1.1 General This European Standard applies to water-tube boilers with volumes in excess of 2 litres for the generation of steam and/or hot water at an allowable pressure greater than 0,5 bar and with a temperature in excess of 110 °C as well as auxiliary installations (other plant equipment). The purpose of this European Standard is to ensure that the hazards associated with the operation of water-tube boilers are reduced to a minimum and that adequate protection is provided to contain the hazards that still prevail when the water-tube boiler is put into service. This protection will be achieved by the proper application of the design, manufacturing, testing and inspection methods and techniques incorporated in the various parts of this European Standard. Where appropriate, adequate warning of residual hazards and the potential for misuse are given in the training and operating instructions and local to the equipment concerned (see prEN 12952-8, prEN 12952-9 and prEN 12952-16). 1.2 Boiler assembly For the purpose of this standard, the boiler assembly includes: the water-tube boiler including all the pressure parts from the feedwater inlet (including the inlet valve) up to and including the steam and/or hot water outlet (including the outlet valve or, if there is no valve, the first circumferential weld or flange downsteam of the outlet header). All superheaters, reheaters, economizers, the associated safety accessories and interconnecting tubing that are heated by means of the gases of combustion and are not capable of isolation from the main system by interposing shut-off valves. Additionally, the tubing that is connected to the boiler involved in services such as draining, venting, desuperheating, etc., up to and including the first isolating valve in the tubing line downstream of the boiler. Reheaters which are heated by the flue gas or independently fired, and are separately provided with their safety accessories including all control and safety systems. isolatable superheaters, reheaters, economizers and related interconnecting tubing; the heat supply or firing system; the means of preparing and feeding the fuel to the boiler including the control systems; the means of providing the boiler with feedwater including the control system; the pressure expansion vessels and tanks of hot water generating plant. 1.3 Other plant equipment the boiler supporting structural steelwork, the thermal insulation and/or brickwork and the casing; the means of providing the boiler with air including the forced draught fans and air pre-heaters which are heated by the gases of combustion; the facilities for moving flue gases through the boiler up to the stack inlet, including the induced draught fans and the air pollution reducing equipment located in the flue gas removal path; all other equipment necessary for the operation of the boiler plant. For a description of the types of operating systems used for water-tube boiler plant, see prEN 12952-7. 1.4 Exclusions This European Standard does not apply to the following types of boiler plant: boilers other than stationary boilers; shell type boilers including electrical boilers; nuclear primary circuits, the failure of which can cause an emission of radioactivity.