Practice Test Flashcards
The measure of a pump’s ability to convert motor brake horsepower to water horsepower is known as:
Pump Efficiency
On a venturi meter, the pressure in the throat while water is moving through the meter is ______ than the pressure in the cylindrical inlet and is______
Lower, proportional to the square of the velocity
How many gallons of 15% industrial liquid chlorine bleach (assume 8.5 lbs/gal) are required to disinfect a 525,000 gallon tank full of water with a 25 mg/L chlorine dosage.
86 gal
Where a water line crosses beneath a railroad, the line should be laid inside a culvert pipe or steel casing that is at least _____ inches larger in diameter.
2
In all but the largest systems, the greatest determining factor of the amount of storage required and size of distribution mains is:
Fire-flow demand
Currently, the minimum pressure desirable in a water system is normally:
20 psi
The velocity of water in pipelines and valve internals is conventionally expressed in which units?
fps
In determining the required pipe size in a distribution system, velocity within the pipes considered red. Pipe velocities are normally limited to ____ ft/s.
5
Domestic water service meters are called totalizing water service meters because:
Measure and record the total volume that passes through the meter
What is the most common type of water serve meter?
Displacement
Once of the reasons to use a hydropneumatic system is to:
Reduce the frequency with which a pump needs to be turned on and off.
When a service pump sounds as if it is pumping gravel, cavitation is occurring and stopped by:
Restricting the discharge (e.g. valve or orifice plate)
The five areas within a traffic control zone are, in order:
Advance warning, transition, buffer, work, termination
A centrifugal pump when operating normally shows a discharge pressure of 100p venturi meter shows a flow rate of 900 gpm. The discharge pressure suddenly drops the flow rate increases to 1,300 gpm. You would suspect _____.
A large leak in the pump discharge line
Many distribution systems utilize chloramines for dlsinf ecr .
the formation of TH Ms. When considering the disinfecting strength
of chorine versus chloramines an operator must realize that
Chloramines require a longer contact time
The person who is assigned the responsibility of monitoring workers in a “permit required confined space” is referred to as the _______. This person must remain in position at all times
Site supervisor
During or after the repaving of a street, valve-box covers must be brought up to the new street
level by using
Extension (“grade”) rings
Every water utility needs a safety program. These safety programs should be organized so
that:
They stress that every employee realizes and accepts personal responsibility for his/her own safety and the safety of fellow employees.
The vertical distance from the liquid supply level to the pump centerline when the supply is
below the pump called
Static suction lift
The underground components of a properly installed fire hydrant are (in order from the main to
the hydrant):
Auxiliary valve, inlet pipe, foot-piece
The point at which chlorine dosage satisfies the chlorine demand is called ________.
Breakpoint
When constructing new underground water mains, each bend in the pipe and each valve and hydrant should have a:
Thrust block installed
If a trench has been dug to install a water line and the trench is deep enough to require entry and exit with a ladder, this ladder must extend at least _______ above the trench.
3 feet
The leading cause of death and injury to operators in underground construction is:
Lack of shoring or shoring failure
Where should air relief valves be installed in a distribution system?
At the high points
If it suspected that a water customers water meter is not giving accurate readings, the operator should:
Bench test the meter
How often should a fusible plug in a chlorine cylinder be changed?
Never
