Where foul water drainage from a building is to be pumped, the effluent receiving chamber should be sized to contain 24 hour inflow to allow for disruption in service. The minimum daily discharge of foul drainage should be taken as 150 litres per head per day for domestic use. For other types of building, the capacity of the receiving chamber should be based on the calculated daily demand of the water intake for the building. Where only a proportion of the foul sewage is to be pumped, then the capacity should be based pro-rata. In all pump systems, the controls should be so arranged to optimise pump operation.
Example : 6 bedroom house to be ‘pumped’ = 2 people in the master bedroom, 1 in each of the remaining = 7 x 150L = 1050L
It is considered bad practice to pump facilities from ground level and above if they can be designed to be discharged by gravity.
It may not be necessary to allow for storage capacity on a pro-rata basis for basement application where alternative gravity facilities are available in accordance with BS6465.