Two Marks Questions with Answers

TWO MARK QUESTION AND ANSWERS

 

1. What do you mean by water distribution?

After treatment, water is to be stored temporarily and supplied to the consumers through the network of pipelines called distribution system. The distribution system also includes pumps, reservoirs, pipe fittings, instruments for measurement of pressure, flow, leak detectors etc.

 

2. What are the requirements of water distribution system?

 (i) It should supply water to all places in the city with sufficient pressure

(ii) It should be capable of supplying required amount of water for fire fighting

(iii) It should be cheap with least capital construction cost

(iv) It should be simple, easy to repair and operate keeping RMO cost (Running, Maintenance and Operation) and troubles to minimum

(v) It should be safe against pollution of water

(vi) Water should be made available even during breakdown or repairs

 

3.What are the different systems of water supply?

Continuous: Water is supplied during all the 24 hours of the day. Provides greater comfort for the consumers. Water usage and losses are more. Small diameters pipes are used. Used in places where there is plenty of water throughout the year.

Intermittent: Water is supplied only during specific periods ie., peak hours in the morning and evening. Inconvenient to consumers. Wastage is less. Adopted in India.

 

4. Write down the methods of distribution of water?

a. Gravitational system

b. Pumping system

c. Combined gravity and pumping system die

5. What are the different types of distribution reservoirs?

• Surface reservoirs

 •  Elevated reservoirs

•  Stand Pipes

 

6. How will you determine the capacity of storage reservoirs?

Storage reservoir capacity is equal to the sum of balancing or equalizing reserve, breakdown reserve and fire reserve. The balancing reserve is found using hydrographs and mass curve methods

 

7. What are prime functions of service reservoirs?

(i) They absorb hourly variations in demand by allowing the pumps to operate at constant rate to reduce RMO cost

(ii) They help in maintaining constant pressure in the distribution mains

(iii) Pumping of water in shifts can be made with service reservoirs gool bezolovne

(iv) Stored water can be used for emergencies like breakdowns and fire outbreaks

(v) Leads to overall economy by reducing sizes of pumps, pipes and treatment dily units

8. What are the layouts or networks of water distribution system?

(i) Dead end system

(ii) Grid iron system

(iii) Ring system

(iv) Radial system

 

9. Give the advantages and disadvantages of dead end system?

Advantages:

• Calculation of discharge and pressure is easy for the distribution network

• Number of Valves required is less

• Smaller diameter pipes can be used

• Cheap and economical

• Laying of pipes is simple

Disadvantages:

• Stagnant water at dead ends causes water contamination

• During repairs, there will be no supply in some areas obi noyob woll

• The water available for fire-fighting will be limited in quantity

 

10. What is Grid iron system?

Layout of the distribution system by a network of inter-connected pipes with water flowing in any direction with least resistance to flow is known as grid iron system. 

 

11. What are the methods used for the analysis of distribution networks?

a. Hardy cross Method

b. Equivalent Pipe Method

 

12. What are the assumptions in Hardy Cross method?

At each junction, inflow-outflow. The algebraic sum of water entering and leaving any junction is zero.

In any closed loop, algebraic sum of head loss is zero

 

13. What is an equivalent pipe?

The equivalent pipe is one which will replace a given system of pipes with equal head loss for a given flow.

Principles of equivalent pipes are

(i) head loss through pipes in series are additive

(ii) head loss through pipes in parallel are same 

 

14. What is the role of computer application in water supply system?

EPANET, BRANCH and LOOP as well as commercial softwares like Aquis, H20 map, KYPipe, WaterCAD, WaterGEMS, AUTOCAD, GIS etc. are used for the analysis of water distribution networks. They are used to determine the pipe diameter, head loss and pressure etc. These are used for hydraulic and water quality modeling, model building supported with geospatial tools.

Computer applications allows

• Allow extended period hydraulic simulations

• Possess integrated module for water quality simulations

• Handle virtually unlimited size of the network in any configuration

• Have excellent graphical interface for presentation of results

 

15. How do you identify leakage in pipe lines?

Leakages in pipe line can be identified by the following methods.

 1) By direct observations:

Practically observing a wet soft spot on the unpaved ground or in lawn or emergence of spring in odd place

(ii) By using sounding rods

(iii) By plotting the hydraulic gradient line

(iv) By using waste detection meters

 

16. Name any two appurtenances used in water distribution system?

(i) Fire hydrants

(ii) Water meters

(iii) Water taps

(iv) Stop cocks

(v) Pipe bends

 

16. What factor control water supply to buildings?

a. Source of water supply like city mains or ground water

b. Type of water supply like continuous and intermittent

c. Pressure in water supply main

d. Head loss in pipes and fittings

e. Loss of head in top floors during peak hours in high rise buildings

f. Excess pressure in ground floor pipes

g. Location of over head tank

 

17. What is hydro-pneumatic system?

System of pumping water by compressed air to fixtures in a building is known as

hydro pneumatic system.

 

18. List out the components of a service connection pipe?

a. Ferrule

b. Goose neck

c. Service pipe

d. Stop cock

e. Water meter 

 

19. What is ferrule in water service connection?

Ferrule is a right angled sleeve made of gun metal or brass, joined to a hole drilled in the water main, to which it is screwed down with a plug. Diameter is 10-50 mm

 

20. What is a goose neck?

It is a 50 cm long curved piece of flexible pipe made of brass which prevents the breaking of main pipe due to the movement between water main and service pipe and provides greater flexibility at the junctions.

 

21. What do you mean by sanitary fitting?

Sanitary fittings are made of porcelain, stainless steel, brass and plastics which receive and transfer foul liquids and water containing solids which are produced by human activities in buildings. Sanitary fittings are sinks, wash-tubs, baths, lavatories, water-closets, sinks and urinals.

 

22. What are the advantages of laying pipes in parallel?

To facilitate repair works

To increase the supply to any area if required

To use smaller diameter pipes.

 

23. What is a distribution pipe?

Supply pipe in building from which connections to fixtures take off is called as distribution pipe.

 

24. What is a service pipe?

Part of house connection from the street main that is under the control of the owner of the premises.

 

25. What are the requirements of plumbing or piping system in buildings?

• It should not permit backflow of water

• All joints should be water tight and no leakage or spill at taps or cocks should  be allowed

• Pipelines should not be carried under walls or foundations

• It should not be close to sewers or waste water drains. There should not be any • possibility for cross connections

• If pipelines are close to electric cables, proper insulation should be observed

• It should afford easy inspection and repair of fixtures and joints

• Number of joints, bends and tees should be less

• It should supply adequate discharge at fixtures

• Economical in terms of materials

• Protected against corrosion, air lock, negative pressure and noise due to flow in pipes.

 

26. What is meant by pipe appurtenances and mention their role?

Pipe appurtenances are components attached in pipe line which aid in the proper functioning of pipe network. Role of appurtenances are ceasing, controlling, diversion and regulating flows through the pipe network. Appurtenances are valves, tees, bends, crosses etc.

 

27. List out any two appurtenances in water conveyance system?

• Sluice valves or gate valves,

• Air valves,

• Reflux valves,

• Relief valves,

• Altitude valves,

• Scour valves