Design begins with the hazard classification. Water density, design area and head type are completely different for an office and for a high-bay racked warehouse. In Turkey the Regulation on Fire Protection of Buildings makes sprinklers mandatory for many building types. After a site survey we set the hazard class, size the pipework and pumps by hydraulic calculation, and hand the system over after hydrostatic and alarm testing.
ATypes and components
Wet pipe system
The pipework is permanently filled with water under pressure, so an opened head discharges immediately. It is the simplest and most reliable arrangement wherever there is no risk of freezing, and the majority of building sprinkler systems are of this type.
Dry pipe system
Pipework above the dry alarm valve is filled with compressed air or nitrogen. When a head opens, the air escapes, the valve trips and water fills the pipes. It is used where freezing is possible, such as unheated warehouses, open car park decks and cold stores.
Pre-action system
The pipes are dry, and water is only admitted after the detection system opens the valve. A single-interlock system needs just the detection signal; a double-interlock system needs both detection and an opened head. It is chosen for archives, data centres and museums where accidental water discharge would be costly.
Deluge system
All heads are open, and when the deluge valve is released by the detection system every head discharges together. It is used where fire can spread very fast, such as transformers, fuel loading areas and chemical process units, often combined with foam.
Alarm valve station
Each sprinkler installation has an alarm valve, main stop valve, pressure gauges, a test and drain valve and a pressure switch at its inlet. Wet alarm valves use a retard chamber to avoid false alarms from mains pressure surges, and a water motor gong for a mechanical alarm.
Sprinkler heads
Heads come as pendent, upright and sidewall patterns. Standard and quick-response heads are made in several operating temperatures, identified by bulb colour; a red bulb, for example, means 68 °C.
Storage heads (ESFR and CMSA)
Large K-factor heads for high-piled storage. Under the right conditions ESFR heads can remove the need for in-rack sprinklers, but they come with strict limits on ceiling height, storage height, commodity class and obstructions.
Zone control and flow monitoring
Floors and areas are separated by zone control assemblies, each with a monitored isolating valve and a flow switch. The fire alarm panel then shows exactly where water is flowing, and maintenance can isolate one zone without taking the whole system out of service.
BHow it works
- Heat from the fire collects at ceiling level and the bulb of the nearest head breaks at its rated temperature.
- Water discharges from the opened head and the flow operates the zone flow switch.
- The alarm valve opens; its pressure switch and water motor gong raise the alarm and the fire panel shows the location.
- As pressure in the system falls, the fire pump starts and supplies the design flow.
- After the fire, the main valve is closed and the operated heads are replaced with new ones of the same type and temperature rating before the system is restored.
CAdvantages
- Controls fire early, close to its origin
- Only heads exposed to heat operate
- Works around the clock without human intervention
- Automatic alarm through alarm valves and flow switches
- A key factor in insurers' risk assessments
DApplications
- Racked and block-stacked warehouses
- Manufacturing plants
- Shopping centres and hotels
- Hospitals and schools
- Enclosed car parks
- Offices and high-rise buildings
- Archives and data centres (pre-action)
EFrequently asked questions
Can sprinkler heads go off without a fire?
A correctly rated, undamaged head very rarely operates on its own. Accidental discharges are usually caused by impact, paint on the head, a low-temperature head installed next to a heat source, or freezing. Heads should never be painted or used to hang things from, and a cabinet of spare heads should be kept on site.
Which buildings need a sprinkler system?
In Turkey this is set by the Regulation on Fire Protection of Buildings. The requirement depends on occupancy, height, floor area and fire load; high-rise buildings, large warehouses, shopping centres, hotels and hospitals are typical cases. Insurers may also ask for sprinklers based on their own risk assessment, so the final decision belongs at design stage.
How often does a sprinkler system need maintenance?
NFPA 25 and TS EN 12845 set out a programme ranging from weekly and monthly visual checks to comprehensive annual tests. Valve positions and supervision, gauge readings, alarm tests and flow through the test and drain valve all need regular attention. Sampling and laboratory testing of heads once they reach a certain age is also part of the programme.