This standard applies to small stationary fuel cell power systems serving as a heating appliance providing both electrical power and useful heat with or without a supplementary heat generator providing peak load function. This standard applies to fuel cell power systems that are intended to be permanently connected to the electrical system of the customer (end user). Connection to the mains directly (parallel operation) is also within the scope of this standard NOTE 1: Parallel operation is subject to the permission of the local electric power supply utility This standard is limited to gas and liquid fuelled fuel cell power systems that have a heat input based on lower heating value of less than or equal to 70 kW. For some regional applications the output electric power is limited. Specific limitations are given in C.1 for Japan. This standard applies to systems as shown in Figure 1. One is a system that both stationary fuel Cell power system and supplementary heat generator are installed in one enclosure without any partition. In case of the system where the stationary fuel cell power system and the supplementary heat generator are not built in one enclosure, and whose ducts are not common (that is, each appliance has its own dedicated duct system), this standard does not have to be applied to the supplementary heat generator. This standard applies to systems intended for operation on the following supplied input fuels: natural gas and other methane rich gases; fuels derived from oil refining (liquefied petroleum gases, propane, and butane); hydrogen as supply gas for the CHP generator NOTE 2: Other fuels such as alcohols (methanol, ethanol), kerosene, or hydrogen for the supplementary heat generator may be added in future amendments or revisions. The following points also apply: The heat transfer fluid (heat output) shall be water or a mixture of water and additives to prevent corrosion and to prevent freezing. The heat transfer fluid circuit (heat output) can be designed for open or sealed operation. The maximum temperature of the heat transfer fluid (heat output) shall not exceed 100 °C, respectively the value given in B.1 for Europe and in D.1 for US. The maximum pressure of the heat transfer fluid (heat output) circuit shall not exceed 0,3 MPa, respectively the limits as given in B.1 for Europe, C.4.3 for Japan and D.1 for the US. The maximum pressure of the domestic hot water circuit, if installed, shall not exceed 0,1 MPa, respectively the limits as given in D.1 for the US. This standard applies to systems with either condensing or non-condensing conditions in the exhaust gas. This standard applies to appliances: with ducts included as part of the appliance (Type B, Type C) without ducts (Type A) NOTE 3: Duct systems are shown in Annex F and the chimney in the figures is part of the building and is not subject to this standard. Different combustion air / flue duct circuit configurations are accommodated, see Annex F. This standard applies to both indoor and outdoor installations. This standard applies to systems with or without integrated batteries. This standard applies to Type Testing only. This standard specifies the requirements for construction, safety, installation, fitness for purpose, rational use of energy, marking, and performance measurement of these appliances. This Standard also provides regional and country specific requirements to facilitate the worldwide application of this IEC standard. These essential regional and country specific requirements are given in Annex B for Europe, in Annex C for Japan and Annex D for the US and will facilitate that the essential requirements for applications are given clearly. If the user or manufacturer chooses a regional specific annex to apply this standard, then that annex shall be apply to the appliance entirely. It is not permissible to mix requirements between annexes.