Class 3 Questions Flashcards
What is accepted amount of unaccounted water in distribution center
10%
Minimum water pressure required in a water system
20 psi
Purpose of a foot valve
Keep water in the suction line and pump primed
Thrust blocks are used for ?
To prevent damage due to internal pressures. Example keeps water pressure from blowing off 90s 45s etc.
When should a water main be disinfected
After it is laid in the trench
What is tuberculation
Development of small amounts of corrosion inside the pipe
Most common water distribution set up?
Grid system
Form in which chlorine has shortest shelf life
Liquid form
Way in which you can you can determine water loss in system
Water audit
What is caused when there is negative pressure
Back siphonage
What is caused when the water flow is higher on unapproved water supply then on domestic system
Back flow
Metallic compound used to prevent corrosion
Zinc
If signs of contamination or tampering in a water system what should you do
Notify consumer and local media
Tank that is used to maintain water pressure and controls operation of a pump
Hydropnuematics
What is the c factor
Refers to the smoothness of the interior of the pipe
Minimum time water must be motionless in pipe to draw lead test
6 hrs
A hydrants residual pressure is always what then then it’s static pressure
Lower
What causes milky water
Trapped air
What agency regulated water distribution systems
EPA (FDEP) in Florida
Most common and accurate type of meter
Nautaiting disk and oscillating piston meters
Proper method of measuring chlorine residuals in water
Using a DPD kit
Measure of grouping is used to determine effectiveness in water system
Coliform group
To ensure conventional flushing is working how many volumes of pipeline is to be removed
3 times out of
What type of organisms is bacteriological testing used to identify
Pathogenic
1 million gallons of water would require how much chemical to obtain dosage of 1 PPM
10lbs
What is THM
Trihalomethanes
What causes the cloudiness of water
Turbidity
How long do you pressure test new water main
4 hours at minimum of 50 percent operating pressure or 150 psi
At what velocity and rate should new water main be filled
No greater then 1ft per second
Process of adding chlorine to water until the demand is satisfied
Breakpoint chlorination
What happens to a water main operating under normal psi when a hydrant is being used
Negative pressure(back siphonage)
Why are gate valves used
They exhibit less friction then other valves
