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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

4. PRINCIPLES OF INSTALLATION

4.100

HYGIENE AND FUNCTION


The buildings are to be fitted with drainage installations which should follow these guidelines in view of hygiene and function.


The waste waters have to flow as fast as possible into the plot's sewerage system without leaving sediments in the pipelines (i.e. to be self-cleaning).

4.200

SAFETY


The drainage system has to be planned and to be installed so that the following conditions are fulfilled:



- Resistant to domestic soil and waste waters and gases



- To absorb the soil waste waters


Protection provided against:



- Exit of any soil and waste waters and gases



- Mechanical influences of all kinds



- Outside influences of temperatures



- Back-flow



- Corrosion and erosion

4.300

NOISE CONTROL


Drainage installations are to be collected and reasonably fitted in those rooms where normally no noise control is required, (e.g: bathrooms, kitchens, etc.).

4.400

PROHIBITION OF DIRECT CONNECTION WITH THE WASTE WATER PIPELINE


Drinking water (and overflows and drainages of containers and appliances, which are fed from a drinking water pipeline) must never be connected directly to the drainage pipes, (prevention of back-siphoning)!

4.500

SEPARATION OF RAIN WATER AND WASTE WATERS


Rainwater and soil/or waste waters have to be drained separately, and (if permitted) may only be joined outside the building into the ground pipeline.

4.600

CHEMICALLY LOADED WASTE WATER


Chemically loaded waste waters are to. be led separately to a pre-processing plant.


Waste waters require a special pre-processing plant, especially when they contain:



a) Floating matter and heavy sediments;



b) Oils and greases in large quantities or on demand of the concerned authorities;



c) Strong poisons;



d) Acids



e) Strong alkalinous reacting substances



f) Radiation exposure


The damaging effects of these substances are opposed by means of:



a) Silt traps, filters or sieve plants



b) Oil or grease arrestors



c) Detoxication



d &e) Neutralization



f) Decontamination plants



- Processing plants are to be established and to be operated according to the Government's laws.



- The achievement of determined limiting values by means of dilution is prohibited.

4.700

SECURING OF AERATION AND VENTILATION


Sewerage plants are to be constructed so that the air can circulate, also during the drainage of waste waters.

4.800

MAINTAINING OF FLOW SECTION


Soil and/or waste water pipes are not to be reduced in their sections in the direction of drainage.

4.900

CLEANING


The cleaning of drainage systems is to be secured by means of relevant cleaning openings (clean out, cleaning eye, manhole, etc.)

4.910

Siphon (Traps) - The entry of foul air to the building should be prevented by suitable siphons, properly sited. Each drainage appliance is to be fitted with such a siphon, which needs to be installed at the place of the outflow of water, e.g. waste coupling. Out of use drainage appliances are to be removed and the apparatus connector pipeline must be closed tightly by professional skills.

4.920

Back-flow - Where a back-flow from the public canalization is to be expected, an overflowing of endangered basement rooms is to be avoided by means of a suitable precaution (e.g. pump). The level of the back-flow is to be asked from the concerned authorities.

4.930

Gravity flow - All drainage appliances situated above the back-flow level are to be drained directly through gravity flow.

4.940

Drainage of rainwater (storm water) - Roofs, balconies and other building annexes are to be drained by means of rain gutters, roof drains and through leaders, provided they are projecting over accessible surfaces (walk ways, forward squares, side walks, etc.).