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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

10. RAIN WATER

10.100

PRINCIPLES


The drainage of rainwater from roofs, terraces, etc., has to be according to the climatic conditions and must follow the rules of the building inspectorate. Spouts are to be applied only beyond walkways. Rain water drainage requires separate pipe-work for the entire building installation. Any possible joining with a drainage system are to be made outside the building only!

10.200

LEADERS


The rain water leader shall be situated outside the building, where possible, and shall be continued upwards without diminution of it's diameter to the roof outlet. Pipes are preferably to be in a vertical line, and except where it is unavoidable bends should be utilized. Changes of directions to be made with bends having larger radius, and approx. 15° up to 45° (no elbows!)

10.300

TERRACES


Where terraces are connected to the drainage system, this must be made with a separate leader and with a siphoned device and situated in a frost-protected place.

10.400

ACCESSIBLE ROOFS


On accessible roofs (as for example Penthouses) the rain waterleader requires a siphon or mud trap (with siphon). Exception: Divided systems, i.e. rainwater drainage led into an outfall ditch.



Figure

10.500

ROOF SURFACES AT DIFFERENT LEVELS


On buildings with roof surfaces at different levels it is suggested to design separate rain water leaders. Where this suggestion is not followed, the installation has to be made in such a way that no damage may occur due to back-flow.



Figure

10.600

OUTSIDE RAIN WATER LEADERS (=DOWNPIPES)


Are to be made of mechanical resistant (impact-strengthened) material up to a height of min. 1m, measured from above terrain level, and to have a sliding piece (for easy removal of downpipe when required).

10.700

PROTECTION OF RAINWATER PIPES AT ROAD SIDES


Rain pipes adjoining public pavements or roads should be recessed up to a height of 3 m into the building facade.



Figure

10.800

RAINWATER OUTLETS


The funnel and gutter outlets have to be conical, in order to ensure proper swallowing of rain water.



Figure

10.900

SAFETY OVERFLOW


Flat roofs are to be provided with a safety overflow!