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close this bookResidential and Non-Residential - Drinking water installations and drainage requirements in Nepal (MTC - SKAT, 1988, 188 p.)
close this folderPART 2 - DRAINAGE REQUIREMENTS
View the document1. SCOPE
View the document2. FIELD OF APPLICATION
View the document3. TERMS AND DEFINITIONS
View the document4. PRINCIPLES OF INSTALLATION
View the document5. PRINCIPAL REQUIREMENTS FOR PARTS OF PIPELINE
View the document6. PRINCIPAL REQUIREMENTS FOR DRAINAGE APPLIANCES
View the document7. PRINCIPLES FOR THE PLANNING AND FITTING OF DRAINAGE PIPES
View the document8. SANITARY APPARATUS (Fixture, Appliance)
View the document9. VENTILATION
View the document10. RAIN WATER
View the document11. MATERIALS
View the document12. PRINCIPLES OF CALCULATION
View the document13. DIMENSIONING
View the document14. INSPECTION AND TESTING

11. MATERIALS

11.100

PLASTIC PIPES, PRINCIPLES - Plastic pipes require special attention:



- Contraction/expansion to be taken care of by including special sockets, and by clamps which provide longitudinal movement.



- Horizontal pipelines to be fitted with galv. M.S. half-shells, or additional number of clamps, in order to provide required strength.



Figure

11.200

FIXED JOINTS


Fixed joints of plastic pipes are achieved by welding (e.g. butt welding with a hot plate for HDPe, or by solvent weld joint using solvent cement on to uPVC pipes).

11.130

Ring seal sockets - Are joints having a neoprene ring seal and allow easy fitting on site. They have a limited capability to absorb little changes in length. Protection of sensitive sealing parts from any ingress of dirt is to be maintained, especially at the building site (wrapping of joints with pieces of cloth and securing it with adhesive tape).

11.140

Preparation of pipe ends - The end to be inserted should be bevelled all around to an even angle of approx. 15°


Before joining: sockets and spigot ends are to be cleaned from any impurities.



Figure

11.150

Insertion depth - It is required to mark the depth of insertion on the spigot end, prior to joining. When using flexible joints (e.g. ring seal sockets), in winter at lower temperature, insert to approx. 5 mm less than entire insertion length.



Figure

11.160

Fixation of horizontal pipelines - Exposed lay-outs' require attention to physical strength and changes in length. Satisfactory fixings can be achieved partly by using appropriate sealing sockets, and with a pipe lay-out allowing flexibility for limited movement. (Prevention of movement is possible when having a fixed lay-out by embedding the pipe in concrete or by having strongly fixed pipes).


It is recommended to have horizontal pipelines fitted with half-shells, as follows:



Figure


Alternatively, instead of having half-shells, one could provide a greater number of appropriate clamps.



Figure



11.200

CAST-IRON PIPES, PRINCIPLES


C.I. pipes can be used for soil and/or waste waters and also for ventilation pipes.

11.210

Quality - C.I. pipes shall be sand cast iron or centrifugally cast (spun) iron pipes as per accepted standards.

11.220

Application - C.I. pipes can be used:



a) in unstable ground where limited soil movement is expected;



b) in made-up or tipped ground;



c) To provide for increased strength where a sewer is laid at insufficient depth, where it is exposed or where it has to be carried on piers or above ground;



d) under buildings and where pipes are suspended in basements and similar situations;



e) In reaches where the velocity is more than 2.4 m/s;



f) For crossing of watercourses.

11.230

Corrosion of C.I. pipes - It shall be noted that cast iron pipes even when given a protective paint are liable to severe external corrosion in certain soils. Among such soils are:



- soils affected by peaty waters, and



- soils in which the subsoil contains appreciable concentrations of sulphates.

11.300

REINFORCED CEMENT PIPES


Are commonly used for house drainage systems and they shall conform to accepted standards. They are not recommended for underground situations. If used underground the life of reinforced cement pipes may be increased by lining the inside of the pipes with suitable coatings like epoxy/polyester resins, etc.

11.400

SALT GLAZED STONEWARE PIPES
For all sewers and drains in all soils, except where supports are required as in made-up ground, glazed stoneware pipes may be used. They are suitable particularly where acid effluents or acid subsoil conditions are likely to be encountered. Salt glazed stoneware pipes shall conform to accepted standards.