Fire sprinkler system

Sprinkler (from English to sprinkle sprinkle ( make wet ) ) prevent as automatic fire extinguishing systems, that an escaped fire can develop into major fire. They are used in special structures such as high-rise buildings, commercial buildings, shopping centers, industrial facilities, meeting halls and underground garages. They are part of the fire protection devices, which are generally required by authorities or insurance companies.

History and Operation

Sprinklers were invented by the Americans Henry S. Parmalee, a manufacturer of pianos in 1874. Originally, the water outlet nozzles were closed with a metal plate, which was held by a connected device with fusible link in place. Because of the temperature effect of melting the solder, the fixture was the metal plates free, this was pushed out by the water pressure and water was sprayed following on closes.

Today's sprinkler heads are sealed with glass ampoules which are filled with a colored liquid specialty, which in turn contains a bubble. On the ceiling or in the upper region of the side walls of a plurality of such heads are mounted, which are connected to a water pipeline network. Within the sprinkler system there is a constant water pressure, which is controlled in the sprinkler. In a fire, the liquid is heated in glass ampoules, expand and burst the vials so that the nozzles are open and leaking water from the sprinkler piping. In case of fire selectively open only the sprinklers that have reached operating temperature the ampoules. This temperature depends on the size of the entrapped air bubbles, and is characterized over the color of the liquid vial. On average, the operating temperature is about 30 ° C above the expected ambient temperature.

The pressure drop in the pipe network is detected and leads to opening of special valves (alarm valve stations ) and the starting of pumps (system- specific). From this point, water is pumped from the designated tank or a dimensioned for water supply with high pressure in the sprinkler system. This occurs on all open water jets and deletes or minimized the fire.

Pipe network and water supply are dimensioned so that only water is available for a certain number of water jets (called active surface ). Open more sprinkler heads are provided for the designed effective area per sprinkler head to the available quantity of water drops and decreases the effectiveness of the system.

Sprinkler systems are therefore mainly to combat the early stages of a fire ( initial fire ) and not for fighting a fire in the full position. There must be a fire-resistant enclosure to be erected between areas with no sprinkler system and sprinkler areas, thus, to compensate in an unprotected area full of fire can not spread to the protected with a sprinkler section of the building.

Alarm Check Valve

An alarm check valve is installed between a group of sprinklers and water supply and connected to a so-called Sprinklerüberwachungszentrale ( IIP ). Bursts a Sprinklerfässchen, this causes a pressure drop in the line, which is recorded by the alarm valve station. The valve station is the water supply for the deletion, removes hydromechanically an alarm by means of a bell and signals the alarm by a pressure switch to the IIP on. This sends the signal to either a host fire alarm control panel or directly to the fire department on.

Drying plant

Especially in areas where freezing temperatures exist and could freeze the sprinkler, so-called dry systems are used. In these systems, the pipeline network between sprinkler head and alarm valve station (here: "dry alarm valve station " short TAV ) filled with compressed air. Only after the triggering of a sprinkler head, the system is filled with water.

Pre-action sprinkler system

In particularly sensitive areas so-called " pilot operated " sprinkler ( " Preactionanlage " ) can be installed. Again, the lines are filled behind the sprinkler heads to the alarm check valve with compressed air, at ( bursting through a glass keg verursachtem ) pressure drop, however, water is only given if in the affected area at the same time, an automatic fire alarm (usually a smoke detector) triggers an alarm. If no fire is detected by the detector, the ( pilot-operated dry pipe ventilation) VTAV remains locked. However Throws a fire alarm before a glass bulb bursts at the sprinkler, the pipe network is already flooded. However, water can escape only now, when a glass bulb bursts at the sprinkler. If due to a malfunction of the fire alarm system, the feedforward control is canceled at the VTAV and VTAV station operates as a normal TA valve, so that the function of the extinguishing system is guaranteed at all times.

Interpretation

In Germany the design of sprinkler systems is generally carried out according to the protocol VdS CEA 4001 ( VdS, CEA, Comité Européen des Assurances ). In Austria the interpretation according to ÖNORM EN 12845 and the additional TRVB carried S 127

The American standards of NFPA ( National Fire Protection Association ) - in a modified or further developed form of guidelines and FM ( Factory Mutual ) standards - but also popular with both international clients increasingly popular and are now generally accepted by German regulatory authorities. The design is a function of the fire risk in the area to be protected by defining the water impact of the fire source between 2.25 mm / min and 30 mm / min ( 1 mm / min corresponding to 1 l / m² / min), the operative time between 30 and 90 min and the distance between the sprinkler heads.