What is a Sprinkler System ?
A fire Sprinkler system is a vigorous fire protection methodology, consisting of a water system, providing adequate pressure and rate of flow to a water distribution piping system to which fire sprinklers are connected.
TYPES OF SPRINKLER SYSTEMS
- Antifreeze Sprinkler
- Circulating Closed Loop Sprinkler
- Combined Dry Pipe Pre-action Sprinkler
- Deluge Sprinkler
- Dry Pipe Sprinkler
- Gridded Sprinkler
- Looped Sprinkler
- Multicycle Sprinkler
- Pre-action Sprinkler
- Wet Pipe Sprinkler
Requirements of Fire Sprinkler System:
- An automatic water supply Source
- Sprinklers attached to the network of hydraulically designed and specially sizes Pipes.
- Control valves placed in the Piping system.
- An Alarm actuated on Heat from Fire
- Pressure Gauge to regulate the pressure of water flow in the Piping system
INSTALLATION OF SPRINKLER SYSTEM
- Ensure sufficient number of Brackets are fixed to the Ceiling of the proposed operational Area.
- As per the approved Drawing the pipes are secured to the brackets with suitable Bolts and fasteners.
- Selected Fittings as per the specification of the Pipe are secured to the pipes for change in direction and elevation of the system based on the Approved Drawing.
- Ensure Inspection and working of Piping System
- Ensure Fire Alarms are fixed to the Piping System as per approved Drawing
- Ensure Control Valves, Drain Risers and Pressure Gauges are installed properly as per specification and the Approved Drawing.
- Ensure all open ends of Piping System are plugged.
- Finally to ensure the integrity of Fire Sprinkler Pipes make sure to perform a Hydrotest.
How do sprinkler systems gets activated?
- Fire sprinklers gets activated by heat as described below.
- Usually Fire Sprinklers has a glass plug filled with a glycerine based solute that prevent water flow in normal conditions. As the temperature reaches 135-degree Fahrenheit and above, the solute expands to burst the glass plug and releases the water beneath the sprinkler.
- A sprinkler head design with a metal plug works similar to Glass Plug Model. Here the heat melts the metal in the sprinkler head and starts spraying water..
- Sprinkler head with Fire Sprinkler Pipe is connected to a water source external to the building. As the heat stimulates the sprinkler head, the valve opens allowing pressurized water to sprinkle.
How does a Fire sprinkler system works?
Fire sprinklers works due to the triggering of high heat. When there is fire, the air above it gets heated quickly. This hot air rises and spreads along the ceiling and causes the Sprinkler Head to break open.
In a sprinkler head with a glass plug. This liquid inside the Plug expands when it comes in contact with air heated above 135 degrees. As the liquid expands, it breaks open its glass wall and activates the sprinkler head to spray water. Also water in the fire sprinkler system should be pressurized. This allows the water to spray uniformly to extinguish the fire.
OISD 117 – hearth Protection Facilities for crude oil Depots, Terminals, Pipeline Installations and make full oil installations
DESIGN FLOW RATE
Fire water rate of flow for a country shall be combination of the following:
Water flow calculated for cooling a tank afire at a rate of three lpm/m2 of shell space.
- Water flow calculated for exposure protection for all different tanks falling at intervals a radius of (R+30) m from centre of a tank afire (R-Radius of tank on fire) and set within the same dyke at a rate of three lpm/m2 of shell space.
- Water flow calculated for exposure protection for all different tanks falling outside a radius of (R+30) m from centre of a tank afire and set within the same dyke at a rate of one lpm/m2 of shell space.
- For water flow calculations, all tank farms having category A or B crude oil storage shall be thought-about regardless of diameter of tanks and whether or not fastened water spray system is provided or not.
NFPA 13 – – customary for the Installation of mechanical device Systems
The designation of sprinkler system sizes are often known by nominal K-Factor. The K-factor formula is employed to calculate the discharge rate from a nozzle.
Nominal K-factor shall be larger than twenty [L/min/ (bar) 1/2]
NFPA 15 – Standard for Water Spray Fixed Systems for Fire ProtectionMinimum in operation pressure of any nozzle protective out of doors hazards shall be one.4 bar.
OISD 244 – Storage and handling of crude oil merchandise at depots and terminals as well as standalone petroleum storage facilities.
Spray nozzles shall be directed radially to a tank at a distance not olympian zero.6 m from the tank surface.
Sprinkler system hydraulic calculations
The hydraulic calculation procedure is required to determine the following:
- In the event of Fire, to determine the quantum of Water required to extinguish it
- To determine whether the available water will be enough to supply the system.
- To determine the efficient layout of the fire sprinkler pipes in piping system, and friction losses produced.
The hydraulic calculation uses the below formula:
Where CD is the Discharge Co-efficient
D is the Diameter
P is the Pressure