Chapter # 9 Fireground Hydraulic Calculations Flashcards
Name six fire ground hydraulic calculation methods.
Flowmeter. Hydraulic Calculators. Pump Charts. Hand Method. Condensed “Q” Formula. GPM Flowing.
T or F The number displayed on the flowmeter requires no further calculation because it reflects how much water is moving through the discharge valve and consequently the nozzle. This quantity of water only diminishes before it reaches the nozzle if there is a leak or break in the hoseline.
True
Flowmeters are particularly advantages when supplying hoselines or master stream devices equipped with what?
Automatic Nozzles.
T or F Flowmeters make it possible for drivers to pump the correct volume of water without having to know what?
Hose length. Friction Loss. Elevation pressure.
NFPA 1901 allows flowmeters to be used instead of pressure gauges on what size of discharges?
1 1/2” to 3”
NFPA allows flowmeters to be placed on discharges that are 3 1/2” or larger but they also must have what?
A pressure gauge.
What increment of gpm must be on a flowmeter?
no larger then than 10
Name the two most common type of flowmeters in the fire service.
Paddlewheel and Spring Probe
Mounted in the top of a straight section of pipe, very little extends into the waterway. Placement reduces problems with impeded flow and damage by debris. Sediment doesn’t affect it due to being at the top of the pipe.
Paddlewheel flowmeter.
Uses a stainless probe to sense water movement. The greater the flow, the more the probe bends. The bending sends a digital signal to a display. Relatively maintenance free due to probe being the only moving part.
Spring Probe flowmeter.
Flowmeters should be accurate to a tolerance of what?
+/- 3%
How close to the discharge is the flow digital display?
Within 6”
What information is provided by a central flowmeter?
The flow through any particular discharge at that time. Total amount of water being flowed through the pump at that time. The total amount of water that has been flowed through the pump for the duration of the incident. The amount of foam being flowed.
Name three incidents when a flowmeter is especially useful to a driver.
Diagnosing water problems. Relay Operation. Standpipe operations.
What is a advantage of having a flowmeter when performing a relay operation?
You do not need to know the number of gallons flowing from the pumper receiving the water?
How do you use a flowmeter when supplying a pumper in a relay operation?
Increase the engine speed until the flowmeter reading no longer increases. This sets the pump at the correct discharge pressure pressure to supply an adequate flow to the receiving pumper.