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The problem of unpleasant sewer odor and excessive noise in the sewage system are the result of inefficient or non-existent ventilation in the sewer system.
At the moment when a large amount of water is discharged into the sewer in a very short period of time (for example, when draining water in the toilet), the air pressure in the sewer system decreases.
If the ventilation of the riser is sufficient, then there will be no unpleasant effects.
In the event of ventilation problems, air will be drawn in through a nearby plumbing fixture with the smallest water seal. This moment is characterized by a loud squelching sound and an unpleasant odor entering the apartment from the sewer.
An air valve for sewerage helps to cope with this problem.
An air valve (aerator) is a device that supplies and retains air in a sewer pipe.
If there is a ventilation pipe leading to the roof, then the valve is most often installed in the room itself (in the kitchen, in the toilet, etc.). The main thing is that the ambient temperature at the installation site does not fall below zero.
The standard air valve is a plastic part with a side hole.
The main functional part of this device is a rod or a membrane, depending on the modification.
Stem models are preferred as the rubber diaphragm often wears out and needs to be replaced again.
The principle of its operation is very simple. At the moment when a drain occurs and a vacuum is created in the system, the valve membrane opens slightly, allowing the required amount of air to enter. As soon as the pressure is equalized, it closes.
In models with a stem, the principle of operation is similar: the stem rises and falls, giving access to air.
The air valve helps to maintain normal pressure in the sewer system, thereby reducing the risk of water seal failure.
Mounting Features
In buildings with two or more floors, according to SNiPs, it is necessary to install a fan valve. It is mounted on the free end of the pipe or in a special socket. The choice of installation location depends on the presence of a floor drain.
If there is a ladder (floor grate), then the valve is installed vertically, the height from the floor level must be at least 350 mm. This is due to the need to exclude the possibility of splashes and dirt entering the valve.
In the absence of a ladder, the installation is carried out 100 mm higher than the location of the highest point of the drainage inlet.
If the valve is installed in niches or ducts, then it is necessary to ensure unhindered air flow to it.
When installing the valve in a cold attic, it should be borne in mind that at a negative temperature its normal operation is impossible. Therefore, it is necessary to insulate the riser itself, without blocking the air access to the valve.
Valve types
The industry produces two main modifications of air valves:
Valve 50 mm for one plumbing fixture - For a common riser - valve 110 mm,
- For separate plumbing fixtures - a 50 mm sewer air valve.
It should be borne in mind that a 50 mm valve can only be installed for one or two plumbing fixtures.
The appearance may vary slightly, or there may be some technical changes, but the principle of operation and diameter remain unchanged.
Of course, there are products of a different diameter that are installed on pipes of the appropriate size, but they are not very widespread.
Air sewer valves for non-ventilated risers
The exhaust part of the riser performs two functions:
- During periods when the liquid does not move along the riser, the polluted sewer air escapes through it into the atmosphere, providing ventilation of the system;
- When water is drained through the drain pipe, air from the atmosphere enters the riser, which contributes to the stability of the water seals of plumbing fixtures.
But in some cases it is not possible to bring the risers of the sewer system above the roof of the building, although this is required by building rules and regulations. Then an unventilated riser is installed.
It must be designed in such a way that the rarefaction of air that occurs during the descent of water does not lead to the failure of the water seal.
Especially for such risers, air sewer valves have been developed to satisfy the ejection needs of the liquid moving along the riser and not allowing polluted air to escape into the room.
Air valves for non-ventilated risers are widely used in construction. However, until 2003 their use was not regulated by any design and installation document.
And only a little over 10 years ago, the document SP 40-107-203 appeared in the code of rules, including a description and calculated data for ventilation valves.
When installing a sewer system, every detail is important. An air valve will help prevent a number of problems during its operation.
Of course, the decision to install it should be made by a specialist who has an idea of ββββthe situation at the facility. However, ceteris paribus, its installation will not be superfluous. It does not create negative moments, and in many cases it is simply impossible to do without it.