Pressure equipment

Boiler general definition

A boiler is a vessel or an arrangement of vessels and interconnecting parts, in which steam or vapour is generated or in which water or other liquid is heated at a pressure above the atmosphere, by the application of fire, the products of combustion, electrical power, or similar high temperature means.


It includes the superheaters, reheaters, economisers, boiler piping, supports, mountings, valves, gauges, fittings, controls, the boiler setting and other equipment directly associated with those vessels.

A boiler does not include:

  • a fully flooded or pressurised system where water or other liquid is heated to a temperature lower than the normal atmospheric boiling temperature of the liquid;
  • a direct fired process heater;
  • boilers with less than 5 square metres heating surface or 150 kilowatt output;
  • unattended boilers certified in compliance with AS2593:2004.

BS Boiler standard

This licence class includes the operation of a boiler with a single fuel source that does not have a pre-heater, superheater or economiser attached.

BA Boiler advanced

The scope of work for advanced boiler operation includes the operation of a boiler, including a standard boiler, which may have one or more of the following:

  • multiple fuel sources
  • pre-heater
  • superheater
  • economiser.

It is a prerequisite that applicants for an advanced boiler licence already hold or have previously passed assessment for a lower level boiler operation licence.

ES Reciprocating steam engine operation

Reciprocating steam engine means equipment that is driven by steam acting on piston causing the piston to move, and includes an expanding (steam) reciprocating engine.


This includes all expanding (steam) reciprocating engines and reciprocating steam engines with any piston diameter of greater than 250 millimetres.

TO Turbine operation

The class includes the operation of a turbine that has an output of 500kW or more and includes one of the following:

  • multi-wheeled
  • capable of a speed greater than 3600 revolutions per minute
  • has attached condensers
  • has a multi-staged heat exchange extraction process

A turbine means equipment that is driven by steam acting on a turbine or rotor to cause a rotary motion.