These are fixed fire protection systems in which the pipe system remains empty until a valve, termed the deluge valve, opens in response to a fire. This releases pressurized water from open nozzles or sprinklers. Deluge systems are more complex than wet and dry pipe systems. Depending on its configuration, a deluge system can be activated hydraulically, pneumatically, electrically, manually, or by any combination of these means. But, in all cases, the deluge valve itself is activated hydraulically. When a detection device is activated, the deluge valve opens sand water flows into the piping system. The water is discharged through all spray nozzles or sprinklers simultaneously.