Chapter 4, Fundamentals Of BackFlow Flashcards
These items are believed to be the most common temporary cross connection.
Hoses
We’re cross connections are necessary, installing the appropriate mechanical backflow preventer creates a:
Protected cross connection
These are physical links that allow backflows
Cross connections
These are short-term links between potable and non-potable water sources. They are frequently created by a hose or some other type of extension of the permanent water supply line.
Temporary cross-connections
Permanent cross connections are generally created by what?
Solid pipe connections
A tank truck carrying pesticides connecting to a fire hydrant, creating a cross connection is an example of what type of cross connection?
Temporary Cross Connection
Water being supplied to a boiler, and air-conditioning system, or any piece of equipment or holding vessel that could pollute or contaminate the potable water supply is an example of what type of cross connection?
Permanent cross connection
This is any arrangement of pipes, fixtures, or devices connecting a portable water supply directly to a non-potable source that is subject to back siphonage and back pressure
A direct cross connection
These types of cross connections are subject to back siphonage only and have the potential for backflow only when conditions exist to create a cross connection, and back siphonage is possible
Indirect cross connection
A submerged bathtub inlet is an example of what type of cross connection?
And indirect and permanent cross connection
Why do cross connections exist?
- People unaware of a problem.
- Convenience.
- Inadequate devices.
One of the most hazardous, temporary cross connections arises through the use of a:
Siphon mixer
A bath to shower adapter and easily create a _______ showerhead is submerged in the bathwater
Temporary cross connection
A spray nozzle extension, installed on a kitchen sink faucet can accidentally create a cross connection. If the spray head is left in the sink, this is classified as what type of cross connection?
Direct cross connection
These hazards occur when water moves through a cross connection in a direction it was not intended to move
Backflow hazards
Fluid reversal is generally caused by what?
A pressure differential
This is a measurement of force. Force is any kind of push or pull.
Pressure
This is a force generated when the earths gravity attracts an object that has mass
Weight
This is the amount of matter, making up an object.
Mass
This is how much space and object occupies
Volume
This depends on the mass and volume of an object
Density
The greater the mass of an object:
The more it weighs
This is a measure of force acting on a unit of area, example a square inch.
Pressure
In the US, the most common measurement for pressure is
Pounds per square inch (PSI)
This is the science that deals with fluids and motion and rest
Hydraulics
Fluids in motion exert:
Pressure
The pressure that moving water generates is called:
Kinetic energy
Water at rest has what kind of energy?
(Static) or potential energy
One cubic inch of water weighs
0.036 psi
The bottom of a 1 foot column of water is equal to what psi?
0.433 psi
A 2 foot column exerts a pressure of 2 “feet of head”, which is equivalent to:
0.866 psi
1.0 psi of water pressure is equivalent to how many feet acting on one square inch of surface area?
2.31 feet (27.75 inches)
The shape of a container that holds the water has no effect on the
Pressure
Water pressure is dependent on
Depth
1.0 psi of water pressure is equivalent to ______ inches
27.75 inches (2.31 feet)
This is caused by the weight of air from the atmosphere (25 miles thick) on the Earth’s surface.
Atmospheric pressure
Atmospheric pressure is equivalent to what psi?
14.7
At higher elevations for instance in the mountains, the atmospheric pressure is less than 14.7 psi because the column of air is shorter and the air is:
Less dense
Pressure gauges do not include the:
Atmospheric pressure
These readings do not include atmospheric pressure, and are measured and units of pounds per square inch
Gauge pressure
What is the abbreviation for gauge pressure?
psig
This pressure is the gauge pressure plus the atmospheric pressure at a given altitude
Absolute pressure
Atmospheric pressure is important in hydraulics because atmosphere exerts pressure on the surface of water water at rest redistributes this pressure how?
Equally in all directions
Water movement is caused by
Pressure differentials
Water will flow from high to
Low pressure
A partial vacuum or negative pressure is created when atmospheric pressure is:
Reduced
Negative pressure is any pressure less than atmospheric pressure (14.7psia) ? This is also called:
Sub-atmospheric
14.7 Pisa equals _____ psig?
Zero
Theoretically, if atmospheric pressure is totally removed from inside of a pipe, water can rise how many feet?
33.9 feet
This is an old method of backflow prevention that relies on pressure principles to prevent back siphonage backflow. It is simply a 34 foot Vertical Loop of piping.
Barometric loop
What law of physics states that as the temperature of water rises, either the volume must increase or the pressure must increase
The Ideal Gas Law
Where the velocity of the fluid is high, the pressure is:
Low
This is caused by water traveling at high, velocity past or through a small opening
The Venturi effect
When water is forced to flow through a smaller pipe, it’s velocity must increase, and therefore the pressure at the point must:
Decrease
This principle states that pressure differentials can be created whenever a large pipe feeds a smaller pipe, when there are obstructions and pipes, or when devices are fittings are placed in line to reduce pressure
Bernoulli’s Principal
Pumps can increase the pressure in a non-potable supply over that over the:
Portable supply
True or false pressure differentials can be created whenever a larger pipe feeds a smaller pipe
True
Pumps can also create a reduction and pressure. The reduction and pressure occurs on the:
Intake side of the pump
This type of backflow occurs whenever the pressure on the non-potable system is greater than the pressure and the potable water supply system
BackPressure
This is also referred to as superior pressure
Back pressure
This is also referred to as superior pressure
Back pressure
Boilers are also prime candidates for:
Back pressure backflow
This type of backflow can occur whenever cross connection exist in a negative or sub atmospheric pressure is generated in the potable water supply
Back siphonage
These seem to be the most common causes of backflow caused by back siphonage
Broken water mains
The weight of one cubic foot of water is equal to:
62.4 pounds
