Definitions and general knowledge Flashcards by Andrew Cox

Term applied to any wye, siamese,
deluge monitor, reducer, adapter, fitting or other
piece of hardware used in conjunction with fire
hose for the purpose of delivering water.’

Appliance

How well did you know this?

Not at all

Perfectly

The loss of
pressure created by the turbulence of water
moving through an appliance.

Appliance friction loss (AFL)

How well did you know this?

Not at all

Perfectly

Pressure exerted by the
atmosphere at the surface of the earth due to the
weight of air. At sea level atmospheric pressure
is 14.7 PSI. Atmospheric pressure affects the
amount of vacuum that can be generated inside
a centrifugal pump which determines how high
water can be drafted (lift)

Atmospheric pressure

How well did you know this?

Not at all

Perfectly

The process of flushing water
through the pump, with pressure, either from
a hydrant or another pump, into the discharge
side of the pump and out of the intake fittings
to remove any foreign materials that could
accumulate inside the pump body and impellers.

Back flushing

How well did you know this?

Not at all

Perfectly

More commonly known as water tank
baffles, used to control water flow/surges in a
water tank

Baffles

How well did you know this?

Not at all

Perfectly

A unit of energy
needed to cool or heat one pound of water by
one degree Fahrenheit (measured at 60° F). In
the fire service, we use BTU’s to measure energy
output of fire and the corresponding amount
of water necessary to cool (absorb heat) and
extinguish fire.

British Therma Unit (BTU)

How well did you know this?

Not at all

Perfectly

A condition in which vacuum pockets
form, due to localized regions of low pressure at
the vanes in the impeller of a centrifugal pump
resulting in vibrations, loss of efficiency, and
possible damage to the impeller. This can be
caused by water being discharged from the
pump faster than it is coming in. Cavitation is
sometimes expressed as “the pump running
away from the water.” Some signs that cavitation
is occurring: a sound of “gravel” in the pump and/
or an increase in pump RPM with a corresponding
decrease in discharge pressure. Most modern
fire pumps now have pressure governor systems
which have built in cavitation protection.

Cavitation

How well did you know this?

Not at all

Perfectly

Pump with one or more
impellers that utilize centrifugal force to move
water throughout the pump.

Centrifugal Pump

How well did you know this?

Not at all

Perfectly

NFPA standard
for the gallons per minute per square foot of foam
needed for extinguishment of flammable liquid
fires. For hydrocarbons, the rate is 0.1 GPM/ft².
For polar solvents the rate is 0.2 GPM/ft²

Critical Application Rate (CAR)

How well did you know this?

Not at all

Perfectly

Critical velocity is the point
at which the speed of water from a centrifugal
pump creates so much turbulence that it makes it
impossible to move any more water. Centrifugal
pumps are able to take advantage of incoming
pressure to produce discharge pressures and
flow rates past their rated capacity and up to
critical velocity.

Critical Velocity

How well did you know this?

Not at all

Perfectly

The height that a column
of water can be lifted in sufficient quantity to
provide a reliable fire flow. Per IFSTA standard
this is 14.7 feet at sea level.

Dependable Lift

How well did you know this?

Not at all

Perfectly

The quantity of water flowing from an
opening expressed in GPM. We figure discharge
flow from solid bore nozzles and solid stream
orifices such as a hydrant port using Freeman’s Formula: GPM = 29.7 x D² x √NP

Discharge

How well did you know this?

Not at all

Perfectly

The process of obtaining water from a
static source and transferring it into a pump that
is above the source’s level. Atmospheric pressure
onto the water surface forces the water into the
pump where a partial vacuum has been created.

Drafting

How well did you know this?

Not at all

Perfectly

Operation where a strong hydrant
is used to supply two pumpers by connecting the
pumpers intake to intake. The second pumper
receives the excess water not being pumped by
the first pumper, which is connected directly to
the water supply source.

Dual Pumping

How well did you know this?

Not at all

Perfectly

Refers to application
percentage rate settings for eductors- 3% for
hydrocarbons and 6% for polar solvents. Class A
foam application percentage rates will vary from
0.1% - 1.0% based on situational need

Eductor rate (ER)

How well did you know this?

Not at all

Perfectly

Gain or loss of pressure
in a hoseline due to a change in elevation

Elevation Pressure (EP)

How well did you know this?

Not at all

Perfectly

An expansion ratio
assigned to aeration nozzles and foam expanding
attachments used as part of a formula to calculate
the amount of area that aerated foam will cover.

Expansion rating ratio

How well did you know this?

Not at all

Perfectly

Point at
which the fire department can connect into a
sprinkler or standpipe system to boost the water
pressure and flow in the system. The standard
PDP for sprinkler systems is 150 PSI.

Fire department connection (FDC)

How well did you know this?

Not at all

Perfectly

The average weight (per ft2) of the
contents of the room. The typical bedroom has
an average load of 4.3 lbs./ft2.

Fire load

How well did you know this?

Not at all

Perfectly

Defined as a stream of water or
water solution that leaves a nozzle until it reaches
its desired destination. There are three basic
types of streams: solid, fog, and broken streams.
The goal of a good fire stream is to hit the target
at the desired GPM. Characteristics include:
maintaining continuity without breaking into a
shower or spray and remaining stiff enough to
attain the required height despite a moderate
breeze

Fire stream

How well did you know this?

Not at all

Perfectly

Pressure created by the rate of
flow or velocity of water coming from a discharge
opening (measured using a Pitot gauge).
Sometimes referred to as Velocity Pressure.

Flow pressure

How well did you know this?

Not at all

Perfectly

A simple measurement of weight, usually
expressed in lbs. or kilograms. Force is produced
by gravity and/or the centrifugal fire pump.

Force

How well did you know this?

Not at all

Perfectly

The loss of pressure created by
turbulence of water moving against the interior
walls of hose, pipe, and fittings.

Friction loss

How well did you know this?

Not at all

Perfectly

The total quantity of combustible
contents of a building, space, or fire area including
interior finish and trim. Expressed in heat units of
the equivalent weight in wood.

Fuel load

How well did you know this?

Not at all

Perfectly

A unit expressing rate of discharge. Used when calculating water flowing/ fire flows.

Gallons per minute (GPM)

Pressure generated by the weight of a column of water above the pump. For every 1-foot increase in elevation, .434 PSI is gained.

Head pressure

A large caliber hose stream capable of flowing 350 GPM or more. Also defined as a fire stream that is too large to be controlled safely when hand held or without mechanical aid.

Master stream

This is the height a pumper in good condition can be expected to lift water at draft. Generally, this is considered 2/3 of theoretical lift, or between 22 and 25 feet

Maximum lift

75% of the total capacity of an engine. This is the maximum flow for an engine during a relay operation (NFPA standard).

Maximum dependable flow

A specific value assigned to each size of hose when formulating friction loss.

Multiplier

The amount of water (in GPM) needed to control the fire within 1 minute.

Needed fire flow

The actual amount of pressure being produced by the pump. The difference between the intake pressure and the discharge pressure. Expressed as: Net PDP = discharge pressure - incoming supply pressure.

Net pump discharge pressure

Pressure in a water system during regular domestic consumption.

Normal operating pressure

The velocity pressure at which water is discharged from the nozzle.

Nozzle pressure (NP)

Counterforce directed against a person holding a nozzle or a device holding a nozzle by the velocity of water being discharged

Nozzle reaction (NR)

When a two-stage pump transfer valve is set in volume. The source water flows from the intake manifold into the eye of both impellers simultaneously. Each of the impellers pumps water at its rated pressure while flowing 50% of the rated capacity of the pump; therefore, the total amount of water the pumper can deliver is equal to the sum of the two stages. If the pump is rated at 1750 GPM at 150 PSI, each impeller will flow 875 GPM

Parallel (Volume)

Instrument that is inserted into a stream of water to measure the velocity pressure of a stream

Pitot gauge

Defined as the amount of pressure applied to one square inch of surface area. This is the pressure we read on fire pump gauges (PSIG Gauge), which is PSI + existing atmospheric pressure. But for fire service purposes, we consider it PSI.

Pounds per square inch (PSI)

Force per unit area exerted by a liquid or gas measured in lbs./in2 (PSI) or kilopascals (kPa)

Pressure (P)

Term used to denote the removal of air from a centrifugal pump and intake hose, creating a partial vacuum in preparation for receiving water at atmospheric pressure.

Prime

A positive displacement pump which pumps air out of centrifugal pumps. These pumps are usually piston or rotary type. When a priming pump is activated, air and water are discharged from the centrifugal pump creating a partial vacuum of less than 14.7 PSI (Atmospheric pressure). These pumps are necessary to create a pressure differential between the outside atmosphere and the inside of the centrifugal pump so priming and drafting water is possible

Priming pump

Actual pressure of the water as it leaves the pump and enters the hoseline; total amount of pressure being discharged by a pump. PDP is expressed as: PDP = NP + FL ± EP +AFL. Or as PDP = NP + TPL (total pressure loss = FL ± EP + AFL)

Pump discharge pressure (PDP)

Term to describe the percentage of water that is actually converted to steam when applied to a fire. The accepted amount is 80%.

Reasonable efficiency

Using two or more pumpers to move water over a long distance by operating them in series. Water discharged from one pumper flows through hoses to the inlet of the next pumper, and so on. The source pumper is connected to the water supply source. The relay pumper or pumpers receive water from the source pumper and boost the pressure to the attack pumper located at the fire scene.

Relay pumping

Pressure at the test hydrant while water is flowing; represents the pressure remaining in the water system while the test water is flowing and is that part of the total pressure that is not used to overcome friction or gravity while forcing water through the hose, pipe, or fittings, and adapters.

Residual pressure

When a two-stage pump transfer valve is set in pressure. All of the water from the intake manifold is directed into the eye of the first impeller. Depending on the pump manufacturer, the first stage (impeller) increases the pressure and discharges 50%-70% of the volume capacity through the transfer valve and into the eye of the second impeller. The second impeller increases the pressure and delivers water at a higher pressure into the pump discharge port. All of the water pumped passes through each impeller

Serie (pressure)

Hose appliance that has two or more female inlets and a single male outlet. Equipped with clapper valves that prevent water from being discharged through an open outlet.

Siamese

This is the amount of heat needed to raise the temperature of a specific quantity of material, and the amount of heat needed to raise the temperature of an identical weight of water by the same number of degrees. Measured in BTU’s

Specific Heat

The stored potential energy available to force water through pipes, fittings, fire hose, and adapters while water is at rest

Static pressure

Short relay operation in which the pumper connected to the water source pumps into the intake of the second pumper. Second pumper then boosts the pressure of the water even higher. This method is used when pressures higher than the capabilities of a single pump are required.

Tandem pumping

Theoretical, scientific height that a column of water may be lifted by atmospheric pressure in a true vacuum; at sea level it is considered 33.9 feet. The height will decrease as elevation increases. Expressed as 14.7 x 2.304 PSI = 33.9

Theoretical lift

Consists of the pounds per square inch (PSI) x number of square inches in a crosssection of an area upon which force is exerted

Total pressure

Two impellers are mounted in a single housing. The two impellers are usually mounted on a single shaft driven by a single drive train. The impellers are identical, have the same capacity, and can be arrange in either volume (parallel) or pressure (series).

Two stage centrifugal pump

A Centrifugal pump that delivers 100% of its capacity at 150 PSI discharge pressure, 70% capacity at 200 PSI, and 50% of capacity at 250 PSI as measured from draft lifting water higher than 10 feet.

Type 1 pumper

In the fire and emergency services, a pressure that is less than atmospheric pressure; a vacuum is needed to facilitate drafting of water from a static source.

Vacuum

Speed at which water travels through fire hose - measured in feet per second (FPS).

Velocity

The volute consists of the casing that receives the fluid being pumped by the impeller. It is a curved funnel, within a centrifugal pump, that increases in area as is approaches the discharge port. The volute directs the flow through to the discharge.

Volume

Force created by the rapid deceleration of water; causes a violent increase in pressure that can be powerful enough to rupture piping or damage fixtures. Generally resulting from closing a nozzle or valve too quickly.

Water hammer

Hose appliance with one female inlet and two or more male outlets; the outlets are usually smaller than the inlet and are gated.

Wye

weight of 1 cubic foot of water

62.4 lbs.

Weight of one gallon of water

8.34 lbs.

percentages of effect one gallon of water has on fire

80% will have effect on fire (steam), 20% will be wasted

10/15/25 rule formula

10% drop from initial residual compound reading = additional 3 times the current GPM flow 15% drop from initial residual compound reading = additional 2 times the current GPM flow 25% drop from initial residual compound reading = additional 1 time the current GPM flow

Master stream tip size and GPM

1 3/8" - 500 gpm 1 1/2" - 600 gpm 1 3/4" - 800 gpm 2" - 1000 gpm

As a general rule, each open head requires approximately how much gpm?

20 GPM

Sprinkler head GPM equatio

GPM = 0.5 x P + 15 P = Sprinkler head pressure (typically 7-10 PSI)

Starting pressure of sprinkler system?

Starting pressure will be 150 PSI

Sprinkler system are annually tested at?

175 PSI, FD should not exceed this pressure

How many head can 1,750 gpm pump supply?

88 heads at 150 PSI

3 types of standpipe systems are...

* Class 1 – 2 ½” outlets for firefighting * Class 2 – 1 ½” inch hose outlets for occupant use * Class 3 – Combination standpipe, integrates class 1 and 2 into one system.

Factors that determine relay pumping need:

- GPM needed at the scene - The distance water needs to be pumped - Size of the pumpers on the scene.

Factors when setting up maximum distance relay (standard):

- GPM required for incident (how much water is attack pumper flowing) - Maximum distance between pumpers - Size of pumpers available (smallest pump will determine flow) - Number of pumpers needed

Considerations as engineer on relay pumping

- Keep 20 PSI residual pressure - Max net PDP will be approximately 180 psi. - FL +/- EP+20= starting pressure from one pump to the next.

Foam percentages

- 0.1% class A fire (overhaul) - 0.4% class A fire (fire attack) - 3% class B fire (Hydrocarbons - fuels that float on water or won't mix with water) - 6% class B fire (polar solvents)

Definitions and general knowledge Flashcards

SKCFTC pump manual