Ch. 10 Operating Fire Pumps

Question 1

Making the Pump Operational

“putting it in pump”

Answer 1

-Referred to “putting the pump in gear” after properly positioning apparatus
-Most apparatus designed to put pump in gear from the cab
-IFSTA recommends the wheels be chocked every time you exit the cab

Question 2

Operating from the Water Tank

Answer 2

• soul source of supply on many incidents
• may begin w/ tank water then transition to external water supply
  -must transtion quickly and efficiently w/ no disruption to the operation

Question 3

Putting the Pump into Operation

Answer 3

-Open tank to pump
-Open discharge to hose lines
-Open the valves and the hose lines will begin to fill
-Increase the throttle
-Reach the proper pressure only when water is flowing
-Monitor gauges
-Adjust throttle until desired flow rate is achieved

Question 4

Cavitation to the Pump

Answer 4

• In order to properly open tank fill valve and not create cavitation drivers open the valve the distance of their thumb
• You must:
  -Monitor water level
  -Estimate time onboard water will last
  -Circulator valve to prevent pump from overheating

Question 5

Transition to an External Water Supply

Answer 5

-Must be done quickly and efficiently
-Connect supply line to appropriate intake
-Make connection to intake with a closed gate valve
-Open bleeder valve so air can escape ahead of water supply
-The water supply is now at pump and ready for transfer
-The water supply is now at pump and ready for transfer
-Nozzle on attack line open air will bleed off

Question 6

Operating from a Pressurized Supply Source

Answer 6

• Two basic supplies:
  -hydrant
  -supply hose from another pumper
• Pumping at a low residual pressure (below 20 psi) while being supplied by other apparatus is equally dangerous
• Water mains must maintain residual pressure of at least 20 psi at all times
  -contamination from sources outside the main may occur at lower pressures
  -overtaxing may cause sediment and debris to losen which can damage piping and reduce water flow

Question 7

Choosing a Hydrant

Answer 7

-Closest hydrant may not be most prudent (create safety hazard to apparatus and personnel)
-Hydrants are marked by color system
-Least desirable hydrant is located dead end mains (mains from one direction)
-Open briefly to flush debris

Question 8

Making a Forward Lay

Answer 8

• Most common way for pumper to be supplied
  -Stop at hydrant
  -Drop end of one or more supply line
  -Proceed to fire location
• In long lay pumper may be placed at hydrant to boost pressure

Question 9

4-Way Hydrant Valve

Answer 9

• Has second discharge usually 4 ½ or 5-inches
• Equipped with shutoff valve
• Allows second pumper to connect without interrupting flow
  -Connect valve to hydrant
  -Connect supply line to supply line outlet
  -Open hydrant
  -Connect second pumper to pumper intake
  -Open pumper intake valve and 4-way vale
  -Connect one of pumper discharge to second intake of hydrant valve
• Attach gate valves to unused hydrant discharges on dry barrel hydrants

Question 10

Making Reverse Lays

Answer 10

-Size up incident before laying lines
-Hose is laid from fire to water source
-Load hose with male coupling to come out of bed first
-If set up for forward lay, use double female adapters at the hydrant and double males at the pump
-Common when setting up water supply using medium diameter hose
-Most direct method for supplementing hydrant pressure or drafting operations
-Disadvantage: delay due to attack line and all tools needed must be in place before proceeding to water source
-Medium Diameter Hose- 2 ½-inch or 3-inch hose for both attack and supply

-Two-Pumper operation:
Attack Pumper- The first pumper reports directly to the incident scene
Water Supply Pumper- Lays a supply line from attack pumper to water source

Question 11

Getting Water into the Pump

Answer 11

• When the pump is full of water and the pressure in system has stabilized with no water flowing a reading of pressure indicates static pressure
  -This reading is important for estimating the remaining capacity of the hydrant as the water begins to move
  -Close tank-to-pump after transitioning to external water source

Question 12

Putting the Pump in Service

Answer 12

• When operating a two-stage pump driver must set the transfer valve to proper position before increasing the throttle
• X-Setting transfer valve when supplying upper floors to high rise
• Pumps supplying relay operations or master stream require use of parallel (volume) setting of the transfer valve
  -Except when high pressure is needed
  -i.e. extended/elevated supply lines, upper high rise floors
• Open all valves slowly, especially when using large diameter hose
• Throttle should not be increased if master intake gauge drops below 20 psi (pump may cavitate)
• During prolonged pumping:
  -bypass circulation may not cool water
  -Open discharge
  -Partially open the tank to fill valve to prevent overheating

Question 13

Additional Water Available from Hydrant

Answer 13

• When pumper is connected to a hydrant and is not discharging water, the pressure shown on the intake gauge is static pressure
• When the pumper is discharging water, the intake gauge displays the residual pressure
• The difference between the two pressures is used to determine how much more water the hydrant can supply
• 3 Methods
  -Percentage Method
  -First-Digit Method
  -Squaring-the-Lines Method

Question 14

Percentage Method

Additional water available from hydrant

Answer 14

• Calculate the drop-in pressure as a percentage
  Percentage Drop= [(Static-Residual)(100)]/Static
  -Percentage 10 or less three lines
  -Percentage 11-15 two lines
  -Percentage 16-25 one line
  -Percentage 25+ additional water may be available but not as much flowing through 1st line
• Example: A pumper is supplying one line flowing 250 gpm. The static pressure was 70 psi and the residual pressure is reading 63 psi. Determine how many additional lines may be added
  -Percentage Drop= (70-63)(100)70 = 7070 = 10
  -This means three additional lines flowing 250 gpm each may be added

Question 15

First-Digit Method

additional water available from hydrant

Answer 15

STEP 1: Find the difference in psi between static and residual pressure
STEP 2: Multiply the first digit of static by 1,2, or 3 to determine how many more lines

-Psi drop less or equal to 1st digit of static pressure multiplied by 1 then 3 lines
-Psi drop less or equal to 1st digit of static pressure multiplied by 2 then 2 lines
-Psi drop less or equal to 1st digit of static pressured multiplied by 3 then 1 line

Example A pumper is supplying one line flowing 250 gpm. The static pressure was 65 psi, and the residual pressure is 58 psi. How many lines can be added.

Difference in psi= Static Pressure-Residual pressure

Difference in psi= 65-58=7psi

First digit of static pressure x 1
6x1=6

Seven is not less than six, but is less than 12 (2x6), so two more lines can be added

Question 16

Squaring-the-Lines Method

additional water available from hydrant

Answer 16

-Must note static pressure before any discharges are open

Example pumper connects to hydrant with static pressure of 60 psi. when 250 gpm hand line is open pressure drops to 52.

Difference in psi= Static pressure-Residual pressure
Difference in psi = 60-52= 8 psi

If second 250 gpm line were added and pressure drop would be as follows:

Mulitplication Factor = (# of lines)²
2² = 4

New Flow Rate = (Mult. factor) x (Original Pressure Drop)
4x8=32 psi
If pressure drop is 32 psi residual pressure will be 28 psi. not advised to add third line

Question 17

Shutting Down the Hydrant Operation

Answer 17

-Water hammer may carry enough force to damage hydrants
-Bring engine rpms to idle gradually
-Discontinue a pressure control device if in operation
-Close valves in a slow and smooth motion
-Close the hydrant; operate the valve in same slow and smooth manner

Question 18

Drafting Operations

Answer 18

Pressure Differential:
- Atmospheric pressure acts on water’s surface to force water into pump
- Pressure decreases 0.5 psi for every 1,000 feet of altitude gain
- Most pumps are able to develop vacuum capacity of 22 inches mercury
- Example figure:
-Pressure has been reduced inside pump and intake hose to reduce the atmospheric pressure inside the pump intake hose to 12.7 psi
-With atmospheric pressure 14.7 a partial vacuum of -2 psi is measured (compound pressure guage of 4 in. of mercury
-Vacuum cause water to rise 4.6 feet

Friction loss:
-Amount of friction loss depends on diameter and hose length as well as intake strainer and adapters
-Friction loss is proportional to the velocity of the moving water moving through the hose or appliance
-also the inertia

Question 19

Cavitation During Drafting Operations

Answer 19

• Can be described water being discharged faster than it is coming in
• Air cavities are created in the pump or bubbles pass through pump
• Pressure drops below atmospheric pressure
  -causes boiling point to drop
  -water turns to vapor
  -creates a void
• water temp, lift height, amount of discharged water affect the point at which cavitation begins
• indicators of cavitation:
  -pressure guage will fluctuate
  -hose streams are pulsating, water leaving nozzle will create a popping sound
  -Severe:
  1.pump may make noise described as gravel passing through the pump
  2. lack of reaction on pressure guage to increases in throttle

Question 20

Indicators of Cavitation

Answer 20

• pressure guage will fluctuate
• hose streams are pulsating, water leaving nozzle will create a popping sound
• Severe:
  -pump may make noise described as gravel passing through the pump
  -lack of reaction on pressure guage to increases in throttle

Question 21

Factors for the point at which cavitation will begin

Answer 21

water temp
lift height
amount of discharged water

Question 22

Selecting Drafting Site

amount of water, type or quality of water, accessibility

Answer 22

Amount of Water
-Must be at least 24 inches of water over and around the strainer
-Rapid intake of water in strainer may cause a whirlpool, allowing air into intake hose(place capped plastic jug above strainer)
-Floating strainer used for drafting from swift moving low water (also dam can be constructed)
-When using portable tank or swimming pool use low-level strainer designed to sit on bottom of tank
-Water temp below 35 or above 90 impact the ability of pump to reach capacity

Types and Quality of Water
-Each time nonpotable water is used pump should be flushed
-Sand acts as an abrasive between the clearance rings and impeller
-Increases the spacing, causing slippage from discharge
-Dirty water causes the packing to become contaminated, making a good seal impossible

Accessibility
-As lift required to pump increase, the following occur (Elevation pressure increase, less friction loss can be overcome, and capacity of pump decrease)
-Required to pump their capacity 10 feet (good truck can do 25 feet)
-Lift no greater than 20 feet

Question 23

Connecting to the Pump and Preliminary Actions

Answer 23

• Place apparatus directly at the location where intake hose may be deployed
• Set Parking Brake and chock wheels
• Do not engage pump until all connections are made
• Park vehicle short of final drafting spot
  -if space to work is limited, connect suction hose and position prior to driving up to the final drafting position
• Inspect the gaskets to be sure they are in place
• use rubber mallet to tighten
• connect w/o placing it on the ground
• Place each hose in-line with each other before coupling is turned
• Fasten a rope to strainer to aid in handling
• easier to first place strainer into water
• Butterfly valve usually removed before connecting to intake

Question 24

Priming the Pump and Beginning Operation

Answer 24

-For two stage pumps transfer valve must be parallel (volume)
-Most priming pumps intend to work between 1,000 and 1,200 rpm
-RPM kept low on vacuum-type primer (engine may stall)
-1 foot of lift = 1 inch of mercury reading on master intake as air is evacuated
-reading should increase as hose fills and the weight will cause hose to drop
-The primer discharges water onto ground under apparatus
-Priming should not be halted until steady stream of water and all air has been removed
-Priming typically requires 10-15 seconds
-as long as 30 seconds
-Most common cause of air leak is open drain or valve
-Increase throttle slowly after priming pump between 50 and 100 psi
-if it drops below 50psi, pause and let stabilize
-Discharge pressure set when water is flowing and discharge gauge is stable
-Set relief valve when desired pressure has been established

Question 25

Problems During Operating Pump from a Draft

Answer 25

• Air leak on intake side of pump- Most common air is coming into pump
  -re-check couplings
• Whirlpool- If there is not enough water above the drafting strainer
• Air leakage due to defective pump packing- Water tank will empty
  -tank-to-pump line may have leak
• Blockage occurs after pump has been operating at a high rate of discharge
  -Increase in vacuum with no change in flow rate while pump is drafting
  -Most common place for blockage is at the strainer
  -Equipment problems may also lead to blockage
• Attempting to exceed the pump will lead to cavitation

Question 26

Shutting Down the Operation

Answer 26

-Slowly decrease the engine speed to idle
-Take pump out of gear
-Allow pump to drain
-Prime for several seconds until primer oil or fluid comes out
-Will aid in lubrication of priming pump
-thoroughly flush

Question 27

Supporting Automatic Sprinkler Systems

Answer 27

-Designed to support the flow of a specified number of fire sprinklers
-If water supply is 200’ or more from FDC or is Static source should use reverse lay
-Water supply is designed to supply only a fraction number of total sprinklers
-Fire department connection (FDC) and hydrant should be identified in pre incident plan
-FDC consist of a Siamese with at least two 2 ½-inch female connections, or 1 LD sexless connection
-Multistage pumps should be operated in parallel (volume) position
-suggested discharge pressure may be printed near FDC
-General guidline is to pump at 150 psi
-Sprinkler control valves are often located in fire pump room (check as soon as is practical)
-Closed valves should be open

Question 28

Supporting Standpipe Systems

Answer 28

• Allows for quicker access to water supply for attack (connect left side first)
• Fire attack may connect to the 2 ½-inch 150psi or 1 ½-inch 100 psi connections
• Crews should bring attack lines with them to initiate standpipe operations
• Standpipes may be wet or dry
• Wet pipe system contain water under pressure
  -Wet systems used as soon as hose line is stretched and valve is opened
  -most common and reliable
• Dry pipe system must be charged with water from occupant’s water supply, building pump, FD pump, or combination (Time delay)
• Both wet and dry should be supplied by pumper
  -Connect to the left side first

Friction loss:
- Variables:
-Low unless supplying large flow rate
-Pressure loss 25 psi if flow exceeds 350 gpm
-Friction loss in hose lay from pumper to FDC
-Friction loss in hose on fire floor
-Nozzle pressure
-Elevation pressure (height of building)
- Add approximately 5 psi for each floor above the fire department connection

• Pressure reducing valve- the pressure must be based on total height of standpipe
• Adapters may be used to connect to standpipe
• Dry standpipe is charged there is time delay as water fills system
• Pump standpipe at 150 psi
• Aerial device may be used to create an external standpipe
• Supply hose can also be stretched up the interior stairs (often time consuming)

Question 29

Automatic Sprinkler Components-
Sprinklers (Head)

Answer 29

-Contains discharge orifice, fusible link, deflector
-Most occupancies have fusible link with rating of 165*F
-Amount of water discharged from sprinkler dependent on size or orifice and pressure
-Most common size orifice is ½”
-Upright= Deflect water downward
-Pendant-=Areas were upright are impractical/unsightly. Makes circular pattern of water
-Sidewall= Most water discharged on one side, used in corridors, offices, etc

Question 30

Automatic Sprinkler Components-
Piping

Answer 30

• Three types of pipe used, Ferrous Metal (most common), Copper, Plastic
  -Ferrous Metal= Most common Steel piping life expectancy of several hundred years but will corrode and is heavy
  -Copper= Most expensive, weighs less, less FL and less corrosive
  -Plastic= Susceptible to damage, less expensive, and easiest to install
• Water main= All piping below sprinkler valve
• Riser= Piping that extends up from sprinkler valve to 1st horizontal feed main
• Feed Mains= Large pipes that supply water to each cross main
• Cross Mains= Feed Branch Lines
• Branch Lines= Pipes that contain sprinklers

Question 31

Automatic Sprinkler Components-
Valves

Answer 31

• Control Valves= Used to shut off water to perform maintenance located between water source and sprinkler system. Most or PIV to ensure they are opened again after and include, PIV, WallPIV, OS&&, and Indicating Butterfly valve. To further control systems usually chained and locked or electronically monitored
• Other valves include, check valves, auto drain valves, cock valves, globe valves
  -Globe valves- clock-wise to open, counter clock-wise to close used on test drains/valves

Question 32

Automatic Sprinkler Components-
Water Supply

Answer 32

• Most common/reliable system used is municipal water source
• Elevated tanks oldest method, tanks filled with 2/3rd water and 1/3rd air and pressured to 75psi
• Pipe Schedule design – Minimum 15psi to highest sprinkler
• Hydraulically Calc design- Minimum 7psi to highest sprinkler

Question 33

Automatic Sprinkler Components-
Preincident Inspection/Planning

Answer 33

• 3 primary causes of bad performance:
  1. Closed valve in system
  2. Inadequate water supply to sprinkler
  3. Changes to occupancy overwhelm sprinkler capabilities
  -Most common reason for closed valve is forgetting to open again after maintenance
• Pumper connected to hydrant supplying FDC can cause reduced performance
• Serious deficiencies found during PIP should be reported immediately to Fire Prevention