This document gives specific requirements for gaseous fire-extinguishing systems, with respect to the IG-541 extinguishant. It includes details of physical properties, specification, usage and safety aspects and is applicable to systems operating at nominal pressure of 150 bar, 200 bar and 300 bar at 15 °C. This does not preclude the use of other systems; however, design data for other pressures were not available at time of publication.