Chptr 5- Principles Of Water Flashcards
What remained the most common weapon in the firefighter’s arsenal?
Plain water
Freezing and boiling point of water
32 (0° C) degrees and 212 degrees (100° C)
Ordinary fresh water is considered to weigh ___lb/gal
8.3
What are ways that a water can extinguish fire
Cool/absorb heat from the fire, as well as smother (exclude oxygen from) fires.
Specific gravity of water
1.0
Is gasolines specific gravity less than water or more? Does that make it float on top of water or water on top of gasoline?
Less than
Gasolines specific gravity= 0.72-0.76
Gasoline on top of water
The greater the ______ ____ of water exposed, the more rapidly heat is absorbed.
Surface area
Water converted to steam occupies approx. ____ times its original volume
1,700
Water has a ____ surface tension,
Making it somewhat difficult to soak into dense materials
High
_______ ______ may be mixed with water to reduce its surface tension and increase its penetrating ability
Wetting agents
Water is a ____ conductor of electricity
Good
Force per unit area exerted by a liquid or gas measured in pounds per square inch (psi)
Pressure
Simple measure of weight, usually expressed in lbs or kg
Force
The speed at which a fluid travels through a pipeline or hose is often called ________
Velocity
Pressure applied to a confined fluid is transmitted _______ in all directions
Equally
The pressure of a liquid in an open vessel is proportional to its _____
Depth
Mercury is _____ times denser than water
13.55
Pressure of a liquid in an open vessel is proportional to the _______ of the liquid
Density
Mercury also has a specific gravity _______ than one, as it will sink in the water
Greater
The pressure of a liquid at the bottom of a vessel is ___________ of the shape of the vessel.
Independent
Atmospheric pressure at sea level ____ psi, which is considered standard atmospheric pressure
14.7
Any pressure less than atmospheric pressure is called _______
Vacuum
____ refers to the height of a water supply above the discharge orifice
Head
The water flow definition of ______ ________ is stored potential energetic available to force water through pipes, fittings, hose, and adapters.
Static pressure
_____ ________ may be produced by an elevated water supply, atmospheric pressure, or a pump.
Water pressure
If water is not moving, the pressure exerted is ______
Static
______ means at rest, or without motion.
Static
Difference between static pressure and normal operating pressure
The friction caused by water flowing through pipes, valves, and fittings on the system
________ _________ 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 is the remainder or that which is left
Residual pressure
While water is flowing from a discharge opening, the forward velocity pressure is considered the ____ ________
Flow pressure
________ is the position of an object in relation to sea level
Altitude
_________ refers to the center line of the pump or bottom of a static water supply course above or below ground level
Elevation
Gain or loss in pressure of a hose line due to change of elevation
Elevation pressure
Above sea level, atmospheric pressure decreases approximately ___ psi for every 1,000 ft
0.5
Loss of pressure created by the turbulence of water moving against the interior walls of the hose or pipe
Friction loss
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
Water hammer
Rivers and lakes are two examples of ______ _____ supply
Surface water
Water wells or water producing springs are two examples of ______ _____ supply
Ground water
Primary water supply can be obtained from either ______ water or ______ water
Surface, ground
What are the 3 methods of moving water in a system
Direct pumping system
Gravity system
Combination system
Part of an overall water supply system that receives the water from the pumping station and delivers it throughout the area to be served
Distribution systems
Water supply system that utilizes lateral feeders for improved distribution
Grid system
Fire hydrant that receives water from only one direction is known as a
Dead end hydrant
When a fire hydrant receives water from two or more directions, it is said to have __________ _____ or a looped line
Circulating feed
A distribution system that provides circulating feed from several mains constitutes a ____ ______
Grid system
-
-
Primary feeders
Secondary feeders
Distributors
One of the most important factors in a water supply system is the
Water departments ability to promptly operate the valves during emergency or breakdown of equipment
Valves should be inspected and operated ______ by the water supply utility
Yearly
An __________ valve visually shows whether the gate or valve seat is open, closed, or partially closed.
Indicating
Two common indicating valves
Outside screw and yoke
Post indicator valve
This type of indicator valve is most commonly used on sprinkler systems
Outside screw and yoke
This type of indicator valve is commonly used on private water supply systems
Post indicator valve
Most common type of valve used on public water distribution systems, normally installed in valve boxes or manholes
Nonindicating valve
3 basic rates of consumption are considered by engineers when they design water distribution systems
Average daily consumption (ADC)
Maximum daily consumption (MDC)
Peak hourly consumption (PHC)
What type of supply systems are most commonly found on larger commercial, industrial, or institutional properties, but may also be found in some residential developments?
Private water supply systems
Private water supply systems maintain _______ piping for fire protection and domestic/industrial services.
Separate
What are the purposes of a private water supply system?
Provide water strictly for fire protection,
For sanitary and fire protection,
And for fire protection and manufacturing processes
Tip sizes and flows of master stream
1 3/8”-502 GPM
1 1/2”- 598 GPM
1 3/4”- 814 GPM
2”- 1063 GPM
Water is a compound when two ________ atoms combine with 1 ______ atom
Hydrogen
Oxygen
At waters freezing point it converts to a ______, and at its boiling point it converts to a ___
Solid
Gas
Water is considered to be virtually ______________
Imcompressible
Water’s density, or its weight per unit of volume is measured in pounds per cubic foot (kg/m^3).
Ordinary fresh water is considered to weigh
_kg/liter
__lb/gallon
___lb/ft^3 (cubed)
____kg/m^3 (cubed)
1 kg/liter
8.3lb/gallon
62.4lb/ft^3
1000kg/m^3
Water may be used to smother fires in a combustible liquid when the liquid’s specific gravity is _______ than 1.
Higher
Water has _______ heat-absorbing capacity than other common extinguishing agents
Greater
A column of water ____ feet high exerts pressure of 1 psi at its base.
An elevated water supply ___ft higher than your hydrant will deliver 43.4 psi at the hydrant
2.304
100’
Radiant heat ______ passes through water, rendering water curtains ___________
Easily
Ineffective
Fluid pressure is ____________ to any surface on which it acts
Perpendicular
Fluid pressure at a point in fluid at rest is the ____ intensity in all directions
Same
Pressure applied to a confined fluid is transmitted _______ in all directions
Equally
___________ pressure that surrounds the earth has depth and density, exerting pressure on everything.
Atmospheric
Absolute zero pressure is called a
Perfect vacuum
Water pressure may be produced by an _______ _____ ______, ___________ ________, or a ____.
Elevated water supply
Atmospheric pressure
A pump
The pressure found in a water distribution system during normal consumption demands is considered the _______ _________ ________
Normal operating pressure
FL varies directly with the ______ of the hose or pipes
Length
FL develops much ______ than the change in velocity
Faster
FL in a hose will ________ when the diameter of the hose is increased
Decrease
FL for a given velocity is approximately the _____, regardless of the pressure on the water
Same
The smaller the hose, the _______ the velocity needed to deliver the same volume of a larger hose.
Greater
FL in a water system _________ as the length of the hose or piping increases.
Increases
For water supply, most communities use a
Combination of gravity systems and direct pumping systems
Control valves in public water distribution systems are generally ____ valves
Gate
Most commonly, private water supply systems receive their water from
Municipal water supply systems
In municipal water systems, fire hydrants and water for domestic/industrial use are connect to the ____ mains
Same
