(Elements of a Drainage System)

sanitary drainage system

is an essential component of building infrastructure designed to safely and efficiently remove wastewater and sewage from residential, commercial, and industrial structures.

sanitary drainage system

This system consists of a network of pipes, fittings, traps, vents, and other components that collect and transport sanitary waste to the municipal sewer system or on-site treatment facilities.

D - For Drainage of Solid Waste

W - For Waste coming from various fixtures other than water closet

V - For Ventilation of the piping system

The Drainage Installation is sometimes referred to as DWV which means:

Solid Waste

wastewater that is being discharged by water closet

Liquid Waste

wastewater that are coming from various fixtures

Soil Pipe

Any pipe which conveys the discharge of water closet or fixtures having similar functions.

Waste Pipe

Any pipe which conveys only liquid wastes free of fecal matter.

Stack

A general term used for any vertical line of soil, waste, or vent piping

Soil stack Pipe

A vertical soil pipe conveying fecal matter and liquid waste.

Branch

Any part of a piping system other than the main, riser, or stack

Branch Interval

A length of soil or waste stack corresponding in the general to a story height, but in no case less than 2.43 m within which the horizontal branches from 1 floor are connected to the stack.

Main

is the principal artery of the system to which branches may be connected

Vent

A pipe or opening used for ensuring circulation of air in a plumbing system and for reducing pressure

exerted on trap seals

Wet Vent

That portion of vent pipe through which liquid waste flow.

Dry Vent

A vent that does not carry water or waterborne wastes

Stack Vent

An extension of a soil or waste stack above the highest horizontal drain connected to the stack. Also called “waste vent” or “soil vent”

Vent Stack

A vertical pipe installed primarily for the purpose of providing circulation of air to different parts of the drainage system

Branch Vent

A vent pipe connecting from a branch of the drainage system to a vent stack

Unit Vent

An arrangement of venting so installed that one vent pipe will serve two (2) traps

Common Vent

Is a drain from two or three fixtures connected to a single trap. Also called “Dual Vent”

Circuit Vent

Is a branch vent that serves two or more traps, and extend from the front of the last fixture connection of a horizontal branch to the vent stack

Continuous Vent

Is a vertical vent that is continuation of the drain to which the vent connects.

Looped Vent

Same as Circuit Vent except that it loops back and connects with a stack vent instead of a vent stack.

Relief Vent

A vertical vent, the primary function of which is to provide additional circulation of air between the drainage & vent systems or to act as an auxiliary vent on a specially designed system such as yoke vent, connection between the soil & vent stacks.

Backvent Pipe

The part of the vent line, which connects directly with an individual trap underneath or behind the fixture and extends to the branch or main vent pipe at any point higher than the fixture or fixture trap it

serves. Also called individual Vent”.

Battery of Fixtures

Any of two or more similar adjacent fixtures which discharge into a common horizontal soil or waste branch.

Horizontal Pipe

Means any pipe or fitting which makes an angle of more than 45deg with the vertical

Lateral

A common sewer to which no other common sewer is tributary. It receives sewage only from building sewer.

Trap

Is a fitting or device so designed as to provide when properly vented a liquid seal that will prevent the back passage of air without materially affecting the flow of sewage through it.

Trap Seal

Is the maximum vertical depth of a liquid that trap will retain, measure between the crown weir and top of the dip of the trap.

House / Building Drain

part of the lowest horizontal piping of a plumbing system which receives the discharge from soil, waste, and other drainage pipes inside of a building and conveys it to the house sewer. 0.6 m outside the building wall.

House / Building Sewer

That part of a plumbing system extending from a point about 4 or 5 feet from the inner face of the foundation wall of a building to the junction with another sewer

House Trap

A trap connected to lowest horizontal piping.

Combination Waste & Vent System

A specially designed system of waste piping embodying the horizontal wet venting of one or more sink or floor drains by means of a common horizontal waste & vent pipe, adequately sized to provide free movement of air above the flow line of the drain.

Drain

A pipe which carries ground surface water, storm water, or wastewater into a building drainage system.

Drainage System

Includes all the piping within public or private premises which convey sewage or other liquid wastes to a legal point of disposal but does not include the mains of a public sewer system or a public sewage system or disposal plant.

1. Soil Drainage System

2. Waste Drainage System

3. Vent System

4. Storm Drainage System

Four Sub-Systems of a Drainage System

Soil Drainage System

The piping that conveys the discharge of water closets or fixtures having similar functions (containing fecal matter), with or without the discharges from other fixtures.

Waste Drainage System

The piping that receives the liquid discharge, from plumbing fixtures other than those fixtures (water closets) receiving fecal matter. This piping is free of fecal flow.

Vent System

The piping system that receives a flow or air to or from a drainage system or to provide a circulation of air within such system to protect trap seals from siphonage or back pressure.

Storm Drainage System

The piping system that receives clear water drainage from leaders, downspouts, surface run-off, ground water, subsurface water, condensate water, cooling water or other similar discharges and conveys them to the point of disposal. All sanitary wastes must be excluded.

Sewage

Any wastewater containing animal or vegetable matter in suspension or solution and may include liquids containing chemicals in solution

Sewer

A pipe or conduit for carrying sewage & wastewater.

Sewerage or Sewerage Works

Including all constructions for collection, transportation, pumping, treatment & final disposition of sewage.

Siphonage

A suction created by the flow of liquids in pipes. A pressure less than atmospheric.

Vent System

A pipe installed to provide flow of air to or from a drainage system or to provide a circulation of air within such system to protect trap seals from siphonage & back pressure.