Polypropylene pipes for sewerage: GOST, characteristics

Today, polymer pipes are used in various fields. Polypropylene sewer pipes are very popular. Such products are distinguished by their versatility and high inertia, so they are ideal for any drainage structures. In addition, a wide range of such parts allows you to select suitable elements for different communications.

Polypropylene sewer pipes are suitable for all types of drainage systems

What are polypropylene pipes

Polypropylene pipes for sewerage are considered to be the most successful choice of material both in terms of performance and price. Plastic has special properties - being the least dense among all types of plastics, polypropylene is harder than polyethylene. It does not tolerate ultraviolet radiation and contact with atmospheric oxygen, which is compensated for in manufacturing using stabilizing additives. Polypropylene pipes are the cheapest of all alternative options, but in terms of operational and technical characteristics they are superior to analogues made from other materials. The sewage system assembled from them lasts a very long time and does not require any maintenance. It is resistant to all influences, aggressive chemical compounds, and temperature changes.

Polypropylene pipes for sewerage, the technical characteristics of which are optimally suited for use on both the internal and external parts of the system. They are fully compatible with pipelines and fittings made from other materials. The only limitation that must be applied to PP products for outdoor use is compliance with the requirements for immersion depth (at least 0.7 m). This is important, since they are quite soft and can be deformed by soil pressure, passing cars or people moving around.

There are several types of PP sewerage. Most types are intended for use in water supply systems, in particular, PPR varieties made from type 3 polypropylene. They are able to withstand operating water pressure and other operating loads. Sewage networks are predominantly free-flow, so they most often use units made of PP polypropylene. They are cheaper, but have less resistance to stress.

Features of installation of external sewerage

To create an external sewage system, two-layer pipes with a smooth inner wall and a corrugated outer surface are used. Installation of such pipe products is carried out with a slight deviation in the range of 10 - 20 mm. When laying pipes, the earth is carefully compacted so that the pipe product is not subject to destruction under soil pressure. Before installing the pipes directly, the bottom is covered with sand to a depth of 20 cm.
Pipe products are laid in the ground based on the characteristics of the soil layer, weather conditions and the level of load on the area under which the PP pipes will be laid. Focusing on the Russian climate, manufacturers advise installing pipe products at a depth of up to 0.8 meters , provided that the soil pressure is low.

Thus, the high performance properties of polypropylene make it possible to use this material in many areas of construction , including when installing a sewer system. Ease of installation and reliable design have made polypropylene pipe structures one of the most popular building materials on the market.

Advantages and disadvantages of PP pipes

Sewage pipes made of polypropylene have the following advantages:

long service life. According to manufacturers, they do not lose their working qualities for up to 50 years, and if only cold water is supplied - up to 100 years;
not prone to the formation of layers or solid deposits;
do not spread noise;
polypropylene has low thermal conductivity, so there is no condensation on the surface of the pipes;
sewerage made from polypropylene pipes is 9 times lighter than the same system made from metal pipelines;
ease of installation work;
do not require care or special maintenance;
do not react to exposure to water or aggressive chemical compounds;
have high elasticity and resist mechanical stress well;
The cost of PP pipes is low and available to the mass buyer.

The disadvantages of the material include:

have a high coefficient of linear expansion with temperature changes;
difficulty in bending pipes. Despite its elasticity, the material has high memory and always returns to its original shape. The only option for bending is fixation using external mandrels or pouring concrete;
when the temperature drops, they become brittle, so the systems are used for external areas with certain restrictions.

Of all similar products, it is polypropylene sewer pipes that demonstrate the optimal set of performance qualities combined with a low price.

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Types of sewer PP pipes

GOST for polypropylene sewer pipes requires manufacturers to provide certain properties for each type of product. The marking consists of an alphanumeric code. The first two letters PN are accompanied by numbers indicating the maximum permissible pressure in kg/cm2:

PN10. The most common pipes are the conventional type. Used for assembling internal sewerage; with some restrictions, they can be used for underfloor heating or cold water supply systems;
PN16. Designed for use in non-pressure sewer systems;
PN20. They have increased impact strength. Used in pressure sewer systems, special-purpose ventilation networks;
PN25. Reinforced pipelines with a low coefficient of thermal expansion and high strength. This was achieved by adding additional layers of aluminum foil, fiberglass and other materials. Used for external sewerage areas, as well as in pressure systems.

Reinforcement has solved a lot of problems with ultraviolet radiation or exposure to oxygen. Strength has increased, and it has become possible to withstand the chemical and mechanical effects of groundwater. This made it possible to expand the scope of application, increase demand and preference among users.

Application area

The main area of application of PP pipelines is sewerage systems for domestic and industrial purposes. They are used in both pressure and non-pressure systems.

For gravity (non-pressure) networks, sewer socket pipes made of PP polypropylene grade PN16 are used. The estimated service life of such pipes is 200 years, although this cannot be verified in practice. They have a socket at one end that acts as a coupling. A rubber O-ring is installed inside, facilitating and speeding up the assembly process. Used in different parts of the system:

sewer pipes made of polypropylene for internal sewerage. The main part of the system consists of pipes with a diameter of 50 mm, with the exception of the tee for the toilet bowl and the vertical riser, the size of which according to GOST is usually 110 mm;
for external sewerage. A special type of pipe (red color) with reinforced double-layer walls is used. Some of them have a corrugated layer on the outside that can withstand mechanical stress.

The use of PP pipes in pressure systems is quite common, although this type of sewage system itself is rare. According to GOST requirements, PP pipes for sewerage must meet the requirements of the PN20 or PN25 standard, which fully corresponds to the specifics of the operation of pressure systems.

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Some numbers

The density of the polymer is 900 kg/m³, but at the same time its weight is small, and installation of the system will not take much time.
The high viscosity of PP makes it possible to absorb impact energy at a high level, so the degree of withstanding mechanical loads is quite high.
The temperature at which PP drainage can be used varies in the range – 15ºС to +140 ºС.
The chemical inertness of polypropylene according to GOST allows for disposal through the wastewater system, which contains up to 60% sulfuric acid.
During the heating process, PP acquires plasticity, which makes it possible to produce segments with a diameter of 16 – 1200 mm.
Raw materials for the manufacture of pipes are determined by GOST 26996-86. Non-pressure pipes are suitable for sewerage.

Installation of PP pipelines

Installation of polypropylene pipelines is carried out in two ways:

bell-shaped For connection, there is a special coupling at one end into which the free end of the other pipe is inserted. In turn, the next part is inserted into its coupling - and this way you can assemble a line of any length.
welded Typically, this connection method is chosen if a pressure system is being installed. A specially designed welding machine is used to heat the joint area to the melting temperature of the material. As a result, a monolithic connection is formed, allowing the pipeline to be used in difficult conditions and under standard operating pressure.

The properties possessed by a polypropylene sewer pipe are defined by GOST and other regulatory documents as the most successful, efficient and cost-effective. Simplicity and high speed of installation make it possible to create sewerage systems in any residential or industrial premises operating in difficult conditions and withstanding heavy loads.

Pipeline installation using the socket method

Usually, when creating a sewer system, the pipeline is extended through a connection with a socket. The installation method is no different for both products with a smooth surface and for pipes with corrugation. Fittings are used for tapping.

The method of building up a drain using the socket method has several features:

the incoming element should be cut at a right angle;
processing is carried out in such a way that a 45-degree chamfer is obtained;
the pipe into which the segment will be inserted must be turned towards the incoming fragment with a socket;
a seal ring is mounted in the socket;
the incoming element is mounted with force.

The socket connection is very reliable and simple. This reduces installation time significantly. If you need to join sections at different angles, use fittings. The connection is made using glue applied to the inner surface of the fitting and to the outer surface of the pipes being connected.

There are the following types of connecting parts:

Removable socket - it is used on elements from 310 mm to make connection with a socket possible.
Transition pipe - thanks to this element, you can connect pipe sections of different cross-sections. A special marking has been developed for this designation. For example, Ф 110/50 means the possibility of joining pipes with a diameter of 110 and 50 mm.
Knee – this connection can be made at various angles.
Couplings - they are used to secure drains without sockets. In this case, expansions are formed at the ends of the coupling.
Cross tees - such parts are intended for installation of branches from the main water pipeline. The ends of the elements may have the same or different diameters.
Tee with plug - this part is used for hidden installation. Through it, access is provided to the pipeline located in the mills.

Knowing how to connect sections of pipeline with fittings, you can build a reliable and durable sewer network.