Water Based Sprinkler Systems

1. Water Based Sprinkler Systems • 2 major different types of water sprinkler systems • Wet pipe system • Dry pipe system

2. Wet Pipe System • Water is in all piping • As sprinkler heads open, water is discharged

3. Wet Pipe Clapper Valve

4. Dry Pipe System • Air is in system from above the clapper valve to to sprinkler head. • As sprinkler heads open, air escapes then water is discharged.

5. Dry Pipe Clapper Valve

6. Pre-action Systems • Sensors in the area of the fire are activated. • The water valve is then open. • And water flows to the area.

7. Deluge System • All sprinklers are activated at once when a detecting device is activated.

8. Typical Wet Pipe System • In a typical wet pipe system, water enters the building at a determined pressure.

9. Backflow Preventers • Backflow preventers are placed before the riser. • If there are significant decreases in water pressure, the backflow preventers prevent water from being sucked out of the sprinkler system. • These backflow preventers must be checked by certified plumbers at least annually (EPA requirements).

10. Back Flow Preventer

11. Sprinkler Riser • The water then flows to the riser. • At the riser, a series of valves and gauges, maintain the water in the system.

12. OS & Y Valve • Outside stem and yoke valve. • The water first passes through an outside stem and yoke valve. (OS & Y valve). • To close this valve, the handle must be rotated out.

13. OS & Y Valve

14. OS & Y Valve

15. OS & Y Valve Example

16. Tamper Switches • In some instances, there are tamper switches on these valves. • If they are turned, the monitoring service will receive a trouble alarm. • This valve should be alarmed and chained open.

17. Tamper Switches

18. Main Water Clapper • The water then enters the main section of the riser. • There is a main water clapper that sits at the base of the riser. • If there is major water pressure loss, the water will stay in the sprinkler system.

19. Water Gauges • Water pressure gauges are found above and below the water clapper. • This will alert the person to pressure problems in the water lines. • In a wet pipe system, both pressure gauges may read the same. • Check the design spcifications!!

20. Water Flow Alarm • These are found above the main clapper. • If there is a flow of water, the alarms will be activated.

21. 2" Main Drain • A two inch pipe comes out of the main riser area to a drain. • This two inch line is used for testing purposes. • Closing the water valve above the 2 inch line then opening the 2 inch water line tests water coming in from the municipal service.

22. Riser • The next section of pipe is the riser pipe itself. • The riser pipe goes up to the sprinkler branch lines in the building.

23. Branch Lines • The branch lines are typically smaller than the riser. • This decrease in the diameter of the branch lines increase the pressure in the lines.

24. Inspectors Test • Located at the furthest point from the riser • Simulates the opening of one sprinkler head

25. Wet Pipe Sprinkler System Inspections • Inspector's test • 2 inch main drain test • Water flow alarm test

26. Inspectors Test • Signifies that one sprinkler head at the sprinkler head furthest from the riser has been opened. • This verifies that adequate pressure and flow can be achieved.

27. Water Flow Alarm • "Trip test“. • At the inspector's test valve, open the inspectors test valve. • A slight decrease in pressure should be observed. • The water flow alarm should be activated and the fire department should receive a signal that the fire alarm has been activated. • There should be a short time delay from when the water flows and the alarm is activated. • The delay should not be any greater than 90 seconds. • Close the inspectors valve and reset the system.

28. Two Inch Main Drain Test • The purpose of the two inch drain is to determine if there is adequate water supply to the system. • Open the two inch drain fully, check and record the water pressure. • There should not be a significant drop in water pressure when the two inch drain is open. • If there is, there may be a blockage in the supply line. • Close the two inch drain and record the pressures. • The pressure should return to approximately normal.