ifsta Chapter 5 Flashcards
Water is considered to be
) incompressible
Water can be used to smother fires in what kind of combustible liquids?
Those with a specific gravity higher than 1
What principle of water makes it somewhat difficult to soak into dense material?
Its high surface tension
Water has the ability to extinguish fire in several ways
It can cool or absorb
heat from the fire, as well as smother (exclude oxygen from) fires
The term force is a simple measure of weight that is expressed in what unit of measurement:
pounds or Newtons.
The term pressure may have a variety of meanings. In this manual, pressure is defined as force per unit area and or?
Pressure may be expressed as pounds per square foot (psf), pounds per square inch (psi), or kilopascals (kPa).
The weight of 1 cubic foot of water
62.4lbs
A 1-inch square column of water 1 foot high therefore exerts a pressure at its base
0.434
a column of water 2.304 feet high exerts pressure of
1psi
The speed at which a fluid travels through a hose or pipe is determined by the pressure upon that fluid as well as the size of the orifice through which it is flowing.
velocity
Atmospheric pressure that surrounds the earth is
depth and density, exerting pressure on everything. This pressure is greatest at low altitudes and least at very high altitudes.
Atmospheric pressure is commonly measured using what substance
mercury
how many times denser is mercury compared to water?
mercury is 13.55 times denser than water
In the fire and emergency services, a pressure that is somewhat less than atmospheric pressure;
vacuum
the height of a water supply above the discharge orifice
Head
The water flow definition of ________________________________ is stored potential energy avail-able to force water through pipes, fittings, hose, and adapters.
Static Pressure
_________ is the portion of the total available pressure not used to overcome friction loss or gravity while forcing water through pipes, fittings, hoses, or adapters.
Residual Pressure
__________refers to the center line of the pump or the bottom of a static water supply source above or below ground level. fire and rescue term
Elevation
The pressure losses or gains due to gravity _______
Elevation Pressure or also known Elevation Loss
Loss of pressure created by the turbulence of water moving against the interior walls of the hose or pipe.
Friction Loss