As per IS 1742-1983, normally a sewer shall be designed for discharging ____ times the dry weather flow flowing half-full with a minimum self-cleansing velocity of ____.
Sewage may be defined as the used water or liquid waste of the community which includes human and household wastes, industrial waste and stormwater.
Gradient of Sewer Lines
As per IS 1742-1983, Normally the sewer shall be designed for discharging three times the dry weather flow, flowing half full with a minimum self-cleaning velocity of 0.75m per sec. The approximate gradient gives this velocity for the size of sewer pipes commonly used in the building.
The minimum gradient for laying sewer is 1 in 57. (For 100 mm dia pipe).
Manning’s N to be considered while designing of sewers to be 0.015.