Chapter 8 - Fireground Hydraulic Calculations Flashcards
- 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).
Flowmeter
p 281
The ___________ relieves you from relying on calculations based on the friction loss, elevation pressure, and length of hoseline.
flowmeter
p 282
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.
NFPA 1901 / 10gpm
p 282
Several designs of flowmeters are available that operate by different principles. The two most common to the fire service are:
- _____________
- ________ ______
- Paddlewheel
- Spring probe
p 282
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?
Paddlewheel
p 282
Flowmeters:
This type employs a stainless steel spring probe to detect water movement in the discharge piping?
Spring probe
p 282
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.
3 percent / 3 gallons
p 282
Each discharge equipped with a flowmeter must have a digital readout display mount within _____ inches of the control valve for that discharge.
6 inches
p 282
If a pressure gauge is mounted at the _____ inch location, then the flowmeter must be mounted within ____ inches adjacent to the pressure gauge.
6 inch / 2 inches
p 282
Relay pumping:
Apparatus equipped with electronic pressure governors involved in relay pumping, with the exception of the attack pumper, should operate in ?
revolutions per minute (rpm)
p 283
___________ reduce the number of pressure calculations required of the driver/operator.
Flow meters
p 281-282
Standpipe Operations:
When a line is shut down, lower the pressure accordingly or the standpipe system will attempt to flow the ?
excess through the remaining hoselines
p 283
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.
psi / rpm
p 283-284
The driver/operator can use a _____________ _____________ to determine the pump discharge pressure required for virtually any hose layout without relying on mental calculations.
hydraulic calculator
p 284
Hydraulic calculators can be either __________ or ____________.
manual or electronic
p 284
- Charts carried on a fire apparatus to aid the pump operator in determining the proper pump discharge pressure when supplying hoselines.
Pump Charts
p 284
The ____________ ____ formula may be used for operations in which the friction loss can be determined for 3-,4-, or 5- inch hose.
Condensed Q
p 287
What is the Condensed Q formula for 3-inch hose?
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
What is the Condensed Q formula for 4-inch hose?
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
What is the Condensed Q formula for 5-inch hose?
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
______________ reduce the number of pressure calculations required of the D/O.
Flowmeters
p 282
- 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.
Pump Discharge Pressure (PDP)
p 281
____________ measure and display water flow in gallons per minute.
Flowmeters
p 282
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.
Paddlewheel
p 282
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.
bent / electrical charge
p 282
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 ___________ __________.
increases / receiving pumper
p 283
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.
20 psi
p 283
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.
flow rate / volume of water
p 283
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.
slide or dial
p 284
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.
length / diameter / elevation
p 284
______ ________ are often developed by a FD and contain information specific to that jurisdictions equipment and common hose layout operations.
Pump charts
p 284
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.
- master stream
- pumper / wye
- number / diameter
p 284-285
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.
- 5 psi
- test
- PDP / PDP
- residual
p 285
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.
solid and fog / metric
p 288
