This document specifies requirements for gaseous fire-extinguishing systems, with respect to FK-5-1-12 extinguishant. It includes details of physical properties, specification, usage and safety aspects. This document is applicable only to systems operating at nominal pressures of 25 bar, 34,5 bar, 42 bar, 50 bar and 70 bar1 with nitrogen propellant. This does not preclude the use of other systems. 1 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm².