Today, the presence of fire sprinkler system has become mandatory in all newly constructed tall-rise buildings. The features of the fire sprinkler system to be installed depend on the availability of water supply, number of fire pumps, sprinklers required etc.
Hazard Class of the Sprinkler System
There are four types of hazard classes into which a sprinkler system gets categorized with occupancy being the main factor that determines the selection. Following are the various hazard classes that a building can contain:
· Light Hazard: Low-industrial structures or buildings which have lesser fire load are covered under this category.
· Ordinary Hazard: Industrial and trading buildings with fire loads falling in the medium range are covered here.
· High Hazard Processing: Industrial buildings wherein the fire load of materials handled or processed is high and chances of the fire spreading are also high get covered under this category.
· High Hazard Storage: Industrial buildings wherein the fire load of materials stored are high and chances of fire spreading very high get covered under this class.
Role of Fire Pumps in Sprinkler Systems
A fire pump has an important role to play in the working of the fire sprinkler system. It is the source of water that is supplied at high pressures to the sprinklers and hose standpipes when needed. The fire pumps get their water from a static water source such as reservoir, tank or lake etc or through a connection to the public underground water supply piping. Fire fighting pump dealers ensure that the testing and listing of these pumps before use is done by a third party testing and listing agency. The fire pump is activated when the sprinkler system’s pressure falls below the threshold level. Exposure to heat above their designed temperature is one of the reasons for the pressure of the sprinkler systems to fall significantly They open up releasing water at such times. Fire pumps operate through a diesel engine or an electric motor. Fire fighting pump dealers stock several varieties of pumps such as vertical split case, horizontal split case, vertical turbine, vertical inline and end suction.
Types of Sprinkler Systems
The two main factors that determine the type of sprinkler system to be installed are the type of the building under consideration and the purpose for which it is used. Some of the varieties are:
· Wet Pipe System: One of the most commonly used varieties; the pipes contain water filled under high pressure which is released after the sprinkler system indicates the need to do so.
· Dry Pipe System: This type is used in areas of extreme temperature where frost can render the wet pipe system inoperable. These however, are not as fast acting as the wet pipe variety.
· Deluge Systems: In this type, the connected sprinklers are all kept open and the water reaches the sprinklers when a signal from a fire alarm system activates the deluge valve.
· Pre-action Systems: Areas where accidental activation is undesirable uses this type of sprinkler system. This is more suited for museums, data centres, special technology companies etc.