Sanitation means the study and application of procedures and measures designed to protect public health, as in the provision of clean water and the disposal of sewage and waste. The principles and procedures to be followed while constructing and laying sewer lines in private buildings are term as house drainage.
It is necessary to prepare the detailed plans showing the proposed house drainage system and to get it approved or sanctioned from the competent authority. Following points should be noted:
- The site plan of the building should be drawn to a convenient scale and positions of gully traps should be marked on it as shown in fig.
- The longitudinal section of proposed sewer line should be drawn to a convenient scale. Generally the longitudinal sections of drains greater than 150 mm in diameter are drawn.
- The longitudinal sections should show distances, ground levels, invert levels, depths of cutting, sizes of chambers and manholes, size and gradient of pipes etc. as shown in fig.
- The position of public sewer should be clearly shown on the site plan and longitudinal section of drain. It is advisable to join the house drain to a manhole on public sewer line.
- The detailed plans of the different floors of building show the positions of floor traps, sanitary fittings etc. They are to be connected by keeping in mind the general principles of house drainage.
The proper design and construction of house drainage the following general principles are adopted:
- The house drains are laid as per details on the approved drainage plan of the building.
- It is advisable to lay sewers by the side of building rather than below the building drains should be laid straight between inspection chambers or manholes.
- All sharp bends and junctions should be avoided except through chambers or manholes.
- The house drain should be connected to the public sewer only if the level permits i.e., only when public sewer deeper than the house drain. Otherwise there will be reverse flow from the public sewer to the house drain.
- The entire system should be properly ventilated from the starting point to the final point house drainage of disposal.
- The house drainage should contain enough number of traps at suitable points for efficient functioning of it.
- The house drain should be disconnected from the public sewer by the provision of an intercepting trap so as not to allow foul gases from the public sewer to enter the house drain.
- The joints of sewers should be watertight and should be properly tested before putting the drainage line in use.
- The lateral sewers should be laid at proper gradient so that they will develop self cleaning velocity.
- The layout of house drainage system should permit easy cleaning and removal of obstructions.
- The materials of sewer should comply with the standard requirements. They should be non absorbent and an earth cushioning should be provided to protect them from external loads.
- The possibilities of formation of air lock, siphonage, undue deposits etc should be properly studied and adequate remedies should be accommodated in the design to avoid them.
- The size of lateral sewers should be such that they will not overflow at the time of maximum flow discharge.
- The rain water from houses is collected form roofs and it is allowed to discharge into the rainwater harvesting tank.
- The sewage formed should be conveyed as early as possible after its formation.
- Water Supply And Sanitary Engineering By S.C.Rangwala
- 'Building A Sweet Home' By Suraj Ambadas Laghe