There are 2 different method for designing the sub soil drain system:
A- Balding with site:
If building has a larger site plan than the building foot print and there are adequate lands around the building, then can install a 4” perforated PVC pipe loop around the exterior of the building and at the building foundations (by coordination with the structural engineer for the location of pipe versus foundations) with 0.5% slope, then run a solid PVC pipe from the nearest point of the loop to the sump pump system’s pit inside the basement.
B- Balding without site:
If building does not have a larger site plan than the building foot print and there are not lands around the building, then can install a 4” solid PVC pipe loop inside the basement within a reasonable distance from the building foundations (by coordination with the structural engineer for the location of the pipe versus foundations) with 1% slope, then run a solid plastic pipe from each foundation pocket or every 10 ft from foundations’ continues trench (provided by structural engineer for foundations) to the loop and connect the loop by a solid PVC pipe from the nearest point of the loop to the sump pump system’ pit inside the basement.
If the building foundations are utilized with a hydrostatic wall (design by structural engineer), then no sub soil drain is needed.
Click on below link for sizing sump pump:
http://www.mepanet.com/230/size-sump-waste-water-collection-storm-drain-subsoil-drain
See below detail for typical sizing the Sump PumP Pit:
