Guide To Fire Sprinkler Hydraulic Calculations

By Young Lindsay


Many types of sprinklers that can be classified according to its activation temperature, fast opening, orifice size of sprinkler discharge or flow rate, type of fuse element, jet application form, coverage area waterjet among many other factors involved in risk analysis and project design by the specialist (fire sprinkler hydraulic calculations).

Automatic sprinklers have an outlet for releasing water, a firing mechanism and a deflector to convert the output stream in a spray of water in area where there is fire. The trigger sprayer can be done by two mechanisms: a thermo-sensitive element or a flame detector. In this type of sprayer, the jet has a stopper that prevents the leakage of water and a stopper device releasing the trigger mechanism in this case is a device for releasing the plug.

It consists of a thermo-sensitive element that is designed to destroy at predetermined temperatures, automatically causing the release of plug and the outlet of a water spray, which should extinguish the flame right in area where it has started. This device can be of two types: side of a disassembled sprayer without bulb or fuse Vista.

Fuse trip. The plug is held in position by a mechanism formed by two metal plates joined with a weld, with a melting point of carefully calibrated. In a blaze, the heat generated softens the solder, causing the water pressure acting on the cap and then disarm the system to skip the plug, allowing the escape of liquid. The water goes through the hole and strikes against a sheet, designed to distribute the jet way to rain (deflector). Each spray has its own fuse, so that only those sprinklers that are in zone of influence of trigger.

Therefore, in case of fire, after the destruction of temperature sensor, the lid remains tightly spray glued to the hull and the water from the system is not received. Such cases were reported in the fire at many places in USA. After that, the producers was conducted large-scale action to recall and replace all sprinklers with rubber sealing rings. In some countries the use of sprinklers with a rubber seal is prohibited.

The response time of these systems shall not exceed 300 seconds for low-temperature sprinklers (57 and 68 degrees C) and 600 seconds for the highest-temperature sprinklers. In 1806, an automatic fire extinguishing installation was patented by Englishman John Carey. He proposed to build in the protected area network of pipelines from the water head tank, and on the network to install sprinklers with small holes.

In protected space stretching combustible cord, which when blown open locks that hold the valve, the valve is released and the water flowed to a sprinkler. The device consisted of a cylindrical sealed tanks of about 95 tys.litrov system and 10-inch (250 mm) of the distribution of the aqueduct, covering all parts of the theater. Series of pipes of smaller diameter departed from the distribution pipes and were imbued with a number of half an inch (13 mm) holes through which poured water in case of fire. But the system was not automatic.

Another advantage of such a system is that the shot can be caused by smoke detection or detection of air ionization, since there are smoke detectors these extremes, while the temperature sensing function of temperature only. Its disadvantage is that, of course, is a more expensive installation.




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