Lakhta Center is a multifunctional complex in St. Petersburg with the Gazprom headquarter and public spaces occupying a third of the area. Construction was completed in October 2018, now start work on the arrangement of business and public areas. The opening will take place in about a year, when the complex will be fully prepared to meet guests.
Innovative Fire Fighting System
The-state-of-the-art fire fighting system will be installed in the complex which uses water mist. Due to the structure of sprinklers and high pressure this system considerably reduces the size of droplets and increases their density in a room.
Water evaporation is improved up to 60% (cooling of a room, of seat of fire and dilution with steam of oxygen concentration in a room), precipitating effect of water on combustion products is improved. Owning to this system spread of fire in a building is avoided.
Despite the invention of new fire extinguishing substances (various foam, gas, gas spray and powder compositions), the most widespread fire extinguishing substance in the world is water. Especially in populated areas.
Ideally 0,5 liters of water is required to extinguish 1 sq.m. of solid combustible substance. In actual fire hundreds of liters and sometimes tons of water are poured out per a square meter. More damage is often caused not by fire but by water.
The diameter of droplets supplied to seat of fire is what affects considerably the efficiency of water usage for fire extinguishing. Experiments demonstrated that droplets of a diameter less 150 micron are the most efficient for fire extinguishing, water mist fire extinguishing technology. Fine water particles supplied under high pressure have high penetration capacity.
Nowadays a water mist fire extinguishing technology is the most advanced and efficient fire extinguishing method, it will be applied in Lakhta Center.
Only corrosion-resistant pipes from steel of special grades are used in fire extinguishing units of the water mist fire extinguishing system. Operating pressure 140 bar, test pressure 210 bar.
Water pressure at an output of pumping units amounts to 14,0 MPa (140 kg/cm2).
Water flow of one typical pumping unit is between 96 and 1600 liters/minute. The area protected by one sprinkler of water mist fire extinguishing system is between 12 and 25 sq.m.
Water evaporation and precipitating effect of droplets on combustible products is up to 60% of water used. During ordinary washing down is just 10 %, the rest goes to sewage and slots in floor slabs.
Power source-wise the system is mixed, electric, diesel and pneumatic.
Fire extinguishing units of the water mist fire extinguishing system can be sprinkler and drencher.
A sprinkler system means water is continuously in water pipes, automatically activated when temperature goes above the preset rates. The temperature at which sprinkler flasks are destroyed is above 57 °С
Drencher systems are activated under a command from sensors or manually. Drencher curtains over five meters long at the height of ceilings over 15m can be created with the help of water mist.
It should be noted that water mist fire extinguishing equipment is costly. However the time of operation is 50 years. It is two and a half times as long as a typical sprinkler system.
Much attention should be paid to water treatment for water mist fire extinguishing system. However as compared to other fire extinguishing methods water saving is by over 10 times.