House Drain System

House Drain

• The House Drain is a part of the plumbing system that receives discharges from soil and waste stacks within a building and conveys them to the House Sewer.
• It is also known as the Collection Line of a Plumbing System.
• The House Drain can be installed underground, suspended below the floor, or inside the ceiling.

Types of House Drains

• Sanitary Drain: receives only sanitary and domestic waste, and conveys it to a public sewer or septic tank; storm water is not allowed in the sanitary drain.
• Storm Drain: conveys only storm clear water or surface water waste, and terminates into lakes, rivers, dry runs, or natural basins.
• Combined Drain: receives both sanitary waste and storm water; this type of drain is no longer permitted.
• Industrial Drain: receives discharges from industrial equipment containing acid wastes, and terminates into a separate drainage basin.

Size of House Drain

• The size of the House Drain depends on its service, whether it's for sanitary waste or storm drain.
• For sanitary waste, the Fixture Unit load discharge is the basis of computation.
• For storm drain, the roof area that accumulates the major rainfall waste is the basis for determining the pipe size.

Grade or Slope of House Drain

• A minimum slope of 2% is recommended for the House Drain.
• In some cases, a slope of less than 2% may be adapted, but it should not be less than 1%.
• A slope greater than 2% increases the velocity and discharge capacity of the pipe, but may cause decreased water depth and negative pressure.

Change of House Drain Direction

• Changes in direction should be done with long radius fittings; short tees, 1/4 bends, and short turn L fittings are not permitted.
• Soil branch should be run at a right angle to the main.
• Fixture connections should run at a right angle to the branch.

House Drain Cleanout

• The House Drain should be provided with adequate cleanouts to prevent breaking of the floor in case of drain stoppage.
• Cleanouts should be located where they are readily accessible, and should be equipped with a threaded screw cover.
• Any branch of the House Drain terminating at a floor drain or fixture should be provided with a 100 mm diameter pipe, extended at least 2 inches above the floor, inserted in a 45-degree Y branch in the direction of the drain flow.

House Drain Appliances

• House Trap: a device installed in the House Drain to prevent gases from the public sewer or septic tank from circulating through the plumbing system.
• Back Flow Valve: a device used in a drainage system to prevent the reversal of flow; it is installed in a House Drain or branches of the House Drain that are subjected to reversal flow of liquid.
• Area Drain: a device used to receive water to be drained from the basement floor, and is equipped with a cleanout.
• Floor Drain: a receptacle used to receive water to be drained from the floor into the plumbing system; it is usually installed on the basement floor, near heating equipment, below the kitchen sink, and in the vicinity of the laundry.
• Yard Catch Basin: a receptacle used to catch surface water drained from cemented courts, driveways, and yards.
• Garage Catch Basin: a device used to convey wastes from garage, wash rack, grease pits, and repair floors into the House Drain; it includes drain tile receptor, sewage ejector, automatic water siphon, sump pit, and grease basin.