Chapter 14
How is static pressure measured?
Pressure gauge is placed on a hydrant outlet and hydrant valve is opened - no water can be flowing out of hydrant.
When the maximum amount of water is flowing, the residual pressure is ____.
0
Flow available at 20 PSI of a class A hydrant?
1000-1499 gpm (5678 L/min)
Flow available at 20 PSI of a class AA hydrant?
1500 gpm or greater (5678 L/min)
NFPA 24 requires a minimum of _____ in. from the center of a hose outlet to the finished grade.
18
Static water sources have to be within _____ ft. for a fire engine to draft through a hard suction hose.
20
What is the minimum pressure for water coming from a fire hydrant?
20 psi
What is the minimum usable residual pressure necessary to reduce the risk of damage to underground water mains or pumps?
20 psi
Water pressure ranges from ____ lbs psi to ___ psi.
20-80
1 gal = ____ L.
3.785L
Fire hydrants may be placed how far apart in high-value commercial areas?
300ft
Portable pumps can deliver as much as ____ gpm.
500 (1893 L/min)
Flow available at 20 PSI of a class B hydrant?
500-99 gpm (1893-3781 L/min)
Fire hydrants may be placed how far apart in residential areas?
500ft
1 PSI = ______ kPa
6.894kPa
Portable tanks typically hold between ____ and ____ gal of water.
600 - 5000
Drafting hydrant
A fixed piping system with a strainer on one end and a connection for a hard suction hose on the other end.
Water hammer
A surge in pressure caused by suddenly stopping the slow of a stream of water.
Secondary feeders
AKA branch lines Distribute water to a smaller area
Primary feeders
AKA truck lines Carry large quantities of water to a section of a town or city
The valve of a dry-barrel hydrant that controls the flow of water into the barrel of the hydrant is located where?
At the base below the frost line
Where are shut off valves located?
At the connection points where the underground mains meet the distributor mains.
How can a water hammer be avoided?
By opening and closing fire hydrant valves slowly.
Fire hydraulics
Deals with the properties of energy, pressure, and water flow as related to fire suppression.
How are number of attack lines calculated?
Difference between static pressure and residual pressure
What are the smallest mains?
Distributors
____ carry water to the users and to fire hydrants along individual streets.
Distributors
Which fire hydrants are connected to a pressurized municipal water system?
Dry-barrel
Dump valve
Enables the tankers to offload as much as 3000 gal of water in 1 minute into a portable tank.
How is volume calculated?
Firefighters measure the water pressure at the center of the stream as it passes through the opening
Municipal-type water system
Furnishes water under pressure through fire hydrants.
Color of class A hydrant
Green
Water mains in a well-designed distribution system will follow a ___ pattern.
Grid
Where are dry-barrel hydrants used?
In climates where temperatures fall below freezing.
Where are wet-barrel hydrants used?
In locations where temperatures do not drop below freezing.
When a stream of water flows out through an opening, the pressure is converted to ___ energy.
Kinetic
_____ energy is the energy possessed by an object as a result of its motion.
Kinetic
Static water sources
Lakes, streams, or other bodies of water.
Steamer port
Large diameter port
As more water flows, there is _____ residual pressure in the system.
Less
Flow available at 20 PSI of a class C hydrant?
Less than 500gpm (1893 L/min)
Color of class AA hydrant
Light blue
What is used to deliver water to fight fires?
Mobile water supply apparatus'
How often should fire hydrants be inspected?
Once a year
Color of class B hydrant
Orange
Water that is not moving has ___ energy.
Potential
Water flow
Quantity of water moving through a pipe, hose, or nozzle
NFPA 291
Recommended Practice for Fire Flow Testing and Marking of Hydrants
Color of class C hydrant
Red
NFPA 24
Standard for the Installation of Private Fire Service Mains and Their Appurtenances
NFPA 1142
Standard on Water Supplies for Suburban and Rural Fire Fighting
Water pressure
The amount of energy of force per unit area of water measured in PSI
Static pressure
The amount of pressure in a system when water is not moving.
Normal operating pressure
The amount of pressure in a water distribution system during a period of normal consumption.
Residual pressure
The amount of pressure that remains in the system when water is flowing.
Friction loss
The decrease in pressure that occurs as water moves through a pipe or hose due to the resistance it meets as it travels.
What are the three components of a municipal water system?
The water source, the treatment facility, and the distribution system
What is the function of elevated storage towers?
They maintain the desired water pressure in the distribution system, ensuring that water can be delivered under pressure even if the pumps are used.
Water flow is measured in?
Volume
What occurs in a dead-end water main?
Water is supplied in one direction
What does a pitot gauge measure?
Water pressure in psi and volume in gallons
Municipal water systems can draw water from?
Wells, rivers, streams, lakes, or reserviors
___ hydrants usually have separate valves that control the flow of water to each individual outlet.
Wet-barrel
_____ hydrants always have water in the barrel and do not have to be drained after each use.
Wet-barrel
