Study Questions Flashcards
What are the four classes of working pressure.
100, 150, 200, 250 psi
What year was the Safe Drinking Act established.
1974
What are the four main steps to water life cycle.
Evaporation, Precipitation, Condensation and Groundwater (Collection).
What are the sources for water supply.
Groundwater and Surface Water.
What is turbidity.
The cloudy appearance of water caused by the presence of suspended and colloidal matter.
What is soft water.
Is surface water that is characterized by low calcium and magnesium.
What are the characteristics of groundwater.
High concentrations of dissolved solids, dissolved gases and high hardness.
What is head.
The vertical distance, height or energy of water above a reference point.
How is head measured.
Pressure and height.
Storage facilities for treated water at a water plant is called.
Clear wells
What are some examples of operational service storage tanks.
Pressure tanks, elevated tanks, ground-level tanks/reservoirs and underground facilities.
What does s distribution system consist of.
Pipes, valves, fire hydrants, service lines and pumping stations.
What are some water quality problems only groundwater would have.
Nitrates, sand, sulfide and corrosivity.
What are water quality problems only surface water would have.
Coliforms or microbial contamination, turbidity, odors and trihalomethanes.
What does MCL stand for.
Maximum contaminant level
What are macroscopic organisms.
Organisms big enough to be seen by the eye without an aid of a microscope such as worms, bugs or milky water due the air.
What is cross connection.
Is an unprotected connection between any part of the water system used or intended to be used to supply water for drinking water purposes.
What is backflow.
A reverse flow condition created by a difference in water pressures that causes water to flow back into the distribution pipes.
What is backsiphonage.
Is a form of backflow caused by a negative or below atmospheric pressure within a water supply piping
What is back pressure.
Is when the user’s water system is at a higher pressure than the public water supply.
What are the two greatest water quality nuisances.
Corrosion and precipitation of iron.
What are slimes.
They are organic substances of a visous nature formed from microbiological growth
What are biofilms.
They are the result of a complex interaction among microorganisms.
What are the six common types of storage facilities.
Clear well, elevated tank, standpipe, ground-level service reservoir, hydro-pneumatic, and surge tank.
How often should an elevated tank be inspected.
Internal inspection every 5 years and an external inspection every year.
What is the major difference between an elevated tank and a standpipe.
An elevated tank provides pressure whereas a standpipe provides volume.
What is the recommended water-to-air ratio for a hydro-pneumatic tank.
Two-thirds water to one-third air.
What is the most common consumer complaint regarding water quality.
Red water
What are some factors that may increase biofilm growth and increase corrosion.
Water temperature, flow, age of facilities, operating procedures and age of water in a specific point.
Primary contaminations are considered to be
Health hazards.
Secondary contaminations are considered to be
Non-health hazards
What is hydraulic transient.
It a temporary change in pressure or flow, also known as surge, shock or water hammer.
What determines the size of a hydraulic transient.
A change in flow velocity, the liquid density or the speed of sound in the pipe.
What are the two factors that determine the type of storage facility or tank a system needs.
The system’s individual needs and the type of terrain.
What is the purpose of a surge tank and where should it be located.
A surge tank controls problems with surge or water hammers and they should be located at the closest point to the activity that creates the water hammer.
What are the three types of tank inspections.
A visual inspection, a detailed inspection and an inspection with divers.
What are some factors that affect hydraulic grade line.
Fire, high demand, obstructions in the pipe such as throttle valves, and water hammers or thrust.
What are two problems exercising a valve can cause.
Water hammer and cavitation.
What is an altitude valve.
A valve that automatically shuts off the flow into an elevated tank when the water level in the tank reaches a predetermined level.
What are the different types of control systems used to monitor water levels in tank.
Electrodes, ultrasonic signal, pressure switches, and differential-pressure altitude valve.
What type of pump requires water on the impeller to operate.
Centrifugal pump
What factors of a microbiological type can cause water quality problems.
Loss of chlorine residual, growth of bacteria, dead rodents and/or debris.
What is the minimum gap for in an air gap.
2”
What are the two types of cleaning methods for storage tanks.
Out-of-service or in-service.
Provide examples of substances in the water that influence rate of corrosion.
Dissolved oxygen, carbon dioxide lowers pH, dissolved minerals such as salt and sulfatereducing bacteria.
What are some methods of controlling corrosion for a tank
Painting, metallic coating, nonmetallic coating, chemicals added in the treatment process and cathodic protection.
What is commonly used as a disinfectants for storage tanks.
Liquid chlorine, calcium hypochlorite and sodium hypochlorite.
What is available chlorine.
?
What are boosters pumps primary functions.
Booster pumps are used to increase the pressure in the mains on the discharge side of the main pumps or to supply water to an elevated storage tank.
What type of pump is a booster pump.
Centrifugal pump.
What is a regulator station’s main function.
Its main function is to reduce pressure and maintain an even acceptable pressure downstream from a high pressure system.
Where are gauges commonly found.
They’re usually found on the discharge side of a pump.
What is the purpose of a distribution system.
To provide sufficient pressure and deliver adequate water.
What is the maximum pressure in a system.
100 psi
What is the normal pressure for resident.
35-40 psi
What is absolute minimum pressure in a system.
20 psi.
What is C Factor.
A factor or value used to indicate the smoothness of the interior of a pipe.
What is friction loss.
The head or pressure lost by water flowing in a pipe as a result of turbulence or the roughness of the pipe.
What maximum velocity should a main flow.
2-4 ft/sec
What velocity should a main be flushed at.
2.5 ft/sec
Dead end mains exceeding a 1000ft should be constructed of what size pipe.
At least 6”.
Dead and mains exceeding 2000 ft in length should be constructed of what size pipe.
It should exceed 8”.
What is the maximum distance valves on water mains should be located.
1000ft
What is the maximum distance fire hydrants should be located from the next hydrant.
No more than 500ft.
What are transmission main usually constructed of.
Concrete with steel cylinder because it is less expensive in larger sizes.
A distribution reservoirs are used primarily for.
To balance out fluctuations in demand that occur over short periods, to provide local storage in case of an emergency, and to control the pressure in the system.
What are the three types of water main system layouts.
Grid, loop and tree systems
What are the basic requirements for pipes in a water distribution system.
Adequate strength, durability, maximum corrosion resistance and no adverse effect on water quality.
What are some types of materials that are available to be used for water mains.
Ductile iron, steel, reinforced concrete , asbestos-cement and plastic.
What are service lines typically constructed of.
Copper, PVC, PE, and PB
What is galvanic corrosion.
When two different metals that are link together and corrode.
When using ductile iron pipe what types of joints are most commonly used.
Mechanical and push-on.
What is the minimum cover when laying water mains.
30” from grade
What is the Centerline of a pipe called.
Springline
What is the minimum depth of the rock bed under a newly laid water main.
6”
What type of pipe is especially susceptible to corrosion and requires more protection than other types.
Steel pipe
What is the minimum distance between water and sewer laterals when installed horizontally.
10ft
What is the minimum distance between a water and sewer laterals when installed vertically.
1ft
What is the best way to check if metal pipe has been damaged.
Gently tap the pipe with hammer listening for a ring or a hum.
What is the maximum days plastic pipe can be stored unprotected in the sun.
30 days
When digging a trench spoils should be placed how far from the edge of the of the hole if it is 5ft and deeper.
Spoils need to 4ft or more from the edge of the hole.
When digging a trench if a trench is 5 ft or less how far does the spoils have to be from the edge of the hole.
The spoils have to be 2’ from the edge of the hole.
When a trench is 4ft deep it needs ladders how far apart.
Every 25’
Shoring depends on many factors name some of those factors.
The depth of the trench, the width of the trench, type of soil and nearby activities that cause vibration.
What does OSHA stand for.
Occupational Safety and Health Administration
What year was OSHA enacted.
1970
What is a competent person.
A person capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary hazardous or dangerous to an employee.
What are the six types of shoring.
Hydraulic shores, screw jacks, air shores, solid sheeting, cylinder shoring and shield shoring
When laying pipe out for installation it is called what.
Stringing
What types of fittings should have restraints or thrust blocks.
Tees, bends, caps, plugs, hydrants or other fittings that change the direction of flow.
What is the first layer of backfill above the bedding called.
Haunching.
What is the horizontal centerline of a pipe called.
Springline
What are the four stages of backfilling.
Bedding, haunching, initial backfill and final backfill
When preparing for a pressure test how long should a pipe sit full of water before starting the test.
24 hours
What pressure should the pipe be at for a pressure test.
50% higher than the normal expected operating pressure or 150 psi
How long should the pressure test be conducted.
4 hours
A leak test on asbestos-cement and ductile iron pipe are reported in.
Gallons lost per day per mile
A leak test on plastic pipe is reported in.
Gallons per hour for each 100 joints of pipe.
What are some types of rotary valves.
Ball valve, butterfly valve, plug valve, and diaphragm valve
How does a linear stroke valve close.
Up and down
What are two examples of a linear stroke valve.
Globe valve and gate valve
What are four main parts to a hydrant.
Main valve, the barrel, the inlet pipe, and the head
What are the two different types of hydrants.
Dry-barrel and wet-barrel
Name three types of meters.
Displacement meters, velocity meters and combination meters.
Small meters are what type of meter.
Positive displacement
Large meters are what type of meter.
Velocity meter
What are two types of displacement meters.
Nutating-disc and piston
What’s another name for a velocity meter.
A current meter
What are some types of velocity meters.
Turbine meter, propeller meter and Venturi
What are the three types of backflow devices that are approved for use at service connections.
Air gap, RP and double check
What is the minimum distance from grade to the bottom of a backflow device.
12”
What are the three reasons distribution system should be under surveillance.
To detect and correct any problems that are sanitary hazards, any significant deterioration of the facilities and encroachment of other utilities.
What are the three rules that federal and state regulations require monitoring water quality in a system.
Total Coliform Rule, Lead and Copper Rule and Trihalomethane Rule.
What is the lowest residual acceptable in a distribution system.
0.2 mg/L
Routine non-source sampling performed by utilities includes test for.
Bacteriological samples, turbidity, total trihalomethanes, chlorine residual, taste, odor and color, and Lead and Copper Rule.
What are the two monitoring periods for lead and copper sampling.
January to June and July to December