Ch. 6: What is Water and Where Does it Come From? Flashcards
What by far, remains the most commonly used fire extinguishing agent?
water
What is water considered for all practical purposes?
incompressible
What abilities does water have to extinguish a fire?
cooling, absorbing heat from the fire; smothering, excluding oxygen
What govern the heat-absorbing ability of water?
specific heat and latent heat of vaporization
What is a measure of the heat-absorbing capacity of a substance?
specific heat
What is the amount of heat required to raise the temperature of 1 pound of water 1 degree F?
A BTU
What is 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 of any substance
Water absorbs ______ times as much heat as does an equal amount of carbon dioxide.
five
What is the quantity of heat absorbed by a substance when it changes from a liquid to a vapor?
latent heat of vaporization
What is the temperature at which a liquid absorbs enough heat to change to vapor known as?
boiling point
At its boiling point of 212 degrees F, water expands approximately how much its original volume?
1700 times
What is the tendency of a liquid to possess internal resistance to flow?
viscosity
What is the density of liquids in relation to water known as?
specific gravity
What is defined as force per unit area?
pressure
What is a simple measure of weight and is usually expressed in pounds or kilograms?
force
What is the weight of 1 cubic foot of water?
~62.5 lbs
What is the speed at which fluid travels referred to as?
velocity
What is considered standard atmospheric pressure?
At sea level, 14.7 psi
What is any pressure that is less than atmospheric pressure called?
vacuum
What is absolute zero pressure called?
a perfect vacuum
What misnomer do gauge readings of less than 0 psi or kPa often referred to in the fire service?
“negative pressure”
What is referred to the height of a water supply above the discharge orifice?
head
What is the stored potential energy available to force water through pipe, fittings, fire hose, and adapters?
static pressure
What is the pressure in a water system before water flows from a hydrant considered as?
static pressure
What is pressure found in a water distribution system during normal consumption demands?
normal operating pressure
What is that part of the total available pressure not used to overcome friction loss or gravity while forcing water through pipe, fittings, fire hose, and adapters?
residual pressure
What means a remainder or that which is left?
residual
What that forward velocity pressure at a discharge opening while water is flowing?
flow pressure
What refers to the center line of the pump or the bottom of a static water supply source above or below ground level?
elevation
What is the position of an object above or below sea level?
altitude
When a nozzle is above the pump,
there is pressure loss.
When the nozzle is below the pump,
there is pressure gain.
What is referred to as elevation pressure?
pressure loss and gain
What is the common term for pressure loss due to friction?
friction loss
What is that part of total pressure lost while forcing water through pipe, fittings, fire hose, and adapters?
friction loss
What is referred to as suddenly stopping water moving through a hose or pipe results in an energy surge being transmitted in the opposite direction?
water hammer
What can be obtained from either surface water or groundwater?
primary water supply
What system use one or more pumps that take water from the primary source and discharge it through the filtration and treatment processes?
direct pumping systems
What system uses a primary water source located at a higher elevation than the distribution system?
a gravity system
What is a fire hydrant that receives water from only one direction known as?
a dead-end hydrant
What is known as a hydrant that receives water from two or more directions ?
circulating feed or a looped line
What is a distribution system that provides circulating feed from several mains constitute?
a grid system
What are 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
What are 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 fire flow at any point?
secondary feeders
What are grid arrangement of smaller mains serving individual fire hydrants and blocks of consumers?
distributors
What is the recommended size for fire hydrant supply mains in residential areas?
at least 6 inches
What is the minimum recommended size of a main in the business and industrial districts?
8 inch main
What size mains may be used on principal streets and in long mains not cross-connected at frequent intervals?
12 inch mains
What are two common indicator valves?
PIV and OS&Y
What valve has a yoke on the outside with a threaded stem that controls the gate’s opening or closing?
OS&Y valve
What valve is the most commonly used on sprinkler systems?
OS&Y
What are the most common types of valves used on most public water distribution systems?
nonindicating valves
What is the average of the total amount of water used in a water distribution system over the period of one year?
average daily consumption (ADC)
What is the maximum total amount of water that was used during any 24-hour interval within a 3-year period?
maximum daily consumption (MDC)
What is the maximum amount of water used in any 1-hour interval over the course of a day?
peak hourly consumption (PHC)
What systems are most commonly found on large commercial, industrial, or institutional properties, but may also be found in some residential developments?
private water supply systems
What is the most commonly used fire extinguishing agent in the fire service?
water
What is the freezing point of water?
32 degrees F
What is the boiling point of water?
212 degrees F
The amount of heat required to raise 1 lb of water 1 degree F is known as a -
BTU
The ratio to the amount of heat needed to raise the temperature of a specific quantity of a material and the amount of heat needed to raise an identical quantity of water by the same amount of degrees is called -
Specific heat.
The quantity of heat absorbed by a substance when it changes from a liquid to a vapor is called -
Latent heat of vaporization.
The temperature at which a liquid absorbs enough heat to change to a vapor is called its -
Boiling point
How many BTUs is absorbed when 1 pound of water is heated to 212 degrees F?
970
What is the weight of 1 gallon of water at 60 degrees F?
8.33 lbs.
How many BTUs are required to raise 1 lb. of water at 60 degrees F to 212 degrees F?
152
212 - 60 = 152
One gallon of water at 60 degrees F will absorb __ getting to 212 degrees F.
1266
152 BTU/lb x 8.33 lb = 1,266
Once water reaches a temperature of 212 degrees F, how many BTUs/lb are required to convert 1 lb of water to steam?
970
Once water reaches a temperature of 212 degrees F, how many BTUs/lb are required to convert 1 gallon of water to steam?
8080
970 Btu/lb x 8.33lb = 8,080
How many BTUs of heat can water at a temperature of 60 degrees F absorbed when it is converted to steam?
9346
1,266 + 8,080 = 9,346 BTU
If 1 gallon of water at a temperature of 60 degrees F absorbs 9,346 BTU of heat, how much heat can be absorbed if water at a temperature of 60 degrees F is projected from a fog nozzle pumping at 100 gallons per minute?
934,600 BTU
9,346 BTU x 100gpm = 934,600
The speed in which water absorbs heat -
Is proportional to the surface area of water exposed to the heat.
When heated to 212 degrees F, water will expand approximately __ times its original volume.
1700
The density of a liquid in relation to water is known as -
Specific gravity.
What is the specific gravity of water?
1
Most flammable liquids -
Have a specific gravity less than 1
If most flammable liquids have a specific gravity less than water, then the flammable liquid would have a tendency to -
Float on top of water.
______ is defined as force per unit area.
Pressure
The weight of 1 cubic foot of water is approximately -
62.5 lb
How much pressure is exerted upon a surface by a 1 cubic foot volume of water?
0.434 psi
The speed in which water travels is referred to as -
velocity
The stored potential energy available to force water through a pipe is known as -
Static pressure.
The height of a water supply above it’s discharge orifice divided by 2.304 is referred to as -
Head pressure
What is considered standard atmospheric pressure at sea level?
14.7 psi
The discharge velocity pressure at a an open discharge while the water is flowing is called
Flow pressure
The pressure left in a distribution system at a specific location when a quantity of water is flowing is called -
Residual pressure
The pressure found in a water distribution system during normal consumption demands is called -
Normal operating pressure
The centerline of the pump or the bottom of a static water supply source above or below ground level is called -
Elevation
The position of an object above or below sea level is called-
Altitude
When a nozzle is below the pump there is a pressure gain.
When a nozzle is above the pump there’s a pressure loss.
The losses and gains in pressure due to the position of the nozzle are a result of which of the following?
Gravity.
Both pressure loss and pressure gain are referred to as-
Elevation pressure.
Altitude affects the production of fire streams because -
Atmospheric pressure drops as the height above sea level increases.
Above sea level atmospheric pressure decreases approximately __ for every 1,000 ft.
0.50 psi.
That part of the total pressure loss while forcing water through pipe, fittings, fire hose, and adapters is called which of the following?
Friction loss.
Fire departments that use old hose may increase friction loss within the hose by as much as-
50%
Realistically, hose larger than __ cannot be used for handlines.
3 inches
One can reduce friction loss by -
- Decreasing hose length.
- Increasing host diameter.
- Eliminating sharp bends in the hose.
The sudden stopping of water flowing from a hose or pipe results in an energy surge which is transmitted in the opposite direction. This surge of energy is called a -
Water hammer
There are practical limits to the velocity in which a stream of water can travel through hoseline. If the velocity of the water increases beyond its limits, the friction within the hose becomes so great that the entire stream is agitated by the resistance. This agitation causes a degree of turbulence called -
Critical velocity
In order to flow more water through a hoseline after its speed has reached critical velocity, it is necessary to-
Parallel hoselines by using Siamese connections to increase flow and reduce overall friction loss.
The amount of water needed for fire protection in small towns is __ than the amount of water needed for industrial and domestic use.
Greater
Which of the following would not be considered one of the three methods of moving water in a system?
Vacuum pumping system
Which method of moving water uses a primary water source located at a higher elevation than the distribution system?
Gravity system
Which water pumping system uses one or more pumps to take water from a primary source, and discharge it through a filtration and treatment process?
Direct pumping system
Most communities will use which of the following methods for moving water from a primary water source to a distribution system?
Combination system
What is a fire department’s main concern regarding water treatment facilities?
The fear that a maintenance error, natural disaster, loss of power supply, or fire could disable the pumping stations or severely hamper the purification process.
A fire hydrant that receives water in only one direction is called a -
Dead-end hydrant.
A fire hydrant that receives water in more than one direction is called a(an) -
Circulating-feed hydrant or looped line
Large mains, with relatively widespread spacing, that convey large quantities of water to many locations of a system, that are locally distributed to smaller mains are called -
Primary feeders.
A grid arrangement of smaller water mains that serve individual fire hydrants and blocks of consumers are called?
Distributors
A network of intermediate-sized pipes that reinforce a grid within the various loops of a primary feeder system and aid the concentration of the required fire flow at any point are called -
Secondary feeders
Fire hydrant supply mains in residential areas should be at least __ in diameter.
6 inches
Fire hydrant supply mains in business and industrial areas should be at least __ in diameter.
8 inches
Water main valves should be operated __ to keep them in good working order.
At least once a year.
Residential, business, an industrial district fire-hydrant supply mains should be closely gridded by cross connecting mains every -
600 ft.
An indicating water system valve -
Shows whether or not a gate or valve seat is open, closed or partially opened.
The water main valve that has the words Open or Shut, indicating the valves present position is called -
A Post Indicator valve (PIV).
Which of the following water main valves is normally buried or installed in manholes, and operated above ground through a valve box?
A Nonindicating valve.
Control valves in water distribution systems are -
Gate valves or butterfly valves.
Nonrising-stem gate valves are normally marked with a number. What does this number indicate?
The number of turns necessary to completely close the valve.
Which water main valve rotates 90 degrees from the fully opened position to tightly shut?
Butterfly valve.
Which water main valve has a yoke on the outside with a threaded stem that controls the gate’s opening or closing?
OS&Y valve.
Water pipes are usually made from which of the following materials?
(1) Cast Iron (2) Ductile Iron (3) Asbestos Cement (4) Steel (5) Plastic (6) Concrete
Water pressure is measured using a -
Pitot tube
The maximum total amount of water that was used during a 24 hour interval within a three year period is called -
The maximum daily consumption. (MDC)
The maximum amount of water used in any one-hour interval over the course of a day is called -
The peak hourly consumption. (PHC)
The average of the total amount of water used in a water distribution system over a period of one year is called -
The average daily consumption. (ADC)
The maximum daily consumption of water is normally approximately __ times the average daily consumption.
1 1/2
In fire fighting elevation refers to -
The position of the nozzle in relation to the pumping apparatus.
The primary way water extinguishes fire is by -
Cooling the fire.
Which of the following governs the heat-absorbing ability of water.
Specific heat and Latent heat of vaporization.
The tendancy of a liquid to possess internal resistance to flow is known as -
Viscosity.
Private water systems are most commonly found in all but which of the following situations?
Large residential housing developments.
