FASP PIPE®

FASP® – “French Angle Slotted Pipe” is a patented product designed to deal with sub-surface water causing containment or affecting a structure which cannot be controlled with drainage systems with basins and roof guttering.   It is also used  for de-watering grounds that are excessively over-saturated with water containment down into the soil  where water will not move upward into basins.                 

French drain pipe:   to be 4” S D R 35  which is the heaviest gauge with tolerances compatible with standard drain products.  This base pipe to have elongated slots at angles off setting along both sides of pipe to allow substantially a continuous entrance of water into the pipe while retaining wall strength.  Slot angles and length to be in pipe to allow maximum water entrance while bottom half of pipe remains unobstructed so that soil particles will be flushed along with water flow to exhaust rather than accumulating to cause stoppage.  Elongated slots to be narrow on curvature wall of pipe so gravel back-fill will not block water moving into pipe.  Slots angled to spread water flow on wall of pipe to break surface tension and enhance water flow with soil particles to wash to exhaust.

French drain trench:  to be hand dug so that walls of trench are precisely shaped to exactly form the gravel filter material and retain native soil to control water leaching out of  the system.   The trench size to be a minimum width of two (2) times the pipe size.  Trench bottom to be bedded and compacted with site soil selected with most clayey content.

Gravel Filtering Material:  Washed natural river gravel designated as ¾” in size but varies to smaller and larger sizes.  The rounded surface of gravel and pipe combine to provide openings that encourage water flow exceeding smaller pea gravel and flat surface crushed granite.

Installation:  Provide combination vent test clean-out at the origination point of the pipe system.  This fixture to be installed on a riser above ground to limit water intake.  Provide additional vents at approximately 100 ft. intervals.  Install FASP®  pipe with slots upward and maintain uniform fall to exhaust point.