This document specifies the evaluation of the firefighting performance of water mist systems for false ceilings and false floors with heights between 300 mm and 800 mm. This fire test protocol is applicable to pendent or upright automatic nozzles to be used in unlimited volume. This document is applicable for horizontal, solid, flat ceilings. It is not possible to apply these tests to other applications than the ones specified within this fire test protocol. In case of a positive result of the tests, the water mist system can be applied for the protection of the following risks: False ceilings and false floors between 300 mm and 800 mm.