Fire Sprinkler System
The fire sprinkler system is considered one of the best products for the protection of buildings. A sprinkler system is an integral part of an active Fire Protection system. Sprinkler systems are normally recommended to cover the basement, shopping complex, parking space, large unsegregated halls, high rise building and hazardous industries.
I assure you that this blog will be interesting enough and will provide you with great value. Here we will be discussing the working, components and types of sprinkler system.
What are the components of a Fire Sprinkler System?
Branch line- The pipes supplying sprinklers, either directly or through sprigs, drops, return bends or arm-over.
Cross mains- The Pipes in a system that supplies to the branch lines either directly or through the riser.
Feed mains- The pipes supplying cross main, either directly or through riser (vertical supply pipes in a sprinklers).
Sprinkler heads- Sprinkler head activate when it is exposed to the temperature that would be excessive for the particular area of the building. However, there are several types of sprinkler head with variation in system types, activation temperature, orifice size, thread size, coverage as well as heat response element types.
Note: The specific sprinkler exposed to high temperature will only sprinkle the water around the fire. Its a misconception that all sprinkler head will sprinkle the water in case of fire detection which is shown by Hollywood movies.
Water-flow alarm device- A device attached to the sprinkler system that detects a predetermined water flow. It is connected to a fire alarm system to initiate alarm conditions as well as an electrically operated fire pump.
How sprinkler system works?
The sprinkler system consists of a pipe layout designed hydraulically to provide the required amount of water at particular design pressure. These pipes are sealed with thermally operated fire sprinkler heads at regular intervals.
Sprinklers are operated through melting fusible element or breaking of the frangible glass bulb. Once this fusible element breaks the water shoots out from the sprinkler.
Water supply from the tank is generally provided in such a manner to give positive pressure to the pump suction side. Pumps are used to pressurise the system. These are installed in series to meet the increasing demand for particular sprinkler head in the fire zone.
The Sprinkler system is fitted with a set of valves to control the water supply. Valve set comprises of the main stop valve, alarm valve and water motor alarm and gong.
- Main stop valve- Provided to stop the supply of water after the extinction of fire. The main stop valve is fitted immediately downstream of the alarm valve.
- Alarm valve- This valve comprises of freely moving disc which is held under the pressure of air/water. Any fall in pressure above the disc due to the operation of any sprinkler will lift the disc and allow water to flow in the sprinkler system.
- Water motor alarm and Gong- A small quantity of water goes to the alarm gong through an opening. This enables alarm gong and will aware people in the vicinity about the fire incident.
What are the types of a sprinkler system?
Considering the various aspects, the main objective of the sprinkler system is to extinguish the fire at its incipient stage. The type of sprinkler system is installed depending upon the local climatic condition, nature of burning material, buildings characteristic and adjoining risks.
Mainly the types of sprinkler system are as given below:
Wet system
This type of sprinkler system is installed in the premises where there is no danger of water freezing. The pipe network is always charged with water under pressure. The system is fed from dual source of water supply and are provided with stop valve and non return valve. During fire condition, the sprinklers give way and water is instantaneously available to extinguish the fire. Moreover, through the alarm valve water also passes to the alarm motor and gong to produce alarm.
Deluge system
A sprinkler system employing open sprinklers that are attached to a piping system that is connected to a water supply through a valve that is opened by the operation of a heat or smoke detection system installed in the same areas as the sprinkler. When the wall opens, water flows into the piping system and discharges from all sprinklers attached thereto.
Dry system
In this system, the pipe network is charged with air under pressure. This system is preferred in the building where the temperature is normally maintained near to zero degree Celsius or about 70 degrees Celsius. The control valve of the dry pipe system comprises of Main stop valve and differential air valve. The differential air valve consists of two valves: one large and one small. The upper wall is 8 times as large as the lower wall and is held in position by air pressure and water seal. During fire condition, the sprinkler releases air which reduces pressure on the upper valve that causes the lower valve to open so that water flows to the main network of the sprinkler system. An accelerator is fitted in the system to release the air speedily.
Pre-action system
This system is a combination of a sprinkler system and a fire detection system. The fire is detected by the heat or smoke detection system before the operation of the sprinkler system which allows water to flow to the system. The detection signal actuates the solenoid air valve in the system which open and releases air. As a result, the diaphragm air valve lifts and allows water to flow above in the installation.
Antifreeze system
It is a type of wet sprinkler system which contains an antifreeze solution. The antifreeze solution is immediately discharged during the operation of sprinkler opened by heat from a fire.
Gridded system
In this type of sprinkler system parallel cross mains are connected by multiple branch lines. The sprinkler in action will receive water from both ends of its branch line while other branch lines help transfer water between cross mains.
Loop system
A sprinkler system in which multiple cross mains are tied together. This provides more than one path for water to flow to an operating sprinkler. The branch lines are not tied together.
Multi-cycle system
A type of sprinkler system capable of repeated on-off flow cycle in response to heat.
CONCLUSION
After conduction of several tests on the performance of the sprinkler system, the researchers found the great importance of sprinkler system on the premises.
Some of the findings are:-
- Full control of fire is much faster for a particular size of the fire.
- The maximum temperature of ceiling level with sprinkler would be 190 degree Celsius compared to 940 degree Celsius without sprinklers.
- Nearly, additional one minute is available for the evacuation of the building.
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