Sump ventilation: design and installation

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Sump ventilation: design and installation
Sump ventilation: design and installation

Installation of ventilation in the drain pit. Types of systems, their features and design rules. Tips for using ventilation and improving its performance.

Sump ventilation is the process of removing waste gases. Accumulating in the tank, they become potentially dangerous, as they can cause poisoning. Today we will tell you about the correct structure of such a system.

The need for ventilation of the cesspool

Sump ventilation

First you need to decide whether ventilation of the cesspool is needed at all. Usually, gases from the sewer network are removed through a waste pipe located in the house. Its head rises above the roof as the highest point of the drainage system. Such ventilation, in addition to isolating unpleasant odors, stabilizes the pressure in the sewer line, normalizing its operation.

If there is no drain pipe, the network is ventilated through a cesspool. The sewer inlet can be located at a depth of up to 1.5 m and more than 1.5 m from the ground level outside. In the second case, an exhaust hood in the drain pit must be done, even if a fan pipe runs through the house.

There are two types of removal of gases from the sewer:

  1. Natural ventilation… This is a natural air exchange due to physical laws. Air movement according to this scheme is carried out due to the difference in its pressure in the cesspool, where it is higher, and on the ground surface. Such ventilation is the simplest to perform, but it is difficult to call it effective. After all, gas, which is naturally discharged outside, can easily spread throughout the country, causing discomfort to its inhabitants with its smell.
  2. Forced ventilation… It is carried out using pipes and fans installed in a closed drain pit. The air ducts of the system can be connected to a waste outlet. Then the problem of sewage odors is completely solved. Forced ventilation is more expensive, but much more efficient. For its organization, engineering calculations are required, in which the diameter of the air ducts, their length and the required power of the fans are determined.

For the organization natural ventilation drain pits use an air duct, which is equipped with a tank lid. Most often it is a plastic pipe, the material of its manufacture is the most resistant to any aggressive environment. The height of the outer part of the pipe above the cover can be any. It depends on the required ventilation efficiency. The depth of the bottom of the pipe in the tank is strictly standardized. Its bottom end should be 200 mm above the normal filling level of the tank.

When device forced ventilation the cesspool cover is an inspection hatch equipped with an opening. With its help, gas is removed and fresh air enters the tank, which is extremely necessary for the normal processing of waste. There is another hole made in the upper part of the tank for installing the ventilation pipe. An exhaust fan is connected to the bottom of the pipe, located in the pit, using an electric cable.

Features of the design of ventilation of the sewer pit

Sump design

When performing work on your own, the first thing to calculate is diameter of the ventilation pipe and air window… According to the requirements of sanitary standards, air exchange during ventilation of the drain pit must occur at a speed of at least 80 m3/hour. This level can be achieved when using pipes with a diameter of 110 mm or more.There are special formulas for the selection of the diameter, and tables for determining the length of the ducts. All calculated indicators should be rounded up.

When determining the height of the pipe for removing gases from the cesspool, several rules should be taken into account:

  1. The height of the air duct of the waste tank must be the same length as the waste pipe. If this condition is violated due to different pressures of the suction streams, odors from the container can penetrate into the house.
  2. If there is a stove in the house, it is important to place the chimney and ventilation pipe at the same level. Otherwise, smoke can enter the pit, preventing the fermentation process in it.
  3. If there is no waste pipe, the air duct should be raised above the roof by at least 1 m. When installing, take into account the wind conditions of the region. If storms are often observed in it, the branch must be additionally strengthened.

The device of natural ventilation of the cesspool

Sump ventilation scheme

To create a system that uses natural air exchange in the cesspool, two pipes with a diameter of 110 and 50 mm are required. Both are installed vertically. The bottom of the first pipe is always in the cesspool. The above-ground part of the duct should rise 2 m in relation to the ground surface. The length of the ventilation duct can be increased by connecting a sewer pipe with a diameter of 50 mm to it. This will help in saving and in relation to private buildings.

For the device of natural ventilation of a cesspool in a private house, the overlap of the structure must be provided with an opening. Its diameter should be slightly larger than the size of the duct. In the process of installing the ventilation pipe into the prepared hole, it is worth making sure that the end of the lower branch pipe is at least 20 cm from the maximum level of the waste liquid.

The outer part of the duct can be fixed in different ways. If the cesspool is located under the yard toilet, fastening can be done with clamps to its wall. In other cases, ventilation can be laid underground and then brought out with a branch pipe for fixing on a fence or on a building wall.

Important! The outlet of the air duct fixed to the wall must be located at least 0.7 m above the roof of the house. The joint at the outlet of the air duct from the cesspool must be sealed with any moisture-resistant compound that can withstand temperature changes.

How to make forced ventilation of the drain pit?

Septic tank ventilation

To organize such ventilation in the cesspool, a fan will need to be connected to the base of the pipe. Its characteristics are selected taking into account the volume of the tank.

The fan model must be selected according to its performance. Air exchange rate not less than 80 m3/ hour, provided for by sanitary standards, can be provided by devices with a power of 30 watts. The dimensions of the selected device are very important, because it is installed inside the duct. The dimensions of the mechanism must match the diameter of the air outlet.

When organizing ventilation of a cesspool from concrete rings, you should adhere to the following recommendations:

  1. The installation of the air duct is carried out according to the principle of a natural ventilation device, with the exception of one point: the bottom of the branch pipe must be under the ceiling.
  2. The selected duct-type fan is installed at the bottom end of the pipe and is fastened with self-tapping screws. Using self-tapping screws, it is necessary to ensure that such a mount does not cling to the impeller blades.
  3. You can conduct electricity to the drain pit underground and by air. To implement the first method, you need to dig a trench, into which the cable is then laid. The depth of the trench, according to GOST, must be at least 0.7 m. To protect the cable from ground water, a steel or PVC pipe should be used. The air method involves an external cable laying. For it, a metal cable is used to fasten the cable by winding.
  4. To automate the process of turning on or off the fan, you can use a time relay. Its settings take into account the peculiarities of the home sewage system.
  5. It is recommended to inspect the ventilation system of the cesspool a couple of times a year. Increased attention should be paid to the fan impeller blades, as they may accumulate solid deposits.

Advice! When installing the fan, it is necessary to correctly determine where the air flow is moving. Its direction should be oriented upwards, but not vice versa.

Useful tips when creating ventilation in a drain pit

Septic tank ventilation made of concrete rings

In addition to the above material, here are some tips.

When organizing ventilation of the cesspool, it is recommended to avoid vacuuming the air in the tank. If in a courtyard toilet a ventilated area is formed between the reservoir and the air duct, then it is recommended to install a supply pipe in a closed container. The two air inlet and outlet openings are usually located at opposite corners of the drain pit. The air outlet is always higher than the air inlet.

Moisture appearing on the surface of the ventilation pipe can freeze in winter, reducing the passage of the duct and thereby reducing the intensity of the air flow. To eliminate this problem, the upper pipe opening must be equipped with a deflector. It will accelerate air movement and protect the channel from street debris.

The most rational option is to ventilate the cesspool when installing an autonomous sewage system. Then you do not have to change the existing system and it is easier to choose a convenient place for installing the exhaust pipe.

As for the type of ventilation of the drain pit, it is not always necessary to arrange forced air exchange. Some sedimentation tanks make do with natural ventilation. The final conclusion on this issue can be given by the relevant specialists after getting acquainted with the network operating conditions on the spot.

How to make ventilation in a cesspool - watch the video:

After the ventilation of the cesspool in a private house, it is important to ensure that the tank does not overflow and the air channel does not block waste. In addition, you need to monitor the air permeability of the fan pipe. For the possibility of prevention and repair in the ventilation system, it is worthwhile to provide for the installation of inspection hatches.

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