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close this book Water purification, distribution and sewage disposal for Peace Corps volunteers
close this folder Section 5: Construction techniques
View the document Overview:
View the document Scheme
View the document Concrete
View the document Construction at the source
View the document Construction at the pumping station
View the document Construction at storage facility
View the document Construction on supply line
View the document Lesson plans

Construction on supply line

Pipe trenches must slope uniformly to avoid pressure variations in the pipes. Whenever a pipe has to pass over a gap in the trench, structures should be installed to support the pipes, especially at the joints. Once laid, the pipes should be coated, and accurately recorded in the systems map.

Different joints are used for different connections, The choice of a joint depends on the number of branches desired at a point. Positions of joints with many branches should be marked and protected as it is usually the main source of trouble.

The diagrams attached illustrate the various joints used in distribution systems. The supplier should provide simple guides, for joining pipes. If not available, a plumber's manual should be obtained. This should not prove necessary however, since this often involves only screwing parts together.

VALVES

Valves are used for specific purposes:

a. Gate valves - control the flow of water. Should be placed in junctions so that sectional repairs can be carried out without interruption of service. Should have manholes and be easily accessible. b. Check valves - allows one directional flow only. Used between pumps and pipe lines.

c. Air-Valves - allows air to escape from high points in the pipelines

d. Pressure-reducing valves - to reduce water pressure in pipes of any desired value.

METERS are not essential in rural water supply systems.

HYDRANTS - Where fire protection is provided, these should be designed to provide connections for 2 1/2 inch diameter fire hoses.

SERVICE PIPE -Connects street distribution pipe to the houses plumbing system. Should be rigidly connected to the street pipe.


Fig. 57 American standard cast iron flange fittings