PRESSURE REGULATING DEVICES

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PRESSURE REGULATINGDEVICES

• By Sgt. Larry Baker
• FF/Medic Len Clowser
• FF/EMT Terry Orndorff

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OBJECTIVES

• Understand how Pressure Regulating Devices (PRDs)
  work
• Overcome the limitations of PRDs.
• Identify structures in the City of Winchester
  with PRDs.

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Automatic Sprinkler Systems

• Automatic Sprinkler Systems control 96 of fires
  in sprinklered structures
• What do we do with the other 4?

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One Meridian Plaza

• Occurred
• February 23, 1991
• Philadelphia, PA
• Tragedy
• 3 Firefighter Fatalities
• 1 Occupant Fatality

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One Meridian Plaza

• FACTS
• Fire started on the 22nd floor
• Destroyed 8 floors
• 10 sprinkler heads
• A 5 supply line was stretched to the 22nd floor
• After 10 hrs, changed to a defensive operation
• Fire was extinguished from adjoining buildings
• TOTAL LOSS 2 Billion dollars

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So, what went wrong?

• Inoperable equipment
• Lighting
• Elevators
• Pumps
• Pressure reducing devices
• Reduced the discharge pressure on the night of
  the fire to 60 psi

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WHAT DID WE LEARN?

• Because of this tragedy at One Meridian Plaza,
  PRDs received a lot of attention. The fire
  service recognized these devices as a potentially
  serious problem!

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3 Basic Types

• Pressure control valves
• Pressure reducing valves
• Pressure restricting devices

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The Bad News

• If the static pressure at a standpipe connection
  exceeds 175 psi, according to NFPA 13/14, the
  pressure needs to be reduced to a maximum of 100
  psi

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The Good News

• We can adjust the pressure or simply remove the
  PRD.
• Outside the box with 100 psi, that is more than
  enough pressure to flow a
• 2 ½ line with a smooth bore nozzle

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PRDs in the City of Winchester

• Winchester Medical Center
• 333 W. Cork Street
• Likelihood of more

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Winchester Medical Center

• Two different types both work on the same
  principle.
• Both are mechanical limiting devices that work by
  limiting the valve from being fully opened

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Winchester Medical Center
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Winchester Medical Center
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Removal
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333 W. Cork Street

• All 1 ½ connections are limited to 70 psi for
  the old class II, occupant connection.
• These cabinets do not have an adjustment and are
  not intended for Fire Department use.
• Class I connections are approximately 20 from a
  class II connection.
• Cabinets that are not close to a class I
  connection have an approved class I connection at
  the lower left corner.

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333 W. Cork Street
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CONCLUSION

• Now that we know these devices are in place and
  the tragedy they can cause when we are not aware
  of their existence, lets continually keep our
  eyes open and inform others and take the
  appropriate action if PRDs are located.