The installation of drain system in a bathroom must begin from horizontal drains, which connect the waste stack with individual devices. Washbasins, bathtubs and shower cubicles can have joint horizontal drains. Each toilet should have a separate drain, below the remaining drains.
Toilet drains can be 1 m long at most, whilst washbasin, bathtub and shower drains – up to 3 m. In order to avoid problems with slow water drainage or drain pipe clogging, their slopes and diameters must be properly adjusted. The slope of drain pipes should be 2 to 15 cm per each meter of length. The diameter of a pipe depends on the device connected – the pipes for toilets should have 110 mm diameter, the pipes for bathtub and shower cubicle – 50 mm, and the pipes for washbasin drainage – 32-49 mm.
Depending on the connected device, drain inlet is to be placed at different height level. In the case of washbasins the drain inlet should be 50 to 60 cm above the floor. In the case of shower cubicles – up to a few cm above the floor, whilst for the bathtubs – up to over a dozen (usually 15-16 cm above the floor). All drains should be, of course, equipped with elbows, preventing any bad smells from the drainage system from entering the bathroom.
The drains of toilet bowls can be implemented in two ways: We can select from among toilets with vertical and horizontal drain. The more common one is horizontal drain, although in some (mainly old) buildings vertical drains can also be found. Depending on the type of toilet rain, we should choose an adequate toilet bowl.
The drainage system is only a fragment of the bathroom "piping". The other, equally important part is the water supply system, comprising pipes providing water to bathroom devices. Thanks to the use of proper pipes, water in bathroom can run to any place we like.
Pipes can be laid under the floor or in trenches made in the walls. You can choose from classic steel pipes or plastic pipes. Unfortunately, the most popular steel pipes have many flaws – low-quality steel and polluted water make such pipes corrode and scale quickly and so they need to be replaced every 7-10 years. Therefore, it is worth considering installing a copper (more expensive) or plastic (at a price comparable to the steel one) installation.
Plastic pipes are lighter than steel, so they are easier to install. Their low thermal conductivity translates into lower heat loss. The internal surface of those pipes is very smooth in order to reduce flow resistance and prevent scaling on the internal walls. Plastic pipes have lower impact on the taste, colour and scent of water. They are, however, sensitive to solar radiation and higher temperatures.
Copper installations are resistant to higher temperatures and solar radiation, and they also exhibit good thermal and electrical conductivity. It is a ductile material, which makes the pipes easy to install. Copper pipes are highly durable, when properly manufactured they can be used even for 50 years. However, copper installations are very sensitive to certain kinds of corrosion.
What should we focus on when installing water system? It must not be located above gas pipes or electrical wiring. Also avoid connecting pipes under the floor.