Drainage systems – Getting Waste Water Out of the House
To remove the wastewater we have a system called drainage or sanitary drainage. This includes the pipes that the sinks, toilets, bath and shower are connected to.
It consists of a series of pipes and water seals that allow the waste fluid to exit the house into the main soil or sewer pipe.
As with most systems that carry fluids and gases, pressures and vacuums are present within the system, you will often see terms such as “vents”, “siphonage” and “seals” and these are paramount to most plumbing and drainage systems.
The basic definitions and systems are explained here so that the fittings described can be understood and directed to where they can be used appropriately.
One of the most basic principals in good drainage and plumbing is allowing the free flow of air above the mass of fluid in a horizontal sanitary plumbing pipeline, or in center of the falling volume of water of a vertical stack.
There has to be room in the pipes for gases, they cannot be totally full of fluid. This reduces the risk of siphonage or suction that pulls the water out of the seal of a sanitary fitting allowing noxious odours to escape from the system into the living space.
The periodical buildup of fluid to the situation of filling the entire pipe creates the problem of siphonage occurring. This is when the water seal can be sucked away and should be avoided. The water seal, is the water that you see sitting in the base of the toilet, or if you look under a sink you will see a u shaped pipe that contains water to act as a seal.
Correct venting of the system will alleviate this however the design of plumbing and drainage systems goes beyond the scope of this introduction. We want you to be aware of the systems and the basic principals behind them.