1.1 Firing systems This document specifies requirements, for liquid and gaseous fuel firing systems of steam boilers and hot water generators as defined in EN 12952-1:2015. These requirements also apply to firing systems of chemical recovery boilers (black liquor boilers) with the additions and amendments specified in Annex A of this document. These requirements also apply to gas turbines in combination with fired/unfired heat recovery steam generators with the additions and amendments specified in Annex B of this document. NOTE 1 This standard is not applicable to coil type boilers (flash boilers/small boilers) that use burners in accordance with EN 12953-7 apply for single burner installations. NOTE 2 This standard is not applicable to the storage of liquid fuels and to transfer stations of long-distance gas pipelines. 1.2 Fuels This document specifies requirements, which cover the use of liquid and gaseous fuels as defined in this standard. Fuels deviating from standardized commercially available types may require additional or alternative safety measures. For black liquor these safety measures are given in Annex A.