Chapter 8 - Fireground Hydraulic Calculations

Question 1

• Mechanical device installed in a discharge line that senses the amount of water flowing and provides a readout in units of gallons per minute or (liters per minute).

Answer 1

Flowmeter

p 281

Question 2

The ___________ relieves you from relying on calculations based on the friction loss, elevation pressure, and length of hoseline.

Answer 2

flowmeter

p 282

Question 3

Based on NFPA _______ standard, for every discharge outlet equipped with a flowmeter, a pressure gauge shall also be provided. These flowmeters must display flow in increments of _____ gpm or less.

Answer 3

NFPA 1901 / 10gpm

p 282

Question 4

Several designs of flowmeters are available that operate by different principles. The two most common to the fire service are:

• _____________
• ________ ______

Answer 4

• Paddlewheel
• Spring probe

p 282

Question 5

Flowmeters:
This type is mounted at the top of a straight section of the discharge pipe so that only a small portion of the device extends into the waterway?

Answer 5

Paddlewheel

p 282

Question 6

Flowmeters:

This type employs a stainless steel spring probe to detect water movement in the discharge piping?

Answer 6

Spring probe

p 282

Question 7

With proper calibration, a flowmeter in good working order should be accurate to a tolerance of plus or minus _____ percent. In other words, based on flow of 100 gpm, the display should be no more than ____ gallons higher or lower than the actual discharge.

Answer 7

3 percent / 3 gallons

p 282

Question 8

Each discharge equipped with a flowmeter must have a digital readout display mount within _____ inches of the control valve for that discharge.

Answer 8

6 inches

p 282

Question 9

If a pressure gauge is mounted at the _____ inch location, then the flowmeter must be mounted within ____ inches adjacent to the pressure gauge.

Answer 9

6 inch / 2 inches

p 282

Question 10

Relay pumping:
Apparatus equipped with electronic pressure governors involved in relay pumping, with the exception of the attack pumper, should operate in ?

Answer 10

revolutions per minute (rpm)

p 283

Question 11

___________ reduce the number of pressure calculations required of the driver/operator.

Answer 11

Flow meters

p 281-282

Question 12

Standpipe Operations:

When a line is shut down, lower the pressure accordingly or the standpipe system will attempt to flow the ?

Answer 12

excess through the remaining hoselines

p 283

Question 13

Apparatus equipped with electronic pressure governors set in _______ mode should compensate for this shutdown. A pressure governor in the ______ mode will not automatically compensate for the reduced flow.

Answer 13

psi / rpm

p 283-284

Question 14

The driver/operator can use a _____________ _____________ to determine the pump discharge pressure required for virtually any hose layout without relying on mental calculations.

Answer 14

hydraulic calculator

p 284

Question 15

Hydraulic calculators can be either __________ or ____________.

Answer 15

manual or electronic

p 284

Question 16

• Charts carried on a fire apparatus to aid the pump operator in determining the proper pump discharge pressure when supplying hoselines.

Answer 16

Pump Charts

p 284

Question 17

The ____________ ____ formula may be used for operations in which the friction loss can be determined for 3-,4-, or 5- inch hose.

Answer 17

Condensed Q

p 287

Question 18

What is the Condensed Q formula for 3-inch hose?

Answer 18

FL = Q^2

FL = Friction loss in psi for 100 feet of 3 inch

Q = Flow rate in hundreds of gallons per minute (gpm/100)

p 287

Question 19

What is the Condensed Q formula for 4-inch hose?

Answer 19

FL = Q^2 / 5

FL = Friction loss in psi for 100 feet of 4 inch

Q = Flow rate in hundreds of gallons per minute (gpm/100)

p 287

Question 20

What is the Condensed Q formula for 5-inch hose?

Answer 20

FL = Q^2 / 15

FL = Friction loss in psi for 100 feet of 5 inch
Q = Flow rate in hundreds of gallons per minute (gpm/100)

p 288

Question 21

______________ reduce the number of pressure calculations required of the D/O.

Answer 21

Flowmeters

p 282

Question 22

• Actual pressure of the water as it leaves the pump and enters the hoseline; total amount of pressure being discharged by a pump. In mathematical terms, it is the pump intake pressure plus the net pump discharge pressure. Measured in pounds per square inch.

Answer 22

Pump Discharge Pressure (PDP)

p 281

Question 23

____________ measure and display water flow in gallons per minute.

Answer 23

Flowmeters

p 282

Question 24

Types of flowmeters:

As water moves past the _____________, a sensor measures the speed at which it spins and translates the information into a flow measurement.

Answer 24

Paddlewheel

p 282

Question 25

Types of flowmeters: Spring probe - The greater the flow, the more the spring is ______. An ___________ _________ is transmitted from the spring to a display unit for review by the D/O.

Answer 25

bent / electrical charge p 282

Question 26

Flowmeter Applications Relay Pumping As you increase the throttle, the discharge reading on the flowmeter will rise at a corresponding level. Increase the engine speed until the flowmeter reading no longer __________. This will establish the correct discharge pressure to supply an adequate volume of water to the ___________ __________.

Answer 26

increases / receiving pumper p 283

Question 27

Flowmeter applications: Relay pumping Throughout the duration of the incident, monitor the flowmeter as well as the intake pressure. The intake pressure reading cannot be allowed to drop below _____ psi.

Answer 27

20 psi p 283

Question 28

When operating an apparatus equipped with a flowmeter(s), the number and types of nozzles on lines operating from the standpipe may be factored by adding the ______ ______ for each nozzle together and pumping the __________ of _______ that matches that rate.

Answer 28

flow rate / volume of water p 283

Question 29

Hydraulic Calculators The manual version of the calculator consist of a ______ or ______ that can be moved to cover or reveal rates of flow, size of hose, and length of hose layout in order to come to a conclusion to a problem.

Answer 29

slide or dial p 284

Question 30

Hydraulic Calculators: Electronic hydraulic calculators are specially programmed to allow you to input the variables of each hose layout, including the ________, __________ of hose, and ___________ changes. The calculator then applies preprogrammed formulas to arrive at the pump discharge pressure.

Answer 30

length / diameter / elevation p 284

Question 31

______ ________ are often developed by a FD and contain information specific to that jurisdictions equipment and common hose layout operations.

Answer 31

Pump charts p 284

Question 32

Pump charts: Guidelines * Include friction loss for ________ _________ appliances ( those flowing in excess of 350 gpm) * Ensure that the length of the wyed hoseline layout is the distance between the _________ and the ______. * Factor each scenario in cases where a master stream may be supplied by a different _________ or __________ of hoselines.

Answer 32

* master stream * pumper / wye * number / diameter p 284-285

Question 33

Pump chart guidelines: * Round pump discharge pressure calculations to the nearest ___ psi * Do not let the pump discharge pressure exceed the _____ pressure for the diameter hose or the pumper involved in calculations. * Do not exceed the department's maximum ______ policy if the department has one and the policy maximum varies from the hose manufactures max ______. * To perform relay pumping calculations, the pump discharge pressure should provide for __________ pressure at the intake of the pumper being supplied that is based on jurisdictional policy.

Answer 33

* 5 psi * test * PDP / PDP * residual p 285

Question 34

GPM Flowing The gpm flowing method is applicable to both ______ and _____ steams and is calculated using flow in gallons per minute. It may be used for various diameter hose, although it is not applicable to the _________ system of measurement.

Answer 34

solid and fog / metric p 288