Pump Manual - Definitions Flashcards
Atmospheric pressure
14.7
Affects amount of vacuum that can be generated inside a pump and how high water can be drafted
Back flushing
Flowing water through a discharge and out of an intake to remove debris
British Thermal Unit (BTU)
energy needed to cool or heat one point of water by one degree Fahrenheit
Critical application rate (CAR)
GPM per sqft of foam needed to extinguish flammable liquid fires
- 1 GPM/sqft for hydrocarbons
- 2 GPM/sqft for polar solvents
Critical velocity
Point at which sped of water from a centrifugal pump creates so much turbulence that it makes it impossible to move any more water
Dependable lift
height that a column of water can be lifted to provide a reliable fire flow
14.7 ft at sea level
Freeman’s formula
Calculates GPM flow from solid bore/hydrant
GPM = 29.7 x D^2 x sqrt(NP)
Dual pumping
Using a strong hydrant to supply two pumpers by connecting intake to intake
Eductor rate (ED)
Application % for eductors:
3% for hydrocarbons
6% for polar solvents
Class A: 0.1 - 1.0%
Expansion rating ratio
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
FDC standard pressure for spinklers
150 PSI
Fire Load
Avg weight lbs/sqft of contents of a room
Avg begroom has 4.3 lbs/sft
Fuel load
Total quantity of combustible contents of a building, space or fire area including interior finish and trim.
Expressed in heat units of equivalent weight in wood
Head pressure
For every 1’ increase in elevation .434 PSI increase
e.g. 5 lbs per floor
Master stream
large caliber hose that flows 350 GPM or more
Maximum lift
Height a pumper in good condition can be expected to life water at draft.
Generally considered 2/3 of the theoretical life, or between 22-25 feet
Max dependable flow
75% of the total capacity of an engine
this is the max flow for an engine during a relay operation
Needed Fire Flow (NFF)
The amount of water (in GPM) needed to control the fire within 1 min
Normal operating pressure
Pressure in a water system during regular domestic consumption
Parallel (Volume) mode
In a two-stage pump, source water flows from intake into the eye of both impellers simultaneously
Each impeller pumps 50% of that rated GPM capacity of the pump
Priming Pump
Positive displacement pump that pumps air out of centrifugal pumps…when activated, reduces pressure inside pump below 14.7 (atmospheric pressure)
Pump Discharge Pressure Formula
PDP = NP + FL +- EP + AFL
Reasonable Efficiency
% of water that is actually converted into steam in a fire = 80%
Series (Pressure) mode
First stage impeller increases pressure and dishcarges 50-70% of the volume capacity through the transfer valve and into the eye of the 2nd impeller
Specific heat
amount of heat needed to raise the temp of a specific quantity of material, and the amount of heat needed to raise the temp of a identical weight of water by the same # of degrees (measured in BTUs)
Static pressure
Stored potential energy available to force water through pipes, fittings, fire hose, and adapters while water is at rest
Tandem pumping
Short relay. Pumper at water source pumps to the intake of second pumper.
Used when pressures higher than the capabilities of a single pump are required.
Theoretical lift
Theoretic height that a column of water can be lifted by atmospheric pressure in true vacuum
33.9 ft at sea level (14.7 x 2.304 psi = 33.9)
Total pressure
PSI X number of square inches in a cross-section of an area upon which force is exerted
Type 1 Pumper
100% of its rated capacity at 150 psi
70 % of its rated capacity at 200 psi
50% of its rated capacity at 250 psi
Measured from draft lifting water at least 10 ft
