Sewerage freezes at a depth of 0.5 m: 5 installation rules that will prevent the pipe from freezing

The man was one of the first to finish the construction of a house in a cottage village, and in the very first winter due to freezing, his sewer pipes on the street tore. They were laid at a depth of about half a meter - this is what the builders advised to do. After this incident, rumors spread throughout the village that in this region the sewage system should be laid exclusively below the freezing depth.

In fact, you can lay sewer pipes at a shallow depth. This is often even more rational. But you need to follow a few simple rules.

Sewer pipes overwinter normally even at a shallow depth.

Why is it not recommended to bury sewer pipes deeply?

The deeper we lower the sewer pipe, the deeper we have to make a well or a septic tank. We lose the usable storage volume and get extra cubic meters (and often tens of cubic meters) of earthworks.

If, at the exit from the house, the sewer pipe is lowered beyond the freezing depth - below 1.5-2 m, due to the slope at the entrance to the well, it turns out to be another 0.5-1 m lower.

• Septic tanks with the ability to connect at such a depth are much more expensive.
• For cesspools, you have to mount another well and install an overflow pump there - to make a so-called sewage pumping station (SPS).
• At great depths, the likelihood of "running into" ground and flood waters is higher.

It is cheaper and easier to lay a sewage system at a shallow depth. At the same time, it will serve properly and will not freeze.

What to do to prevent the sewerage system from freezing at a shallow depth

Do not narrow the diameter

Thirty-second and fiftieth pipes are used locally for internal sewerage. They are not suitable for laying highways. In order to drain the drains from a private house, a pipe with a diameter of 110 is laid.

Observe slopes

The standard slope of a sewer pipe with a diameter of 110 mm is 2 cm per meter.

• If the slope is less than the specified one, the drains run off worse, they can stagnate and lead to blockages.
• If the slope is greater than the specified one, the liquid fraction drains faster, and sand or solid fraction can settle on the pipes. This also leads to blockages.
• If there is a counter slope in the line (in some of the sections, the pipe does not fall, but rises), in this local understatement, water will constantly stagnate. In the cold, it freezes, which can lead to a gust of the line.

A visual demonstration of what happens when the slope is not observed (demonstration in transparent tubes):

Organize sewer ventilation

If there is no ventilation, condensation will form on the pipe due to high humidity and temperature differences. In the cold, it freezes. For a sewer pipe to burst for this reason, there must be some kind of extreme weather conditions. However, there is a risk of defrosting and should be avoided.

For ventilation of the sewer system, two conditions must be met:

• From the upper points of the sewer, a fan pipe goes out and rises above the roof.
• The lower end of the sewer pipe in a cesspool or septic tank is located above the level of the drains.

In this case, air is constantly circulating in the sewage system. Excess moisture "blows out" into the atmosphere.

Insulate pipes on the street

According to the technology, if the pipe is within the depth of seasonal freezing, it must be insulated. Perhaps this is relevant for some northern regions. I have not seen non-insulated pipes freezing in the middle lane, provided all other conditions are met.

Nevertheless, since the technology requires it, it is necessary to insulate the street part of the sewage system. For this, sheets of extruded polystyrene foam - EPS are laid on top of the pipe. It is better to take material that is intended for the construction of foundations and roads.

Avoid overfilling the well

When the drains in the well rise above the level of the pipe outlet, according to the principle of communicating vessels, the pipeline is filled with liquid. If the sewage system is within the freezing depth, the liquid freezes and breaks the pipe. This is exactly what happened with the man I was talking about at the very beginning.

The man finished the construction of the house, removed the sewerage system, but did not install the septic tank yet - he postponed it until spring (as well as moving to a new house). We temporarily cut the sewer into an ordinary barrel. In the summer, water was pumped out of the barrel with a pump. The pump was removed for the winter. The barrel was filled to the top. Water filled the pipes. In winter they froze over and burst - finita la comedy.

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