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.

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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).

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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.

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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.

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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.

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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.

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Inspectors Test

• Located at the furthest point from the riser
• Simulates the opening of one sprinkler head

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Wet Pipe Sprinkler System Inspections

• Inspector's test
• 2 inch main drain test
• Water flow alarm test

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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.

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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.

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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.