This European Standard specifies requirements and test methods for nozzles which introduce the extinguishing agent into a CO2S protected zone. The design of the nozzles will influence discharge rate and thus the pressure drop in the piping network. The extinguishing agent normally arrives at the nozzle in two-phase flow form (liquid-gaseous mixture). It expands into the protected volume to form a gas or a gas-and-dry-ice mixture depending on the nozzle type. This standard should only be used as guidance for testing nozzles which work on different principles.