Back arrowBack to FAQs

6.6 Discharge Performance

The electronic activation ensures only one watermist nozzle activates with not less than the pressure and flow given by the pass criteria determined by the BS8458 fire test in Annex C. The system is designed to run at 6 lpm, 80-110 bar pressure. The minimum and default runtime is 30 minutes.

IMPORTANT! 30 mins or longer (60 mins for cat 4 sprinkler equivalent) is available on request. An unlimited runtime is possible when Automist is connected to the main water supply and not limited by a tank.

Increasing the visibility of spray heads

It is always possible to increase the robustness of the spray head placement from obstructions by adding additional heads.  This does not increase the discharge density as only one spray head, per system, will activate (electronically controlled). In rooms where there is an increased likelihood of obstruction adding additional heads, over and above the minimum requirement, is an easy way to reduce the risk.  A Person-Centred Fire Risk Assessment (PCFRA) can be used to identify any attributes of individuals with greater propensity to obstruct the head or tamper with the system.

Installing two Automist systems in parallel for increased density or robustness

It is possible to increase the resilience of the system and double the watermist output by installing two systems in parallel. This can be achieved by protecting the same space with two heads from different pumps. Care must be taken to consider double the water supply for this configuration as both systems may run at the same time depending on the fire.

Automist in parallel for greater robustness


Read more - Does Automist conform to the requirements of BS 8458?