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Relay in the Urban Setting

Relay in the Urban Setting. Making Water Supply Work for You!. Does the City of Henderson Have an Adequate Water Supply System to Fight Large, Defensive Fires?. Parowan Fire Crystal Creek Fire Pallet Yard Fire Quail Run Fire. Case Study : Quail Run Fire. January 15, 2011 (approx. 10am)

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Relay in the Urban Setting

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  1. Relay in the Urban Setting Making Water Supply Work for You!

  2. Does the City of Henderson Have an Adequate Water Supply System to Fight Large, Defensive Fires? • Parowan Fire • Crystal Creek Fire • Pallet Yard Fire • Quail Run Fire

  3. Case Study : Quail Run Fire • January 15, 2011 (approx. 10am) • Large custom home in District 94 • E94 hooks closest hydrant (100’) for offensive attack, uses 2 1/2” valve w/3” line for additional supply • T82 sets up behind E94 for Roof Div. assignment • Fire transitions to defensive, truck uses aerial streams • E98 who is staged at hydrant (500’), forwards in and supplies truck • Aerial, A Div., B Div., and D Div. play “musical master streams” due to inadequate water supply

  4. E98 Supplies T82 on Quail Run Fire

  5. E98 is Approx. 20’ uphill from House with White Tile Roof

  6. Hydrant is Located 500’ away, 20’ downhill

  7. Water Supply Facts • 100’ of 5” hose = 5psi FL per 1000gpm flowing • 20’ of elevation gain = 10 psi FL • 2nd principle of fluid pressure states fluid at rest (static) is of the same intensity (pressure) in all directions • 6th principle of fluid pressure states the pressure of a fluid on the bottom of a container is independent of the shape of the container

  8. Water Facts Cont… • A 70-psi hydrant static pressure (SP) will read 70 psi no matter the length of 5” we attach, because we are simply changing the shape of the container • Once water is flowing FL occurs • A 70-psi hydrant would lose 25 psi on the supply side once water is flowing by the time it reaches the pumper’s inlet with 500’ of 5” on the ground without factoring in any potential elevation gain

  9. Furthermore… • 35 psi FL (500’ of 5” & 20’ elevation) is about a 50% drop on most hydrants • 16-25% drop is the highest for flowing 1 like-line • If we have a 1500gpm hydrant how much less water we will be available after a percentage drop twice that? • Regardless of the flow available in any given hydrant, we are not using its’ full potential by forwarding large distances from a secondary hydrant on potential defensive fires!

  10. Water Supply Test on Station 82 Drill Grounds on 1/31/11 • Lay 40’ bypass to engine, record flow • Lay 600’ of 5” to engine, record flow • Place supply pumper at hydrant, lay 600’ of 5” to attack pumper, record flow • Results

  11. 5” Bypass to Attack Engine • Static Pressure = 55 psi • Volume of Flow = 1350 gpm • Residual Pressure = 20psi

  12. 5” & 3” Bypass to Attack Engine • Static Pressure = 55 psi • Volume of Flow = 1700 gpm • Residual Pressure = 20psi

  13. 600-Foot Forward to Attack Engine • Static Pressure = 55 psi • Volume of Flow = 750 gpm • Residual Pressure = 20psi

  14. 600-Foot Relay to Attack Engine • Static Pressure = 55 psi • Volume of Flow = 1300 gpm w/ only 5” • Residual Pressure = 20psi 20psi

  15. 600-Foot Relay to Attack Engine • Static Pressure = 55 psi • Volume of Flow = 1680 gpm w/ 3” added • Residual Pressure = 20psi 20psi

  16. Results • Showed hydrant had at least 1700 gpm available with shortest lay possible • Showed as we laid 600’ away, on flat ground, we lost more than ½ of available water • Showed static pressure reading tricks us into believing we have same water regardless of 5” length • Showed adding a source pumper enabled us to maximize hydrant’s available water • Adding source pumper enables us to use additional 3” to our advantage

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