Just a few decades ago, problem of choosing the type sewer pipe did not arise - steel or cast-iron pipes and fittings are purchased usually. But now everything has changed - the building materials market offers a wide variety types of pipes for drainage systems, and their main characteristic can be called the manufacturing material. The pipes and fittings can be divided into several types:
Manufacturers produce several types of cast iron drainage pipes:
Pressure pipes with socket is most often used when installing of underground and ground drainage systems, and they are characterized by durability, also they can withstand high pressure - up to 16 bar, so that they can be used in heating systems. Most often the pressure pipes are used at industrial facilities.
Cast iron raw materials for ductile iron is improved by adding magnesium - it ensures the absence of cracks on the pipeline. Other advantages of ductile iron are:
Non-pressure pipes are suited for systems which do not suffer extreme stress: they are recommended for domestic drainage systems of low-rise residential buildings and industrial facilities.
SML systems have one important difference from other types of cast iron equipments for drainage systems - the internal walls are covered by special epoxy layer, which eliminates the probability of formation of deposits. This prolongs the service life of the pipeline and reduces the risk of clogging.
Cast iron pipes are not recommended for installation of drainage systems in areas with saline soils or with weak ground.
Plastic (polymer) pipes and fittings are gaining in popularity because they have indisputable advantages. All drainage pipes and fittings of the polymers can be divided into several types:
Polyethylene pipeline is made of high-strength polyethylene, and manufacturers produce the conventional, and two-layer, and corrugated pipes. Plastic pipes are characterized by:
However, they have a drawback - the presence of high linear expansion under the influence of temperature. Also this type of pipeline equipment is suitable for disposal effluents with temperature no higher than +40 °C. Accordingly, PE pipes should not be used for installation of the hot water supply systems.
HDPE pipes are made of high density polyethylene. This type of pipeline equipment has the following advantages:
HDPE pipes have disadvantages. Thus, they lose their properties under ultraviolet light. Also they have low mechanical strength and low resistance to high temperature - the material begins to soften at temperature +80 °C and it melts at temperatures above +105 °C. However, manufacturers produce pipes which are made of cross-linked polyethylene that can withstand temperatures up to +400 °C.
Polypropylene pipes are the most common among the different types of plastic equipment for drainage systems. They have the following advantages:
Drawbacks of products from PP includes:
Installation of PP pipe should be at temperature not below +5 °C, but some manufacturers add to the raw low-temperature plasticizers, so that the pipes can be installed at temperatures down to -10 °C.
PVC products are used for installation of gravity drainage systems, ie those systems in which wastewater moves by itself due to small deviation of pipes, as well as the weight of the waste masses. The main advantages of PVC products include:
However, there is a significant drawback this type of pipeline equipment, which is why it is not recommended to use when installing domestic drainage systems - if ignited PVC pipes release toxic gas phosgene into the environment
Multilayer pipes consist of several layers, and internal layer is made of plastic which increases capacity due to absolute smoothness of the internal walls. Also the smoothness of the internal walls reduces the likelihood of deposits.
The external layer is made of cross-linked polyethylene, and the middle layer is made of aluminum. All elements are connected together using glue mixture. So that the pipeline is resistant to internal and external influences.
The main advantages of multilayer pipes:
Multilayer pipes have several drawbacks, and one of the main is low resistance to temperature extremes – it can result to stratification of glue mixture. Also multilayer pipes are inflammable materials.
When choosing drainage pipes and fittings you should give special consideration to material from which they are made - it determines the service life of the pipeline and the cost of its installation.