An article about " Sewage system at home "

Sewage system at home

The efficient disposal of foul and surface water from your building is of great importance to public health and is an essential part of construction of the building.

The drain-waste-vent system transports all the used water and waste material from the house to the septic/sewer system. It is a network of drain pipes that runs to all the sinks, toilets, baths, showers and washer.

The soil stack is the main component of the waste drain. It is a vertical “stack” of pipes that starts in the basement/crawl space floor or wall where it is connected to the outbound sewer/septic line. The top end of the stack acts as a vent. It extends vertically through the roof, allowing gases to escape outside and also helps promote drain flow by drawing air inward. A plugged vent can trap dangerous gases and inhibit drainage. Trapped sewer gases can be dangerous and can cause serious structural problems. A system

without a vent may actually suck water out of a sink's trap, or do the reverse and fill the sink with water

when another fixture drains.

Sewage moves by gravity, which means the sewage lines coming into the house need to be at a higher level than where they go to connect to the city sewer line. To make the connection from your home

to the public sewer, you need to find out from your civil engineer where the sewers are. You should have at least a minimum of two or three percent fall and the amount of fall in your sewer system would depend on the elevation of the city connection location. The fall for the drain waste vent system is ¼ - inch per foot, which carries fluids through the sewage system. The lateral should be two degrees, which means

you have a four- inch pipe with a ¼ - inch fall, going into a six inch sewer lateral that results in a two-degree fall into the main line.

The position of the pubic sewer in relation to the proposed building and the invertlevel of the public sewer is important for efficient functioning of the disposal system. The system should enable rapid and

efficient removal of liquid waste without leakage. It should prevent foul gases from reaching the living

area of the building. It should enable access for cleaning. It should not create air locks and should provide

long service life.

The new waste systems use rigid plastic PVC (polyvinyl chloride) or ABS (acrylonitrile butadiene styrene) pipes that are sealed with glue. Older homes generally have cast-iron pipe sealed with lead solder.

The drainage pipe should be kept clear for all other services. Provision may be made during the construction of the building for entry of the drainage pipes. This can be done conveniently by building a sleeveinto or under the structure at appropriate locations.

U shaped trap

A trap looking like “U” shape is installed below the drain to block the sewer /septic gases without which sewer and gases can flow up the stack and the drain pipes and come out wherever there is a drain. When the water is drained, the trap's shape causes a small amount of water to remain in the bend. That water blocks any gases from moving up the pipe and entering the room. Traps are needed on all sinks, tubs, showers, washers, floor drains. In most cases, a toilet has a built in trap and doesn't require a trap in the drain line.

Soil Pipe

A soil pipe carrying liquid or solid wastes should be circular and have a minimum diameter of 100 mm. It should never be connected to any rain water pipe.

Waste Pipe

Every pipe in a building for carrying waste or overflow water from bath, washbasin or sink to a drain should be minimum 30 mm diameter and should be trapped immediately below by an efficient siphon trap with adequate means for inspection and cleaning.

Venting Pipe

Venting pipes should be so installed that water cannot be retained in them. They should be fixed vertically. The venting pipe should be taken to such a height that a safe outlet for foul smell is afforded.

Manholes of proper design and at sufficient intervals should be provided for periodic inspection and cleaning.

Damage to building

All pipe shafts should be plastered before installing any pipe. This will provide smooth surface and preventins ect and vermin infestation. Leaking sewage pipes should be repaired before they affect the building. It is leakage of the sewage which affects the RCC building. When sewer trenches have to be excavated near a building adequate precaution is necessary to prevent damage to the existing structures. Sewage and sullage can be connected to the sewer. Rain water should be dealt with separately.