Decide whether the following statements are true or false according to the text.

1) Pressure conduits are more expensive than canals or flumes.

2) Pressure conduits may be used to avoid loss of water by seepage and evaporation.

3) Pipes must withstand stresses created by internal and external pressures, external loads and temperature changes.

4) Water-hammer pressures can’t be reduced by use of slow-closing valves, automatic relief valves, air chambers and surge tanks.

5) The principal pipe materials are copper, wrought iron, plastics, asphaltic fiber and brick.

6) Check valves permit flow in any direction.

7) Drain or blow off valves are necessary at the low points of a pipeline to prevent entry of pollution into the pure water.

8) Pressure-relief valves open manually at a predetermined pressure.

9) Surge tanks are installed on medium pipelines and they are usually open at the top and of sufficient height.

10) The bottom of the surge tank must be near reservoir level.

11) Surge tanks are often built wholly or partially underground.

12) Siphon action doesn’t exist in pressure pipe.

13) To prevent deposition of suspended solids at the bottom of the sag, the velocity in the sag pipe should be great enough.

Answer the following questions.

1) What is a pressure conduit?

2) Why are pressure conduits preferable for public water supplies?

3) What stresses must pipes withstand?

4) What is caused by static pressure and water hammer?

5) What is known as water hammer?

6) How can water-hammer pressures be reduced?

7) What are the principal pipe materials?

8) What valves are required for the proper functioning of a pipeline?

9) Gate valves are used to regulate the flow in the pipe, aren’t they?

10) Do check valves permit flow in one direction only?

11) Where are check valves required at? Why?

12) Where are drain or blow off valves necessary at? What is their function?

13) Why must the bottom of the surge tank be far enough below reservoir level?

14) Surge tanks aren’t often built partially or wholly underground, are they?

15) What are exposed surge tanks usually built of?

16) Must a surge tank be protected from freezing?

17) When should the minimum velocity in the sag pipe be great enough to prevent deposition of suspended solids at the bottom of the sag?