The SEM-SAFE® high-pressure water mist system consists of a pump unit, pipes, fittings, valves, nozzles and a fire hose reel cabinet. From the SEM-SAFE® pump unit, a main pipe goes to the roof, and from there, a network of pipes supplies water to each protected area in the building. In each prison cell, open nozzles are installed with an anti-ligature mounting kit, which is a dedicated safe and secure solution for prison cells. The open nozzles are activated by a fire detection system and local automatic valves, eliminating the need for manual intervention. In the event of a fire within a protected cell, the fire alarm system sends a signal to open the relevant solenoid valve.

Once the valve has opened and water begins to flow, the subsequent pressure loss prompts the pumps to start, initating the propulsion of water through the distribution pipework. Water mist is then discharged solely into the affected area. The staff can manually bypass the solenoid control valve for each cell, enabling them to start or stop water flow to the nozzles independently of the fire alarm system signal. In addition to the cell nozzles, the system protects corridors with a closed nozzle installed on the wall (sidewall installation). The associated spaces are protected by a closed nozzle installed in the ceiling (pendant installation). SEM-SAFE® water mist fire hose reel cabinets are installed on each floor with a 50-m-long flexible hose. The SEMSAFE® water mist fire hose reel cabinets are compliant with the MOJ Technical Standards. The SEM-SAFE® high-pressure water mist system can be integrated with all forms of custodial fire detection.