

(1) BOARD. The Board of Boilers and Pressure Vessels.

(2) BOILER. A closed vessel in which water or other liquid is heated, steam or vapor is generated, or steam is superheated, or in which any combination of these functions is accomplished, under pressure or vacuum, for use externally to itself, by the direct application of energy from the combustion of fuels or from electrical, solar, or nuclear energy. The term "boiler" shall include fired units for heating or vaporizing liquids other than water where these units are separate from processing systems and are complete within themselves. The term "boiler" is further defined to include any of the following terms:

a. Heating boiler. A steam or vapor boiler operating at pressures not exceeding 15 psig or a hot water boiler operating at pressures not exceeding 160 psig or temperatures not exceeding 250 degrees Fahrenheit.

b. High pressure, high temperature water boiler. A water boiler operating at pressures exceeding 160 psig or temperatures exceeding 250 degrees Fahrenheit.

c. Power boiler. A boiler in which steam or other vapor is generated at a pressure of more than 15 psig.

(3) CERTIFICATE OF INSPECTION. An inspection, the report of which is used by the chief inspector to determine whether or not a certificate as provided by subsection (c) of Section 25-12-15 may be issued.

(4) DEPARTMENT. The Department of Labor.

(5) PRESSURE VESSEL. A vessel other than those vessels defined in subdivision (2) in which the pressure is obtained from an external source or by the application of heat.

(6) SECRETARY. The Secretary of Labor.