A deluge fire sprinkler system is similar to a pre-action system except the sprinkler heads are open and the pipe is not pressurized with air. Delugesystems are connected to a water supply through adeluge valve that is opened by the operation of a smoke or heat detection system.
Deluge Valves are used in conditions that require for quick application of large volumes of water and, for that reason, are often integral components in fire protection systems.
Deluge systems deliver large quantities of water, over a large area, in a relatively short period of time. They are commonly used in fixed fire protection systems whose pipe system is empty until the deluge valve distributes pressurised water from open nozzles or sprinklers.Deluge Valve used for fast application of water in a spray system. Deluge valve protects areas such as power transformer installation, storage tank, conveyor protection and other industrial application etc. With the addition of foaming agent they do protect aircraft hanger and inflammable liquid fires also.
Deluge Valve Operation
Deluge valve is a quick release, hydraulically operated diaphragm valve. It has three chambers, isolated from each other by the diaphragm operated clapper and seat seal. While in ‘SET’ position, water pressure is transmitted through an external bypass check valve and restriction orifice from the system supply side to the top chamber , so that supply pressure in the top chamber acts across the diaphragm operated clapper which holds the seat against the inlet supply pressure because of differential pressure design. On detection of fire the top chamber is vented to atmosphere through the outlet port via opened actuation device(s). The top chamber pressure cannot be replenished through the restricted inlet port, thus it reaches less than half the supply pressure instantaneously and the upward force of the supply pressure lifts the clapper allowing water to enter the system piping network and alarm devices.
Applications for Deluge Valves
Deluge systems are used in conditions that require quick application of large volumes of water. They create a ‘buffer zone’ in hazardous areas or in areas where fires can spread rapidly. They can also be used to cool surfaces to prevent deformation or structural collapse. Or to protect tanks, transformers, or process lines from explosion.
Other examples include: tanks containing combustible solutions; equipment pits; storage or process areas containing substances with a low flash point; or product handling systems.
Advantages and disadvantages of Deluge Valves
Advantages
– Entire Transformer is flooded with water, which extinguish fire at earliest as well as avoid further destruction.
– Very quick in response.
– The fire losses is kept low as the area near fire get cooling due to water and so chances of spreading fire is negligible.
– Less expensive than other methods
Disadvantages
– Can damage sensitive or electronic equipment
– Longer clean-up time than powder and gas systems
– Requires a large water reservoir to operation.
