Soil and Waste Disposal System

8/11/2019 Soil and Waste Disposal System

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Soil and Waste Disposal System

University of BelizeEngineering DepartmentPlumbing BLDG 1252


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Principle of Soil and Waste Systemor Drainage Above Ground

Soil and waste pipe systems should be

designed to carry away the discharges

from sanitary fittings quickly and quietly

without the risk of injury to the health of

occupants of the building.


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Definitions

Soil appliances includes water closet, urinals,bed pan basin, slop sink.Soil pipe A pipe which conveys soil water aloneor along with waste or rain water.

Ventilating pipe- A pipe open to the external airwhich ventilates the drainage system.Waste Appliances includes lavatory basin,domestic sink, tubs, wash fountain, shower tray.

Waste pipe A pipe which conveys waste watereither alone or together with rain water.

Waste water water not contaminated by soil

water.


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Soil appliances


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Waste Appliances


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Drainage System Requirements

1. Water seal in trap Prevent foul air fromentering back in the building through thefixtures or appliances.

1. Sizes of Pipes Internal diameter of soil,waste or ventilation pipe shall not be lessthan any branch pipe inlet or outlet pipes.

(50mm - 75 mm for one or more urinals.

32 mm for lavatory basin .)


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Water seal in trap


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Drainage System Requirements

3.

Materials, fixing and joints

Soil, wasteor vent pipe shall be of suitable materials instrength and durability.

Bends in pipes should have the largestpractical radius.

Pipes should be adequately supportedthroughout its length


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Bends in pipes


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Basic Plumbing Drain and Vent System


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Branch pipe


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TRAPS


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A S


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TRAPS


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Drainage System Requirements4. Traps Traps should be fitted close to waste

or soil appliances, unless the appliance hasan integral trap.

A waste pipe serving a number of lavatorymay used one trap fitted at the end of thepipe, providing the length of does not exceed5 meter in length.

TRAPS


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TRAPS

A waste pipe serving two ormore appliances , may

discharge into a commonwaste pipe with eachappliance provided its owntrap.


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Loss of Trap Seal

1. Self-siphonage moving plug of water in the

waste pipe. A partial vacuum is created at the

outlet of the trap, thus causing siphonage of

the water.


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If the waste pipe from a wash basin is at too steep agradient self-siphonage may occur. This is where thecontents of the trap are sucked out into the waste pipe

because the water flows away too quickly thusemptying the trap.


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Loss of Trap Seal

2. Compression or back pressure caused by a

build up of air pressure near the bend at the

foot of the stack. A waste pipe connected to

the stack in the pressure zone may have the

seal of the trap lost by compressed air forcing

out the water.


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Loss of Trap Seal

3. Capillary Attraction caused by porousmaterials being caught at the outlet of the trap sothat the other end is in the water.

4. Wavering out High velocity gusts of windpassing over the vent pipe.

5 . Evaporation When the trap is not in use.

6. Leakage Faulty joints or crack in trap.


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CapillaryAttraction Wavering out


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Venting the drainage system

Venting allows free circulation of air atatmospheric pressure and allow the

system to function properly.

Take away fouled gases away from the

system to open air space usually above

roof


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Method of Venting


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Method of Venting


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Venting Methods


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Venting Methods

V ti g


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Venting


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Venting Methods


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Venting Methods


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Venting Methods


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Single stack system


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Drain Waste Vent System

Documents

Soil and Waste Disposal System