4.5 The method of operation and maintenance of fixed installation systems Assessment criteria: 4.1-4.6: Outline the principles for fire protection, detection, and prevention. Sprinklers A fire sprinkler system is an active fire protection measure, consisting of a water supply system, providing adequate pressure and flow rate to a water distribution piping system, onto which fire sprinklers are connected. Automatic sprinkler systems are used more than any other fixed fire protection system. The purpose of an automatic sprinkler system is to detect the fire, extinguish or control the fire and raise the alarm.
Each closed-head sprinkler is held closed by either a heat-sensitive glass bulb or a two-part metal link held together with fusible alloy. The glass bulb or link applies pressure to a pip cap which acts as a plug which prevents water from flowing until the ambient temperature around the sprinkler reaches the design activation temperature of the individual sprinkler head. In a standard wet-pipe sprinkler system, each sprinkler activates independently when the predetermined heat level is reached. Because of this, the number of sprinklers that operate is limited to only those near the fire (in reality, normally one or two will activate), thereby maximizing the available water pressure over the point of fire origin. This also minimizes the water damage to the building or structure. Drencher Systems Drencher systems provide a curtain of water to protect parts of the building. They protect against radiated heat or they can flood a high-risk process area with water. A drencher system consists of pipework similar to that of a sprinkler system. The opening of a valve can operate drenchers, or some systems work in the same way as a sprinkler. Drenchers can be found on roofs, over windows and in external openings. There are three types of drencher systems: Roof Drencher: These operate similarly to a sprinkler. It throws a water curtain from the roof ridge, which runs down the roof. Wall or Curtain Drenchers: One side of the outlet is drenched with water over the opening or part of a building that may admit a fire.
©SHEilds – All rights reserved FC V 5 JUN 2021
Page 36 of 41
Made with FlippingBook Digital Publishing Software