Chapter 4 - Water Supply Systems Flashcards
Despite the development of many new innovations and techniques for controlling and fighting fires, _________ continues to be the primary extinguishing agent.
water
p 77
Three reasons water is used as the primary extinguishing agent:
*
*
*
- availability
- affordability
- effectiveness
p 77
Water is _________ and has its ________ density close to its freezing point.
heaviest / highest
p 78
Water is __________ and has its _________ density close to its boiling point.
lightest / lowest
p 78
For fire protection purposes, ordinary fresh water is generally considered to weigh _____ lb/ft^3 or ______ pounds per gallon.
62.4 / 8.34
p 78
The primary way water extinguishes fire is by _________, namely ____________ _______ from the fire.
cooling / absorbing heat
p 78
Another way water extinguishes is _____________, which occurs when _________ is excluded from the fire.
smothering / oxygen
p 78
Smothering works especially well on the surface of burning liquids that are __________ than water.
heavier
p 78
__________ _________ is a measure of the heat absorbing capacity of a substance, which means the amount of heat required to change a unit quantity of a substance by 1 degree in temperature.
Specific heat
p 79
The amount of heat transfer is usually measured in _________ __________ ________ or in the International System of Units (SI) as _________.
British thermal units (Btu) / joules
p 79
A ______ is the amount of heat required to raise the temperature of 1 lb of water 1*F.
Btu
p 79
The _______, also a unit of work, has taken the place of the calorie in the SI heat measurement.
joule
p 79
The ratio between the amount of heat needed to raise the temperature of a specified quantity of a material and the amount of heat needed to raise the temperature of an identical quantity of water by the same number of degrees ?
Specific heat
p 79
This is the quantity of heat absorbed by a substance when it changes from a liquid to a vapor ?
latent heat of vaporization
p 79
The temperature at which a liquid absorbs enough heat to change to vapor is known as the ?
boiling point
p 79
In fire fighting terms, if water from a 100 gpm fog nozzle is projected into a highly heated area, it can absorb approximately ___________ Btu of heat per minute if all of the water is converted to steam.
934,600 Btu
p 80
The speed with which water absorbs heat increase in proportion to the _________ _________ exposed to the heat.
water surface
p 80
If water is divided into _______ _______, the rate of heat absorption increases hundred of times.
many drops
p 80
_____________ helps cool the fire by driving heat and smoke from the area.
Expansion
p 81
The _____________ of the fire area will determine the amount of heat expansion. At _____ *F, water expands approximately ________ times its original volume.
temperature / 212 / 1700
p 81
The density of liquids in relation to water is known as ________ _________. Water is given the value of _____.
specific gravity / 1
p 81
Liquids with a specific gravity less than 1 are _________ than water and therefore ?
lighter / float on water
p 81
Liquids with a specific gravity greater than 1 are _________ than water and will ?
heavier / sink to the bottom
p 81
If the other liquid also has a specific gravity of 1, it ?
mixes evenly with water
p 81
Most flammable liquids have a specific gravity of ?
less than 1
p 81
Advantages of water:
* _______ - __________ capacity - Water has a greater ______ - __________ capacity than other common extinguishing agents due to the relatively large amount of heat required to change water to ________.
- Heat-absorbing / heat-absorbing / steam
p 81
Advantages of water:
* _________ _______ - Water applied to a fire by fog patterns and deselected solid streams greatly increases its _________ _______ and causes heat to be absorbed more rapidly.
- Surface area / surface area
p 81
Advantages of water:
- ____________ - In most areas, water is plentiful and readily __________.
- _______ - Water is relatively inexpensive when compared to other commercially available extinguishing agents.
- Availability / available
- Cost
p 81
Disadvantages of water:
- _______ __________ _________ - Water does not readily soak into dense materials.
- ____________ - Water is ___________ with certain substances such as combustible metals.
- Low _________ and _____________ - Water allows radiant heat to easily pass through it.
- ___________ point - In cold climates, ice may form in and on equipment, causing the potential for malfunction.
- High surface tension
- Reactivity / reactive
- opacity and reflectivity
- Freezing
p 81-82
Disadvantages of water:
- ______________ - Water __________ electricity, which can be a hazard when fire fighting operations are taking place around energized electrical equipment.
- ______________ runoff - Water can carry ______________ away from the fire scene.
- _________ - Excessive water __________ can contribute to structural instability.
- Conductivity / conducts
- Contaminated / contaminants
- Weight / weight
p 82
In fire service terminology, _________ refers to the force that moves water through a conduit - either a pipe or hose.
pressure
p 82
A 1 in^2 column of water 1 ft high exerts a pressure _______ psi at its base.
0.433 psi
p 82
Six principles of pressure:
- First Principle: Fluid pressure is ______________ to any surface in which it acts.
- Second Principle: Fluid pressure at a point in a fluid at rest is the same intensity in ______ ___________ - In other words, fluid pressure at a point in a fluid at rest has no ___________.
- perpendicular
- all directions / direction
p 83
Principles of pressure:
- Third principle: Pressure applied to a confined fluid will be transmitted _________ in all directions.
- Fourth principle: The pressure of a liquid in an open vessel is proportional to its ________
- equally
- depth
p 83
Principles of pressure:
- Fifth principle: The pressure of a liquid in an open vessel is proportional to the ________ of the liquid.
- Sixth principle: The pressure of a liquid on the bottom of a vessel is independent of the _________ of the vessel.
- density
- shape
p 84
Principles of pressure:
Regardless of the shape of the container and its opening, the ____________ of the water column is the same for a given height.
pressure
p 84
Atmospheric pressure is greatest at ?
low altitudes
p 85
At sea level, atmospheric pressure is ______ psi.
14.7
p 85
As the altitude increases, atmospheric pressure _____________.
decreases
p 85
- Alternate term for pressure, especially pressure due to elevation. For every 1 foot increase in elevation ________ psi is gained.
Head / .434 / also called head pressure
p 85
To convert to head pressure, divide the number of feet by ________.
2.304
p 86
- The height of a water supply above the discharge orifice.
Elevation Head
p 86
If the nozzle or orifice flowing water is below the pump there will be a ___________ ________. Alternatively, if the nozzle or orifice is above the pump, then there will be a ____________ ________.
pressure gain / pressure loss
p 86
_________ _____________ is defined as stored potential energy available to force water through pipes, fittings, fire hose and adapters.
Static pressure
p 86
The term _________ means at rest or without motion.
static
p 86
____________ ____________ pressure is that pressure found in a water distribution system during normal consumption demands.
Normal operating
p 86
_____________ ____________ is that part of the total available pressure not used to overcome friction loss or gravity while forcing water through pipes, fittings, fire hose, and adapters.
Residual pressure
p 86
______________ means a remainder of that which is left.
Residual
p 86
It is important to remember that residual pressure is measured at the location where a _____________ reading is taken, not at the point of water flow.
pressure
p 86
________ _____________ is the forward velocity pressure while water is flowing.
Flow pressure
p 86
A _______ _______ is used to measure flow pressure at the hydrant.
pitot tube
p 87
- The part of the total pressure lost as water moves through a hose or piping system; caused by water turbulence and the roughness of interior surfaces of hose or pipe.
Friction loss
p 87
Friction loss:
First principle: If all other conditions are the same, friction loss varies proportionately with the __________ of the hose or pipe.
length
p 87
Friction loss
Second Principle: When hoses or pipes are the same size, friction loss varies approximately with the square of the increase in the ____________ of the ________.
velocity / flow
p 88
Friction loss:
Third principle: For the same discharge, friction loss varies inversely to the _________ power of the diameter of the hose.
Fifth
p 88
Friction loss
Fourth principle: For a given flow velocity, friction loss is approximately the same regardless of the _____________ on the water.
pressure
p 88
In fire fighting operations, any extra ________ should be eliminated to reduce excess friction loss.
hose
p 88
Water for human consumption comes from one of two basic sources: ?
from a well or a public (municipal) water system
p 88
Every water supply system has to have a __________ _________ that is both adequate and reliable for the area being served.
supply source
p 90
The second component of a water supply system is the _____________ or _____________ facility.
processing or treatment
p 90
The third component of a water supply system is a means of ?
moving water
p 90
This system uses one or more pumps to take water from the primary source and discharge it into the distribution system ?
Direct pumping system
p 91
This system uses a primary water source located at a higher elevation than the distribution system ?
Gravity system
p 91
This system uses a combination of direct pumping and gravity systems ?
Combination system
p 93
The last components of the water supply system are the _________ and ______________ systems.
storage and distribution
p 93
______________ _________ are used to balance the pressure on a water system during periods of peak demand.
Elevated tanks
p 94
To reduce the effect of friction loss on water pressure, fire hydrants are typically supplied from ?
two or more directions
p 94
- Fire hydrant that receives water from two or more directions
Circulating feed
p 94
- Large pipes (mains) with relatively widespread spacing that convey large quantities of water to various points of the system for local distribution to the smaller mains.
Primary feeders
p 94
- Network of intermediate sized pipes that reinforce the grid within the various loops of the primary feeder system and aid the concentration of the required free flow at any point.
Secondary feeders
p 94
- Grid arrangements of smaller mains serving individual fire hydrants and blocks of customers.
Distributors
p 95
Most commonly, private water supply systems receive their water from a ?
municipal water supply system
p 96
The performance of the distribution system is affected by several variables, including the following:
- Piping ____________
- Pipe __________
- Piping _____________
- materials
- diameter
- arrangements
p 97
Piping systems are generally made of _______ iron, _________ iron, __________ cement, steel, _________ ________ (______), plastic or concrete.
cast / ductile / asbestos / polyvinyl chloride (PVC)
p 97
The __________ __________ of the pipe should be such that it offers the least potential for friction loss.
internal surface
p 97
It is recommended that fire hydrants supply mains be at least ____ inches in diameter. These should be closely gridded by ____ inch mains at intervals of not more than _______ feet.
6 / 8 / 600
p 98
A ________ ____________ is an arrangement of water mains where the water will be supplied to a given point from more than one direction.
loop system
p 98
A _______ __________, also known as a complex loop, is a large piping distribution system that is characterized by multiple water pathways.
grid system
p 98
A well designed grid system uses pipe sizes of ___ inch and larger, which is one of the identifying features of a ___________ distribution system.
8 / strong
p 98
A _______-_____ ________ is a single pipe that extends from a looped or grid system that is supplied from one direction.
dead-end main
p 98
__________ are placed on water distribution systems to provide the ability to isolate portions of the system.
Valves
p 99
Ideally, these valves should be located on each branch at the intersection of the mains and no more than _______ feet apart in high-value areas.
500
p 99
An ____________ _________ visually shows the position of the valve: fully open, fully closed or partially closed.
indicating valve
p 100
Two common indicator valves are the ______ __________ ________ and the ____________ ________ and _______.
post indicator valve (PIV) / outside stem and yoke
p 100
OS&Y
The threaded portion of the stem is out of the yoke when the valve is _________ and inside the yoke when the valve is _________.
open / closed
p 100-101
____________ stem gate valves should be marked by a number indicating the number of turns necessary to completely close the valve.
Nonrising
p 102
___________ valves are tight closing and they usually have a rubber or a rubber composition seat that is bonded to the valve body.
Butterfly
p 103
The most common type of hydrant used in the United States is the _____-__________ type.
dry-barrel
p 103
A common variety of dry-barrel hydrant has two _____ outlets and one ______ outlet.
2 1/2 inch / 4 1/2 inch
p 103
Whether they are wet-barrel or dry-barrel, hydrants are attached to the waters main by a short piece of pipe called a __________. This _________ should be at least ____ inches in diameter.
branch / branch / 6 inches
p 104
Communities are given credit for those hydrants that are within a _______ feet of the property to be protected.
1000
p 106
In addition, hydrants must deliver a minimum of ______ gpm at _____ psi residual pressure for a duration of ____ hours.
250 / 20 / 2
p 106
In more congested areas and high fire risk areas, it is recommended that hydrants be located ______ feet apart, one hydrant at every street _____________, in the middle of ______ _________ and near the end of a long ______-______ street.
300 / intersection / long blocks / dead-end
p 106
