Extinguishing systems prevent disasters
Regardless of whether a building is a brick house, a prefabricated house, a wooden or combined house, a detached house, a holiday home or an apartment, a business facility, a commercial facility, a manufacturing facility, a plant or a warehouse – the purpose of technical fire protection remains the same: to detect a potential risk of generation or spread of fire in time and to report it, as well as, optionally, to take immediate action (to start automatic fire extinguishing).
Technical or active fire protection measures
Technical or active fire protection measures include integrated fire detection installations, integrated fire extinguishing installations, smoke and heat exhaust installations, security and emergency lighting, door control on an evacuation route and emergency electricity supply installations.
Thinking about the fire protection system before the occurrence fire
It is a good idea to think about fire protection before any unpleasant event occurs. Even though technical protection does represent a certain cost, the cost is minimal compared to that caused by fire or burglary.
Technical security design has become an interdisciplinary science
Project design is an engineering discipline and is very important in the framework of engineering services. The preparation of the technical security design, facility risk assessment and consulting a technical security designer are of vital importance.
Water, water mist or a combination of gases minimize the damage in the event of fire
Contrary to the portable fire extinguishing systems, the integrated systems are fixed on and within the facility they protect. As such, they are in the state of constant readiness and turn on as soon as a fire breaks out. Inbuilt fire extinguishing systems are usually automatic, which means that in the event of fire they turn on automatically and extinguish the fire or at least limit its spreading until the arrival of the fire-fighters who put the fire out.
Ordinary sprinkler system
These have been in use for a very long time and are very reliable, without unnecessary system activations. Due to increased temperature caused by fire, the ampoule in the head of the sprinkler breaks and opens the valve, causing the water to start spraying from the nozzle until the fire-fighters close the main valve. Their advantage is limited fire extinguishing, as only the nozzles at the site of the fire are activated. Given its great evaporation energy, water is a very efficient fire extinguishing agent, however with ordinary sprinkler systems the majority of water flows away unused, causing flooding, and the damage can exceed that caused by the fire itself.
Some project designers and investors erroneously believe that ordinary sprinkler systems can prevent greater damage to the facility. Protection against greater damage is only possible when a fire extinguishing system is combined with an early fire detection system (fire alarm).
Water mist sprinkler systems
Fire extinguishing systems using high pressure water mist Hi-Fog operate similarly to ordinary sprinklers, however there is one important difference – the high pressure in the system (150 bar) and special nozzles spray the water into microscopically small droplets, which has a number of advantages:
up to ten times lower water consumption in comparison with the ordinary sprinkler,
- triple fire extinguishing effect: cooling, blocking radiation and locally decreasing oxygen concentration, the high pressure allows the droplets to penetrate the area of fire,
- people can remain inside even while the fire is being extinguished,
- stainless hoses with smaller diameters without welding are used, which simplifies the process of installation and ensures that the water coming from the system is clean at all times,
- fire extinguishing does not cause additional damage after the fire, allowing business operations to be resumed immediately,
- cleansing the smoke and combustion products from the air is an additional effect,
- highly reliable operation,
- to further increase its efficiency, the system may be divided into areas and connected with the fire detection and fire alarm system, which given the site of the fire opens the adequate valve and thus triggers fire extinguishing only in the space with fire (the deluge system).
A high pressure water mist fire extinguishing system can replace an ordinary sprinkler system in most cases. Upon replacement, attention must be paid to appropriate certificates which specify the dimensions of the premises and fire hazard the system has been certified for.
In some environments, such as engine rooms with propulsion engines or gas turbines, the water mist system is indispensable, as it is incomparably more effective compared to all other systems.
For some special applications, the use of water as a fire extinguishing agent seems unsuitable at first sight, however the use of water mist under specific implementation is also recommended for computer centres and other premises with expensive and sensitive electronic devices, medical diagnostic centres, art galleries, warehouses for paintings and other valuable exhibits which require constant temperature and humidity, museums, archaeological and other collections of priceless historical value, wooden and other delicate buildings of cultural and historical importance, as well as for operas, theatres and similar halls.
Gas system with carbon dioxide
The system operates in connection with the fire detection and alarm system, with the fire alarm central control panel triggering the fire extinguishing by opening the valves when the requirements are met.
Gas system with inert gases
Its operation is similar to that of the carbon dioxide system, also in connection with the fire detection and fire alarm system. Inert gases used for fire extinguishing are mixtures of natural gases (inergen, argonite) or pure natural gases (nitrogen, argon). Fire extinguishing operates on the principle of decreasing the oxygen concentration in the area to about 12 percent, which puts out the fire while still allowing people to breathe.
Gas system with replacements of the prohibited halon
Two gases are mostly used: the older FM-200 and the newer Novec 1230. The latter has no greenhouse effect, while the greenhouse effect of FM-200 is minimal.
The extinguishing must be completed within ten seconds (the requirement of the appropriate standard), which is faster than any other type of fire extinguishing, while with this system the people are also required to leave the premises before the system activation (the same standard – ISO 14520 – applies for all gas systems with the exception of those with carbon dioxide).
The system with foam is mostly used in special environments, such as in large storage facilities for petroleum products. It operates with water which is mixed with a foaming agent at the exit nozzle, thus forming a thick foam which thickly engulfs the area of fire and prevents oxygen from accessing the fire. Powder is usually not used in automatic systems.
The Bonpet System is a system in which water is mixed with a special Bonpet liquid, whose chemical action is a much more efficient fire extinguisher than water alone (even in case of fire involving highly flammable liquids – petrol, oil – where water cannot be used as a fire extinguishing agent).
Connection to the early fire detection and alarm system
Self-sufficient systems (sprinklers) are unfortunately slow. The majority of fires in buildings start out slowly with heating and smouldering, when visible or invisible smoke begins to form. Only later does the fire break out, causing sufficient heating of the ampoule in the sprinkler head and subsequent opening of the valve once the ampoule breaks.
If the fire continues to spread, other detectors also detect smoke. The fire alarm central control panel is designed so as to activate the process of automatic fire extinguishing in case of alarm from at least two smoke detectors in the facility with an integrated fire extinguishing system: the beginning of countdown (usually 30 seconds so that people can leave the premises) and the activation of the warning sirens and optical alarms which send out the warning that the extinguishing process is under way. The fire detection system also controls all the important functions of the extinguishing system and reports errors and interferences either locally or transmits them to a permanently occupied duty room.