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Water mist system

Introduction

Water mist system

  • At the high pressure water mist system as the extinguishing factor, water (changed into water mist) is used.
  • System is designed in a special way, so that one could get passing the extinguishing agent for at least 30 minutes in accordance with the most demanding protected area.

System’s characteristic

  • Basic task of the SEM-SAFE® water mist is to extinguish fore and minimalize damages that arose from fire and its extinguishing at the protected areas.
  • System uses high pressure water mist system.
  • Water mist effectively controls fire by cooling the protected area and locally neutralized atmosphere.
  •  It stops heat radiation and allows for evacuating people from dangerous areas and limits the possibility of spreading the fire.
  • Composition of proper size of drops (50-120µm) with high speed of water mist flow provides effective filling the area.
  • Gist of the success is properly chosen size of water drops and their cinetic energy.
  • High pressure water mist system has CNBOP technical approval.
  • High pressure water mist system does not require full tightness of the protected area.
  • Usage of mist sprinklers at the water mist system provides conducting the extinguishing only at the area, where the fire apeared. Other rooms, in which there is no fire, are not filled with water mist but are still protected with water mist system (mist system stays ready to start extinguishing).
  • For protected areas maximum time of continuous extinguishing, according to NFPA750, is 30 minutes.
  • There is a possibility of earlier switching off the system by special units and people with proper permissions, after making sure that the fire is entirely extinguished.

Elements of the system

Fire protection system’s installation consists of following elements:

  • source of water in form of water supply tank;
  • set of filters and electric pump supporting filling with water;
  • low pressure water pipeline made of the stainless steel or plastic (suction pipeline);
  • main pump unit (indirect tank, pump set, switch cabinet);
  • highpressure water pipelines made of stainless steel (distribution pipelines);
  • zone valves;
  • mist sprinklers

High pressure pipelines

  • Distribution line pipelines of the mist system are designed to operate at a high pressure and should be made according to DIN, EN 10217-7 (or its equivalent’s) guidelines, what provides long lasting system and devices and proper clearance of the water.
  • Calculations of the pipes’ strenght should be consistent with guidelines and restrictions.
  • Connections should be made in the form of ring caps.
  • Connections should be made of stainless steel.
  • Pipelines should be assembled to the superstructures with special ring (allowed to usage)

Low pressure pipelines

  • Low pressure pipelines of line supplying mist system.
  • From water supply tank to high pressure mist pump should be made of stainles steel pipes and plastic pipes according to pressure guidelines.

Section valves

  • Assembly of the mist fire protection is divided into zones by using section valves.
  • Due to that, after closing one section for the maintenance or service, other sections are constantly ready to extinguish.
  • Section valves of the mist system for “wet” sections are activated automatically by bursting of the glass bulb of the mist nozzle.
  • Valves cutting-off the “wet” section in the standby mode are constantly in the opened position.

 Mist nozzles

  • Mist nozzles are precisely designed components made to produce water mist that flows in concentration and amount guaranting effective fire extinguishing.
  • Mist nozzles are assembled by special mounting adapters to distributive line (according to NFPA 13).

Water mist extinguishing systems provide:

  • rapid reaction to fire;
  • the most effective cooling of extinguished areas;
  • safety of people, environment and property;
  • avoidance of the re-ignition;
  • conduction of 90% less water, used by classic sprinkler systems;
  • minimalizing damages, caused during fire extinguishing;
  • small size and low system weight;
  • low costs of re-filling of the system.

Water mist protects wide range of objects:

  • carbonation systems;
  • cable ducts;
  • gas turbines;
  • gas turbounits;
  • oil and hydraulic infrastructure;
  • tinternal and external transformators;
  • power generators and fuel tanks;
  • engine rooms;
  • high pressure buildings;
  • computer rooms;
  • ssubway stations;
  • road tunnels;
  • hotels;
  • offices;
  • monuments, museums, galleries and theatres
  • sacral objects and many others.