What is Deluge system?

A deluge system is normally the main firefighting system on any  offshore installation, used to protect process-areas, drilling-areas and other high-risk areas. A Deluge system is normally an automatic system, which is triggered by a fire detector in the protected area, and which is using water as the extinguishing agent.

How piping of deluge system works

  • A fire is detected by a fire alarm system.
  • The fire alarm system sends a signal to the deluge valve.
  • The deluge valve opens, releasing water into the piping network.
  • The water flows through the piping network and discharges through the open nozzles.
  • The water extinguishes the fire.

A deluge system consists basically of a Deluge Control Valve, and a distribution piping network with open deluge nozzles. The Deluge Valve is normally closed, and the distribution pipework is dry. The deluge valve is activated automatically when a fire is detected. The distribution piping network is then immediately pressurized, and all nozzles in the deluge system starts flooding the protected area with a predetermined application rate of water.

what is deluge

Deluge is typically used in high-hazard areas where fire may spread rapidly. They are also used in areas where traditional sprinkler systems are not practical, such as areas with flammable liquids or gases.

The deluge valve is usually installed on a skid together with piping, isolation valves, bypass and test/drain facility.

Application of Deluge system

A deluge system may be used to protect almost any area as it provides:

  • Flame extinguishment
  • Cooling
  • Fire control
  • Deluge systems, using water or water/foam, will extinguish fires in any or in a combination, of the following ways:
  • Surface Cooling
  • Smothering, by produced steam
  • Emulsification
  • Dilution

Except in very rare cases, where the application of water may cause certain chemicals to burn or explode, deluge systems will have a beneficial effect on all types of fires. Even in cases, such as fires in leaking, pressurized Gas equipment, where flame extinguishment cannot be achieved, the overall cooling effect, with the resulting protection of adjacent equipment, will prevent the fire from spreading and will greatly reduce the damage to both equipment and structure.

The extinguishing effect of water on Hydro-Carbon pool-fires can be greatly increased using various types of foaming agent, such as AFFF or ATC.

Hazard types where Deluge Systems are used

  • Hydrocarbon fires
  • Wellhead Area
  • Drill floor
  • Process Areas
  • Storage and Piping facilities

Gas (Jet) fires

  • Wellhead Area
  • Drill floor
  • Process Areas
  • Chemical Storage
  • Solids

Material used for Deluge system

One of the major considerations, when specifying a Deluge System, is resistance against corrosion. A deluge system will be operated, for testing purposes, only a limited number of times per year, and yet be required to be fully functional 24 hours a day, 365 days per year. Time has proven the Norwegian Offshore environment very hostile to equipment, especially those in contact with seawater, which is stale, i.e. which is not being refreshed continuously.

For this reason, the material requirements are constantly under development, and there has, on the Norwegian sector, been a progression, from Steel (Galvanized) over Bronzes (CuNiFer piping, Bronze valves) and High Molybdenum (6Mo) Stainless Steels to, now, Titanium.

  • Titanium, all piping and valves
  • Titanium, with Deluge Valve and permanently wetted Isolation valves in Titanium and normally dry downstream valves and accessories in Al. Bronze.
  • CuNi 90/10 piping, with Deluge Valve and isolation valves in Al. Bronze
  • Stainless Steel 316L piping and valves.
  • Galvanized piping, with Bronze (Gunmetal) Deluge Valve and Rubber Lined valves.

Deluge systems are used in the following industries

  • Oil and gas facilities: Deluge systems are often used in oil and gas facilities to protect against fires involving flammable liquids and gases.
  • Power plants: Deluge systems are also used in power plants to protect against fires involving electrical equipment.
  • Chemical plants: Deluge systems are also used in chemical plants to protect against fires involving flammable chemicals.
  • Aircraft hangars: Deluge systems are also used in aircraft hangars to protect against fires involving aircraft fuel.

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