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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

6. PRINCIPAL REQUIREMENTS FOR DRAINAGE APPLIANCES

6.100

PRINCIPLE


To each water tap in buildings there belongs a drainage appliance (Exception: fire fighting equipment).

6.200

DISCHARGE VALUE


The discharge value of soil and/or waste water of any drainage appliance depends on its function.

6.300

OVERFLOW


Drainage appliances having outlets with stoppers (e.g. washbasins, kitchen sinks, bath tubs, etc.) require an overflow.

6.400

BACK FLOW PREVENTION


Drainage appliances have to be above the level of back-flow or are to be secured against exit of waste water by means of appropriate measures.

6.500

PREVENTION OF EXIT OF GASES

6.510

Siphon drainage appliance - Each drainage appliance (with exception of inlets, e.g. drain inlets) has to be fitted with a siphon to prevent the exit of gases. This siphon can be an integral part of an appliance or be directly attached to the outlet of the appliance. The pipe bore should be uniform throughout and have a smooth surface.



Figure

6.520

Siphon rainwater - Rainwater pipelines, from which disturbing odours may occur, are to be fitted with a siphon, fitted in a frost-secured place.

6.600

REQUIREMENTS OF SIPHONS (traps)

6.610

Water Seal - The siphon prevents the exit of gases by means of it's water seal.



Figure


h =

height of water seal (odour lockage)



for water closets, min. 50 mm



for all other siphons, min. 70 mm


S =

level of water seal


SL =

(partial) loss of water seal (e.g. trough siphonage)

6.620

Self-cleansing - Siphons should always be of a self-cleansing pattern, by means of the discharged waste and/or soil water.


Anyhow, a cleaning opening must be provided.

6.630

Placement of siphon - Siphons for use in domestic waste installations and all other siphons should be accessible. A siphon has to be directly attached to the outlet of the appliance, or to be an integral part of the appliance (e.g. water closets).

6.640

Removable connection - Where openly fitted, such a siphon has to be easily fitted and removed.

6.650

Concealed siphons - The construction and fitting of siphons must guarantee an easy removal of parts of the siphon and therefore enable easy access to the connector pipeline.


Where the siphon is an integral part of the appliance, the connector pipeline has to be accessible through either easy removal of the drainage apppliance (closet, urinal, etc.), or by means of reasonably placed cleaning openings. The cleaning opening has to be adjacent to the siphon or be directly part of it (e.g. floor drain with siphon).


Where the siphon is concealed in the building construction, with the exception of shower tray and bathtub, the possibility for cleaning is to be secured by means of a manhole or a cleaning opening.

6.660

Guarantee of water level - To maintain the minimal required water level at each siphon, a permanent guarantee has to be provided by appropriate means.

6.670

Water replacement - Closets and urinals with self-siphoning flushing systems have to be fitted with a device which replaces the water in the siphon automatically after each flushing.

6.680

Mechanical odour barriers and aeration valves - both are prohibited for installation in domestic waste systems.

6.700

Prohibition of direct connection with soil and/or waste water pipelines - Appliances, refrigerators, refrigerator plants, fish cabinets, food cabinets and other containers for food may only be connected to the soil and/or waste water pipeline by means of a inlet funnel. This same is also valid for drains of safety valves and other devices of the drinking water system.



Figure



gap to be of min. 2 cm, or of same diameter as inlet.

6.800

PROTECTION AGAINST POLLUTION OF PIPELINES

6.810

Protection from solid matter - no solid matter, such as sand, garbage, textiles, vegetable wastes, etc., may be fed into a drainage system.

6.820

Protection from gross pollution - The outlet of a drainage appliance has to be constructed in such a way that no blocking solid matter may reach the siphon. The fitting of a kitchen waste chopper is prohibited.

6.830

Closet arrangements - They have to be fitted with flushing cisterns, in order to guarantee the self-cleansing of the soil water system.