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PRESSURE REGULATING DEVICES. By: Sgt. Larry Baker FF/Medic Len Clowser FF/EMT Terry Orndorff. OBJECTIVES. Understand how Pressure Regulating Devices (PRDs) work Overcome the limitations of PRDs. Identify structures in the City of Winchester with PRDs. Automatic Sprinkler Systems.
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PRESSURE REGULATINGDEVICES By: Sgt. Larry Baker FF/Medic Len Clowser FF/EMT Terry Orndorff
OBJECTIVES • Understand how Pressure Regulating Devices (PRDs) work • Overcome the limitations of PRDs. • Identify structures in the City of Winchester with PRDs.
Automatic Sprinkler Systems • Automatic Sprinkler Systems control 96% of fires in sprinklered structures • What do we do with the other 4%?
One Meridian Plaza Occurred: • February 23, 1991 • Philadelphia, PA Tragedy: • 3 Firefighter Fatalities • 1 Occupant Fatality
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
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
WHAT DID WE LEARN? Because of this tragedy at One Meridian Plaza, PRD’s received a lot of attention. The fire service recognized these devices as a potentially serious problem!
3 Basic Types • Pressure control valves • Pressure reducing valves • Pressure restricting devices
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
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
PRDs in the City of Winchester • Winchester Medical Center • 333 W. Cork Street • Likelihood of more
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
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.
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.