Chapter 5: Principles Of Water Flashcards
For fire protection purposes, _______ is 62.4 lb/ft3.
Water density
Water may also be used to smother fires in combustible liquids whose specific gravity is higher than ______.
1
Water is a solid at ______.
32°F
Water is a liquid at _______.
32°F to 212°F
Water is a gas above _____.
212°F
The greater the _______ of water exposed, the more rapidly heat is absorbed.
Surface area
At 212°F, water converted to steam occupies approximately _______ times its original volume.
1,700
__________: Force per unit area exerted by a liquid or gas measured in pounds per square inch
Pressure
__________: A simple measure of weight, usually expressed in pounds or kilograms.
Force
How many principles of pressure are there?
6
The first principle of pressure states fluid pressure is _______ to any surface on which it acts.
Perpendicular
The second principle of pressure states fluid pressure at a point in fluid at rest is the same ________ in all directions
Intensity
The third principle of pressure-pressure applied to a confined fluid is transmitted ________ in all directions.
Equally
Fourth principle of pressure-the pressure of a liquid in an open vessel is proportional to its_______.
Depth
Fifth principal of pressure-the pressure of a liquid in an open vessel is proportional to the ________ of the liquid.
Density
The sixth principle of pressure-the pressure of a liquid at the bottom of the vessel is __________ of the shape of the vessel
Independent
Atmospheric pressure is greatest at ________ and least at________.
Low altitudes
High altitudes
Atmospheric pressure at sea level is ______ psi, which is considered standard atmospheric pressure.
14.7
_________: A pressure that is somewhat less than atmospheric pressure; needed to facilitate drafting of water from a static source.
Vacuum
Absolute zero pressure is called a________.
Perfect vacuum
_________: The height of water supply above the discharge orifice.
Head pressure
__________: stored potential energy available to force water through pipes, fittings, and adapters.
Static pressure
_________: The pressure found in a water distribution system during normal consumption demands.
Normal operating pressure
__________: pressure at the test while water is flowing; the pressure remains in the water supply system while the test water is flowing and is the part of the total pressure that is not used to overcome friction or gravity while forcing water through pipes, fittings, and adapters.
Residual pressure
_________: height of a point above sea level or some other reference point.
Elevation
________: geographic position of a location or object in relation to sea level.
Altitude
When a nozzle is above the level of the pump, you will have ________.
Pressure loss
Above sea level, the lessening of ________ means fire department pumpers must work increasingly harder to produce the pressure required for effects of fire streams.
Atmospheric pressure
_________: loss of the pressure created by the turbulence of water moving against the interior walls of the hose or pipe.
Friction loss
6 causes of friction loss in a firehose:
Movement of water molecules against each other
Lining of fire hose/delaminating hose
Couplings
Sharp bends/kinks
Change in hose size or orifice by adapters
Improper gasket size
Friction loss in older hose may be as much as _____ greater than that of new hose.
50%
First Principle of Friction Loss- if all other conditions are the same, friction loss varies directly with the ________.
Length of hose or pipe
Second Principle of Friction Loss- when hoses are the same size, friction loss varies approximately with the square of the increase in the _________.
Velocity of the flow
Third Principle of Friction Loss- use _______ diameter hose size to reduce friction loss.
Larger
Fourth Principle of Friction Loss- for a given velocity, friction loss is approximately ________, regardless of the pressure on the water.
The same
The diameter of the hose determines the ________ for a given volume of water.
Velocity
________ will always be greatest near the source of supply and lowest at the furthest point in the system.
Flow pressure
If the velocity is increased beyond it’s practical limits, the friction will become so great that the entire system is agitated by resistance. This is known as _______.
Critical velocity
__________: A force created by the rapid deceleration of water; causes a violent increasing pressure that can be powerful enough to rupture piping or damage fixtures.
Water hammer
When a large volume of water is needed, the fire department should request the water utility department to _______ the water pressure in an area where there is a very large firefighting operation.
Increase
___________: uses one more pumps that takes water from the primary source and discharge it through the filtration and treatment process. From there, a series of pumps force water into the distribution system.
Direct pumping system
_________: uses a primary water source located at a higher elevation than the distribution system.
Gravity system
Most communities use a _________ of the direct pumping and gravity systems.
Combination
Water for fire protection may be available to some communities from storage systems, such as________ , that are considered a part of the distribution system.
Cisterns
Water may be treated by _______, _________, ________or the addition of chemicals, bacteria, or other organisms.
Coagulation
Sedimentation
Filtration
The fire department’s main concern regarding treatment facilities are that a _________ or ________ could disable the pumping stations or severely hampered the purification process.
Maintenance failure
Natural disaster
_________ is a compound of hydrogen and oxygen formed when two hydrogen atoms combine with one oxygen atom.
Water
___________: 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 system
A fire hydrant that receives water from only one direction is known as a __________.
Dead-end hydrant
_________: he water supply system that utilizes lateral feeders for improved distribution.
Grid system
With in a grid system, _______ are large pipe (mains), with relatively widespread spacing, that convey large quantities of water to various points for the system for local distribution to the smaller means.
Primary feeders
Within a grid system, ________ are networks of intermediate size pipes that reinforce to grid within the very loops of the primary feeder system and aid concentration of the required fire flow at any point.
Secondary feeders
__________: grid arrangement of smaller mains serving individual fire hydrants and blocks of consumers.
Distributors
The function of a ________ in a water distribution system is to provide a means for controlling the flow of water through the distribution piping.
Valve
__________: visually shows whether the gate or valve seat is open, closed, or partially closed.
Indicating valve
_________: A type of valve used to control underground water mains found on the supply main of installed fire protection systems. The operating system of the valve extends above ground, and a visual means is provided at the top of the post for indicating open or shut.
Post indicator valve
_________: type of control valve for sprinkler system in which the position of the center screw indicates wether the valve is open or closed.
Outside Screw and Yolk (OS & Y) Valve
_________ these are the most common types of valves used on most public water distribution systems.
Non-indicating valves
Friction loss can be reduced by ________ hydrants periodically.
Flushing
___________ are most commonly found on large commercial, industrial, or institutional properties.
Private water supply
Private water supply systems receive their water from a_________ water supply system.
Municipal
