(1) "Boiler" or "boilers" means any boiler or like vessel or container in which water is heated or steam is generated by the application of heat and includes:

(A) Steam boilers that generate steam under pressure and include:

(i) High pressure steam boilers that generate steam under pressure more than fifteen pounds per square inch gauge (15 psig); and

(ii) Low pressure steam heating boilers that generate steam at fifteen pounds per square inch gauge (15 psig) or less for heating purposes;

(B) Hot water heating boilers that heat water for the external use of heating any area or building; and

(C) Hot water heaters that are used for heating water for external use;

(2) "Horsepower" means the evaporation of thirty-four and one-half pounds (34.5 lbs.) of water from a temperature of two hundred twelve degrees Fahrenheit (212 degrees F) into steam at two hundred twelve degrees Fahrenheit (212 degrees F) at fourteen and seven-tenths pounds per square inch absolute (14.7 psia);

(3) "Internal" and "external" inspection means a thorough and proper inspection as provided for in the rules and regulations by the Boiler Advisory Board;

(4)

(A) "Pressure piping" means power piping systems and their component parts within or forming a part of the pressure piping system connected to any boiler or unfired pressure vessel covered by the provisions of this chapter.

(B) This includes only boiler external piping for power boilers and high-temperature, high pressure water boilers in which:

(i) Steam or vapor is generated at a pressure of more than fifteen pounds per square inch gauge (15 psig); and

(ii) High-temperature water is generated at pressures exceeding one hundred sixty pounds per square inch gauge (160 psig) and temperatures exceeding two hundred fifty degrees Fahrenheit (250 degrees F) or one hundred twenty degrees Centigrade (120 degrees C), or both.

(C) Boiler external piping shall be considered as that piping which begins where the boiler proper terminates at:

(i) The first circumferential joint for welding end connections;

(ii) The face of the first flange in bolted flanged connections; or

(iii) The first threaded joint in that type of connection and which extends up to and includes the valve or valves required by regulation;

(5) "Pressure vessel" means any unfired pressure vessel constructed for the accumulation, storage, or transportation of air, liquids, or gases that are under induced pressure; and

(6) "PSIG" means pounds per square inch gauge pressure.