The water supply may be intermittent or constant, usually the latter, whereby the mains are always full of water. By a constant system is meant a system whereby the mains are constantly under pressure. The drinking water is taken direct from the rising main, and consequently it is only necessary to provide a small storage system sufficient for the hot water supply.
The constant system has the following advantages over the intermittent supply:
· The mains are always full and an adequate supply of water may be obtained at any time;
· The danger of drinking water becoming contaminated is lessened owing to a direct supply from the main and the avoidance of large storage cisterns;
· The pipes, constantly under pressure, are less liable to deteriorate;
· In order to maintain a good fire-fighting service, a constant supply is necessary for the fire hydrants.
The chief advantage of intermittent supply is the saving of water, but the constant system is usually preferred.
Service Pipes. The service or supply pipe may be lead, copper, wrought iron, or steel. Lead pipes are extensively used, and the weight in proportion to the diameter will vary slightly in accordance with the regulations of the water authorities.
3.Match the words or notions with their definitions.
1. The water supply...
2. The mains are always...
3. The danger of drinking water...
4. The pipes are less...
5. A constant supply is necessary...
· The service pipe may be...
· Under pressure
· Is lessened to a direct supply
· Liable to deteriorate
· For a fire hydrants
· Lead, copper, iron, steel
· Full of water
· May be intermittent or constant
Ask as many questions to the given statements as possible.
o The drinking water is taken direct from the rising main;
o Large storage tanks are necessary for the water;
o The mains are always full an adequate supply of water;
Complete the sentences.
The service or supply pipe may be...
Lead pipes are extensively...
The danger of drinking water becoming contaminated...
The chief advantage of the intermittent supply is the saving water...
In order to maintain a good fire-fighting service...
By a constant system is meant a system...
The pipes constantly under pressure...
A constant supply is necessary...
6. Answer the questions:
v May the water supply be intermittent or constant?
v When are the main are constantly under pressure?
v It is necessary to provide a small storage system sufficient for the hot water supply?
v Has the constant system the advantages over the intermittent supply?
v Are the mains always full and adequate supply of water?
v The danger of drinking water becoming contaminated is lessened owing to a direct supply, is not it?
