Plastic pipes for sewerage: sizes and prices

Every owner wants everything to work in his household, nothing to break, and to be easy to maintain and install. And sewerage is no exception. It is necessary that it requires as little attention as possible – it is very inconvenient if it becomes clogged, but it is no less unpleasant to clean it. If you want to have a trouble-free sewage disposal system, pay attention to plastic sewer pipes. They are gradually replacing cast iron ones, and all because they cost less, are easier to install, have a large assortment – different diameters and lengths, almost no deposits form on their smooth walls, and even the service life is about 50 years. This whole bunch of properties determines their popularity. 

Types of plastic sewer pipes

Under the general name “plastic” products are sold from different types of polymers:

• polyethylene (PE):
  • high pressure (HPV) – for internal sewerage wiring;
  • low pressure (HDPE) – it is possible to lay outside, in trenches (they have greater strength);
• polyvinyl chloride (PVH);
• polypropylene (PP)

And a number of other thermoplastics and their combinations, but they are rare – people prefer to use already known materials.

The material of plastic sewer pipes is selected depending on the application. For example, polypropylene is more suitable for sewerage wiring inside a house or in an apartment. It has a higher operating temperature range – normally tolerates media up to 70°C, short-term – up to 95°C. In the presence of various household appliances that drain waste hot water into the sewer, this will not be superfluous. PVC pipes, which have lower prices, are more appropriate when laying external sewerage – here the drains are usually already mixed, so that temperatures are lower and PVC can endure them without harm (working up to + 40 ° C, short-term increase to 60 ° C).

Also, sewer pipes are smooth and corrugated. Moreover, not only bends from siphons can be corrugated. There are profiled pipes for sewerage with an internal smooth wall and an external ribbed one. They have greater strength – they better tolerate compressive loads (they have increased ring stiffness), they can be buried to a greater depth. Are issued with diameters from 110 mm to 1200 mm.

Dimensions and diameters

Sewer plastic pipes, unlike water and gas pipes, are produced in the form of segments, 50 cm, 100 cm, 200 cm long, etc. – up to 600 cm. The maximum length is 12 meters, but some manufacturers can make longer lengths on request. When laying long routes, this is convenient – fewer connections, fewer possible problems (leaks or blockages).

Other important characteristics of plastic pipes are the diameter and wall thickness. In the marking, they usually go side by side: there are numbers 160 * 4,2. What stands for: the outer diameter of the pipe is 160 mm, the wall thickness is 4,2 mm. It is worth remembering here that manufacturers indicate the outer diameter of plastic pipes, and for many calculations and planning, you need to know the inner diameter. It is easy to calculate it: we subtract twice the wall thickness from the outer one: 160 mm – 4,2 mm * 2 = 151,6 mm. In calculations and tables, a rounded result usually appears – in this case – 150 mm.

In general, the industry produces plastic pipes for sewerage with a diameter of 25 mm or more. The maximum section depends on the type of pipe (smooth or corrugated) and the material from which it is made. For example, smooth sewer PVC pipes can be up to 630 mm in diameter, and profiled two-layer pipes can be up to 1200 mm. But these dimensions are useless for homeowners or apartment dwellers. In private housing construction, diameters up to 100-110 mm are mainly used, rarely up to 160 mm. Sometimes, for a large cottage with a lot of plumbing fixtures, a pipe 200-250 mm in diameter may be needed.

The organization of sewerage in the country is described here. 

How to choose a diameter for connecting plumbing fixtures

According to the rules, it is necessary to make a calculation; it is completely spelled out in SNiP 2.04.01085. This is a complex matter, it requires a lot of data, so few people really think it is right. Over the years, the practice gained has made it possible to derive the average diameters of polyethylene sewer pipes for each of the plumbing fixtures. You can safely use these developments – all calculations usually come down to these dimensions.

As you can see, plastic sewer pipes with a diameter of 30-40 mm are mainly used. Only the toilet requires a much larger size – 100-110 mm. This is due to the peculiarity of functioning – it is necessary to divert a large amount of water in a short period of time. At the same time, there must be room for air in the pipe, otherwise it will break the water locks on other plumbing and “aromas” from the sewer will enter the room.

There are a few more rules to keep in mind when using the device:

• The system should not make 90° turns. If there is such a need, the turn is made up of two corners of 45 °. Sharp turns are problem areas in which blockages often form, and a cable for cleaning sewers does not pass through such corners.
  

• So that the drains do not stagnate in the pipes, they are laid under a slope (see the table for the slope).
• A fitting with a cleaning hole is installed near the branching, closed with a sealed lid (revision). Blockages are most often formed in these places, so such a measure is clearly not superfluous – you do not have to “extract” the cork through the nearest plumbing fixture. By the way, if there is some device nearby that is easy to disconnect from the sewer, you can not install the revision.
• When moving towards the riser, the diameter of the plastic sewer pipes remains constant or increases. There should be no reduction. All places of narrowing are clogged very quickly.
  

• In a combined bathroom, the arrangement of plumbing is planned so that the toilet is closest to the riser. Otherwise, the smells will be more than unpleasant – solid fragments will remain on the branches.

Still we must not forget about the insulation or heating of the sewer outlet in a private house. The vertical section that goes from the outlet to the entrance to the trench must be well insulated. Additionally, heating cables for pipes are often used. In the case of sewers, they are usually laid outside, then covered with heat-insulating material.

Here, like everything. The rules are simple, but if you follow them, everything will work for a long time and without fail.

Features of the installation of plastic sewer pipes

Plastic pipes for sewerage on one side end with a socket into which a sealing gum is inserted. The segments are connected simply: a smooth edge is inserted into the socket. Since the dimensions are strictly normalized, this is, in principle, sufficient for a hermetic connection. In practice, often the sealing ring is additionally coated with silicone plumbing sealant.

When installing sewer plastic pipes, they sometimes have to be cut. It is convenient to do it with a hand saw with a blade for metal – small teeth cut well and leave an almost even edge. You can also use a grinder or electric jigsaw. In any case, before installing the cut piece, its edge must be treated with fine-grained sandpaper – remove possible burrs, make it even. Some piece of waste may catch on the protruding pieces, as a result, a blockage may form in this place. Therefore, we carefully smooth the place of the saw.

When creating a sewer network in a house or apartment, it is often necessary to make a branch. There are fittings for this – adapters from one diameter to another, tees, angles with different degrees of rotation, etc.