Water mist fire suppression system

Water Mist Fire Suppression System «MIST E1^®»

A new concept of water mist fire suppression system «MIST E1^®», by using water supplied under high pressure as a fire suppression agent and obtaining of droplets with a diameter of less than 100 microns, guarantees the following advantages:

Reducing the costs for acquisition of tanks and reservoirs for water storage;
Significant reduction of damage caused by spilled water, compared with conventional sprinkler and deluge systems with a droplet diameter of 0.4 - 2 mm;
No need to section the protected facilities and ability to start the fire suppression before the evacuation, unlike the fire smothering suppression systems.

Sprinklers and deluge nozzles of the water mist system «MIST E1^®» create a fine mist that quickly saturates the protected room volume, while reducing the oxygen concentration, which greatly increases the efficiency of water fire suppression using a minimal amount of water. During the fires suppression with the systems of water mist fire suppression the amount of water used is ten times lower than in the systems with conventional sprinklers and deluge nozzles that allow dramatically reduce the required fire water supply and as a consequence, minimize damage caused during the water mist fire suppression.

Water mist having a high heat capacity and a high total active surface area of droplets, with the sprinklers and deluge nozzles operating, dramatically reduces the temperature in the fire zone, stopping the chemical reaction of combustion. Quick spraying and high cooling effect of the water mist allow evacuate people staying in the room, and create conditions for special personnel with portable fire suppression equipment. System «MIST E1^®» applies clean water without chemical additives, so the unit and a fine mist created during the operation is completely environmentally safe.

WATER MIST FIRE SUPPRESSION SYSTEM «MIST E1^®» APPLICATION

System «MIST E1^®» complies with the international standards IMO A 800, A 913 and NFPA 750. The system is certified in the Academy of the State Fire Service of the Ministry of Emergency Situations of Russia.

Application of water fire suppression system «MIST E1^®» is recommended by testing laboratories “Factory Mutual” and “VDS” (Germany). Numerous units of «MIST E1^®» were used abroad for the protection of cable tunnels of telecommunication companies, petrochemical companies and railway facilities on the basis of standard NFPA 750. Among the most important facilities we can name Madrid and London subways, cable tunnels of various branches of company "Ericsson".

In accordance with the Code of Regulations SP 5.13130.2009 our company has developed "Guidelines for the design of fire suppression systems using water mist fire suppression modules «MIST E1^®». In accordance to these Guidelines the units of water mist fire suppression system «MIST E1^®» may be used for fire protection of the facilities of groups 1, 2, 4.1, 4.2, 5, 7 (except of flammable and combustible liquids with a flashpoint below 50°C ) and cable structures.

The water mist fire suppression system offered by us includes the following major components:

Pump station of high-pressure with electric pumps (main and standby) to be installed on a single support platform (diesel pump is possible to use as a standby);
Tank with demineralized water of different volume, in accordance with a required volume;
Distributing gears of stainless steel AISI 316 with manual and electric drive for supply of water to the nozzles in different zones (in the deluge system they open by a signal of the automatic fire alarm);
Special sprinkler or deluge nozzles «MIST E1^®» (the amount is determined by the project);
Pipelines and special connectors made of stainless steel of grade AISI 304 with a maximum diameter of up to 3''.

Water fire suppression system «MIST E1^®» can be of the two types: with a pump station of high-pressure and of module type (with cylinders).

WATER MIST FIRE SUPPRESSION SYSTEM WITH PUMP STATION: DESCRIPTION AND OPERATION PRINCIPLE

The pump assembly consists of high-pressure working pumps (from one to six, depending on the project) and one standby unit mounted on a common support frame. The pump directs the water through the check valve into the common manifold of the pump unit. The pump unit manifold is equipped with all necessary connections, pressure switch, pressure gauges, safety valve and pressure control valve. In standby mode, the piping system is filled with water at a pressure of 15 bar (in case of use of water-filled system).

If a fire occurs the thermal locks of one or more nozzles closest to the fire source are destroyed. Flow of water through the nozzles will result in a decrease in pressure in the section of the main manifold. Decrease in pressure in the system is fixed by an area pressure switch which sends a signal to activate the jockey pump which restores the pressure up to a value of 15 bar. With a continued pressure drop after 10 seconds the operation of the jockey pump stops and the first high-pressure pump is actuated. If the pressure drop continues, the required number of pumps starts operating.

PIPELINE SYSTEM DESCRIPTION

Water is directed from the pump unit to dispensers through the pipes of stainless steel of grade AISI 316. The system piping in a diameter of 38 mm and less are connected by means of steel connectors AISI 316. Ball-type cut-off valves are installed on the supply pipeline of each direction (area) of the fire suppression immediately after escaping from the manifold. Each supply pipeline has an area flow sensor installed, its signal is immediately transmitted to the remote control receiver.

DESCRIPTION OF DISPENSERS

In the water mist fire suppression system «MIST E1^®» with a pressure of 100-120 atm. sprinklers and deluge sprinklers of a special design, patented, unparalleled, specially designed for use with this system are applied. The dispensers are selected depending on the group of the protected premises, the amount of fire load, operating conditions. A specific flow coefficient (C-factor) is selected on the basis of the specified characteristics and the response temperature.

DESCRIPTION OF HYDRAULIC POWER SYSTEM

The pump unit is connected to a reservoir of 1000-8000 litres (volume of the reservoir is determined by the project), made of AISI 304 stainless steel, installed in the premises of the pump station and connected to the water supply system of the protected facility (if possible). The water level in the tank is controlled remotely by an electric sensor mounted on the upper part of the tank, and visually - by a level indicator mounted on the tank wall. When water level drops to a minimum level the electrical sensor transmits a signal about a malfunction to the control cabinet, which, in its turn, transmits a signal to the opening of the electric valve of the replenishment of the tank from the water supply line.

The tank is equipped with electric valves, filter, cut-off ball valve, drain valve.

DESCRIPTION OF THE SYSTEM WITH CYLINDERS

Water mist fire suppression system «MIST E1^®» of modular type is used to protect small volumes or in the lack of water. The modular system consists of the following main elements:

Cylinders with nitrogen (N2);
Cylinders with water (Н2О);
Fast-response valves, actuators and safety devices;
Compressor

In standby mode, the system is filled with air under a pressure of 6 atm. At opening of one or more dispensers and decrease of the system pressure below 4 bar, the pressure switch gives a signal to the control unit, which in its turn provides the opening of the solenoid valves of the nitrogen cylinders. The effluent nitrogen displaces water from the cylinders with a capacity of 80/140 litres and delivers it to the distribution manifold to the nozzles. After the system has actuated the water cylinders are re-filled with water and the nitrogen cylinders are recharged or replaced with the cylinders already charged with a pressure of 200 atm.