Oklahoma City Fire-Rescue
Hydraulics
Notes

Water hammer plays a very important role in the use of Large Diameter Hose (LDH).  It is also present in smaller hoselines.  Water hammer is magnified in LDH.  Valves on pumps, nozzles, and appliances MUST be opened and closed slowly.  NOTE:  The 10-second rule should be used to open and close valves when flowing water.  The 10-second rule means the firefighter should count 10 seconds when opening or closing a valve.  Pumps can be cracked or broken, appliances damaged, hose burst, and water mains broken underground by water hammer.

Friction Loss per 100 feet of Hose
"Rule of Thumb"

Formulas

Friction Loss Coefficient Table (C)

Facts

• 1 psi will lift water 2.304 feet.

• Base pressure for every foot of rise is 0.434 psi.

• One cubic foot of water weighs 62.5 lbs.

• 1 gallon of water weighs 8.33 lbs.

• One cubic foot of water is 7.5 gallons.

• Raise or lower pump discharge pressure for supply lines in increments of 25 psi.

• Raise or lower pump discharge pressure for attack lines in increments of 10 psi.

• At 212^oF, a cubic foot of water expands approximately 1,700 times its original volume.  At higher temperatures, expansion is greater.

Electric Priming Method

• Close all discharge valves, drains, pump cooler, and all intakes.

• Open the hydrant or tank to pump valve, depending on water source.

• Open the throttle to approximately 1,000 rpm.  Pull the primer handle and the discharge gauge should rise when the pump is primed.

• The primer motor should not be engaged for more than 30 seconds.

• If the pump does not prime in the appropriate amount of time (30 sec.), check the water source for possible leaks.  Try to prime again.

Manually Priming Pump

• Put the engine in pump gear.

• Open the valve from the booster tank to the pump.

• Remove the cap from the highest 2 1/2" discharge outlet.

• Open the 2 1/2" valve until water discharges.

• Close the 2 1/2" valve.

• The pump should be primed.

Setting the Relief Valve

• Turn the relief valve control all the way in.

• Using the hand throttle, increase the pump pressure to 5 psi above the highest correct discharge pressure.

• Turn the relief valve to the ON position is so equipped.

• Turn the relief valve control out slowly until the pressure gauge shows a drop in pressure.

• Re-adjust the relief valve until the pressure is 5 psi above the highest correct discharge pressure.

• Using the hand throttle, lower the pump discharge pressure 5 psi less that the relief valve.

• NOTE:  Any other lines flowing at pressures below the relief valve pressure setting will have to be controlled by unlocking that particular discharge gate, pinching it down to the correct discharge pressure, and then re-locking it.

• NOTE:  At least one 1 3/4" line or larger must be flowing to set the relief valve.  The booster line CANNOT be used to set the relief valve.

EXAMPLE:
Correct discharge pressure is 150 psi.

Turn the relief valve all the way in.

Set the discharge pressure to 155 psi with hand throttle.

Turn the relief valve to 155 psi.

Set engine pressure to 150 psi with hand throttle.

The relief valve is set 5 psi above the highest discharge.

NOTE:  the proper relief valve setting will always be 5 psi above the highest pump discharge pressure.

Calculating Additional Water Available from a Hydrant
FIRST DIGIT METHOD

• Find the difference in psi between static and residual pressures.

• Multiply the first digit of static pressure by 1, 2, or 3 to determine how many additional lines of equal flow (gpm) may be added.

• If the psi drop is equal to or less that the first digit of the static pressure multiplied by 1, three additional lines of equal flow (gpm) may be added.

• If the psi drop is equal to or less that the first digit of the static pressure multiplied by 2, two additional lines of equal flow (gpm) may be added.

• If the psi drop is equal to or less that the first digit of the static pressure multiplied by 3, one additional lines of equal flow (gpm) may be added.

EXAMPLE:
A pumper is supplying one line with 250 gpm.  The static was 65 psi, residual is 58 psi.

Difference in psi=Static minus Residual (65-58=7)

First digit of static is 6.

6x1=6
6x2=12
6x3=18

7 is not less that 6 but is less than 12, so two more lines at 250 gpm each may be added.

National Fire Academy Fire Flow Formula

• Multiply the length of building by the width.

• Divide by 3.

• Times by the number of floors involved.

• The total is for 100% involvement.

• If 75% involved, multiply by 3/4.

• If 50% involved, multiply by 1/2.

• If 25% involved, multiply by 1/4.

Pump Pressure for Appliances
(Rule of Thumb)

GPM Flow from Solid Bore Nozzles
GPM=29.7 x d2 x Square Root of NP

Hose Loads (4" & 5")

• Loading 4" and 5" hose in the hose bed:

• The first coupling is placed in the front of the hose bed.

• The 4" or 5" hose is loaded in the flat load.  Load the first section with the fold in the front of the hose bed 12 to 14 inches short of the front of the hose bed.

• The next coupling should be placed in the front of the hose bed ahead of the folds in the hose.

• All couplings will be placed at the front of the hose bed no matter where they come in the hose load.

• The second tier of hose should be folded so the bend in the hose will be 4 inches short of the first layer.  The third tier will be the same as the first, continue to lay the hose in folds progressively across the bed to complete the load.

Forward Lay 3" Hose (forward layout with 3" feeder line)

• Apparatus operator spots apparatus approximately 20 feet past hydrant.

• On orders from the officer, firefighter disembarks engine and gives a signal when hose is secured around hydrant.

• On orders from the officer, operator proceeds to the fire and spots apparatus in the most beneficial position for exposure and/or fire attack.  NOTE:  spot apparatus in consideration of other responding apparatus.

• Operator places apparatus in neutral; set parking brake; engage pump; shift transmission into drive.  (This will change the transmission from road gear to pump gear)

• The officer will place the hose clamp on the 3" feeder line.  If 2 lines are used, 1 line will be connected to an intake.

• Operator checks to ensure pre-connect is clear of compartment and apparatus.

• On orders from the officer, operator charges appropriate discharge using water from booster tank or supply line.  NOTE:  after the first line has been charged and is at correct pump discharge pressure, relief valve must be set.

• Operator will then connect feeder line to intake and remove hose clamp.  Once water has reached intake valve, operator will adjust pressure accordingly.

Forward Lay 4" Hose (forward layout with 4" feeder line)

• Apparatus operator spots apparatus approximately 20 feet past hydrant.

• On orders from the officer, firefighter disembarks engine and gives a signal when hose is secured around hydrant.

• On orders from the officer, operator proceeds to the fire and spots apparatus in the most beneficial position for exposure and/or fire attack.  NOTE:  spot apparatus in consideration of other responding apparatus.

• Operator places apparatus in neutral; set parking brake; engage pump; shift transmission into drive.  (This will change the transmission from road gear to pump gear)

• Operator disembarks engine and chocks wheels.

• Operator proceeds to the rear of the apparatus to disconnect supply line and connects to intake/suction.  NOTE:  supply line should be connected on operator side when possible.

• Operator checks to ensure pre-connect is clear of compartment and apparatus.

• On orders from the officer, operator charges appropriate discharge using water from booster tank or supply line.  NOTE:  after the first line has been charged and is at correct pump discharge pressure, relief valve must be set.

Hose Clamps

The officer will place hose clamp 6 feet on the supply side from a coupling and a minimum of 20 feet from tailboard.  It is not recommended to use a hose clamp with Large Diameter Hose because it will slide on the hose when loosened.

4" Hose Intake Connection

• Put pump in gear.

• Open the tank to pump valve and pump proper pressure.

• Set relief valve.

• Call for water if mobile radio is used or signal to the plug catcher if possible.

• Bleed air from the 4" hose.

• Open the intake valve and close the tank to pump valve slowly (10 second rule).

• Re-adjust the pump pressure and set the relief valve.

Hydrassist Operation

• STEP 1-First engine will spot at hydrant for hydrant connection using Hydrassist.  Firefighter disembarks engine for hydrant connection.  Engine proceeds to fire.  Handle on Hydrassist should point to the "B" position after connection is made and before hydrant is opened (FIGURE 1).

• STEP 2-Firefighter opens the hydrant using the 10 second rule.  Firefighter returns to engine company.

• STEP 3-Second engine will spot at the hydrant with largest discharge on the hydrant side.  Soft apparatus for soft suction connection.

• STEP 4-Operator will set park brake, then connect 5" soft suction to side "C" of the Hydrassist.  Operator will then connect soft suction to the 5" intake (FIGURE 2).

• STEP 5-Operator will attach 25 feet of 4" hose to side "D" of the Hydrassist.  The 4" hose is connected to the largest discharge (FIGURE 2).

• STEP 6-Operator will turn handle on the Hydrassist to the "D" position.  Operator will open the intake valve and the discharge valve, then engage the pump (FIGURE 3).

• STEP 7-Second engine operator will pump friction loss plus 20 psi for residual pressure to the first engine.

• STEP 8-Contact the first engine by radio to confirm residual pressure is 20 psi or above.  NOTE:  pump discharge pressure should not exceed 200 psi.

Reverse Lay

• Operator will spot apparatus approximately 20 feet past connection point.

• Operator will set park brake, disembark engine, and assist with unloading necessary equipment.

• Firefighters will pull attack hose and advance toward the fire.

• Firefighters fold approximately 10 feet of hose back on top of supply line and secures with knee.  NOTE:  for safety reasons, the Storz coupling should be in front of the firefighter  Upon signal, operator will proceed to hydrant.

• Firefighters will connect supply line to manifold then assist in advancing attack lines toward the fire.  When connecting to a master stream such as a portable monitor or aerial device, connection can be made as soon as the supply line does not have residual pull.

• Operator will spot engine for soft suction connection.  The operator should turn wheels approximately 45 degrees away from the hydrant.  Operator will make connection to hydrant and to the intake with 5" soft suction.  Operator will then open the hydrant using the 10 second rule.

• Operator will disconnect the feeder line and connect to the 3" large discharge.

• Operator will open discharge valve allowing water to start flowing to purge line.

• Operator will chock wheels, return to the engine, and engage the pump.

Full Strip / Partial Strip

• In cases where it is necessary to place the pumping unit at the water source, the equipment to carry out fire fighting operations will have to be removed from the rig.  According to IFSTA Hose Practices, there are two options for the type and amount of equipment to be removed.

• When a complete complement of equipment is needed to support fire fighting operations for an extended period of time, a "Full Strip" is made.  When a less extensive complement is needed, a "Partial Strip" is made.

• The removal of this equipment will cause some delay in the initial attack, however, a way to expedite the task is to assign specific pieces of equipment to each crew member so that the job is done in the shortest possible time.

Pumping to a Sprinkler Connection or Standpipe

• Operator will spot apparatus approximately 20 feet past sprinkler/standpipe connection and set parking brake.

• Engine crew disembarks engine and offloads enough line to make a sprinkler/standpipe connection.  Adapters needed for 4" hose are a Storz to 2 1/2" male on a 30 degree elbow.  Adapter needed for a 3" hose is a 2 1/2" double male.

• On orders, operator will proceed to hydrant to make connection.

• Firefighters will make connection to sprinkler/standpipe system after a few flakes have deployed off engine and there is no residual pull on the hose.

• Operator will spot apparatus for soft suction connection with wheels turned 45 degrees away from hydrant.  Parking brake is set and tools are gathered to make a steamer connection.  NOTE:  only use soft suction to steamer to make this connection.

• Operator will break the line at the tailboard and connect to appropriate discharge.

• Operator waits for orders before turning water in.

• Operator pumps 125 psi plus friction loss plus 5 psi per floor above the 1st floor.  NOTE:  do not exceed 200 psi as the system is rated at 500 gpm.

Relay Pumping 4" Hose (1,000 gpm)

• An engine must be placed every 900 feet.

• First engine should connect to the hydrant with the Hydrassist and lay out 900 feet of hose, stop and connect at that point, and plug catcher turns in water.

• Second engine will connect to first engine and lay out 900 feet of hose and connect at that point.  First engine will turn in water to the second engine.

• The process continues until the lay is complete.  The next available engine not in the relay operation will connect to the Hydrassist at the hydrant.

• All engines in the relay will pump friction loss plus 20 psi residual.

Preconnects

• The triple layer load can be used on rear deployment or crosslays.

• The minuteman load is used exclusively on rear deployment loads.

• The accordion load is used on the fender mounted Quick Deployment Load and E-One Jump Line.

Triple Layer Load

• Connect all drained hose and extend either to the rear or side of apparatus.

• Connect the female coupling to the discharge.

• Pick up hose at a point 2/3 of its length towards the nozzle and carry to the discharge connection.  This forms 3 layers that should be stacked on top of each other.  This may take some adjusting of layers to achieve this.

• Extend hose straight from the apparatus.

• At 2/3 distance from apparatus, pick up hose and return to the apparatus.

• Stack hose three layers high and flake into hosebed in flat layers until loaded.

Minuteman Load (rear hose bed only)

• Connect the female end of the first section of hose to a 1 1/2" outlet.

• Place one layer of hose in the bed, while the remainder of the section is to be accordion folded on edge, towards the front of the bed.

• Leave a 2 to 3 foot tail on the male end and set aside.

• Place additional sections of hose in the bed starting with the nozzle to the inside at the bottom.

• Couple the free ends of the hose and place into hose bed.

Accordion Load

• Drain and lay out hose to the side of the apparatus.

• If it is the jump line, lay the hose to the front of the apparatus.

• Connect the female end to the discharge.

• Lay the hose on edge, beginning at the back of the tray and zig-zag the hose back and forth, keeping the couplings away from each other.

• For the jump line, fold the hose in the box flat.

• Continue until loaded.

Pulling a Triple Layer Load

• Pull the nozzle and folds of the first tier and place over shoulder facing away from the load.

• Walk away from the apparatus until the entire load is pulled from the bed.

• Drop the folded end from the shoulder and advance nozzle to the fire.

• Be sure all the hose is laid out and air is expelled before advancing the hoseline to the fire.

Pulling a Minuteman Load

• Remove the hose load from the bed onto the shoulder.

• Walk straight from the apparatus approximately 50 feet.

• Turn toward incident and allow hose to lay of shoulder.

• Be sure all the hose is laid out and air is expelled before advancing the hoseline to the fire.

Pulling a Quick Deployment Load

• Open door to quick deployment tray (be sure to close compartment doors before opening).

• Place nozzle and one flake of hose over the shoulder and advance toward fire.

• Be sure all the hose is laid out and air is expelled before advancing the hoseline to the fire.

Portable Sprinkler System

• The portable sprinkler system is primarily used to restrict the spread of fire in an enclosed area such as an attic or cockloft.

• It can aid in control and extinguishment of fire underneath floors, around floor furnaces, and inside walls.

• It can also be used very effectively as a water curtain device in attics and cocklofts.

• Its use can also reduce the convection of heat currents and cool the temperature of unburned fuel gases.

• One set consists of four nozzles, four 10 foot sections of 1 1/2" hose equipped with female connections on each end, and a 1 1/2" end cap.

• Each nozzle has a 1/2" inside diameter and is 18 inches in length.

• Each nozzle flows approximately 25 gpm at 100 psi nozzle pressure.

• 125 psi plus friction loss in the supply line should be pumped to the assembly.

• The wye in the assembly is figured into the 125 psi.

• One set of sprinklers should cover approximately 40 to 50 feet in length.

• By using two sets in series, 90 feet in length may be covered.

• It is not feasible to use two sets with a 1 1/2", 1 3/4", or 2" feeder line because of the reduced water supply.

• It is important that the system be supplied through a wye off the feeder line to provide more adequate volume of water.

• The volume of water being delivered through the nozzles should be checked occasionally.

• If possible, hose rollers or salvage covers should be used where the feeder line comes over a parapet wall or roof edge to prevent kinking and chafing of the line.

• Do not hammer nozzles into roof.  Always use a pick-head axe to make a hole to place nozzles in.

Bundling Portable Sprinklers