Chapter 15: Water Supply and Hose Flashcards
What are the two rules of water supply?
Water is non-compressible
Capable of being pumped
Define flow
How is it expressed?
The volume of water being moved
Gallons per minute or liters mer minute
Define pressure
How is it expressed?
Force applied over a give area, or the force used to move the volume of water through ha hose and out of a nozzle.
Lbs of force per square inch (PSI), or kilopascal (kPa).
Weight of a gallon of water?
8.33 Lbs
How many gallons of water are in 1 cubic foot?
7.48 gallons
What is the weight of 1 cubic foot of water?
62.4 Lbs
What does PSI mean?
Lbs of pressure per square inch, square inch being define as 1 inch x 1 inch x 12 inches of water.
What is the water pressure in 1 inch x 1 inch x 12 inches of water?
.434 psi.
What is the rule for the increase of water pressure related to depth?
Water pressure increases 1 psi for every 2.3 ft.
What is the water pressure at 10 feet of depth?
.434 psi
What is the water pressure at 200 feet of depth?
86.956 psi
What is the water pressure at 400 feet of depth?
173.81 psi
Define elevation head
The pressure created by a column of water.
How many psi are needed to move water up every 10 feet of building height?
5 psi
What is the approximate height of 1 story of a building?
10 feet
Define atmospheric pressure
The weight of the air that makes up the earth’s atmosphere that is exerted on object on the earth.
What is the atmospheric pressure at sea level?
14.7 psi
What does the “g” in psig stand for?
“G” stands for gauge, which means that the reading has been corrected to zero psi after taking the weight of the earth’s atmosphere into account.
Define fraction loss
The amount of energy lost while water is flowing.
When does friction loss increase?
When more water is flowing through a given size hose.
How can friction loss be decreased?
If the size of the hose is increased
Define static pressure
The amount of pressure in a hose line or water main in a street while no water is flowing.
Define risidual pressure
The pressure remaining in a hose or water main while water is flowing.
What can large aquifers be compared to?
Lakes underground
What are the two major sources of water?
Ground water and surface water
Define potable water
Treated water that can be consumed.
What is the most important part of the municipal water system for fire departments?
Distribution system.
What are water main valves/ what do they do?
Used to shut down certain areas of the water system for repair and maintenance. Valves usually left open.
How far apart are water main valves?
500 to 800 feet.
What are other terms for large water mains?
Treated water aqueducts or primary feeders. Up to 20 feet in diameter. Usually 30 to 48 inches. No hydrants connected to these
What is another name for medium sized water mains?
Secondary feeders.- Usually 12 to 24 inches. My hydrants connected to these
What are small sized water mains referred to as?
Distributors- 4-12 inches.- Hydrants are primarily installed on small distributors.
What is the minimum size of pipe used to supply hydrants?
6 inches
Define gate valve or roadway box
Valve between hydrant and water main used to allow water to a hydrant.
Define dead end hydrant
A hydrant that is supplied from only one direction
What does NST or NHT stand for?
National Standard Hose Thread or
National Hose Thread
What is NST or NHT?
The size of thread used on hydrants so that all fire hoses can connect to it.
How many turns to open a hydrant?
10-14, but then turn back 1/4 turn. Do the opposite of this when closing a hydrant.
What is NFPA 291 in regards to ?
Recommended Practice for Fire Flow Testing and Marking of Hydrants. - This should designate the color of the hydrant.
What are the flow rates of given hydrants by color? Red Orange Green Light Blue
Class C- Red- less than 500 gpm
Class B- Orange- 500 to 999 gpm
Class A- Green- 1000-1499 gpm
Class AA- Light Blue- 1500 gpm or above
What does ULDH stand for?
Ultra large diameter hose
What does DJ and SJ stand for in hose lines?
DJ is double jacket
SJ is synthetic jacket
What do MDH and LDH stand for in hose lines?
Medium diameter hose
Large diameter hose
What is the NFPA 1962 for?
Standard for inspection, care, and use of fire hose, couplings, and nozzles and the service testing of fire hose.
Define service test pressure
Used to determine if fire hose is suitable fore use and is the pressure the hose is tested to every year.
Define proof/acceptance test pressure
Pressure the hose is subjected to by the manufacturer at the factory prior to shipment.
This must be no less than twice the service pressure
Define burst pressure
This pressure must be at least three times the service pressure. Tested by manufacturer.
Define operating/ working pressure
This should not exceed 90% of the service test pressure.
How often does the NFPA 1962 require that hoses be tested?
Annually
