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Thursday, November 6, 2014

Abcs Of Fire Sprinkler Hydraulic Calculations

By Young Lindsay


Water-sprinkler systems appeared during the end of XIX century. Favorable results of protection forced inventors to pay serious attention to this kind of firefighting. Before the revolution of liability insurance, companies recognized the impact of fire sprinkler hydraulic calculations in factories to reduce losses.

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.

Hence the name sprayed, which varies depending on the application that you want to give the system sprinkler. The most common use of these sprinkler-systems is the cooling of walls of a storage tank of flammable liquids because they are easier and less costly to maintain than a system of sprinklers, which moreover do not correspond to a pattern of dispersal water required by such facilities.

Thermo-sensitive bulb. The most common sprinkler glass bulb holds the cap in place and containing therein a liquid that does not fill the bulb, leaving a gap. When heat from a fire acts on bulb, the liquid boils and vapor pressure breaks the glass stopper and then releases the pressurized water contained pipe network, download and poured over the baffle forming a jet sprayed water mist.

These processes may take more or less depending on rate of release of surrounding heat to spray, the distance between the sprinkler and ceiling, the distance between the spray and the floor, the roof slope and other factors that have been extensively studied by the NFPA (National Fire Protection Association), UL (Underwriters Laboratories), FM (Factory Mutual), among other research and development in flame protection systems.

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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